The Principles of Psychology

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CHAPTER I. The Scope of Psychology

Psychology is the Science of Mental Life, both of its phenomena and of their conditions. The phenomena are such things as we call feelings, desires, cognitions, reasonings, decisions, and the like; and, superficially considered, their variety and complexity is such as to leave a chaotic impression on the observer. The most natural and consequently the earliest way of unifying the material was, first, to classify it as well as might be, and, secondly, to affiliate the diverse mental modes thus found, upon a simple entity, the personal Soul, of which they are taken to be so many facultative manifestations. Now, for instance, the Soul manifests its faculty of Memory, now of Reasoning, now of Volition, or again its Imagination or its Appetite. This is the orthodox 'spiritualistic' theory of scholasticism and of common-sense. Another and a less obvious way of unifying the chaos is to seek common elements in the divers mental facts rather than a common agent behind them, and to explain them constructively by the various forms of arrangement of these elements, as one explains houses by stones and bricks. The 'associationist' schools of Herbart in Germany, and of Hume, the Mills and Bain in Britain, have thus constructed a psychology without a soul by taking discrete 'ideas,' faint or vivid, and showing how, by their cohesions, repulsions, and forms of succession, such things as reminiscences, perceptions, emotions, volitions, passions, theories, and all the other furnishings of an individual's mind may be engendered. The very Self or ego of the individual comes in this way to be viewed no longer as the pre-existing source of the representations, but rather as their last and most complicated fruit.

Now, if we strive rigorously to simplify the phenomena in either of these ways, we soon become aware of inadequacies in our method. Any particular cognition, for example, or recollection, is accounted for on the soul-theory by being referred to the spiritual faculties of Cognition or of Memory. These faculties themselves are thought of as absolute properties of the soul; that is, to take the case of memory, no reason is given why we should remember a fact as it happened, except that so to remember it constitutes the essence of our Recollective Power. We may, as spiritualists, try to explain our memory's failures and blunders by secondary causes. But its successes can invoke no factors save the existence of certain objective things to be remembered on the one hand, and of our faculty of memory on the other. When, for instance, I recall my graduation-day, and drag all its incidents and emotions up from death's dateless night, no mechanical cause can explain this process, nor can any analysis reduce it to lower terms or make its nature seem other than an ultimate datum, which, whether we rebel or not at its mysteriousness, must simply be taken for granted if we are to psychologize at all. However the associationist may represent the present ideas as thronging and arranging themselves, still, the spiritualist insists, he has in the end to admit that something, be it brain, be it 'ideas,' be it 'association,' knows past time as past, and fills it out with this or that event. And when the spiritualist calls memory an 'irreducible faculty,' he says no more than this admission of the associationist already grants.

And yet the admission is far from being a satisfactory simplification of the concrete facts. For why should this absolute god-given Faculty retain so much better the events of yesterday than those of last year, and, best of all, those of an hour ago? Why, again, in old age should its grasp of childhood's events seem firmest? Why should illness and exhaustion enfeeble it? Why should repeating an experience strengthen our recollection of it? Why should drugs, fevers, asphyxia, and excitement resuscitate things long since forgotten? If we content ourselves with merely affirming that the faculty of memory is so peculiarly constituted by nature as to exhibit just these oddities, we seem little the better for having invoked it, for our explanation becomes as complicated as that of the crude facts with which we started. Moreover there is something grotesque and irrational in the supposition that the soul is equipped with elementary powers of such an ingeniously intricate sort. Why should our memory cling more easily to the near than the remote? Why should it lose its grasp of proper sooner than of abstract names? Such peculiarities seem quite fantastic; and might, for aught we can see a priori, be the precise opposites of what they are. Evidently, then, the faculty does not exist absolutely, but works under conditions; and the quest of the conditions becomes the psychologist's most interesting task.

However firmly he may hold to the soul and her remembering faculty, he must acknowledge that she never exerts the latter without a cue, and that something must always precede and remind us of whatever we are to recollect. "An idea!" says the associationist, "an idea associated with the remembered thing; and this explains also why things repeatedly met with are more easily recollected, for their associates on the various occasions furnish so many distinct avenues of recall." But this does not explain the effects of fever, exhaustion, hypnotism, old age, and the like. And in general, the pure associationist's account of our mental life is almost as bewildering as that of the pure spiritualist. This multitude of ideas, existing absolutely, yet clinging together, and weaving an endless carpet of themselves, like dominoes in ceaseless change, or the bits of glass in a kaleidoscope,-whence do they get their fantastic laws of clinging, and why do they cling in just the shapes they do?

For this the associationist must introduce the order of experience in the outer world. The dance of the ideas is a copy, somewhat mutilated and altered, of the order of phenomena. But the slightest reflection shows that phenomena have absolutely no power to influence our ideas until they have first impressed our senses and our brain. The bare existence of a past fact is no ground for our remembering it. Unless we have seen it, or somehow undergone it, we shall never know of its having been. The experiences of the body are thus one of the conditions of the faculty of memory being what it is. And a very small amount of reflection on facts shows that one part of the body, namely, the brain, is the part whose experiences are directly concerned. If the nervous communication be cut off between the brain and other parts, the experiences of those other parts are non-existent for the mind. The eye is blind, the ear deaf, the hand insensible and motionless. And conversely, if the brain be injured, consciousness is abolished or altered, even although every other organ in the body be ready to play its normal part. A blow on the head, a sudden subtraction of blood, the pressure of an apoplectic hemorrhage, may have the first effect; whilst a very few ounces of alcohol or grains of opium or hasheesh, or a whiff of chloroform or nitrous oxide gas, are sure to have the second. The delirium of fever, the altered self of insanity, are all due to foreign matters circulating through the brain, or to pathological changes in that organ's substance. The fact that the brain is the one immediate bodily condition of the mental operations is indeed so universally admitted nowadays that I need spend no more time in illustrating it, but will simply postulate it and pass on. The whole remainder of the book will be more or less of a proof that the postulate was correct.

Bodily experiences, therefore, and more particularly brain-experiences, must take a place amongst those conditions of the mental life of which Psychology need take account. The spiritualist and the associationist must both be 'cerebralists,' to the extent at least of admitting that certain peculiarities in the way of working of their own favorite principles are explicable only by the fact that the brain laws are a codeterminant of the result.

Our first conclusion, then, is that a certain amount of brain-physiology must be presupposed or included in Psychology[1].

In still another way the psychologist is forced to be something of a nerve-physiologist. Mental phenomena are not only conditioned a parte ante by bodily processes; but they lead to them a parte post. That they lead to acts is of course the most familiar of truths, but I do not merely mean acts in the sense of voluntary and deliberate muscular performances. Mental states occasion also changes in the calibre of blood-vessels, or alteration in the heartbeats, or processes more subtle still, in glands and viscera. If these are taken into account, as well as acts which follow at some remote period because the mental state was once there, it will be safe to lay down the general law that no mental modification ever occurs which is not accompanied or followed by a bodily change. The ideas and feelings, e.g., which these present printed characters excite in the reader's mind not only occasion movements of his eyes and nascent movements of articulation in him, but will some day make him speak, or take sides in a discussion, or give advice, or choose a book to read, differently from what would have been the case had they never impressed his retina. Our psychology must therefore take account not only of the conditions antecedent to mental states, but of their resultant consequences as well.

But actions originally prompted by conscious intelligence may grow so automatic by dint of habit as to be apparently unconsciously performed. Standing, walking, buttoning and unbuttoning, piano-playing, talking, even saying one's prayers, may be done when the mind is absorbed in other things. The performances of animal instinct seem semi-automatic, and the reflex acts of self-preservation certainly are so. Yet they resemble intelligent acts in bringing about the same ends at which the animals' consciousness, on other occasions, deliberately aims. Shall the study of such machine-like yet purposive acts as these be included in Psychology?

The boundary-line of the mental is certainly vague. It is better not to be pedantic, but to let the science be as vague as its subject, and include such phenomena as these if by so doing we can throw any light on the main business in hand. It will ere long be seen, I trust, that we can; and that we gain much more by a broad than by a narrow conception of our subject. At a certain stage in the development of every science a degree of vagueness is what best consists with fertility. On the whole, few recent formulas have done more real service of a rough sort in psychology than the Spencerian one that the essence of mental life and of bodily life are one, namely, 'the adjustment of inner to outer relations.' Such a formula is vagueness incarnate; but because it takes into account the fact that minds inhabit environments which act on them and on which they in turn react; because, in short, it takes mind in the midst of all its concrete relations, it is immensely more fertile than the old-fashioned 'rational psychology,' which treated the soul as a detached existent, sufficient unto itself, and assumed to consider only its nature and properties. I shall therefore feel free to make any sallies into zoology or into pure nerve-physiology which may seem instructive for our purposes, but otherwise shall leave those sciences to the physiologists.

Can we state more distinctly still the manner in which the mental life seems to intervene between impressions made from without upon the body, and reactions of the body upon the outer world again? Let us look at a few facts.

If some iron filings be sprinkled on a table and a magnet brought near them, they will fly through the air for a certain distance and stick to its surface. A savage seeing the phenomenon explains it as the result of an attraction or love between the magnet and the filings. But let a card cover the poles of the magnet, and the filings will press forever against its surface without its ever occurring to them to pass around its sides and thus come into more direct contact with the object of their love. Blow bubbles through a tube into the bottom of a pail of water, they will rise to the surface and mingle with the air. Their action may again be poetically interpreted as due to a longing to recombine with the mother-atmosphere above the surface. But if you invert a jar full of water over the pail, they will rise and remain lodged beneath its bottom, shut in from the outer air, although a slight deflection from their course at the outset, or a re-descent towards the rim of the jar, when they found their upward course impeded, could easily have set them free.

If now we pass from such actions as these to those of living things, we notice a striking difference. Romeo wants Juliet as the filings want the magnet; and if no obstacles intervene he moves towards her by as straight a line as they. But Romeo and Juliet, if a wall be built between them, do not remain idiotically pressing their faces against its opposite sides like the magnet and the filings with the card. Romeo soon finds a circuitous way, by scaling the wall or otherwise, of touching Juliet's lips directly. With the filings the path is fixed; whether it reaches the end depends on accidents. With the lover it is the end which is fixed, the path may be modified indefinitely.

Suppose a living frog in the position in which we placed our bubbles of air, namely, at the bottom of a jar of water. The want of breath will soon make him also long to rejoin the mother-atmosphere, and he will take the shortest path to his end by swimming straight upwards. But if a jar full of water be inverted over him, he will not, like the bubbles, perpetually press his nose against its unyielding roof, but will restlessly explore the neighborhood until by re-descending again he has discovered a path around its brim to the goal of his desires. Again the fixed end, the varying means!

Such contrasts between living and inanimate performances end by leading men to deny that in the physical world final purposes exist at all. Loves and desires are to-day no longer imputed to particles of iron or of air. No one supposes now that the end of any activity which they may display is an ideal purpose presiding over the activity from its outset and soliciting or drawing it into being by a sort of vis a fronte. The end, on the contrary, is deemed a mere passive result, pushed into being a tergo, having had, so to speak, no voice in its own production. Alter, the pre-existing conditions, and with inorganic materials you bring forth each time a different apparent end. But with intelligent agents, altering the conditions changes the activity displayed, but not the end reached; for here the idea of the yet unrealized end co-operates with the conditions to determine what the activities shall be.

The Pursuance of future ends and the choice of means for their attainment, are thus the mark and criterion of the presence of mentality in a phenomenon. We all use this test to discriminate between an intelligent and a mechanical performance. We impute no mentality to sticks and stones, because they never seem to move for the sake of anything, but always when pushed, and then indifferently and with no sign of choice. So we unhesitatingly call them senseless.

Just so we form our decision upon the deepest of all philosophic problems: Is the Kosmos an expression of intelligence rational in its inward nature, or a brute external fact pure and simple? If we find ourselves, in contemplating it, unable to banish the impression that it is a realm of final purposes, that it exists for the sake of something, we place intelligence at tile heart of it and have a religion. If, on the contrary, in surveying its irremediable flux, we can think of the present only as so much mere mechanical sprouting from the past, occurring with no reference to the future, we are atheists and materialists.

In the lengthy discussions which psychologists have carried on about the amount of intelligence displayed by lower mammals, or the amount of consciousness involved in the functions of the nerve-centres of reptiles, the same test has always been applied: Is the character of the actions such that we must believe them to be performed for the sake of their result? The result in question, as we shall hereafter abundantly see, is as a rule a useful one,-the animal is, on the whole, safer under the circumstances for bringing it forth. So far the action has a teleological character; but such mere outward teleology as this might still be the blind result of vis a tergo. The growth and movements of plants, the processes of development, digestion, secretion, etc., in animals, supply innumerable instances of performances useful to the individual which may nevertheless be, and by most of us are supposed to be, produced by automatic mechanism. The physiologist does not confidently assert conscious intelligence in the frog's spinal cord until he has shown that the useful result which the nervous machinery brings forth under a given irritation remains the same when the machinery is altered. If, to take the stock-instance, the right knee of a headless frog be irritated with acid, the right foot will wipe it off. When, however, this foot is amputated, the animal will often raise the left foot to the spot and wipe the offending material away.

Pfluger and Lewes reason from such facts in the following way: If the first reaction were the result of mere machinery, they say; if that irritated portion of the skin discharged the right leg as a trigger discharges its own barrel of a shotgun; then amputating the right foot would indeed frustrate the wiping, but would not make the left leg move. It would simply result in the right stump moving through the empty air (which is in fact the phenomenon sometimes observed). The right trigger makes no effort to discharge the left barrel if the right one be unloaded; nor does an electrical machine ever get restless because it can only emit sparks, and not hem pillow-cases like a sewing-machine.

If, on the contrary, the right leg originally moved for the purpose of wiping the acid, then nothing is more natural than that, when the easiest means of effecting that purpose prove fruitless, other means should be tried. Every failure must keep the animal in a state of disappointment which will lead to all sorts of new trials and devices; and tranquillity will not ensue till one of these, by a happy stroke, achieves the wished-for end.

In a similar way Goltz ascribes intelligence to the frog's optic lobes and cerebellum. We alluded above to the manner in which a sound frog imprisoned in water will discover an outlet to the atmosphere. Goltz found that frogs deprived of their cerebral hemispheres would often exhibit a like ingenuity. Such a frog, after rising from the bottom and finding his farther upward progress checked by the glass bell which has been inverted over him, will not persist in butting his nose against the obstacle until dead of suffocation, but will often re-descend and emerge from under its rim as if, not a definite mechanical propulsion upwards, but rather a conscious desire to reach the air by hook or crook were the main-spring of his activity. Goltz concluded from this that the hemispheres are not the seat of intellectual power in frogs. He made the same inference from observing that a brainless frog will turn over from his back to his belly when one of his legs is sewed up, although the movements required are then very different from those excited under normal circumstances by the same annoying position. They seem determined, consequently, not merely by the antecedent irritant, but by the final end,-though the irritant of course is what makes the end desired.

Another brilliant German author, Liebmann[2], argues against the brain's mechanism accounting for mental action, by very similar considerations. A machine as such, he says, will bring forth right results when it is in good order, and wrong results if out of repair. But both kinds of result flow with equally fatal necessity from their conditions. We cannot suppose the clock-work whose structure fatally determines it to a certain rate of speed, noticing that this speed is too slow or too fast and vainly trying to correct it. Its conscience, if it have any, should be as good as that of the best chronometer, for both alike obey equally well the same eternal mechanical laws-laws from behind. But if the brain be out of order and the man says "Twice four are two," instead of "Twice four are eight," or else "I must go to the coal to buy the wharf," instead of "I must go to the wharf to buy the coal," instantly there arises a consciousness of error. The wrong performance, though it obey the same mechanical law as the right, is nevertheless condemned,-condemned as contradicting the inner law-the law from in front, the purpose or ideal for which the brain should act, whether it do so or not.

We need not discuss here whether these writers in drawing their conclusion have done justice to all the premises involved in the cases they treat of. We quote their arguments only to show how they appeal to the principle that no actions but such as are done for an end, and show a choice of means, can be called indubitable expressions of Mind.

I shall then adopt this as the criterion by which to circumscribe the subject-matter of this work so far as action enters into it. Many nervous performances will therefore be unmentioned, as being purely physiological. Nor will the anatomy of the nervous system and organs of sense be described anew. The reader will find in H.N. Martin's Human Body, in G.T. Ladd's Physiological Psychology, and in all the other standard Anatomies and Physiologies, a mass of information which we must regard as preliminary and take for granted in the present work[3]. Of the functions of the cerebral hemispheres, however, since they directly subserve consciousness, it will be well to give some little account.

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Footnotes [1] Cf. George T.Ladd: Elements of Physiological Psychology (1887), pt. III, chap. III, 9, 12

[2] Zur Analysis der Wirklichkeit, p. 489

[3] Nothing is easier than to familiarize one's self with the mammalian brain. Get a sheep's head, a small saw, chisel, scalpel and forceps (all three can best be had from a surgical-instrument maker), and unravel its parts either by the aid of a human dissecting book, such as Holden's Manual of Anatomy, or by the specific directions ad hoc given in such books as Foster and Langley's Practical Physiology (Macmillan) or Morrell's Comparative Anatomy, and Guide to Dissection (Longman & Co.).

CHAPTER II. The Functions of the Brain

If I begin chopping the foot of a tree, its branches are unmoved by my act, and its leaves murmur as peacefully as ever in the wind. If, on the contrary, I do violence to the foot of a fellow-man, the rest of his body instantly responds to the aggression by movements of alarm or defence. The reason of this difference is that the man has a nervous system whilst the tree has none; and the function of the nervous system is to bring each part into harmonious co-operation with every other. The afferent nerves, when excited by some physical irritant, be this as gross in its mode of operation as a chopping axe or as subtle as the waves of light, conveys the excitement to the nervous centres. The commotion set up in the centres does not stop there, but discharges itself, if at all strong, through the efferent nerves into muscles and glands, exciting movements of the limbs and viscera, or acts of secretion, which vary with the animal, and with the irritant applied. These acts of response have usually the common character of being of service. They ward off the noxious stimulus and support the beneficial one; whilst if, in itself indifferent, the stimulus be a sign of some distant circumstance of practical importance, the animal's acts are addressed to this circumstance so as to avoid its perils or secure its benefits, as the case may be. To take a common example, if I hear the conductor calling ' All aboard!' as I enter the depot, my heart first stops, then palpitates, and my legs respond to the air-waves falling on my tympanum by quickening their movements. If I stumble as I run, the sensation of falling provokes a movement of the hands towards the direction of the fall, the effect of which is to shield the body from too sudden a shock. If a cinder enter my eye, its lids close forcibly and a copious flow of tears tends to wash it out.

These three responses to a sensational stimulus differ, however, in many respects. The closure of the eye and the lachrymation are quite involuntary, and so is the disturbance of the heart. Such involuntary responses we know as 'reflex' acts. The motion of the arms to break the shock of falling may also be called reflex, since it occurs too quickly to be deliberately intended. Whether it be instinctive or whether it result from the pedestrian education of childhood may be doubtful; it is, at any rate, less automatic than the previous acts, for a man might by conscious effort learn to perform it more skilfully, or even to suppress it altogether. Actions of this kind, into which instinct and volition enter upon equal terms, have been called 'semi-reflex.' The act of running towards the train, on the other hand, has no instinctive element about it. It is purely the result of education, and is preceded by a consciousness of the purpose to be attained and a distinct mandate of the will. It is a 'voluntary act.' Thus the animal's reflex and voluntary performances shade into each other gradually, being connected by acts which may often occur automatically, but may also be modified by conscious intelligence.

An outside observer, unable to perceive the accompanying consciousness, might be wholly at a loss to discriminate between the automatic acts and those which volition escorted. But if the criterion of mind's existence be the choice of the proper means for the attainment of a supposed end, all the acts seem to be inspired by intelligence, for appropriateness characterizes them all alike. This fact, now, has led to two quite opposite theories about the relation to consciousness of the nervous functions. Some authors, finding that the higher voluntary ones seem to require the guidance of feeling, conclude that over the lowest reflexes some such feeling also presides, though it may be a feeling of which we remain unconscious. Others, finding that reflex and semi-automatic acts may, notwithstanding their appropriateness, take place with an unconsciousness apparently complete, fly to the opposite extreme and maintain that the appropriateness even of voluntary actions owes nothing to the fact that consciousness attends them. They are, according to these writers, results of physiological mechanism pure and simple. In a near chapter we shall return to this controversy again. Let us now look a little more closely at the brain and at the ways in which its states may be supposed to condition those of the mind.

THE FROG'S NERVE-CENTRES. Both the minute anatomy and the detailed physiology of the brain are achievements of the present generation, or rather we may say (beginning with Meynert) of the past twenty years. Many points are still obscure and subject to controversy; but a general way of conceiving the organ has been reached on all hands which in its main feature seems not unlikely to stand, and which even gives a most plausible scheme of the way in which cerebral and mental operations go hand in hand.

The best way to enter the subject will be to take a lower creature, like a frog, and study by the vivisectional method the functions of his different nerve-centres. The frog's nerve-centres are figured in the accompanying diagram, which needs no further explanation. I will first proceed to state what happens when various amounts of the anterior parts are removed, in different frogs, in the way in which an ordinary student removes them; that is, with no extreme precautions as to the purity of the operation. We shall in this way reach a very simple conception of the functions of the various centres, involving the strongest possible contrast between the cerebral hemispheres and the lower lobes. This sharp conception will have didactic advantages, for it is often very instructive to start with too simple a formula and correct it later on. Our first formula, as we shall later see, will have to be softened down somewhat by the results of more careful experimentation both on frogs and birds, and by those of the most recent observations on dogs, monkeys, and man. But it will put us, from the outset, in clear possession of some fundamental notions and distinctions which we could otherwise not gain so well, and none of which the later more completed view will overturn.

If, then, we reduce the frog's nervous system to the spinal cord alone, by making a section behind the base of the skull, between the spinal cord and the medulla oblongata, thereby cutting off the brain from all connection with the rest of the body, the frog will still continue to live, but with a very peculiarly modified activity. It ceases to breathe or swallow; it lies flat on its belly, and does not, like a normal frog, sit up on its fore paws, though its hind legs are kept, as usual, folded against its body and immediately resume this position if drawn out. If thrown on its back, it lies there quietly, without turning over like a normal frog. Locomotion and voice seem entirely abolished. If we suspend it by the nose, and irritate different portions of its skin by acid, it performs a set of remarkable 'defensive' movements calculated to wipe away the irritant. Thus, if the breast be touched, both fore paws will rub it vigorously; if we touch the outer side of the elbow, the hind foot of the same side will rise directly to the spot and wipe it. The back of the foot will rub the knee if that be attacked, whilst if the foot be cut away, the stump will make ineffectual movements, and then, in many frogs, a pause will come, as if for deliberation, succeeded by a rapid passage of the opposite unmutilated foot to the acidulated spot.

The most striking character of all these movements, after their teleological appropriateness, is their precision. They vary, in sensitive frogs and with a proper amount of irritation, so little as almost to resemble in their machine-like regularity the performances of a jumping-jack, whose legs must twitch whenever you pull the string. The spinal cord of the frog thus contains arrangements of cells and fibres fitted to convert skin irritations into movements of defence. We may call it the centre for defensive movements in this animal. We may indeed go farther than this, and by cutting the spinal cord in various places find that its separate segments are independent mechanisms, for appropriate activities of the head and of the arms and legs respec- tively. The segment governing the arms is especially active, in male frogs, in the breeding season; and these members alone with the breast and back appertaining to them, everything else being cut away, will then actively grasp a finger placed between them and remain hanging to it for a considerable time.

The spinal cord in other animals has analogous powers. Even in man it makes movements of defence. Paraplegics draw up their legs when tickled; and Robin, on tickling the breast of a criminal an hour after decapitation, saw the arm and hand move towards the spot. Of the lower functions of the mammalian cord, studied so ably by Goltz and others, this is not the place to speak.

If, in a second animal, the cut be made just behind the optic lobes so that the cerebellum and medulla oblongata remain attached to the cord, then swallowing, breathing, crawling, and a rather enfeebled jumping and swimming are added to the movements previously observed.[1] There are other reflexes too. The animal, thrown on his back, immediately turns over to his belly. Placed in a shallow bowl, which is floated on water and made to rotate, he responds to the rotation by first turning his head and then waltzing around with his entire body, in the opposite direction to the whirling of the bowl. If his support be tilted so that his head points downwards, he points it up; he points it down if it be pointed upwards, to the right if it be pointed to the left, etc. But his reactions do not go farther than these movements of the head.; He will not, like frogs whose thalami are preserved, climb up a board if the latter be tilted, but will slide off it to the ground.

If the cut be made on another frog between the thalami and the optic lobes, the locomotion both on land and water becomes quite normal, and, in addition to the reflexes already shown by the lower centres, he croaks regularly whenever he is pinched under the arms. He compensates rotations, etc., by movements of the head, and turns over from his back; but still drops off his tilted board. As his optic nerves are destroyed by the usual operation, it is impossible to say whether he will avoid obstacles placed in his path.

When, finally, a frog's cerebral hemispheres alone are cut off by a section between them and the thalami which preserves the latter, an unpractised observer would not at first suspect anything abnormal about the animal. Not only is he capable, on proper instigation, of all the acts already described, but he guides himself by sight, so that if an obstacle be set up between him and the light, and he be forced to move forward, he either jumps over it or swerves to one side. He manifests sexual passion at the proper season, and, unlike an altogether brainless frog, which embraces anything placed between his arms, postpones this reflex act until a female of his own species is provided. Thus far, as aforesaid, a person unfamiliar with frogs might not suspect a mutilation; but even such a person would soon remark the almost entire absence of spontaneous motion-that is, motion unprovoked by any present incitation of sense. The continued movements of swimming, performed by the creature in the water, seem to be the fatal result of the contact of that fluid with its skin. They cease when a stick, for example, touches his hands. This is a sensible irritant towards which the feet are automatically drawn by reflex action, and on which the animal remains sitting. He manifests no hunger, and will suffer a fly to crawl over his nose unsnapped at. Fear, too, seems to have deserted him. In a word, he is an extremely complex machine whose actions, so far as they go, tend to self-preservation ; but still a machine, in this sense-that it seems to contain no incalculable element. By applying the right sensory stimulus to him we are almost as certain of getting a fixed response as an organist is of hearing a certain tone when he pulls out a certain stop.

But now if to the lower centres we add the cerebral hemispheres, or if, in other words, we make an intact animal the subject of our observations, all this is changed. In addition to the previous responses to present incitements of sense, our frog now goes through long and complex acts of locomotion spontaneously, or as if moved by what in our- selves we should call an idea. His reactions to outward stimuli vary their form, too. Instead of making simple defensive movements with his hind legs like a headless frog if touched, or of giving one or two leaps and then sitting still like a hemisphereless one, he makes persistent and varied efforts at escape, as if, not the mere contact of the physiologist's hand, but the notion of danger suggested by it were now his spur. Led by the feeling of hunger, too, he goes in search of insects, fish, or smaller frogs, and varies his procedure with each species of victim. The physiologist cannot by manipulating him elicit croaking, crawling up a board, swimming or stopping, at will. His conduct has become incalculable. We can no longer foretell it exactly. Effort to escape is his dominant reaction, but he may do anything else, even swell up and become perfectly passive in our hands.

Such are the phenomena commonly observed, and such the impressions which one naturally receives. Certain general conclusions follow irresistibly. First of all the following:

The acts of all the centres involve the use of the same muscles. When a headless frog's hind leg wipes the acid, he calls into play all the leg-muscles which a frog with his full medulla oblongata and cerebellum uses when he turns from his back to his belly. Their contractions are, however, combined differently in the two cases, so that the results vary widely. We must consequently conclude that specific arrangements of cells and fibres exist in the cord for wiping, in the medulla for turning over, etc. Similarly they exist in the thalami for jumping over seen obstacles and for balancing the moved body; in the optic lobes for creeping backwards, or what not. But in the hemispheres, since the presence of these organs brings no new elementary form of movement with it, but only determines differently the occasions on which the movements shall occur, making the usual stimuli less fatal and machine-like; we need suppose no such machinery directly co-ordinative of muscular contractions to exist. We may rather assume, when the mandate for a wiping-movement is sent forth by the hemispheres, that a current goes straight to the wiping-arrangement in the spinal cord, exciting this arrangement as a whole. Similarly, if an intact frog wishes to jump over a stone which he sees, all he need do is to excite from the hemispheres the jumping-centre in the thalami or wherever it may be, and the latter will provide for the details of the execution. It is like a general ordering a colonel to make a certain movement, but not telling him how it shall be done.[2]

The same muscle, then, repeatedly represented at different heights; and at each it enters into a different combination with other muscles to co-operate in some special form of concerted movement. At each height the movement is discharged by some particular form of sensorial stimulus. Thus in the cord, the skin alone occasions movements; in the upper part of the optic lobes, the eyes are added; in the thalami, the semi-circular canals would seem to play a part; whilst the stimuli which discharge the hemispheres would seem not so much to be elementary sorts of sensation, as groups of sensations forming determinate objects or things. Prey is not pursued nor are enemies shunned by ordinary hemisphereless frogs. Those reactions upon complex circumstances which we call instinctive rather than reflex, are already in this animal dependent on the brain's highest lobes, and still more is this the case with animals higher in the zoological scale.

The results are just the same if, instead of a frog, we take a pigeon, and cut out his hemispheres as they are ordinarily cut out for a lecture-room demonstration. There is not a movement natural to him which this brainless bird cannot perform if expressly excited thereto; only the inner promptings seem deficient, and when left to himself he spends most of his time crouched on the ground with his head sunk between his shoulders as if asleep.

GENERAL NOTION OF HEMISPHERES.

All these facts lead us, when we think about them, to some such explanatory conception as this: The lower centres act from present sensational stimuli alone; the hemispheres act from perceptions and considerations, the sensations which they may receive, serving only as suggesters of these. But what are perceptions but sensations grouped together? and what are considerations but expectations, in the fancy, of sensations which will be felt one way or another according as action takes this course or that? If I step aside on seeing a rattlesnake, from considering how dangerous an animal he is, the mental materials which constitute my prudential reflection are images more or less vivid of the movement of his head, of a sudden pain in my leg, of a state of terror, a swelling of the limb, a chill, delirium, unconsciousness, etc., etc., and the ruin of my hopes. But all these images are constructed out of my past experiences. They are reproductions of what I have felt or witnessed. They are, in short, remote sensations; and the difference between the hemisphereless animal and the whole one may be concisely expressed by saying that the one obeys absent, the other only present, objects.

The hemispheres would then seem to be the seat of memory. Vestiges of past experience must in some way be stored up in them, and must, when aroused by present stimuli, first appear as representations of distant goods and evils; and then must discharge into the appropriate motor channels for warding off the evil and securing the benefits of the good. If we liken the nervous currents to electric currents, we can compare the nervous system, C, below the hemispheres to a direct circuit from sense-organ to muscle along the line S...C...M of Fig. 2 (p. 21). The hemisphere, H, adds the long circuit or loop-line through which the current may pass when for any reason the direct line is not used.

Thus, a tired wayfarer on a hot day throws himself on the damp earth beneath a maple-tree. The sensations of delicious rest and coolness pouring themselves through the direct line would naturally discharge into the muscles of complete extension: he would abandon himself to the dangerous repose. But the loop-line being open, part of the current is drafted along it, and awakens rheumatic or catarral reminiscences, which prevail over the instigations of sense, and make the man arise and pursue his way to where he may enjoy his rest more safely. Presently we shall examine the manner in which the hemispheric loop-line may be supposed to serve as a reservoir for such reminiscences as these. Meanwhile I will ask the reader to notice some corollaries of its being such a reservoir.

First, no animal without it can deliberate, pause, postpone, nicely weigh one motive against another, or compare. Prudence, in a word, is for such a creature an impossible virtue. Accordingly we see that nature removes those functions in the exercise of which prudence is a virtue from the lower centres and hands them over to the cerebrum. Wherever a creature has to deal with complex features of the environment, prudence is a virtue. The higher animals have so to deal; and the more complex the features, the higher we call the animals. The fewer of his acts, then, can such an animal perform without the help of the organs in question. In the frog many acts devolve wholly on the lower centres; in the bird fewer; in the rodent fewer still; in the dog very few indeed; and in apes and men hardly any at all.

The advantages of this are obvious. Take the prehension of food as an example and suppose it to be a reflex performance of the lower centres. The animal will be condemned fatally and irresistibly to snap at it whenever presented, no matter what the circumstances may be; he can no more disobey this prompting than water can refuse to boil when a fire is kindled under the pot. His life will again and again pay the forfeit of his gluttony.

Exposure to retaliation, to other enemies, to traps, to poisons, to the dangers of repletion, must be regular parts of his existence. His lack of all thought by which to weigh the danger against the attractiveness of the bait, and of all volition to remain hungry a little while longer, is the direct measure of his lowness in the mental scale. And those fishes which, like our cunners and sculpins, are no sooner thrown back from the hook into the water, than they automatically seize the hook again, would soon expiate the degradation of their intelligence by the extinction of their type, did not their exaggerated fecundity atone for their imprudence. Appetite and the acts it prompts have consequently become in all higher vertebrates functions of the cerebrum. They disappear when the physiologist's knife has left the subordinate centres alone in place. The brainless pigeon will starve though left on a corn-heap.

Take again the sexual function. In birds this devolves exclusively upon the hemispheres. When these are shorn away the pigeon pays no attention to the billings and cooings of its mate. And Goltz found that a bitch in heat would excite no emotion in male dogs who had suffered large loss of cerebral tissue. Those who have read Darwin's 'Descent of Man' know what immense importance in the amelioration of the breed in birds this author ascribes to the mere fact of sexual selection. The sexual act is not performed until every condition of circumstance and sentiment is fulfilled, until time, place, and partner all are fit. But in frogs and toads this passion devolves on the lower centres. They show consequently a machine-like obedience to the present incitement of sense, and an almost total exclusion of the power of choice. Copulation occurs per.fas aut nefas, occasionally between males, often with dead females, in puddles exposed on the highway, and the male may be cut in two without letting go his hold. Every spring an immense sacrifice of batrachian life takes place from these causes alone.

No one need be told how dependent all human social elevation is upon the prevalence of chastity. Hardly any factor measures more than this the difference between civili- zation and barbarism. Physiologically interpreted, chastity means nothing more than the fact that present solicitations of sense are overpowered by suggestions of aesthetic and moral fitness which the circumstances awaken in the cerebrum ; and that upon the inhibitory or permissive influence of these alone action directly depends.

Within the psychic life due to the cerebrum itself the same general distinction obtains, between considerations of the more immediate and considerations of the more remote. In all ages the man whose determinations are swayed by reference to the most distant ends has been held to possess the highest intelligence. The tramp who lives from hour to hour; the bohemian whose engagements are from day to day; the bachelor who builds but for a single life; the father who acts for another generation ; the patriot who thinks of a whole community and many generations; and finally, the philosopher and saint whose cares are for humanity and for eternity,-these range themselves in an unbroken hierarchy, wherein each successive grade results from an increased manifestation of the special form of action by which the cerebral centres are distinguished from all below them.

In the 'loop-line' along which the memories and ideas of the distant are supposed to lie, the action, so far as it is a physical process, must be interpreted after the type of the action in the lower centres. If regarded here as a reflex process, it must be reflex there as well. The current in both places runs out into the muscles only after it has first run in; but whilst the path by which it runs out is determined in the lower centres by reflections few and fixed amongst the cell-arrangements, in the hemispheres the reflections are many and instable. This, it will be seen, is only a difference of degree and not of kind, and does not change the reflex type. The conception of all action as conforming to this type is the fundamental conception of modern nerve-physiology. So much for our general preliminary conception of the nerve-centres! Let us define it more distinctly before we see how well physiological observation will bear it out in detail.

THE EDUCATION OF THE HEMISPHERES Nerve-currents run in through sense-organs, and whilst provoking reflex acts in the lower centres, they arouse ideas in the hemispheres, which either permit the reflexes in question, check them, or substitute others for them. All ideas being in the last resort reminiscences, the question to answer is: How can processes become organized in the hemispheres which correspond to reminiscences in the mind ?[3]

Nothing is easier than to conceive a possible way in which this might be done, provided four assumptions be granted. These assumptions (which after all are inevitable in any event) are:

1) The same cerebral process which, when aroused from without by a sense-organ, gives the perception of an object, will give an idea of the same object when aroused by other cerebral processes from within.

2) If processes 1, 2, 3, 4 have once been aroused together or in immediate succession, any subsequent arousal of any one of them (whether from without or within) will tend to arouse the others in the original order.[This is the so-called law of association.]

3) Every sensorial excitement propagated to a lower centre tends to spread upwards and arouse an idea.

4) Every idea tends ultimately either to produce a movement or to check one which otherwise would be produced.

Suppose now (these assumptions being granted) that we have a baby before us who sees a candle-flame for the first time, and, by virtue of a reflex tendency common in babies of a certain age, extends his hand to grasp it, so that his fingers get burned. So far we have two reflex currents in play: first, from the eye to the extension movement, along the line 1-1-1-1 of Fig. 3; and second, from the finger to the movement of drawing back the hand, along the line 2-2-2-2.

If this were the baby's whole nervous system, and if the reflexes were once for all organic, we should have no alteration in his behavior, no matter how often the experience recurred. The retinal image of the flame would always make the arm shoot forward, the burning of the finger would always send it back. But we know that 'the burnt child dreads the fire,' and that one experience usually protects the fingers forever. The point is to see how the hemispheres may bring this result to pass.

We must complicate our diagram (see Fig. 4). Let the current 1-1, from the eye, discharge upward as well as downward when it reaches the lower centre for vision, and arouse the perceptional process s1 in the hemispheres; let the feeling of the arm's extension also send up a current which leaves a trace of itself, m1; let the burnt finger leave an analogous trace, s2; and let the movement of retraction leave m2. These four processes will now, by virtue of assumption 2), be associated together by the path s1-m1-s2-m2 running from the first to the last, so that if anything touches off s1, ideas of the extension, of the burnt finger, and of the retraction will pass in rapid succession through the mind. The effect on the child's conduct when the candle-flame is next presented is easy to imagine. Of course the sight of it arouses the grasping reflex; but it arouses simultaneously the idea thereof, together with that of the consequent pain, and of the final retraction of the hand; and if these cerebral processes prevail in strength over the immediate sensation in the centres below, the last idea will be the cue by which the final action is discharged. The grasping will be arrested in mid-career, the hand drawn back, and the child's fingers saved.

In all this we assume that the hemispheres do not natively couple any particular sense-impression with any special motor discharge. They only register, and preserve traces of, such couplings as are already organized in the reflex centres below. But this brings it inevitably about that, when a chain of experiences has been already registered and the first link is impressed once again from without, the last link will often be awakened in idea long before it can exist in fact. And if this last link were previously coupled with a motion, that motion may now come from the mere ideal suggestion without waiting for the actual impression to arise. Thus an animal with hemispheres acts in anticipation of future things; or, to use our previous formula, he acts from considerations of distant good and ill. If we give the name of partners to the original couplings of impressions with motions in a reflex way, then we may say that the function of the hemispheres is simply to bring about exchanges among the partners. Movement mn, which natively is sensation sn's partner, becomes through the hemispheres the partner of sensation s1, s2 or s3. It is like the great commutating switch-board at a central telephone station. No new elementary process is involved; no impression nor any motion peculiar to the hemispheres; but any number of combinations impossible to the lower machinery taken alone, and an endless consequent increase in the possibilities of behavior on the creature's part.

All this, as a mere scheme,[4] is so clear and so concordant with the general look of the facts as almost to impose itself on our belief; but it is anything but clear in detail. The brain-physiology of late years has with great effort sought to work out the paths by which these couplings of sensations with movements take place, both in the hemispheres and in the centres below.

So we must next test our scheme by the facts discovered in this direction. We shall conclude, I think, after taking them all into account, that the scheme probably makes the lower centres too machine-like and the hemispheres not quite machine-like enough, and must consequently be softened down a little. So much I may say in advance. Meanwhile, before plunging into the details which await us, it will somewhat clear our ideas if we contrast the modern way of looking at the matter with the phrenological conception which but lately preceded it.

THE PHRENOLOGICAL CONCEPTION.

In a certain sense Gall was the first to seek to explain in detail how the brain could subserve our mental operations. His way of proceeding was only too simple. He took the faculty-psychology as his ultimatum on the mental side, and he made no farther psychological analysis. Wherever he found an individual with some strongly-marked trait of character he examined his head; and if he found the latter prominent in a certain region, he said without more ado that that region was the 'organ' of the trait or faculty in question. The traits were of very diverse constitution, some being simple sensibilities like 'weight' or 'color'; some being instinctive tendencies like 'alimentiveness' or 'amativeness;' and others, again, being complex resultants like 'conscientiousness,' 'individuality.' Phrenology fell promptly into disrepute among scientific men because observation seemed to show that large facul- ties and large 'bumps' might fail to coexist; because the scheme of Gall was so vast as hardly to admit of accurate determination at all-who of us can say even of his own brothers whether their perceptions of weight and of time are well developed or not?-because the followers of Gall and Spurzheim were unable to reform these errors in any appreciable degree; and, finally, because the whole analysis of faculties was vague and erroneous from a psychologic point of view. Popular professors of the lore have nevertheless continued to command the admiration of popular audiences; and there seems no doubt that Phrenology, however little it satisfy our scientific curiosity about the functions of different portions of the brain, may still be, in the hands of intelligent practitioners, a useful help in the art of reading character. A hooked nose and a firm jaw are usually signs of practical energy; soft, delicate hands are signs of refined sensibility. Even so may a prominent eye be a sign of power over language, and a bull-neck a sign of sensuality. But the brain behind the eye and neck need no more be the organ of the signified faculty than the jaw is the organ of the will or the hand the organ of refinement. These correlations between mind and body are, however, so frequent that the 'characters' given by phrenologists are often remarkable for knowingness and insight.

Phrenology hardly does more than restate the problem. To answer the question, "Why do I like children?" by saying, "Because you have a large organ of philoprogenitiveness," but renames the phenomenon to be explained. What is my philoprogenitiveness? Of what mental elements does it consist? And how can a part of the brain be its organ? A science of the mind must reduce such complex manifestations as 'philoprogenitiveness' to their elements. A science of the brain must point out the functions of its elements. A science of the relations of mind and brain must show how the elementary ingredients of the former correspond to the elementary functions of the latter. But phrenology, except by occasional coincidence, takes no account of elements at all. Its 'faculties,' as a rule, are fully equipped persons in a particular mental attitude. Take, for example, the 'faculty' of language. It involves in reality a host of distinct powers. We must first have images of concrete things and ideas of abstract qualities and relations; we must next have the memory of words and then the capacity so to associate each idea or image with a particular word that, when the word is heard, the idea shall forthwith enter our mind. We must conversely, as soon as the idea arises in our mind, associate with it a mental image of the word, and by means of this image we must innervate our articulatory apparatus so as to reproduce the word as physical sound. To read or to write a language other elements still must be introduced. But it is plain that the faculty of spoken language alone is so complicated as to call into play almost all the elementary powers which the mind possesses, memory, imagination, association, judgment, and volition. A portion of the brain competent to be the adequate seat of such a faculty would needs be an entire brain in miniature,-just as the faculty itself is really a specification of the entire man, a sort of homunculus. Yet just such homunculi are for the most part the phrenological organs. As Lange says:

"We have a parliament of little men together, each of whom, as happens also in a real parliament, possesses but a single idea which he ceaselessly strives to make prevail"-benevolence, firmness, hope, and the rest. "Instead of one soul, phrenology gives us forty, each alone as enigmatic as the full aggregate psychic life can be. Instead of dividing the latter into effective elements, she divides it into personal beings of peculiar character..'Herr Pastor, sure there be a horse inside,' called out the peasants to X after their spiritual shepherd had spent hours in explaining to them the construction of the locomotive. With a horse inside truly everything becomes clear, even though it be a queer enough sort of horse-the horse itself calls for no explanation! Phrenology takes a start to get beyond the point of view of the ghost-like soul entity, but she ends by populating the whole skull with ghosts of the same order."[5]

Modern Science conceives of the matter in a very different way. Brain and mind alike consist of simple elements, sensory and motor. "All nervous centres," says Dr. Hughlings Jackson,[6] "from the lowest to the very highest (the substrata of consciousness), are made up of nothing else than nervous arrangements, representing impressions and movements... I do not see of what other materials the brain can be made." Meynert represents the matter similarly when he calls the cortex of the hemispheres the surface of projection for every muscle and every sensitive point of the body. The muscles and the sensitive points are represented each by a cortical point, and the brain is nothing but the sum of all these cortical points, to which, on the mental side, as many ideas correspond. Ideas of sensation, ideas of motion are, on the other hand, the elementary factors out of which the mind is built up by the associationists in psychology. There is a complete parallelism between the two analyses, the same diagram of little dots, circles, or triangles joined by lines symbolizes equally well the cerebral and mental processes : the dots stand for cells or ideas, the lines for fibres or associations. We shall have later to criticise this analysis so far as it relates to the mind; but there is no doubt that it is a most convenient, and has been a most useful, hypothesis, formulating the facts in an extremely natural way.

If, then, we grant that motor and sensory ideas variously associated are the materials of the mind, all we need do to get a complete diagram of the mind's and the brain's relations should be to ascertain which sensory idea corresponds to which sensational surface of projection, and which motor idea to which muscular surface of projection. The associations would then correspond to the fibrous connections between the various surfaces. This distinct cerebral localization of the various elementary sorts of idea has been treated as a 'postulate' by many physiologists (e.g. Munk); and the most stirring controversy in nerve-physiology which the present generation has seen has been the localization-question.

THE LOCALIZATION OF FUNCTIONS IN THE. HEMISPHERES.

Up to 1870, the opinion which prevailed was that which the experiments of Flourens on pigeons' brains had made plausible, namely, that the different functions of the hemi- spheres were not locally separated, but carried on each by the aid of the whole organ. Hitzig in 1870 showed, however, that in a dog's brain highly specialized movements could be produced by electric irritation of determinate regions of the cortex; and Ferrier and Munk, half a dozen years later, seemed to prove, either by irritations or excisions or both, that there were equally determinate regions connected with the senses of sight, touch, hearing, and smell. Munk's special sensorial localizations, however, disagreed with Ferrier's; and Goltz, from his extirpation-experiments, came to a conclusion adverse to strict localization of any kind. The controversy is not yet over. I will not pretend to say anything more of it historically, but give a brief account of the condition in which matters at present stand.

The one thing which is perfectly well established is this, that the 'central' convolutions, on either side of the fissure of Rolando, and (at least in the monkey) the calloso-marginal convolution (which is continuous with them on the mesial surface where one hemisphere is applied against the other), form the region by which all the motor incitations which leave the cortex pass out, on their way to those executive centres in the region of the pons, medulla, and spinal cord from which the muscular contractions are discharged in the last resort. The existence of this so-called 'motor zone' is established by the lines of evidence successively given below:

(1) Cortical Irritations. Electrical currents of small intensity applied to the surface of the said convolutions in dogs, monkeys, and other animals, produce well-defined movements in face, fore-limb, hind-limb, tail, or trunk, according as one point or another of the surface is irritated. These movements affect almost invariably the side opposite to the brain irritations : If the left hemisphere be excited, the movement is of the right leg, side of face, etc. All the objections at first raised against the validity of these experiments have been overcome. The movements are certainly not due to irritations of the base of the brain by the downward spread of the current, for: a) mechanical irritations will produce them, though less easily than electrical; b) shifting the electrodes to a point close by on the surface changes the movement in ways quite inexplicable by changed physical conduction of the current; c) if the cortical 'centre' for a certain movement be cut under with a sharp knife but left in situ, although the electric conductivity is physically unaltered by the operation, the physiological conductivity is gone and currents of the same strength no longer produce the movements which they did; d) the time-interval between the application of the electric stimulus to the cortex and the resultant movement is what it would be if the cortex acted physiologically and not merely physically in transmitting the irritation. It is namely a well-known fact that when a nerve-current has to pass through the spinal cord to excite a muscle by reflex action, the time is longer than if it passes directly down the motor nerve: the cells of the cord take a certain time to discharge. Similarly, when a stimulus is applied directly to the cortex the muscle contracts two or three hundredths of a second later than it does when the place on the cortex is cut away and the electrodes are applied to the white fibres below.[7]

(2) Cortical Ablations. When the cortical spot which is found to produce a movement of the fore-leg, in a dog, is excised (see spot 5 in Fig. 5), the leg in question becomes peculiarly affected. At first it seems paralyzed. Soon, however, it is used with the other legs, but badly. The animal does not bear his weight on it, allows it to rest on its dorsal surface, stands with it crossing the other leg, does not remove it if it hangs over the edge of a table, can no longer 'give the paw' at word of command if able to do so before the operation, does not use it for scratching the ground, or holding a bone as formerly, lets it slip out when running on a smooth surface or when shaking himself, etc., etc. Sensibility of all kinds seems diminished as well as motility, but of this I shall speak later on. Moreover the dog tends in voluntary movements to swerve towards the side of the brain-lesion instead of going straight forward. All these symptoms gradually decrease, so that even with a very severe brain-lesion the dog may be outwardly indistinguishable from a well dog after eight or ten weeks. Still, a slight chloroformization will reproduce the disturbances, even then. There is a certain appearance of ataxic in-co�rdination in the movements -the dog lifts his fore-feet high and brings them down with more strength than usual, and yet the trouble is not ordinary lack of co-ordination.

Neither is there paralysis. The strength of whatever movements are made is as great as ever-dogs with extensive destruction of the motor zone can jump as high and bite as hard as ever they did, but they seem less easily moved to do anything with the affected parts. Dr. Loeb, who has studied the motor disturbances of dogs more carefully than any one, conceives of them en masse as effects of an increased inertia in all the processes of innervation towards the side opposed to the lesion. All such movements require an unwonted effort for their execution; and when only the normally usual effort is made they fall behind in effectiveness.[8]

Even when the entire motor zone of a dog is removed, there is no permanent paralysis of any part, but only this curious sort of relative inertia when the two sides of the body are compared; and this itself becomes hardly noticeable after a number of weeks have elapsed. Prof Goltz has described a dog whose entire left hemisphere was destroyed, and who retained only a slight motor inertia on the right half of the body. In particular he could use his right paw for holding a bone whilst gnawing it, or for reaching after a piece of meat.

Had he been taught to give his paw before the operations, it would have been curious to see whether that faculty also came back. His tactile sensibility was permanently diminished on the right side.[9] In monkeys a genuine paralysis follows upon ablations of the cortex in the motor region. This paralysis affects parts of the body which vary with the brain-parts removed. The monkey's opposite arm or leg hangs flaccid, or at most takes a small part in associated movements. When the entire region is removed there is a genuine and permanent hemiplegia in which the arm is more affected than the leg; and this is followed months later by contracture of the muscles, as in man after inveterate hemiplegia.[10] According to Schaefer and Horsley, the trunk-muscles also become paralyzed after destruction of the marginal convolution on both sides (see Fig. 7). These differences between dogs and monkeys show the danger of drawing general conclusions from experiments done on any one sort of animal. I subjoin the figures given by the last-named authors of the motor regions in the monkey's brain.[11]

In man we are necessarily reduced to the observation post-mortem of cortical ablations produced by accident or disease (tumor, hemorrhage, softening, etc.). What results during life from such conditions is either localized spasm, or palsy of certain muscles of the opposite side. The cortical regions which invariably produce these results are homologous with those which we have just been studying in the dog, cat, ape, etc. Figs. 8 and 9 show the result of 169 cases carefully studied by Exner. The parts shaded are regions where lesions produced no motor disturbance. Those left white were, on the contrary, never injured without motor disturbances of some sort.

Where the injury to the cortical substance is profound in man, the paralysis is permanent and is succeeded by muscular rigidity in the paralyzed parts, just as it may be in the monkey.

(3) Descending degenerations show the intimate connection of the rolandic regions of the cortex with the motor tracts of the cord. When, either in man or in the lower animals, these regions are destroyed, a peculiar degenerative change known as secondary sclerosis is found to extend downwards through the white fibrous substance of the brain in a perfectly definite manner, affecting certain distinct strands which pass through the inner capsule, crura, and pons, into the anterior pyramids of the medulla oblongata, and from thence (partly crossing to the other side) downwards into the anterior (direct) and lateral (crossed) columns of the spinal cord.

(4) Anatomical proof of the continuity of the rolandic regions with these motor columns of the cord is also clearly given. Flechsig's 'Pyramidenbahn' forms an uninterrupted strand (distinctly traceable in human embryos, before its fibres have acquired their white 'medullary sheath') passing upwards from the pyramids of the medulla, and traversing the internal capsule and corona radiata to the convolutions in question (Fig. 10). None of the inferior gray matter of the brain seems to have any connection with this important fibrous strand. It passes directly from the cortex to the motor arrangements in the cord, depending for its proper nutrition (as the facts of degeneration show) on the influence of the cortical cells, just as motor nerves depend for their nutrition on that of the cells of the spinal cord. Electrical stimulation of this motor strand in any accessible part of its course has been shown in dogs to produce movements analogous to those which excitement of the cortical surface calls forth.

One of the most instructive proofs of motor localization in the cortex is that furnished by the disease now called aphemia, or motor Aphasia. Motor aphasia is neither loss of voice nor paralysis of the tongue or lips. The patient's voice is as strong as ever, and all the innervations of his hypoglossal and facial nerves, except those necessary for speaking, may go on perfectly well. He can laugh and cry, and even sing; but he either is unable to utter any words at all; or a few meaningless stock phrases form his only speech ; or else he speaks incoherently and confusedly, mispronounc- ing, misplacing, and misusing his words in various degrees. Sometimes his speech is a mere broth of unintelligible syllables. In cases of pure motor aphasia the patient recognizes his mistakes and suffers acutely from them.

Now whenever a patient dies in such a condition as this, and an examination of his brain is permitted, it is found that the lowest frontal gyrus (see Fig. 11) is the seat of injury. Broca first noticed this fact in 1861, and since then the gyrus has gone by the name of Broca's convolution.

The injury in right-handed people is found on the left hemisphere, and in left-handed people on the right hemisphere. Most people, in fact, are left-brained, that is, all their delicate and specialized movements are handed over to the charge of the left hemisphere. The ordinary right-handedness for such movements is only a consequence of that fact, a consequence which shows outwardly on account of that extensive decussation of the fibres whereby most of those from the left hemisphere pass to the right half of the body only. But the left-brainedness might exist in equal measure and not show outwardly. This would happen wherever organs on both sides of the body could be governed by the left hemisphere; and just such a case seems offered by the vocal organs, in that highly delicate and special motor service which we call speech. Either hemisphere can innervate them bilaterally, just as either seems able to innervate bilaterally the muscles of the trunk, ribs, and diaphragm. Of the special movements of speech, how- ever, it would appear (from the facts of aphasia) that the left hemisphere in most persons habitually takes exclusive charge. With that hemisphere thrown out of gear, speech is undone; even though the opposite hemisphere still be there for the performance of less specialized acts, such as the various movements required in eating.

It will be noticed that Broca's region is homologous with the parts ascertained to produce movements of the lips, tongue, and larynx when excited by electric currents in apes (cf. Fig. 6, p. 34). The evidence is therefore as complete as it well can be that the motor incitations to these organs leave the brain by the lower frontal region.

Victims of motor aphasia generally have other disorders. One which interests us in this connection has been called agraphia: they have lost the power to write. They can read writing and understand it; but either cannot use the pen at all or make egregious mistakes with it. The seat of the lesion here is less well determined, owing to an insufficient number of good cases to conclude from.[12] There is no doubt, however, that it is (in right-handed people) on the left side, and little doubt that it consists of elements of the hand-and-arm region specialized for that service. The symptom may exist when there is little or no disability in the hand for other uses. If it does not get well, the patient usually educates his right hemisphere, i.e. learns to write with his left hand. In other cases of which we shall say more a few pages later on, the patient can write both spontaneously and at dictation, but cannot read even what he has himself written! All these phenomena are now quite clearly explained by separate brain-centres for the various feelings and movements and tracts for associating these together. But their minute discussion belongs to medicine rather than to general psychology, and I can only use them here to illustrate the principles of motor localization.[13] Under the heads of sight and hearing I shall have a little more to say.

The different lines of proof which I have taken up establish conclusively the proposition that all the motor impulses which leave the cortex pass out, in healthy animals, from the convolutions about the fissure of Rolando.

When, however, it comes to defining precisely what is involved in a motor impulse leaving the cortex, things grow more obscure. Does the impulse start independently from the convolutions in question, or does it start elsewhere and merely flow through? And to what particular phase of psychic activity does the activity of these centres correspond? Opinions and authorities here divide; but it will be better, before entering into these deeper aspects of the problem, to cast a glance at the facts which have been made out concerning the relations of the cortex to sight, hearing, and smell.

Sight.

Ferrier was the first in the field here. He found, when the angular convolution (that lying between the 'intra parietal' and 'external occipital' fissures, and bending round the top of the fissure of Sylvius, in Fig. 6) was excited in the monkey, that movements of the eyes and head as if for vision occurred; and that when it was extirpated, what he supposed to be total and permanent blindness of the opposite eye followed. Munk almost immediately declared total and permanent blindness to follow from destruction of the occipital lobe in monkeys as well as dogs, and said that the angular gyrus had nothing to do with sight, but was only the centre for tactile sensibility of the eyeball. Munk's absolute tone about his observations and his theoretic arrogance have led to his ruin as an authority. But he did two things of permanent value. He was the first to distinguish in these vivisections between sensorial and psychic blindness, and to describe the phenomenon of restitution of the visual function after its first impairment by an operation; and the first to notice the hemiopic character of the visual disturbances which result when only one hemisphere is injured. Sensorial blindness is absolute insensibility to light; psychic blindness is inability to recognize the meaning of the optical impressions, as when we see a page of Chinese print but it suggests nothing to us. A hemiopic disturbance of vision is one in which neither retina is affected in its totality, but in which, for example, the left portion of each retina is blind, so that the animal sees nothing situated in space towards its right. Later observations have corroborated this hemiopic character of all the disturbances of sight from injury to a single hemisphere in the higher animals; and the question whether an animal's apparent blindness is sensorial or only psychic has, since Munk's first publications, been the most urgent one to answer, in all observations relative to the function of sight.

Goltz almost simultaneously with Ferrier and Munk reported experiments which led him to deny that the visual function was essentially bound up with any one localized portion of the hemispheres. Other divergent results soon came in from many quarters, so that, without going into the history of the matter any more, I may report the existing state of the case as follows:[14]

In fishes, frogs, and lizards vision persists when the hemispheres are entirely removed. This is admitted for frogs and fishes even by Munk, who denies it for birds.

All of Munk's birds seemed totally blind (blind sensorially) after removal of the hemispheres by his operation. The following of a candle by the head and winking at a threatened blow, which are ordinarily held to prove the retention of crude optical sensations by the lower centres in supposed hemisphereless pigeons, are by Munk ascribed to vestiges of the visual sphere of the cortex left behind by the imperfection of the operation. But Schrader, who operated after Munk and with every apparent guarantee of completeness, found that all his pigeons saw after two or three weeks had elapsed, and the inhibitions resulting from the wound had passed away. They invariably avoided even the slightest obstacles, flew very regularly towards certain perches, etc., differing toto coelo in these respects with certain simply blinded pigeons who were kept with them for comparison. They did not pick up food strewn on the ground, however. Schrader found that they would do this if even a small part of the frontal region of the hemispheres was left, and ascribes their non-self-feeding when deprived of their occipital cerebrum not to a visual, but to a motor, defect, a sort of alimentary aphasia.[15]

In presence of such discord as that between Munk and his opponents one must carefully note how differently significant is loss, from preservation, of a function after an operation on the brain. The loss of the function does not necessarily show that it is dependent on the part cut out; but its preservation does show that it is not dependent: and this is true though the loss should be observed ninety-nine times and the preservation only once in a hundred similar excisions. That birds and mammals can be blinded by cortical ablation is undoubted; the only question is, must they be so? Only then can the cortex be certainly called the 'seat of sight.' The blindness may always be due to one of those remote effects of the wound on distant parts, inhibitions, extensions of inflammation,-interferences, in a word,- upon which Brown-S�quard and Goltz have rightly insisted, and the importance of which becomes more manifest every day. Such effects are transient; whereas the symptoms of deprivation (Ausfallserscheinungen, as Goltz calls them) which come from the actual loss of the cut-out region must from the nature of the case be permanent. Blindness in the pigeons, so far as it passes away, cannot possibly be charged to their seat of vision being lost, but only to some influence which temporarily depresses the activity of that seat. The same is true mutatis mutandis of all the other effects of operations, and as we pass to mammals we shall see still more the importance of the remark.

In rabbits loss of the entire cortex seems compatible with the preservation of enough sight to guide the poor animals' movements, and enable them to avoid obstacles. Christiani's observations and discussions seem conclusively to have established this, although Munk found that all his animals were made totally blind.[16]

In dogs also Munk found absolute stone-blindness after ablation of the occipital lobes. He went farther and mapped out determinate portions of the cortex thereupon, which he considered correlated with definite segments of the two retinae, so that destruction of given portions of the cortex produces blindness of the retinal centre, top, bottom, or right or left side, of the same or opposite eye. There seems little doubt that this definite correlation is mythological. Other observers, Hitzig, Goltz, Luciani, Loeb, Exner, etc., find, whatever part of the cortex may be ablated on one side, that there usually results a hemiopic disturbance of both eyes, slight and transient when the anterior lobes are the parts attacked, grave when an occipital lobe is the seat of injury, and lasting in proportion to the latter's extent. According to Loeb, the defect is a dimness of vision ('hemiamblyopia') in which (however severe) the centres remain the best seeing portions of the retina, just as they are in normal dogs. The lateral or temporal part of each retina seems to be in exclusive connection with the cortex of its own side. The centre and nasal part of each seems, on the contrary, to be connected with the cortex of the opposite hemispheres. Loeb, who takes broader views than any one, conceives the hemiamblyopia as he conceives the motor disturbances, namely, as the expression of an increased inertia in the whole optical machinery, of which the result is to make the animal respond with greater effort to impressions coming from the half of space opposed to the side of the lesion. If a dog has right hemiamblyopia, say, and two pieces of meat are hung before him at once, he invariably turns first to the one on his left. But if the lesion be a slight one, shaking slightly the piece of meat on his right (this makes of it a stronger stimulus) makes him seize upon it first. If only one piece of meat be offered, he takes it, on whichever side it be.

When both occipital lobes are extensively destroyed total blindness may result. Munk maps out his 'Seh- sph�re' definitely, and says that blindness must result when the entire shaded part, marked A, A, in Figs. 12 and 13, is involved in the lesion. Discrepant reports of other observations he explains as due to incomplete ablation.

Luciani, Goltz, and Lannegrace, however, contend that they have made complete bilateral extirpations of Munk's Sehsph�re more than once, and found a sort of crude indiscriminating sight of objects to return in a few weeks.[17] The question whether a dog is blind or not is harder to solve than would at first appear; for simply blinded dogs, in places to which they are accustomed, show little of their loss and avoid all obstacles; whilst dogs whose occipital lobes are gone may run against things frequently and yet see notwithstanding. The best proof that they may see is that which Goltz's dogs furnished: they carefully avoided, as it seemed, strips of sunshine or paper on the floor, as if they were solid obstacles. This no really blind dog would do. Luciani tested his dogs when hungry (a condition which sharpens their attention) by strewing pieces of meat and pieces of cork before them. If they went straight at them, they saw; and if they chose the meat and left the cork, they saw discriminatingly. The quarrel is very acrimonious; indeed the subject of localization of functions in the brain seems to have a peculiar effect on the temper of those who cultivate it experimentally. The amount of preserved vision which Goltz and Luciani report seems hardly to be worth considering, on the one hand; and on the other, Munk admits in his penultimate paper that out of 85 dogs he only 'succeeded' 4 times in his operation of producing complete blindness by complete extirpation of his 'Sehsph�re'.[18] The safe conclusion for us is that Luciani's diagram, Fig. 14, represents something like the truth.

The occipital lobes are far more important for vision than any other part of the cortex, so that their complete destruction makes the animal almost blind. As for the crude sensibility to light which may then remain, nothing exact is known either about its nature or its seat.

In the monkey, doctors also disagree. The truth seems, however, to be that the occipital lobes in this animal also are the part connected most intimately with the visual function. The function would seem to go on when very small portions of them are left, for Ferrier found no 'appreciable impairment' of it after almost complete destruction of them on both sides. On the other hand, he found complete and permanent blindness to ensue when they and the angular gyri in addition were destroyed on both sides. Munk, as well as Brown and Schaefer, found no disturbance of sight from destroying the angular gyri alone, although Ferrier found blindness to ensue. This blindness was probably due to inhibitions exerted in distans, or to cutting of the white optical fibres passing under the angular gyri on their way to the occipital lobes. Brown and Schaefer got complete and permanent blindness in one monkey from total destruction of both occipital lobes. Luciani and Seppili, performing this operation on two monkeys, found that the animals were only mentally, not sensorially, blind. After some weeks they saw their food, but could not distinguish by sight between figs and pieces of cork. Luciani and Seppili seem, however, not to have extirpated the entire lobes. When one lobe only is injured the affection of sight is hemiopic in monkeys: in this all observers agree. On the whole, then, Munk's original location of vision in the occipital lobes is confirmed by the later evidence.[19]

In man we have more exact results, since we are not driven to interpret the vision from the outward conduct. On the other hand, however, we cannot vivisect, but must wait for pathological lesions to turn up. The pathologists who have discussed these (the literature is tedious ad libitum) conclude that the occipital lobes are the indispensable part for vision in man. Hemiopic disturbance in both eyes comes from lesion of either one of them, and total blindness, sensorial as well as psychic, from destruction of both.

Hemiopia may also result from lesion in other parts, especially the neighboring angular and supra-marginal gyri, and it may accompany extensive injury in the motor region of the cortex. In these cases it seems probable that it is due to an actio in distans, probably to the interruption of fibres proceeding from the occipital lobe. There seem to be a few cases on record where there was injury to the occipital lobes without visual defect. Ferrier has collected as many as possible to prove his localization in the angular gyrus.[20] A strict application of logical principles would make one of these cases outweigh one hundred contrary ones. And yet, remembering how imperfect observations may be, and how individual brains may vary, it would certainly be rash for their sake to throw away the enormous amount of positive evidence for the occipital lobes. Individual variability is always a possible explanation of an anomalous case. There is no more prominent anatomical fact than that of the 'decussation of the pyramids,' nor any more usual pathological fact than its consequence, that left-handed hemorrhages into the motor region produce right-handed paralyses. And yet the decussation is variable in amount, and seems sometimes to be absent altogether.[21] If, in such a case as this last, the left brain were to become the seat of apoplexy, the left and not the right half of the body would be the one to suffer paralysis.

The schema on the opposite page, copied from Dr.Seguin, expresses, on the whole, the probable truth about the regions concerned in vision. Not the entire occipital lobes, but the so-called cunei, and the first convolutions, are the cortical parts most intimately concerned. Nothnagel agrees with Seguin in this limitation of the essential tracts.[22]

A most interesting effect of cortical disorder is mental blindness. This consists not so much in insensibility to optical impressions, as in inability to understand them. Psychologically it is interpretable as loss of associations between optical sensations and what they signify; and any interruption of the paths between the optic centres and the centres for other ideas ought to bring it about. Thus, printed letters of the alphabet, or words, signify certain sounds and certain articulatory movements. If the connection between the articulating or auditory centres, on the one hand, and the visual centres on the other, be ruptured, we ought a priori to expect that the sight of words would fail to awaken the idea of their sound, or the movement for pronouncing them.

We ought, in short, to have alexia, or inability to read: and this is just what we do have in many cases of extensive injury about the fronto-temporal regions, as a complication of aphasic disease. Nothnagel suggests that whilst the cuneus is the seat of optical sensations, the other parts of the occipital lobe may be the field of optical memories and ideas, from the loss of which mental blindness should ensue. In fact, all the medical authors speak of mental blindness as if it must consist in the loss of visual images from the memory. It seems to me, however, that this is a psychological misapprehension. A man whose power of visual imagination has decayed (no unusual phenomenon in its lighter grades) is not mentally blind in the least, for he recognizes perfectly all that he sees. On the other hand, he may be mentally blind, with his optical imagination well preserved; as in the interesting case publislied by Wilbrand in 1887.[23] In the still more interesting case of mental blindness recently published by Lissauer,[24] though the patient made the most ludicrous mistakes, calling for instance a clothes-brush a pair of spectacles, an umbrella a plant with flowers, an apple a portrait of a lady, etc. etc., he seemed, according to the reporter, to have his mental images fairly well preserved. It is in fact the momentary loss of our non-optical images which makes us mentally blind, just as it is that of our non-auditory images which makes us mentally deaf. I am mentally deaf if, hearing a bell, I can't recall how it looks; and mentally blind if, seeing it, I can't recall its sound or its name. As a matter of fact, I should have to be not merely mentally blind, but stone-blind, if all my visual images were lost. For although I am blind to the right half of the field of view if my left occipital region is injured, and to the left half if my right region is injured, such hemianopsia does not deprive me of visual images, experience seeming to show that the unaffected hemisphere is always sufficient for production of these. To abolish them entirely I should have to be deprived of both occipital lobes, and that would deprive me not only of my inward images of sight, but of my sight altogether.[25] Recent pathological annals seem to offer a few such cases.[26] Meanwhile there are a number of cases of mental blindness, especially for written language, coupled with hemianopsia, usually of the rightward field of view. These are all explicable by the breaking down, through disease, of the connecting tracts between the occipital lobes and other parts of the brain, especially those which go to the centres for speech in the frontal and temporal regions of the left hemisphere. They are to be classed among disturbances of conduction or of association; and nowhere can I find any fact which should force us to believe that optical images need[27] be lost in mental blindness, or that the cerebral centres for such images are locally distinct from those for direct sensations from the eyes.[28]

Where an object fails to be recognized by sight, it often happens that the patient will recognize and name it as soon as he touches it with his hand. This shows in an interes- ting way how numerous the associative paths are which all end by running out of the brain through the channel of speech. The hand-path is open, though the eye-path be closed. When mental blindness is most complete, neither sight, touch, nor sound avails to steer the patient, and a sort of dementia which has been called asymbolia or apraxia is the result. The commonest articles are not understood. The patient will put his breeches on one shoulder and his hat upon the other, will bite into the soap and lay his shoes on the table, or take his food into his hand and throw it down again, not knowing what to do with it, etc. Such disorder can only come from extensive brain-injury.[29]

The method of degeneration corroborates the other evidence localizing the tracts of vision. In young animals one gets secondary degeneration of the occipital regions from destroying an eyeball, and, vice versa, degeneration of the optic nerves from destroying the occipital regions. The corpora geniculata, thalami, and subcortical fibres leading to the occipital lobes are also found atrophied in these cases. The phenomena are not uniform, but are indisputable;[30] so that, taking all lines of evidence together, the special connection of vision with the occipital lobes is perfectly made out. It should be added that the occipital lobes have frequently been found shrunken in cases of inveterate blindness in man.

Hearing.

Hearing is hardly as definitely localized as sight. In the dog, Luciani's diagram will show the regions which directly or indirectly affect it for the worse when injured. As with sight, one-sided lesions produce symptoms on both sides. The mixture of black dots and gray dots in the diagram is meant to represent this mixture of 'crossed' and 'uncrossed' connections, though of course no topographical exactitude is aimed at. Of all the region, the temporal lobe is the most important part; yet permanent absolute deafness did not result in a dog of Luciani's, even from bilateral destruction of both temporal lobes in their entirety.[31]

In the monkey, Ferrier and Yeo once found permanent deafness to follow destruction of the upper temporal convolution (the one just below the fissure of Sylvius in Fig.6) on both sides. Brown and Schaefer found, on the contrary, that in several monkeys this operation failed to noticeably affect the hearing. In one animal, indeed, both entire temporal lobes were destroyed. After a week or two of depression of the mental faculties this beast recovered and became one of the brightest monkeys possible, domineering over all his mates, and admitted by all who saw him to have all his senses, including hearing, 'perfectly acute.'[32] Terrible recriminations have, as usual, ensued between the investigators, Ferrier denying that Brown and Schaefer's ablations were complete,[33] Schaefer that Ferrier's monkey was really deaf.[34] In this unsatisfactory condition the subject must be left, although there seems no reason to doubt that Brown and Schaefer's observation is the more important of the two.

In man the temporal lobe is unquestionably, the seat of the hearing function, and the superior convolution adjacent to the sylvian fissure is its most important part. The phenomena of aphasia show this. We studied motor aphasia a few pages back; we must now consider sensory aphasia.

Our knowledge of this disease has had three stages: we may talk of the period of Broca, the period of Wernicke, and the period of Charcot. What Broca's discovery was we have seen. Wernicke was the first to discriminate those cases in which the patient can not even understand speech from those in which he can understand, only not talk; and to ascribe the former condition to lesion of the temporal lobe.[35] The condition in question is word-deafness, and the disease is auditory aphasia. The latest statistical survey of the subject is that by Dr. Allen Starr.[36] In the seven cases of pure word-deafness which he has collected, cases in which the patient could read, talk, and write, but not understand what was said to him, the lesion was limited to the first and second temporal convolutions in their posterior two thirds. The lesion (in right-handed, i.e. left-brained, persons) is always on the left side, like the lesion in motor aphasia. Crude hearing would not be abolished, even were the left centre for it utterly destroyed ; the right centre would still provide for that. But the linguistic use of hearing appears bound up with the integrity of the left centre more or less exclusively. Here it must be that words heard enter into association with the things which they represent, on the one hand, and with the movements necessary for pronouncing them, on the other. In a large majority of Dr. Starr's fifty cases, the power either to name objects or to talk coherently was impaired. This shows that in most of us (as Wernicke said) speech must go on from auditory cues; that is, it must be that our ideas do not innervate our motor centres directly, but only after first arousing the mental sound of the words. This is the immediate stimulus to articulation; and where the possibility of this is abolished by the destruction of its usual channel in the left temporal lobe, the articulation must suffer. In the few cases in which the channel is abolished with no bad effect on speech we must suppose an idiosyncrasy. The patient must innervate his speech-organs either from the corresponding portion of the other hemisphere or directly from the centres of ideation, those, namely, of vision, touch, etc., without leaning on the auditory region. It is the minuter analysis of the facts in the light of such individual differences as these which constitutes Charcot's contribution towards clearing up the subject.

Every namable thing, act, or relation has numerous properties, qualities, or aspects. In our minds the properties of each thing, together with its name, form an associated group. If different parts of the brain are severally concerned with the several properties, and a farther part with the hearing, and still another with the uttering, of the name, there must inevitably be brought about (through the law of association which we shall later study) such a dynamic connection amongst all these brain-parts that the activity of anyone of them will be likely to awaken the activity of all the rest. When we are talking as we think, the ultimate process is that of utterance. If the brain-part for that be injured, speech is impossible or disorderly, even though all the other brain-parts be intact: and this is just the condition of things which, on page 37, we found to be brought about by limited lesion of the left inferior frontal convolution. But back of that last act various orders of succession are possible in the associations of a talking man's ideas. The more usual order seems to be from the tactile, visual, or other properties of the things thought-about to the sound of their names, and then to the latter's utterance. But if in a certain individual the thought of the look of an object or of the look of its printed name be the process which habitually precedes articulation, then the loss of the hearing centre will pro tanto not affect that individual's speech. He will be mentally deaf, i.e. his understanding of speech will suffer, but he will not be aphasic. In this way it is possible to explain the seven cases of pure word-deafness which figure in Dr. Starr's table.

If this order of association be ingrained and habitual in that individual, injury to his visual centres will make him not only word-blind, but aphasic as well. His speech will become confused in consequence of an occipital lesion. Naunyn, consequently, plotting out on a diagram of the hemisphere the 71 irreproachably reported cases of aphasia which he was able to collect, finds that the lesions concentrate themselves in three places: first, on Broca's, centre; second, on Wernicke's ; third, on the supra-marginal and angular gyri under which those fibres pass which connect the visual centres with the rest of the brain [37](see Fig. 17). With this result Dr. Starr's analysis of purely sensory cases agrees.

In a later chapter we shall again return to these differences in the effectiveness of the sensory spheres in different individuals. Meanwhile few things show more beautifully than the history of our knowledge of aphasia how the sagacity and patience of many banded workers are in time certain to analyze the darkest confusion into an orderly display.[38] There is no 'centre of Speech' in the brain any more than there is a faculty of Speech in the mind. The entire brain, more or less, is at work in a man who uses language. The subjoined diagram, from Ross, shows the four parts most critically concerned, and, in the light of our text, needs no farther explanation (see Fig. 18).

Smell.

Everything conspires to point to the median descending part of the temporal lobes as being the organs of smell. Even Ferrier and Munk agree on the hippocampal gyrus, though Ferrier restricts olfaction, as Munk does not to the lobule or uncinate process of the convolution, reserving the rest of it for touch.

Anatomy and pathology also point to the hippocampal gyrus; but as the matter is less interesting from the point of view of human psychology than were sight and hearing, I will say no more, but simply add Luciani and Seppili's diagram of the dog's smell-centre.[39]

Taste

Of we know little that is definite.[sic] What little there is points to the lower temporal regions again. Consult Ferrier as below.

Touch.

Interesting problems arise with regard to the seat of tactile and muscular sensibility. Hitzig, whose experiments on dogs' brains fifteen years ago opened the entire subject which we are discussing, ascribed the disorders of motility observed after ablations of the motor region to a loss of what he called muscular consciousness.

The animals do not notice eccentric positions of their limbs, will stand with their legs crossed, with the affected paw resting on its back or hanging over a table's edge, etc.; and do not resist our bending and stretching of it as they resist with the unaffected paw. Goltz, Munk, Schiff, Herzen, and others promptly ascertained an equal defect of cutaneous sensibility to pain, touch, and cold. The paw is not withdrawn when pinched, remains standing in cold water, etc. Ferrier meanwhile denied that there was any true anaesthesia produced by ablations in the motor zone, and explains the appearance of it as an effect of the sluggish motor responses of the affected side.[40] Munk [41]and Schiff [42], on the contrary, conceive of the 'motor zone' as essentially sensory, and in different ways explain the motor disorders as secondary results of the anaesthesia which is always there. Munk calls the motor zone the F�hlsph�re of the animal's limbs, etc., and makes it co�rdinate with the Sehsph�re, the H�rsph�re, etc., the entire cortex being, according to him, nothing but a projection-surface for sensations, with no exclusively or essentially motor part. Such a view would be important if true, through its bearings on the psychology of volition. What is the truth? As regards the fact of cutaneous anaesthesia from motor-zone ablations, all other observers are against Ferrier, so that he is probably wrong in denying it. On the other hand, Munk and Schiff are wrong in making the motor symptoms depend on the anaesthesia, for in certain rare cases they have been observed to exist not only without insensibility, but with actual hyperaesthesia of the parts.[43] The motor and sensory symptoms seem, therefore, to be independent variables.

In monkeys the latest experiments are those of Horsley and Schaefer,[44] whose results Ferrier accepts. They find that excision of the hippocampal convolution produces transient insensibility of the opposite side of the body, and that permanent insensibility is produced by destruction of its continuation upwards above the corpus callosum, the so-called gyrus fornicatus (the part just below the 'calloso-marginal fissure' in Fig.7). The insensibility is at its maximum when the entire tract comprising both convolutions is destroyed. Ferrier says that the sensibility of monkeys is 'entirely unaffected' by ablations of the motor zone,[45] and Horsley and Schaefer consider it by no means necessarily abolished.[46] Luciani found it diminished in his three experiments on apes.[47] In man we have the fact that one-sided paralysis from disease of the opposite motor zone may or may not be accompanied with anaesthesia of the parts.

Luciani, who believes that the motor zone is also sensory, tries to minimize the value of this evidence by pointing to the insufficiency with which patients are examined. He himself believes that in dogs the tactile sphere extends backwards and forwards of the directly excitable region, into the frontal and parietal lobes (see Fig. 20). Nothnagel considers that pathological evidence points in the same direction;[48] and Dr. Mills, carefully reviewing the evidence, adds the gyri fornicatus and hippocampi to the cutaneo-muscular region in man.[49] If one compare Luciani's diagrams together (Figs. 14,16, 19, 20) one will see that the entire parietal region of the dog's skull is common to the four senses of sight, hearing, smell, and touch, including muscular feeling. The corresponding region in the human brain (upper parietal and supra-marginal gyri-see Fig. 17, p.56) seems to be a somewhat similar place of conflux. Optical aphasias and motor and tactile disturbances all result from its injury, especially when that is on the left side.[50] The lower we go in the animal scale the less differentiated the functions of the several brain-parts seem to be.[51] It may be that the region in question still represents in ourselves something like this primitive condition, and that the surrounding parts, in adapting themselves more and more to specialized and narrow functions, have left it as a sort of carrefour through which they send currents and converse. That it should be connected with musculo-cutaneous feeling is, however, no reason why the motor zone proper should not be so connected too. And the cases of paralysis from the motor zone with no accompanying anaesthesia may be explicable without denying all sensory function to that region. For, as my colleague Dr.James Putnam informs me, sensibility is always harder to kill than motility, even where we know for a certainty that the lesion affects tracts that are both sensory and motor. Persons whose hand is paralyzed in its movements from compression of arm-nerves during sleep, still feel with their fingers; and they may still feel in their feet when their legs are paralyzed by bruising of the spinal cord. In a similar way, the motor cortex might be sensitive as well as motor, and yet by this greater subtlety (or whatever the peculiarity may be) in the sensory currents, the sensibility might survive an amount of injury there by which the motility was destroyed. Nothnagel considers that there are grounds for supposing the muscular sense to be exclusively connected with the parietal lobe and not with the motor zone. "Disease of this lobe gives pure ataxy without palsy, and of the motor zone pure palsy without loss of muscular sense.[52]" He fails, however, to convince more competent critics than the present writer,[53] so I conclude with them that as yet we have no decisive grounds for locating muscular and cutaneous feeling apart. Much still remains to be learned about the relations between musculo-cutaneous sensibility and the cortex, but one thing is certain: that neither the occipital, the forward frontal, nor the temporal lobes seem to have anything essential to do with it in man. It is knit up with the performances of the motor zone and of the convolutions backwards and midwards of them. The reader must remember this conclusion when we come to the chapter on the Will.

I must add a word about the connection of aphasia with the tactile sense. On p.40 I spoke of those cases in which the patient can write but not read his own writing. He cannot read by his eyes ; but he can read by the feeling in his fingers, if he retrace the letters in the air. It is convenient for such a patient to have a pen in hand whilst reading in this way, in order to make the usual feeling of writing more complete.[54] In such a case we must suppose that the path between the optical and the graphic centres remains open, whilst that between the optical and the auditory and articulatory centres is closed. Only thus can we understand how the look of the writing should fail to suggest the sound of the words to the patient's mind, whilst it still suggests the proper movements of graphic imitation. These movements in their turn must of course be felt, and the feeling of them must be associated with the centres for hearing and pronouncing the words. The injury in cases like this where very special combinations fail, whilst others go on as usual, must always be supposed to be of the nature of increased resistance to the passage of certain currents of association. If any of the elements of mental function were destroyed the incapacity would necessarily be much more formidable. A patient who can both read and write with his fingers most likely uses an identical 'graphic' centre, at once sensory and motor, for both operations.

I have now given, as far as the nature of this book will allow, a complete account of the present state of the localization-question. In its main outlines it stands firm, though much has still to be discovered. The anterior frontal lobes, for example, so far as is yet known, have no definite functions. Goltz finds that dogs bereft of them both are incessantly in motion, and excitable by every small stimulus. They are irascible and amative in an extraordinary degree, and their sides grow bare with perpetual reflex scratching; but they show no local troubles of either motion or sensibility. In monkeys not even this lack of inhibitory ability is shown, and neither stimulation nor excision of the prefrontal lobes produces any symptoms whatever. One monkey of Horsley and Schaefer's was as tame, and did certain tricks as well, after as before the operation.[55] It is probable that we have about reached the limits of what can be learned about brain-functions from vivisecting inferior animals, and that we must hereafter look more exclusively to human pathology for light. The existence of separate speech and writing centres in the left hemisphere in man; the fact that palsy from cortical injury is so much more complete and enduring in man and the monkey than in dogs; and the farther fact that it seems more difficult to get complete sensorial blindness from cortical ablations in the lower animals than in man, all show that functions get more specially localized as evolution goes on. In birds localization seems hardly to exist, and in rodents it is much less conspicuous than in carnivora. Even for man, however, Munk's way of mapping out the cortex into absolute areas within which only one movement or sensation is represented is surely false. The truth seems to be rather that, although there is a correspondence of certain regions of the brain to certain regions of the body, yet the several parts within each bodily region are represented throughout the whole of the corresponding brain-region like pepper and salt sprinkled from the same caster. This, however, does not prevent each 'part' from having its focus at one spot within the brain-region. The various brain-regions merge into each other in the same mixed way. As Mr.Horsley says: "There are border centres, and the area of representation of the face merges into that for the representation of the upper limb. If there was a focal lesion at that point, you would have the movements of these two parts starting together."[56] The accompanying figure from Paneth shows just how the matter stands in the dog.[57]

I am speaking now of localizations breadthwise over the brain-surface. It is conceivable that there might be also localizations depthwise through the cortex. The more superficial cells are smaller, the deepest layer of them is large; and it has been suggested that the superficial cells are sensorial, the deeper ones motor;[58] or that the superficial ones in the motor region are correlated with the extremities of the organs to be moved(fingers, etc.), the deeper ones with the more central segments (wrist, elbow, etc.).[59] It need hardly be said that all such theories are as yet but guesses.

We thus see that the postulate of Meynert and Jackson which we started with on p.30 is on the whole most satisfactorily corroborated by subsequent objective research. The highest centres do probably contain nothing but arrangements for representing impressions and movements, and other arrangements for coupling the activity of these arrangements together.[60] Currents pouring in from the sense-organs first excite some arrangements, which in turn excite others, until at last a motor discharge downwards of some sort occurs.

When this is once clearly grasped there remains little ground for keeping up that old controversy about the motor zone, as to whether it is in reality motor or sensitive. The whole cortex, inasmuch as currents run through it, is both. All the currents probably have feelings going with them, and sooner or later bring movements about. In one aspect, then, every centre is afferent, in another efferent, even the motor cells of the spinal cord having these two aspects inseparably conjoined. Marique,[61] and Exner and Paneth[62] have shown that by cutting round a 'motor' centre and so separating it from the influence of the rest of the cortex, the same disorders are produced as by cutting it out, so that really it is only the mouth of the funnel, as it were, through which the stream of innervation, starting from elsewhere, pours;[63] consciousness accompanying the stream, and being mainly of things seen if the stream is strongest occipitally, of things heard if it is strongest temporally, of things felt, etc., if the stream occupies most intensely the 'motor zone.' It seems to me that some broad and vague formulation like this is as much as we can safely venture on in the present state of science; and in subsequent chapters I expect to give confirmatory reasons for my view.

MAN'S CONSCIOUSNESS LIMITED TO THE HEMISPHERES

But is the consciousness which accompanies the activity of the cortex the only consciousness that man has? or are his lower centres conscious as well?

This is a difficult question to decide, how difficult one only learns when one discovers that the cortex-consciousness itself of certain objects can be seemingly annihilated in any good hypnotic subject by a bare wave of his opera- tor's hand, and yet be proved by circumstantial evidence to exist all the while in a split-off condition, quite as 'ejective'[64] to the rest of the subject's mind as that mind is to the mind of the bystanders.[65] The lower centres themselves may conceivably all the while have a split-off consciousness of their own, similarly ejective to the cortex-consciousness; but whether they have it or not can never be known from merely introspective evidence. Meanwhile the fact that occipital destruction in man may cause a blindness which is apparently absolute (no feeling remaining either of light or dark over one half of the field of view), would lead us to suppose that if our lower optical centres, the corpora quadrigemina, and thalami, do have any consciousness, it is at all events a consciousness which does not mix with that which accompanies the cortical activities, and which has nothing to do with our personal Self. In lower animals this may not be so much the case. The traces of sight found (supra, p. 46) in dogs and monkeys whose occipital lobes were entirely destroyed, may possibly have been due to the fact that the lower centres of these animals saw, and that what they saw was not ejective but objective to the remaining cortex, i.e. it formed part of one and the same inner world with the things which that cortex perceived. It may be, however, that the phenomena were due to the fact that in these animals the cortical 'centres' for vision reach outside of the occipital zone, and that destruction of the latter fails to remove them as completely as in man. This, as we know, is the opinion of the experimenters themselves. For practical purposes, nevertheless, and limiting the meaning of the word consciousness to the personal self of the individual, we can pretty confidently answer the question prefixed to this paragraph by saying that the cortex is the sole organ of consciousness in man.[66] If there be any consciousness pertaining to the lower centres, it is a consciousness of which the self knows nothing.

THE RESTITUTION OF FUNCTION.

Another problem, not so metaphysical, remains. The most general and striking fact connected with cortical injury is that of the restoration of function. Functions lost at first are after a few days or weeks restored. How are we to understand this restitution ?

Two theories are in the field:

1) Restitution is due to the vicarious action either of the rest of the cortex or of centres lower down, acquiring functions which until then they had not performed;

2) It is due to the remaining centres (whether cortical or 'lower') resuming functions which they had always had, but of which the wound had temporarily inhibited the exercise. This is the view of which Goltz and Brown-S�quard are the most distinguished defenders.

Inhibition is a vera causa, of that there can be no doubt. The pneumogastric nerve inhibits the heart, the splanchnic inhibits the intestinal movements, and the superior laryngeal those of inspiration. The nerve-irritations which may inhibit the contraction of arterioles are innumerable, and reflex actions are often repressed by the simultaneous excitement of other sensory nerves. For all such facts the reader must consult the treatises on physiology. What concerns us here is the inhibition exerted by different parts of the nerve-centres, when irritated, on the activity of distant parts. The flaccidity of a frog from 'shock,' for a minute or so after his medulla oblongata is cut, is an inhibition from the seat of injury which quickly passes away.

What is known as 'surgical shock' (unconsciousness, pallor, dilatation of splanchnic blood-vessels, and general syncope and collapse) in the human subject is an inhibition which lasts a longer time. Goltz, Freusberg, and others, cutting the spinal cord in dogs, proved that there were functions inhibited still longer by the wound, but which reestablished themselves ultimately if the animal was kept alive. The lumbar region of the cord was thus found to contain independent vaso-motor centres, centres for erec- tion, for control of the sphincters, etc., which could be excited to activity by tactile stimuli and as readily reinhibited by others simultaneously applied.[67] We may therefore plausibly suppose that the rapid reappearance of motility, vision, etc., after their first disappearance in consequence of a cortical mutilation, is due to the passing off of inhibitions exerted by the irritated surface of the wound. The only question is whether all restorations of function must be explained in this one simple way, or whether some part of them may not be owing to the formation of entirely new paths in the remaining centres, by which they become 'educated' to duties which they did not originally possess. In favor of an indefinite extension of the inhibition theory facts may be cited such as the following: In dogs whose disturbances due to cortical lesion have disappeared, they may in consequence of some inner or outer accident reappear in all their intensity for 24 hours or so and then disappear again.[68] In a dog made half blind by an operation, and then shut up in the dark, vision comes back just as quickly as in other similar dogs whose sight is exercised systematically every day.[69] A dog which has learned to beg before the operation recommences this practice quite spontaneously a week after a double-sided ablation of the motor zone.[70] Occasionally, in a pigeon (or even, it is said, in a dog) we see the disturbances less marked immediately after the operation than they are half an hour later.[71] This would be impossible were they due to the subtraction of the organs which normally carried them on. Moreover the entire drift of recent physiological and pathological speculation is towards enthroning inhibition as an ever-present and indispensable condition of orderly activity. We shall see how great is its importance, in the chapter on the Will. Mr. Charles Mercier considers that no muscular contraction, once begun, would ever stop without it, short of exhaustion of the system;[72] and Brown-S�quard has for years been accumulating examples to show how far its influence extends.[73] Under these circumstances it seems as if error might more probably lie in cutailing its sphere too much than in stretching it too far as an explanation of the phenomena following cortical lesion.[74]

On the other hand, if we admit no re-education of centres, we not only fly in the face of an a priori probability, but we find ourselves compelled by facts to suppose an almost incredible number of functions natively lodged in the centres below the thalami or even in those below the corpora quadrigemina. I will consider the a priori objection after first taking a look at the facts which I have in mind. They confront us the moment we ask ourselves just which are the parts which perform the functions abolished by an operation after sufficient time has elapsed for restoration to occur?.

The first observers thought that they must be the corresponding parts of the opposite or intact hemisphere. But as long ago as 1875 Carville and Duret tested this by cutting out the fore-leg-centre on one side, in a dog, and then, after waiting till restitution had occurred, cutting it out on the opposite side as well. Goltz and others have done the same thing.[75] If the opposite side were really the seat of the restored function, the original palsy should have appeared again and been permanent. But it did not appear at all; there appeared only a palsy of the hitherto unaffected side. The next supposition is that the parts surrounding the cut-out region learn vicariously to perform its duties. But here, again, experiment seems to upset the hypothesis, so far as the motor zone goes at least; for we may wait till motility has returned in the affected limb, and then both irritate the cortex surrounding the wound without exciting the limb to movement, and ablate it, without bringing back the vanished palsy.[76] It would accordingly seem that the cerebral centres below the cortex must be the seat of the regained activities. But Goltz destroyed a dog's entire left hemisphere, together with the corpus striatum and the thalamus on that side, and kept him alive until a surprisingly small amount of motor and tactile disturbance remained.[77] These centres cannot here have accounted for the restitution. He has even, as it would appear,[78] ablated both the hemispheres of a dog, and kept him alive 51 days, able to walk and stand. The corpora striata and thalami in this dog were also practically gone. In view of such results we seem driven, with M.Francois-Franck,[79] to fall back on the ganglia lower still, or even on the spinal cord as the 'vicarious' organ of which we are in quest. If the abeyance of function between the operation and the restoration was due exclusively to inhiibition, then we must suppose these lowest centres to be in reality extremely accomplished organs. They must always have done what we now find them doing after function is restored, even when the hemispheres were intact. Of course this is conceivably the case; yet it does not seem very plausible. And the a priori considerations which a moment since I said I should urge, make it less plausible still.

For, in the first place, the brain is essentially a place of currents, which run in organized paths. Loss of function can only mean one of two things, either that a current can no longer run in, or that if it runs in, it can no longer run out, by its old path. Either of these inabilities may come from a local ablation; and 'restitution' can then only mean that, in spite of a temporary block, an inrunning current has at last become enabled to flow out by its old path again-e.g., the sound of 'give your paw' discharges after some weeks into the same canine muscles into which it used to discharge before the operation. As far as the cortex itself goes, since one of the purposes for which it actually exists is the production of new paths,[80] the only question before us is: Is the formation of these particular 'vicarious' paths too much to expect of its plastic powers? It would certainly be too much to expect that a hemisphere should receive currents from optic fibres whose arriving-place within it is destroyed, or that it should discharge into fibres of the pyramidal strand if their place of exit is broken down. Such lesions as these must be irreparable within that hemisphere. Yet even then, through the other hemisphere, the corpus callosum, and the bilateral connections in the spinal cord, one can imagine some road by which the old muscles might eventually be innervated by the same incoming currents which innervated them before the block. And for all minor interruptions, not involving the arriving-place of the 'cortico-petal' or the place of exit of the 'cortico-fugal' fibres, roundabout paths of some sort through the affected hemisphere itself must exist, for every point of it is, remotely at least, in potential communication with every other point. The normal paths are only paths of least resistance. If they get blocked or cut, paths formerly more resistant become the least resistant paths under the changed conditions. It must never be forgotten that a current that runs in has got to run out somewhere; and if it only once succeeds by accident in striking into its old place of exit again, the thrill of satisfaction which the consciousness connected with the whole residual brain then receives will reinforce and fix the paths of that moment and make them more likely to be struck into again. The resultant feeling that the old habitual act is at last successfully back again, becomes itself a new stimulus which stamps all the existing currents in. It is matter of experience that such feelings of successful achievement do tend to fix in our memory whatever processes have led to them; and we shall have a good deal more to say upon the subject when we come to the Chapter on the Will.

My conclusion then is this: that some of the restitution of function (especially where the cortical lesion is not too great) is probably due to genuinely vicarious function on the part of the centres that remain; whilst some of it is due to the passing off of inhibitions. In other words, both the vicarious theory and the inhibition theory are true in their measure. But as for determining that measure, or saying which centres are vicarious, and to what extent they can learn new tricks, that is impossible at present.

FINAL CORRECTION OF THE MEYNERT SCHEME.

And now, after learning all these facts, what are we to think of the child and the candle-flame, and of that scheme which provisionally imposed itself on our acceptance after surveying the actions of the frog? (Cf. pp. 25-6, supra.) It will be remembered that we then considered the lower centres en masse as machines for responding to present sense-impressions exclusively, and the hemispheres as equally exclusive organs of action from inward considerations or ideas; and that, following Meynert, we supposed the hemispheres to have no native tendencies to determinate activity, but to be merely superadded organs for breaking up the various reflexes performed by the lower centres, and combining their motor and sensory elements in novel ways. It will also be remembered that I prophesied that we should be obliged to soften down the sharpness of this distinction after we had completed our survey of the farther facts. The time has now come for that correction to be made.

Wider and completer observations show us both that the lower centres are more spontaneous, and that the hemispheres are more automatic, than the Meynert scheme allows. Schrader's observations in Goltz's Laboratory on hemisphereless frogs[81] and pigeons[82] give an idea quite different from the picture of these creatures which is classically current. Steiner's[83] observations on frogs already went a good way in the same direction, showing, for example, that locomotion is a well-developed function of the medulla oblongata. But Schrader, by great care in the operation, and by keeping the frogs a long time alive, found that at least in some of them the spinal cord would produce movements of locomotion when the frog was smartly roused by a poke, and that swimming and croaking could sometimes be performed when nothing above the medulla oblongata remained.[84] Schrader's hemisphereless frogs moved spontaneously, ate flies, buried themselves in the ground, and in short did many things which before his observations were supposed to be impossible unless the hemispheres remained. Steinert[85] and Vulpian have remarked an even greater vivacity in fishes deprived of their hemispheres. Vulpian says of his brainless carps[86] that three days after the operation one of them darted at food and at a knot tied on the end of a string, holding the latter so tight between his jaws that his head was drawn out of water. Later, "they see morsels of white of egg; the moment these sink through the water in front of them, they follow and seize them, sometimes after they are on the bottom, sometimes before they have reached it. In capturing and swallowing this food they execute just the same movements as the intact carps which are in the same aquarium. The only difference is that they seem to see them at less distance, seek them with less impetuosity and less perseverance in all the points of the bottom of the aquarium, but they struggle (so to speak) sometimes with the sound carps to grasp the morsels. It is certain that they do not confound these bits of white of egg with other white bodies, small pebbles for example, which are at the bottom of the water. The same carp which, three days after operation, seized the knot on a piece of string, no longer snaps at it now, but if one brings it near her, she draws away from it by swimming backwards before it comes into contact with her mouth."[87] Already on pp.9-10,as the reader may remember, we instanced those adaptations of conduct to new conditions, on the part of the frog's spinal cord and thalami, which led Pf�ger and Lewes on the one hand and Goltz on the other to locate in these organs an intelligence akin to that of which the hemispheres are the seat.

When it comes to birds deprived of their hemispheres, the evidence that some of their acts have conscious purpose behind them is quite as persuasive. In pigeons Schrader found that the state of somnolence lasted only three or four days, after which time the birds began indefatigably to walk about the room. They climbed out of boxes in which they were put, jumped over or flew up upon obstacles, and their sight was so perfect that neither in walking nor flying did they ever strike any object in the room. They had also definite ends or purposes, flying straight for more convenient perching places when made uncomfortable by movements imparted to those on which they stood; and of several possible perches they always chose the most convenient. "If we give the dove the choice of a horizontal bar (Reck) or an equally distant table to fly to, she always gives decided preference to the table. Indeed she chooses the table even if it is several meters farther off than the bar or the chair." Placed on the back of a chair, she flies first to the seat and then to the floor, and in general ,"will forsake a high position, although it give her sufficiently firm support, and in order to reach the ground will make use of the environing objects as intermediate goals of flight, showing a perfectly correct judgment of their distance. Although able to fly directly to the ground, she prefers to make the journey in successive stages.... Once on the ground, she hardly ever rises spontaneously into the air."[88]

Young rabbits deprived of their hemispheres will stand, run, start at noises, avoid obstacles in their path, and give responsive cries of suffering when hurt. Rats will do the same, and throw themselves moreover into an attitude of defence. Dogs never survive such an operation if performed at once. But Goltz's latest dog, mentioned on p. 70, which is said to have been kept alive for fifty-one days after both hemispheres had been removed by a series of ablations and the corpora striata and thalami had softened away, shows how much the mid-brain centres and the cord can do even in the canine species. Taken together, the number of reactions shown to exist in the lower centres by these observations make out a pretty good case for the Meynert scheme, as applied to these lower animals. That scheme demands hemispheres which shall be mere supplements or organs of repetition, and in the light of these observations they obviously are so to a great extent. But the Meynert scheme also demands that the reactions of the lower centres shall all be native, and we are not absolutely sure that some of those which we have been considering may not have been acquired after the injury; and it furthermore demands that they should be machine-like, whereas the expression of some of them makes us doubt whether they may not be guided by an intelligence of low degree.

Even in the lower animals, then, there is reason to soften down that opposition between the hemispheres and the lower centres which the scheme demands. The hemispheres may, it is true, only supplement the lower centres, but the latter resemble the former in nature and have some small amount at least of 'spontaneity' and choice.

But when we come to monkeys and man the scheme well-nigh breaks down altogether; for we find that the hemispheres do not simply repeat voluntarily actions which the lower centres perform as machines. There are many functions which the lower centres cannot by themselves perform at all. When the motor cortex is injured in a man or a monkey genuine paralysis ensues, which in man is incurable, and almost or quite equally so in the ape. Dr. Seguin knew a man with hemi-blindness, from cortical injury, which had persisted unaltered for twenty-three years. 'Traumatic inhibition' cannot possibly account for this. The blindness must have been an 'Ausfallserscheinung,' due to the loss of vision's essential organ. It would seem, then, that in these higher creatures the lower centres must be less adequate than they are farther down in the zoological scale; and that even for certain elementary combinations of movement and impression the co-operation of the hemispheres is necessary from the start. Even in birds and dogs the power of eating properly is lost when the frontal lobes are cut off.[89]

The plain truth is that neither in man nor beast are the hemispheres the virgin organs which our scheme called them. So far from being unorganized at birth, they must have native tendencies to reaction of a determinate sort.[90] These are the tendencies which we know as emotions and instincts, and which we must study with some detail in later chapters of this book. Both instincts and emotions are reactions upon special sorts of objects of perception; they depend on the hemispheres; and they are in the first instance reflex, that is, they take place the first time the exciting object is met, are accompanied by no forethought or deliberation, and are irresistible. But they are modifiable to a certain extent by experience, and on later occasions of meeting the exciting object, the instincts expecially have less of the blind impulsive character which they had at first. All this will be explained at some length in Chapter XXIV. Meanwhile we can say that the multiplicity of emotional and instincitive reactions in man, together with his extensive associative power, permit of extensive recouplings of the original sensory and motor partners. The consequences of one instinctive reaction often prove to be the inciters of an opposite reaction, and being suggested on later occasions by the original object, may then suppress the first reaction altogether, just as in the case of the child and the flame. For this education the hemispheres do not need to be tabuloe rasoe at first, as the Meynert scheme would have them; and so far from their being educated by the lower centres exclusively, they educate themselves.[91]

We have already noticed the absence of reactions from fear and hunger in the ordinary brainless frog. Schrader gives a striking account of the instinctless condition of his brainless pigeons, active as they were in the way of locomotion and voice. "The hemisphereless animal moves in a world of bodies which... are all of equal value for him.... He is, to use Goltz's apt expression, impersonal.... Every object is for him only a space-occupying mass, he turns out of his path for an ordinary pigeon no otherwise than for a stone. He may try to climb over both. All authors agree that they never found any difference, whether it was an inanimate body, a cat, a dog, or a bird of prey which came in their pigeon's way. The creature knows neither friends nor enemies, in the thickest company it lives like a hermit. The languishing cooing of the male awakens no more impression than the rattling of the peas, or the call-whistle which in the days before the injury used to make the birds hasten to be fed. Quite as little as the earlier observers have I seen hemisphereless she-birds answer the courting of the male. A hemisphereless male will coo all day long and show distinct signs of sexual excitement, but his activity is without any object, it is entirely indifferent to him whether the she-bird be there or not. If one is placed near him, he leaves her unnoticed.... As the male pays no attention to the female, so she pays none to her young. The brood may follow the mother ceaselessly calling for food, but they might as well ask it from a stone.... The hemi sphereless pigeon is in the highest degree tame, and fears man as little as cat or bird of prey."[92]

Putting together now all the facts and reflections which we have been through, it seems to me that we can no longer hold strictly to the Meynert scheme. If anywhere, it will apply to the lowest animals; but in them especially the lower centres seem to have a degree of spontaneity and choice. On the whole, I think that we are driven to substitute for it some such general conception as the following, which allows for zoological differences as we know them, and is vague and elastic enough to receive any number of future discoveries of detail.

CONCLUSION.

All the centres, in all animals, whilst they are in one aspect mechanisms, probably are, or at least once were, organs of consciousness in another, although the consciousness is doubtless much more developed in the hemispheres than it is anywhere else. The consciousness must everywhere prefer some of the sensations which it gets to others; and if it can remember these in their absence, however dimly, they must be its ends of desire. If, moreover, it can identify in memory any motor discharges which may have led to such ends, and associate the latter with them, then these motor discharges themselves may in turn become desired as means. This is the development of will; and its realization must of course be proportional to the possible complication of the consciousness. Even the spinal cord may possibly have some little power of will in this sense, and of effort towards modified behavior in consequence of new experiences of sensibility.[93]

All nervous centres have then in the first instance one essential function, that of 'intelligent' action. They feel, prefer one thing to another, and have 'ends.' Like all other organs, however, they evolve from ancestor to descendant, and their evolution takes two directions the lower centres passing downwards into more unhesitating automatism, and the higher ones upwards into larger intellectuality.[94] Thus it may happen that those functions which can safely grow uniform and fatal become least accompanied by mind, and that their organ, the spinal cord, becomes a more and more soulless machine; whilst on the contrary those functions which it benefits the animal to have adapted to delicate environing variations pass more and more to the hemispheres, whose anatomical structure and attendant consciousness grow more and more elaborate as zoological evolution proceeds. In this way it might come about that in man and the monkeys the basal ganglia should do fewer things by themselves than they can do in dogs, fewer in dogs than in rabbits, fewer in rabbits than in hawks,[95] fewer in hawks than in pigeons, fewer in pigeons than in frogs, fewer in frogs than in fishes, and that the hemispheres should correspondingly do more. This passage of functions forward to the ever-enlarging hemispheres would be itself one of the evolutive changes, to be explained like the development of the hemispheres themselves, either by fortunate variation or by inherited effects of use. The reflexes, on this view, upon which the education of our human hemispheres depends, would not be due to the basal ganglia alone. They would be tendencies in the hemispheres themselves, modifiable by education, unlike the reflexes of the medulla oblongata, pons, optic lobes and spinal cord. Such cerebral reflexes, if they exist, form a basis quite as good as that which the Meynert scheme offers, for the acquisition of memories and associations which may later result in all sorts of 'changes of partners' in the psychic world. The diagram of the baby and the candle (see page 25) can be re-edited, if need be, as an entirely cortical transaction. The original tendency to touch will be a cortical instinct; the burn will leave an image in another part of the cortex, which, being recalled by association, will inhibit the touching tendency the next time the candle is perceived, and excite the tendency to withdraw-so that the retinal picture will, upon that next time, be coupled with the original motor partner of the pain. We thus get whatever psychological truth the Meynert scheme possesses without entangling ourselves on a dubious anatomy and physiology.

Some such shadowy view of the evolution of the centres, of the relation of consciousness to them, and of the hemispheres to the, other lobes, is, it seems to me, that in which it is safest to indulge. If it has no other advantage, it at any rate makes us realize how enormous are the gaps in our knowledge, the moment we try to cover the facts by any one formula of a general kind.

Footnotes [1] It should be said that this particular cut commonly proves fatal. The text refers to the rare cases which survive.

[2] I confine myself to the frog for simplicity's sake. In higher animals, especially the ape and man, it would seem as if not only determinate combinations of muscles, but limited groups or even single muscles could be innervated from the hemispheres.

[3] I hope that the reader will take no umbrage at my so mixing the physical and mental, and talking of reflex acts and hemispheres and reminiscences in the same breath, as if they were homogeneous quantities and factors of one causal chain. I have done so deliberately; for although I admit that from the radically physical point of view it is easy to conceive of the chain of events amongst the cells and fibres as complete in itself, and that whilst so conceiving it one need make no mention of ideas,' I yet suspect that point of view of being an unreal abstraction. Reflexes in centres may take place even where accompanying feelings or ideas guide them. In another chapter I shall try to show reasons for not abandoning this common-sense position; meanwhile language lends itself so much more easily to the mixed way of describing , that I will continue to employ the latter. The more radical-minded reader can alway read 'ideational process' for idea'.

[4] I shall call it hereafter for shortness 'the Meynert scheme;' for the child-and-flame example, as well as the whole general notion that the hemispheres are a supernumerary surface for the projection and association of sensations and movements natively coupled in the centres below, is due to Th. Meynert, the Austrian anatomist. For a popular account of his views, see his pamphlet 'Zur Mechanik des Gehirnbaues,' Vienna, 1874. His most recent development of them is embodied in his 'Psychiatry,' a clinical treatise on diseases of the forebrain, translated by B.Sachs, New York, 1885.

[5] Geschichte des Materialismus, 2d ed., II. p 345.

[6] West Riding Asylum Reports, 1876, p. 267.

[7] For a thorough discussion of the various objections, see Ferrier's 'Functions of the Brain,' 2d ed., pp. 227-234, and Franois-Franck's 'Leons sur les Fonctions Motrices du Cerveau'(1887), Leon 31. The most minutely accurate experiments on irritation of cortical points are those of Paneth, in Pfl�ger's Archiv, vol 37, p. 528.-Recently the skull has been fearlessly opened by surgeons, and operations upon the human brain performed, sometimes with the happiest results. In some of these operations the cortex has been electrically excited for the purpose of more exactly localizing the spot, and the movements first observed in dogs and monkeys have then been verified in men.

[8] J. Loeb: 'Beitr�ge zur Physiologie des Grosshirns;' Pfl�ger's Arciv, XXXIX. 293. I simplify the author's statement.

[9] Goltz: Pfl�ger's Archiv, XLII. 419.

[10] 'Hemiplegia' means one-sided palsy.

[11] Philosophical Transactions, vol. 179, pp. 6, 10(1888). In a later paper (ibid. p. 205) Messrs. Beevor and Horsley go into the localization still more minutely, showing spots from which single muscles or single digits can be made to contract.

[12] Nothnagel und Naunyn : Die Localization in den Gehirnkrankheiten (Wiesbaden, 1887), p.34

[13] An accessible account of the history of our knowledge of motor aphasia is in W.A. Hammond's 'Treatise on the Diseases of the Nervous System,' chapter VII.

[14] The history up to 1885 may be found in A.Christiani: Zur Physiologie des Gehirnes (Berlin, 1885)

[15] Pfl�ger's Archiv, vol.44, p.176. Munk (Berlin Academy Sitzsungsberichte, 1889, XXXI) returns to the charge, denying the extirpations of Schrader to be complete: "Microscopic portions of the Sehsph�re must remain."

[16] A.Christiani: Zur Physiol. D. Gehirnes (Berlin, 1885), chaps. II, III, IV. H. Munk: Berlin Akad. Stzgsb. 1884, XXIV.

[17] Luciani und Seppili: Die Functions-Localization auf der Grosshirnrinde (Deutsch von Fraenkel), Leipzig, 1886, Dogs M, N, and S. Goltz in Pfl�ger's Archiv, vol.34, pp. 490-6; vol. 42, p. 454. Cf. also Munk: Berlin Akad. Stzgsb. 1886, VII, VIII, pp. 113-121, and Loeb: Pfl�ger's Archiv, vol. 39, p. 337.

[18] Berlin Akad. Sitzungsberichte, 1886, VII, VIII, p. 124.

[19] H. Munk: Functionen der Grosshirnrinde (Berlin, 1881), pp. 36-40. Ferrier: Functions, etc., 2d ed., chap. IX, pt. I. Brown and Schaefer: Philos. Transactions, vol. 179, p. 321. Luciani u. Seppili, op. Cit. Pp. 131-138. Lannegrace found traces of sight with both occipital lobes destroyed, and in one monkey even when angular gyri and occipital lobes were destroyed altogether. His paper is in the Archives de M�decine Exp�rimentale for January and March, 1889. I only know it from the abstract in the Neurologisches Centralblatt, 1889, pp. 108-420. The reporter doubts the evidence of vision in the monkey. It appears to have consisted in avoiding obstacles and in emotional disturbance in the presence of men.

[20] Localization of Cerebral Disease (1878), pp. 117-8.

[21] For cases see Flechsig : Die Leitungsbahnen in Gehirn u. R�ckenmark (Leipzig, 1876), pp. 112, 272; Exner's Untersuchungen, etc., p. 83; Ferrier's Localization, etc., p. 11; Francois-Franck's Cerveau Moteur, p. 63, note.

[22] E. C. Seguin: Hemianopsia of Cerebral Origin, in Journal of Nervous and Mental Disease, vol. XIII. P. 30. Nothnagel und Naunyn: Ueber die Localization der Gehirnkrankheiten (Wiesbaden, 1887), p. 10.

[23] Die Seelenblindheit, etc., p. 51 ff. The mental blindness was in this woman's case moderate in degree.

[24] Archiv f. Psychiatrie, vol. 21, p. 222.

[25] Nothnagel (loc. cit. p.22) says: "Dies trifft aber nicht zu." He gives, however, no case in support of his opinion that double-sided cortical lesion may make one stone-blind and yet not destroy one's visual images; so that I do not know whether it is an observation of fact or an a priori assumption.

[26] In a case published by C.S. Freund: Archiv f. Psychiatrie, vol. XX, the occipital lobes were injured, but their cortex was not destroyed, on both sides. There was still vision. Cf. pp. 291-5.

[27] I say 'need,' for I do not of course deny the possible coexistence of the two symptoms. Many a brain-lesion might block optical associations and at the same time impair optical imagination, without entirely stopping vision. Such a case seems to have been the remarkable on from Charcot which I shall give rather fully in the chapter on Imagination.

[28] Freund (in the article cited above "Ueber optisched Aphasie und Seelenblindheit') and Bruns ('Ein Fall von Alexie,' etc., in the Neurologisches Centralblatt for 1888, pp. 581, 509) explain their cases by brokendown conduction. Wilbrand, whose painstaking monograph on mental blindness was referred to a moment ago, gives none but a priori reasons for his belief that the optical 'Erinnerungsfeld' must be locally distinct from the Wahrnehmungsfeld (cf. pp. 84, 93). The a priori reasons are really the other way. Mauthner ('Gehirn u. Auge' (1881), p. 487 ff.) tries to show that the 'mental blindness' of Munk's dogs and apes after occipital mutilation was not such, but real dimness of sight. The best case of mental blindness yet reported is that by Lissauer, as below. The reader will also do well to read Bernard: De 1 Aphasie(1881) chap. V; Ballet: Le Langage Int�rieur (1886), chap. VIII; and Jas. Ross's little book on Aphasia (1887), p. 74.

[29] For a case see Wernicke's Lehrb. D. Gehirnkrankheiten, vol. II. p. 554(1881).

[30] The latest account of them is the paper �ber die optischen Centren u. Bahnen' by von Monakow in the Archiv f�r Psychiatrie, vol. XX. p. 714.

[31] Die Functions-Localization, etc., Dog X; see also p. 161.

[32] Philos. Trans., vol. 179, p. 312.

[33] Brain, vol. XI. p. 10.

[34] Ibid. p. 147.

[35] Der aphasische Symptomencomplex (1874). See in Fig. 11 the convolution marked WERNICKE.

[36] 'The Pathology of Sensory Aphasia,' 'Brain,' July, 1889.

[37] Nothnagel und Naunyn: op. cit., plates.

[38] Ballet's and Bernard's works cited on p. 51 are the most accessible documents of Charcot's school. Bastian's book on the Brain as an Organ of Mind(last three chapters) is also good.

[39] For details, see Ferrier's 'Functions,' chap, IX. Pt. III, and Chas. K. Mills: Transactions of Congress of American Physicians and Surgeons, 1888, vol. I. p. 278.

[40] Functions of the Brain, chap. X. 14.

[41] Uber die Functionen d. Grosshirnrinde (1881), p. 50.

[42] Lezioni di Fisiologia sperimentale sul sistema nervoso encefalico (1873), p. 527 ff. Also 'Brain,' vol. IX. p. 298.

[43] Bechterew (Pfl�ger's Archiv., vol. 35, p. 137) found no anaesthesia in a cat with motor symptoms from ablation of sigmoid gyrus. Luciani got hyperaesthesia coexistent with cortical motor defect in a dog, by simultaneously hemisecting the spinal cord (Luciani u. Seppili, op. cit. p. 234). Goltz frequently found hyperaesthesia of the whole body to accompany motor defect after ablation of both frontal lobes, and he once found it after ablating the motor zone (Pfl�ger's Archiv, vol. 34, p. 471).

[44] Philos. Transactions, vol. 179, p. 20 ff.

[45] Functions, p. 375.

[46] Pp. 15-17.

[47] Luciani u. Sepplili, op. cit. pp. 275-288.

[48] Op. cit. p. 18.

[49] Trans. Of Congress, etc., p. 272.

[50] See Exner's Unters. �b. Localization, plate XXV.

[51] Cf. Ferrier's Functions, etc., chap. IV and chap. X, 6 to 9.

[52] Op. cit. p.17.

[53] E.g. Starr, loc. cit. p. 272; Leyden, Beitr�ge zur Lehre v. d. Localization im Gehirn(1888), p. 72.

[54] Bernard, op. cit. p. 84.

[55] Philos. Trans., vol. 179, p. 3.

[56] Trans. Of Congress of Am. Phys. And Surg. 1888, vol. I.p. 343. Beevor and Horsley's paper on electric stimulation of the monkey's brain is the most beautiful work yet done for precision. See Phil. Trans., vol. 179, p. 205, especially the plates.

[57] Pfl�ger's Archiv, vol. 37, p. 523 (1885).

[58] By Luys in his generally preposterous book 'The Brain'; also by Horsley.

[59] C. Mercier: The Nervous System and the Mind, p. 124.

[60] The frontal lobes as yet remain a puzzle. Wundt tries to explain them as an organ of 'apperception' (Grundz�ge d. Physiologischen Psychologie, 3d ed., vol. I. p. 233 ff.), but I confess myself unable to apprehend clearly the Wundtian philosophy so far as this word enters into it, so must be contented with this bare reference.- Until quite recently it was common to talk of an 'ideational centre' as of something distinct from the aggregate of other centres. Fortunately this custom is already on the wane.

[61] Rech.Exp. sur le Fonctionnement des Centres Psycho-moteurs(Burssels, 1885).

[62] Pfl�ger's Archiv, vol. 44, p. 544.

[63] I ought to add, however, that Franois-Franck(Fonctions Motrices, p. 370) got , in two dogs and a cat, a different result from this sort of 'circumvallation.'

[64] For this word, see T.K. Clifford's Lectures and Essays(1879), vol. II p. 72.

[65] See below, Chapter VIII.

[66] Cf. Ferrier's Functions, pp. 120, 147, 414. See also Vulpian: Leons sur la Physiol. Du Syst. Nerveux, p. 548; Luciani u. Seppili, op. cit. pp. 404-5; H. Maudsley: Physiology of Mind (1876), pp. 138 ff., 197 ff., and 241 ff. In G.H. Lewes's Physical Basis of Mind, Problem IV: 'The Reflex Theory,' a very full history of the question is given.

[67] Goltz: Pfl�ger's Archiv, vol. 8, p. 460; Freusberg: ibid. vol. 10, p. 174.

[68] Goltz: Verrichtungen des Grosshirns. p. 73.

[69] Loeb: Pfl�ger's Archiv, vol 39, p. 276.

[70] Ibid, p. 289.

[71] Schrader: ibid. vol. 44, p. 218.

[72] The Nervous System and the Mind (1888), chaps. III, VI; also in Brain, vol. XI. p. 361.

[73] Brown-S�quard has given a r�sum� of his opinions in the Archives de Physiologie for Oct. 1889, 5me, S�rie, vol. I. p 751.

[74] Goltz first applied the inhibition thoery to the brain in his 'Verrichtungen des Grosshirns,'p. 39 ff. On the general philosophy of Inhibition the reader may consult Brunton's ' Pharmakology and Therapeutics,' p. 154 ff., and also 'Nature,' vol. 27, p. 419 ff.

[75] E.g. Herzen, Herman u. Schwalbe's Jahres-bericht for 1886, Physiol. Abth. P. 38. (Experiments on new-born puppies.)

[76] Franois-Franck: op.cit. p. 382. Results are somewhat contradictory.

[77] Pfl�ger's Archiv, vol. 42, p. 419.

[78] Neurologisches Centralblatt, 1889, p. 372.

[79] Op. cit. p. 387. See pp. 378 to 388 for a discussion of the whole question. Compare also Wundt's Physiol. Psych., 3d ed., I. 225 ff., and Luciani u. Seppili, pp. 243, 293.

[80] The Chapters on Habit, Association, Memory, and Perception will change our present preliminary conjecture that that is one of its essential uses, into an unshakable conviction.

[81] Pfl�ger's Archiv, vol. 41, p. 75 (1887).

[82] Ibid., vol. 44, p. 175 (1889).

[83] Untersuchungen �ber die Physiologie des Froschirns, 1885.

[84] Loc. cit. pp. 80, 82-3. Schrader also found a biting-reflex developed when the medulla oblongata is cut through just behind the cerebellum.

[85] Berlin Akad. Sitzungsberichte for 1886.

[86] Comptes Rendus, vol. 102, p. 90.

[87] Comptes Rendus de l'Acad. D. Sciences, vol. 102, p. 1530

[88] Loc. cit. p. 216.

[89] Goltz: Pfl�ger's Archiv, vol. 42, p. 447; Schrader : ibid. vol. 44, p. 219 ff. It is possible that this symptom may be an effect of traumatic inhitition however.

[90] A few years ago one of the strongest arguements for the theory that the hemispheres are purely supernumerary was Soltmann's often-quoted observation that in new-born puppies the motor zone of the cortex is not excitable by electricity and only becomes so in the course of a fortnight, presumably after the experiences of the lower centres have educated it to motor duties. Paneth's later observations, however, seem to show that Soltmann may have been misled through overnarcotizing his victims (Pfl�ger's Archiv, vol. 37, p. 202). In the Neurologisches Centralblatt for 1889, p. 513, Bechterw returns to the subject on Soltmann's side without however, noticing Paneth's work.

[91] M�nsterberg (Die Willenshandlung, 1888, p. 134) challenges Meynert's scheme in toto, saying that whilst we have in our personal experience plenty of examples of acts which were at first voluntary becoming secondarily automatic and reflex, we have no conscious record of a single originally reflex act growing voluntary. -As far as conscious record is concerned, we could not possibly have it even if the Meynert scheme were wholly true, for the education of the hemispheres which that scheme postulates must in the nature of things antedate recollection. But it seems to me that M�nsterberg's rejection of the scheme may possibly be correct as regards reflexes from the lower centres. Everywhere in this department of psychogenesis we are made to feel how ignorant we really are.

[92] Pfl�ger's Archiv, vol. 44. p. 230-1.

[93] Naturally, as Schiff long ago pointed out (Lehrb. D. Muskel-u. Nervenphysiologie, 1859, p. 213 ff.), the 'R�ckenmarksseele,' if it now exist, can have no higher sense-consciousness, for its incoming currents are solely from the skin. But it may, in its dim way, both feel, prefer, and desire. See, for the view favorable to the text: B.H. Lewes, The Physiology of Common Life(1860), chap. IX. Goltz (Nervencentren des Frosches, 1869, pp. 102-130) thinks that the frog's cord has no adaptive power. This may be the case in such experiments as his, because the beheaded frog's short span of life does not give it time to learn the new tricks asked for. But Rosenthal (Biologisches Centralblatt, vol. IV. p. 247) and Mendelssohn (Berlin Akad. Sitzungsberichte, 1885, p. 107) in their investigations on the simple reflexes of the frog's cord, show that there is some adaptation to new conditions, inasmuch as when usual paths of conduction are interrupted by a cut, new paths are taken. According to Rosenthal, these grow more pervious (i.e. require a smaller stimulus) in proportion as they are more often traversed.

[94] Whether this evolution takes place through the inheritance of habits acquired, or through the preservation of lucky variations, is an alternative which we need not discuss here. We shall consider it in the last chapter in the book. For our present purpose the modus operandi of the evolution makes no difference, provided it be admitted to occur.

[95] See Schrader's Observations, loc. cit. Classics in the History of Psychology An internet resource developed by Christopher D. Green York University, Toronto, Ontario (Return to index)

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CHAPTER III. On Some General Conditions of Brain-Activity.

The elementary properties of nerve-tissue on which the brain-functions depend are far from being satisfactorily made out. The scheme that suggests itself in the first instance to the mind, because it is so obvious, is certainly false: I mean the notion that each cell stands for an idea or part of an idea, and that the ideas are associated or 'bound into bundles' (to use a phrase of Locke's) by the fibres. If we make a symbolic diagram on a blackboard, of the laws of association between ideas, we are inevitably led to draw circles, or closed figures of some kind, and to connect them by lines. When we hear that the nerve-centres contain cells which send off fibres, we say that Nature has realized our diagram for us, and that the mechanical substratum of thought is plain. In some way, it is true, our diagram must be realized in the brain; but surely in no such visible and palpable way as we at first suppose.[1] An enormous number of the cellular bodies in the hemispheres are fibreless. Where fibres are sent off they soon divide into untraceable ramifications; and nowwhere do we see a simple coarse anatomical connection, like a line on the blackboard, between two cells. Too much anatomy has been found to order for theoretic purposes, even by the anatomists; and the popular-science notions of cells and fibres are almost wholly wide of the truth. Let us therefore relegate the subject of the intimate workings of the brain to the physiology of the future, save in respect to a few points of which a word must now be said. And first of [sic]

THE SUMMATION OF STIMULI

[sic] in the same nerve-tract. This is a property extremely important for the understanding of a great many phenomena of the neural, and consequently of the mental, life; and it behooves us to gain a clear conception of what it means before we proceed any farther.

The law is this, that a stimulus which would be inadequate by itself to excite a nerve-centre to effective discharge may, by acting with one or more other stimuli (equally ineffectual by themselves alone) bring the discharge about. The natural way to consider this is as a summation of tensions which at last overcome a resistance. The first of them produce a 'latent excitement' or a 'heightened irritability'-the phrase is immaterial so far as practical consequences go; the last is the straw which breaks the camel's back. Where the neural process is one that has consciousness for its accompaniment, the final explosion would in all cases seem to involve a vivid state of feeling of a more or less substantive kind. But there is no ground for supposing that the tensions whilst yet submaximal or outwardly ineffective, may not also have a share in determining the total consciousness present in the individual at the time. In later chapters we shall see abundant reason to suppose that they do have such a share, and that without their contribution the fringe of relations which is at every moment a vital ingredient of the mind's object, would not come to consciousness at all.

The subject belongs too much to physiology for the evidence to be cited in detail in these pages. I will throw into a note a few references for such readers as may be interested in following it out,[2] and simply say that the direct electrical irritation of the cortical centres sufficiently proves the point. For it was found by the earliest experimenters here that whereas it takes an exceedingly strong current to produce any movement when a single induction-shock is used, a rapid succession of induction-shocks ('faradization') will produce movements when the current is comparatively weak. A single quotation from an excellent investigation will exhibit this law under further aspects:

"If we continue to stimulate the cortex at short intervals with the strength of current which produces the minimal muscular contraction [of the dog's digital extensor muscle], the amount of contraction gradually increases till it reaches the maximum. Each earlier stimulation leaves thus an effect behind it, which increases the efficacy of the following one. In this summation of the stimuli....the following points may be noted: 1) Single stimuli entirely inefficacious when alone may become efficacious by sufficiently rapid reiteration. If the current used is very much less than that which provokes the first beginning of contraction, a very large number of successive shocks may be needed before the movement appears-20, 50, once 106 shocks were needed. 2) The summation takes place easily in proportion to the shortness of the interval between the stimuli. A current too weak to give effective summation when its shocks are 3 seconds apart will be capable of so doing when the interval is shortened to 1 second. 3) Not only electrical irritation leaves a modification which goes to swell the following stimulus, but every sort of irritant which can produce a contraction does so. If in any way a reflex contraction of the muscle experimented on has been produced, or if it is contracted spontaneously by the animal (as not unfrequently happens 'by sympathy,' during a deep inspiration), it is found that an electrical stimulus, until then inoperative, operates energetically if immediately applied."[3]

Furthermore:

"In a certain stage of the morphia-narcosis an ineffectively weak shock will become powerfully effective, if, immediately before its appli- cation to the motor centre, the skin of certain parts of the body is exposed to gentle tactile stimulation....If, having ascertained the subminimal strength of current and convinced one's self repeatedly of its inefficacy, we draw our hand a single time lightly over the skin of the paw whose cortical centre is the object of stimulation, we find the current at once strongly effective. The increase of irritability lasts some seconds before it disappears. Sometimes the effect of a single light stroking of the paw is only sufficient to make the previously ineffectual current produce a very weak contraction. Repeating the tactile stimulation will then, as a rule, increase the contraction's extent."[4]

We constantly use the summation of stimuli in our practical appeals. If a car-horse balks, the final way of starting him is by applying a number of customary incitements at once. If the driver uses reins and voice, if one bystander pulls at his head, another lashes his hind quarters, and the conductor rings the bell, and the dismounted passengers shove the car, all at the same moment, his obstinacy generally yields, and he goes on his way rejoicing. If we are striving to remember a lost name or fact, we think of as many 'cues' as possible, so that by their joint action they may recall what no one of them can recall alone. The sight of a dead prey will often not stimulate a beast to pursuit, but if the sight of movement be added to that of form, pursuit occurs. "Br�cke noted that his brainless hen, which made no attempt to peck at the grain under her very eyes, began pecking if the grain were thrown on the ground with force, so as to produce a rattling sound." [5] "Dr. Allen Thomson hatched out some chickens on a carpet, where he kept them for several days. They showed no inclination to scrape,...but when Dr. Thomson sprinkled a little gravel on the carpet,...the chickens immediately began their scraping movements."[6] A strange person, and darkness, are both of them stimuli to fear and mistrust in dogs (and for the matter of that, in men). Neither circum- stance alone may awaken outward manifestations, but together, i.e. when the stange man is met in the dark, the dog will be excited to violent defiance.[7] Street-hawkers well know the efficacy of summation, for they arrange themselves in a line upon the sidewalk, and the passer often buys from the last one of them, through the effect of the reiterated solicitation, what he refused to buy from the first in the row. Aphasia shows many examples of summation. A patient who cannot name an object simply shown him, will name it if he touches as well as sees it, etc.

Instances of summation might be multiplied indefinetely, but it is hardly worth while to forestall subsequent chapters. Those on Instinct, the Stream of Thought, Attention, Discrimination, Association, Memory, Aesthetics, and Will, will contain numerous exemplifications of the reach of the principle in the purely psychological field.

REACTION-TIME.

One of the lines of experimental investigation most diligently followed of late years is that of the ascertainment of the time occupied by nervous events. Helmholtz led off by discovering the rapidity of the current in the sciatic nerve of the frog. But the methods he used were soon applied to the sensory nerves and the centres, and the results caused much popular scientific admiration when described as measurements of the 'velocity of thought.' The phrase 'quick as thought' had from time immemorial signified all that was wonderful and elusive of determination in the line of speed; and the way in which Science laid her doomful hand upon this mystery reminded people of the day when Franklin first 'eripuit coelo fulmen,' fore- shadowing the region of a newer and colder race of gods. We shall take up the various operations measured, each in the chapter to which it more naturally pertains. I may say, however, immediately, that the phrase 'velocity of thought' is misleading, for it is by no means clear in any of the cases what particular act of thought occurs during the time which is measured. 'Velocity of nerve-action' is liable to the same criticism, for in most cases we do not know what particular nerve-processes occur. What the times in question really represent is the total duration of certain reactions upon stimuli. Certain of the conditions of the reaction are prepared beforehand; they consist in the assumption of those motor and sensory tensions which we name the expectant state. Just what happens during the actual time occupied by the reaction (in other words, just what is added to the pre-existent tensions to produce the actual discharge) is not made out at present, either from the neural or from the mental point of view.

The method is essentially the same is all these investigations. A signal of some sort is communicated to the subject, and at the same instant records itself on a time-registering apparatus. The subject then makes a muscular movement of some sort, which is the 'reaction,' and which also records itself automatically. The time found to have elapsed between the two records is the total time of that observation. The time-registering instruments are of various types. One type is that of the revolving drum covered with smoked paper, on which one electric pen traces a line which the signal breaks and the 'reaction' draws again; whilst another electric pen (connected with a pendulum or a rod of metal vibrating at a known rate) traces alongside of the former line a 'time-line' of which each undulation or link stands for a certain fraction of a second, and against which the break in the reaction-line can be measured. Compare Fig.21, where the line is broken by the signal at the first arrow, and continued again by the reaction at the second. Ludwig's Kymograph, Marey's Chronograph are good examples of this type of instrument.

Another type of instrument is represented by the stopwatch, of which the most perfect from is Hipp's Chronoscope. The hand on the dial measures intervals as short as 1/1000 of a second. The signal (by an appropriate electric connection) starts it; the reaction stops it; and by reading off its initial and terminal positions we have immediately and with no farther trouble the time we seek. A still simpler instrument, though one not very satisfactory in its working, is the 'psychodometer' of Exner & Obersteiner, of which I picture a modification devised by my colleague Professor H.P. Bowditch, which works very well. The manner in which the signal and reaction are connected with the chronographic apparatus varies indefinitely in different experiments. Every new problem requires some new electric or mechanical disposition of apparatus. [8]

The least complicated time-measurement is that known as simple reaction-time, in which there is but one possible signal and one possible movement, and both are known in advance. The movement is generally the closing of an electric key with the hand. The foot, the jaw, the lips, even the eyelid, have been in turn made organs of reaction, and the apparatus has been modified accordingly.[9] The time usually elapsing between stimulus and movement lies between one and three tenths of a second, varying according to circumstances which will be mentioned anon.

The subject of experiment, whenever the reactions are short and regular, is in a state of extreme tension, and feels, when the signal comes, as if it started the reaction, by a sort of fatality, and as if no psychic process of perception or volition had a chance to intervene. The whole succession is so rapid that perception seems to be retrospective, and the time-order of events to be read off in memory rather than known at the moment. This at least is my own personal experience in the matter, and with it I find others to agree. The question is, What happens inside of us, either in brain or mind? and to answer that we must analyze just what processes the reaction involves. It is evident that some time is lost in each of the following stages:

1. The stimulus excites the peripheral sense-organ adequately for a current to pass into the sensory nerve; 2. The sensory nerve is traversed; 3. The transformation (or reflection) of the sensory into a motor current occurs in the centres; 4. The spinal cord and motor nerve are traversed; 5. The motor current excites the muscle to the contracting point.

Time is also lost, of course, outside the muscle, in the joints, skin, etc., and between the parts of the apparatus; and when the stimulus which serves as signal is applied to the skin of the trunk or limbs, time is lost in the sensorial conduction through the spinal cord.

The stage marked 3 is the only one that interests us here. The other stages answer to purely physiological processes, but stage 3 is psycho-physical; that is, it is a higher-central process, and has probably some sort of consciousness accompanying it. What sort?

Wundt has little difficulty in deciding that it is consciousness of a quite elaborate kind. He distinguishes between two stages in the conscious reception of an impression, calling one perception, and the other apperception, and likening the one to the mere entrance of an object into the periphery of the field of vision, and the other to its coming to occupy the focus or point of view. Inattentive awareness of an object, and attention to it, are, it seems to me, equivalents for perception and apperception, as Wundt uses the words. To these two forms of awareness of the impression Wundt adds the conscious volition to react, gives to the trio the name of 'psycho-physical' processes, and assumes that they actually follow upon each other in the succession in which they have been named.[10] So at least I understand him. The simplest way to determine the time taken up by this psycho-physical stage No. 3 would be to determine separately the duration of the several purely physical processes, 1, 2, 4, and 5, and to subtract them from the total reaction-time. Such attempts have been made.[11] But the data for calculation are too inaccurate for use, and, as Wundt himself admits,[12] the precise duration of stage 3 must at present be left enveloped with that of the other processes, in the total reaction-time.

My own belief is that no such succession of conscious feelings as Wundt describes takes place during stage 3. It is a process of central excitement and discharge, with which doubtless some feeling coexists, but what feeling we cannot tell, because it is so fugitive and so immediately eclipsed by the more substantive and enduring memory of the impression as it came in, and of the executed movement of response. Feeling of the impression, attention to it, thought of the reaction, volition to react, would, undoubtedly, all be links of the process under other conditions,[13] and would lead to the same reaction-after an indefinitely longer time. But these other conditions are not those of the experiments we are discussing; and it is mythological psychology (of which we shall see many later examples) to conclude that because two mental processes lead to the same result they must be similar in their inward subjective constitution. The feeling of stage 3 is certainly no articulate perception. It can be nothing but the mere sense of a reflex discharge. The reaction whose time is measured is, in short, a reflex action pure and simple, and not a psychic act. A foregoing psychic condition is, it is true, a prerequisite for this reflex action. The preparation of the attention and volition; the expectation of the signal and the readiness of the hand to move, the instant it shall come; the nervous tension in which the subject waits, are all conditions of the formation in him for the time being of a new path or arc of reflex discharge. The tract from the sense-organ which receives the stimulus, into the motor centre which discharges the reaction, is already tingling with premonitory innervation, is raised to such a pitch of heightened irritability by the expectant attention, that the signal is instantaneously sufficient to cause the overflow.[14] No other tract of the nervous system is, at the moment, in this hair-trigger condition. The consequences is that one sometimes responds to a wrong signal, especially if it be an impression of the same kind with the signal we expect.[15] But if by chance we are tired, or the signal is unexpectedly weak, and we do not react instantly, but only after an express perception that the signal has come, and an express volition, the time becomes quite disproportionately long (a second or more, according to Exner[16] ), and we feel that the process is in nature altogether different.

In fact, the reaction-time experiments are a case to which we can immediately apply what we have just learned about the summation of stimuli. 'Expectant attention' is but the subjective name for what objectively is a partial stimulation of a certain pathway, the pathway from the 'centre' for the signal to that for the discharge. In Chapter XI we shall see that all attention involves excitement from within of the tract concerned in feeling the objects to which attention is given. The tract here is the excito-motor arc about to be traversed. The signal is but the spark from without which touches off a train already laid. The performance, under these conditions, exactly resembles any reflex action. The only difference is that whilst, in the ordinarily so-called reflex acts, the reflex arc is a permanent result of organic growth, it is here a transient result of previous cerebral conditions.[17]

I am happy to say that since the preeceding paragraphs (and the notes thereto appertaining) were written, Wundt has himself become converted to the view which I defend. He now admits that in the shortest reactions "there is neither apperception nor will, but that they are merely brain-reflexes due to practice."[18] The means of his conversion are certain experiments performed in his laboratory by Herr L. Lange,[19] who was led to distinguish between two ways of setting the attention in reacting on a signal, and who found that they gave very different time-results. In the 'extreme sensorial' way, as Lange calls it, of reacting, one keeps one's mind as intent as possible upon the expected signal, and 'purposely avoids'[20] thinking of the movement to be executed; in the 'extreme muscular' way one 'does not think at all'[21] of the signal, but stands as ready as possible for the movement. The muscular reactions are much shorter than the sensorial ones, the average difference being in the neighborhood of a tenth of a second. Wundt accordingly calls them 'shortened reactions' and, with Lange, admits them to be mere reflexes; whilst the sensorial reactions he calls 'complete,' and holds to his original conception as far as they are concerned. The facts, however, do not seem to me to warrant even this amount of fidelity to the original Wundtian position. When we begin to react in the 'extreme sensorial' way, Lange says that we get times so very long that they must be rejected from the count as non-typical. "Only after the reacter has succeeded by repeated and conscientious practice in bringing about an extremely precise co-ordination of his voluntary impulse with his sense-impression do we get times which can be regarded as typical sensorial reaction-times."[22] Now it seems to me that these excessive and 'untypical' times are probably the real 'complete times,' the only ones in which distinct processes of actual perception and volition occur (see above, pp.88-9). The typical sensorial time which is attained by practice is probably another sort of reflex, less perfect than the reflexes prepared by straining one's attention towards the movement.[23] The times are much more variable in the sensorial way than in the muscular. The several muscular reactions differ little from each other. Only in them does the phenomenon occur of reacting on a false signal, or of reacting before the signal. Times intermediate between these two types occur according as the attention fails to turn itself exclusively to one of the extremes. It is obvious that Herr Lange's distinction between the two types of reaction is a highly important one, and that the 'extreme muscular method,' giving both the shortest times and the most constant ones, ought to be aimed at in all comparative investigations. Herr Lange's own muscular time averaged 0".123; his sensorial time, 0".230.

These reaction-time experiments are then in no sense measurements of the swiftness of thought. Only when we complicate them is there a chance for anything like an intellectual operation to occur. They may be complicated in various ways. The reaction may be withheld until the signal has consciously awakened a distinct idea (Wundt's discrimination-time, association-time) and then performed. Or there may be a variety of possible signals, each with a different reaction assigned to it, and the reacter may be uncertain which one he is about to receive. The reaction would then hardly seem to occur without a preliminary recognition and choice. We shall see, however, in the appropriate chapters, that the discrimination and choice involved in such a reaction are widely different from the intellectual operations of which we are ordinarily conscious under those names. Meanwhile the simple reaction-time remains as the starting point of all these superinduced complications. It is the fundamental physiological constant in all time-measurements. As such, its own variations have an interest, and must be briefly passed in review.[24]

The reaction-time varies with the individual and his age. An individual may have it particularly long in respect of signals of one sense (Buccola, p.147), but not of others. Old and uncultivated people have it long (nearly a second, in an old pauper observed by Exner, Pfl�ger's Archiv, VII. 612-4). Children have it long (half a second, Herzen in Buccola, p.152).

Practice shortens it to a quantity which is for each individual a minimum beyond which no farther reduction can be made. The aforesaid old pauper's time was, after much practice, reduced to 0.1866 sec. (loc. cit. p.626). Fatigue lengthens it. Concentration of attention shortens it. Details will be given in the chapter on Attention. The nature of the signal makes it vary.[25] Wundt writes: "I found that the reaction-time for impressions on the skin with electric stimulus is less than for true touch-sensations, as the following averages show:

Average Average Variation Sound 0.167 sec. 0.0221 sec. Light 0.222 sec. 0.0219 sec. Electric skin-sensation 0.201 sec. 0.0115 sec. Touch-sensation 0.213 sec. 0.0134 sec.

" I here bring together the averages which have been obtained by some other observers: Hirsch. Hankel. Exner. Sound 0.149 0.1505 0.1360 Light 0.200 0.2246 0.1506 Skin-sensation 0.182 0.1546 0.1337"[26]

Thermic reactions have been lately measured by A. Goldscheider and by Vintschgau (1887), who find them slower than reactions from touch. That from heat especially is very slow, more so than from cold, the differences (according to Goldscheider) depending on the nerve-terminations in the skin.

Gustatory reactions were measured by Vintschgau. They differed according to the substances used, running up to half a second as a maximum when identification took place. The mere perception of the presence of the substance on the tongue varied from 0".159 to 0".219 (Pfl�ger's Archiv, XIV.529).

Olfactory reactions have been studied by Vintschgau, Buccola, and Beaunis. They are slow, averaging about half a second (cf. Beaunis, Recherches exp. sur l'Activit� C�r�brale, 1884, p.49 ff.)

It will be observed that sound is more promptly reacted on than either sight or touch. Taste and smell are slower than either. One individual, who reacted to touch upon the tip of the tongue in 0".125, took 0".993 to react upon the taste of quinine applied to the same spot. In another, upon the base of the tongue, the reaction to touch being 0".141, that to sugar was 0".552 (Vintschgau, quoted by Buccola, p.103). Buccola found the reaction to odors to vary from 0".334 to 0".681, according to the perfume used and the individual.

The intensity of the signal makes a difference. The intenser the stimulus the shorter the time. Herzen (Grundlinien einer allgem. Psychophysiologie, p.101) compared the reaction from a corn on the toe with that from the skin of the hand of the same subject. The two places were stimulated simultaneously, and the subject tried to react simultaneously with both hand and foot, but the foot always went quickest. When the sound skin of the foot was touched instead of the corn, it was the hand which always reacted first. Wundt tries to show that when the signal is made barely perceptible, the time is probably the same in all the senses, namely about 0.332" (Physiol. Psych., 2d ed., II. 224).

Where the signal is of touch, the place to which it is applied makes a difference in the resultant reaction-time. G.S. Hall and V. Kries found (Archiv f. Anat. u. Physiol., 1879) that when the finger-tip was the place the reaction was shorter than when the middle of the upper arm was used, in spite of the greater length of nerve-trunk to be traversed in the latter case. This discovery invalidates the measurements of the rapidity of transmission of the current in human nerves, for they are all based on the method of comparing reaction-times from places near the root and near the extremity of a limb. The same observers found that signals seen by the periphery of the retina gave longer times than the same signals seen by direct vision.

The season makes a difference, the time being some hun- dredths of a second shorter on cold winter days (Vintschgau apud Exner, Hermann's Hdbh., p.270).

Intoxicants alter the time. Coffee and tea appear to shorten it. Small doses of wine and alcohol first shorten and then lengthen it; but the shortening stage tends to disappear if a large dose be given immediately. This, at least, is the report of two German observers. Dr. J. W. Warren, whose observations are more thorough than any previous ones, could find no very decided effects from ordinary doses (Journal of Physiology, VIII. 311). Morphia lengthens the time. Amyl-nitrite lengthens it, but after the inhalation it may fall to less than the normal. Ether and chloroform lengthen it (for authorities, etc., see Buccola, p.189).

Certain diseased states naturally lengthen the time.

The hypnotic trance has no constant effect, sometimes shortening and sometimes lengthening it (Hall, Mind, VIII. 170; James, Proc. Am. Soc. for Psych. Research, 246).

The time taken to inhibit a movement (e.g. to cease contraction of jaw-muscles) seems to be about the same as to produce one (Gad, Archiv f.(Anat.u.) Physiol., 1887, 468; Orchansky, ibid., 1889, 1885).

An immense amount of work has been done on reaction-time, of which I have cited but a small part. It is a sort of work which appeals particularly to patient and exact minds, and they have not failed to profit by the opportunity.

CEREBRAL BLOOD-SUPPLY.

The next point to occupy our attention is the changes of circulation which accompany cerebral activity.

All parts of the cortex, when electrically excited, produce alterations both of respiration and circulation. The blood-pressure rises, as a rule, all over the body, no matter where the cortical irritation is applied, though the motor zone is the most sensitive region for the purpose. Elsewhere the current must be strong enough for an epileptic attack to be produced.[27] Slowing and quickening of the heart are also observed, and are independent of the vaso-constrictive phenomenon. Mosso, using his ingenious 'plethysmo- graph' as an indicator, discovered that the blood-supply to the arms diminished during intellectual activity, and found furthermore that the arterial tension (as shown by the sphygmograph) was increased in these members (see Fig.23). So slight an emotion as that produced by the entrance of Professor Ludwig into the laboratory was instantly followed by a shrinkage of the arms.[28] The brain itself is an excessively vascular organ, a sponge full of blood, in fact; and another of Mosso's inventions showed that when less blood went to the arms, more went to the head. The subject to be observed lay on a delicately balanced table which could tip downward either at the head or at the foot if the weight of either end were increased. The moment emotional or intellectual activity began in the subject, down went the balance at the head-end, in consequence of the redistribution of blood in his system. But the best proof of the immediate afflux of blood to the brain during mental activity is due to Mosso's observations on three persons whose brain had been laid bare by lesion of the skull. By means of apparatus described in his book,[29] this physiologist was enabled to let the brain-pulse record itself directly by a tracing. The intra-cranial blood-pressure rose immediately whenever the subject was spoken to, or when he began to think actively, as in solving a problem in mental arithmetic. Mosso gives in his work a large number of reproductions of tracings which show the instantaneity of the change of blood-supply, whenever the mental activity was quickened by any cause whatever, intellectual or emotional. He relates of his female subject that one day whilst tracing her brain-pulse he observed a sudden rise with no apparent outer or inner cause. She however confessed to him afterwards that at that moment she had caught sight of a skull on top of a piece of furniture in the room, and that this had given her a slight emotion.

The fluctuations of the blood-supply to the brain were independent of respiratory changes,[30] and followed the quickening of mental activity almost immediately. We must suppose a very delicate adjustment whereby the circulation follows the needs of the cerebral activity. Blood very likely may rush to each region of the cortex according as it is most active, but of this we know nothing. I need hardly say that the activity of the nervous matter is the primary phenomenon, and the afflux of blood its secondary consequence. Many popular writers talk as if it were the other way about, and as if mental activity were due to the afflux of blood. But, as Professor H.N. Martin has well said, "that belief has no physiological foundation whatever; it is even directly opposed to all that we know of cell life."[31] A chronic pathological congestion may , it is true, have secondary consequences, but the primary congestions which we have been considering follow the activity of the brain-cells by an adaptive reflex vaso-motor mechanism doubtless as elaborate as that which harmonizes blood-supply with cell-action in any muscle or gland. Of the changes in the cerebral circulation during sleep, I will speak in the chapter which treats of that subject.

CEREBRAL THERMOMETRY.

Brain-activity seems accompanied by a local disengagement of heat. The earliest careful work in this direction was by Dr. J.S. Lombard in 1867. Dr. Lombard's latest results include the records of over 60,000 observations.[32] He noted the changes in delicate thermometers and electric piles placed against the scalp in human beings, and found that any intellectual effort, such as computing, composing, reciting poetry silently or aloud, and especially that emotional excitement such as an anger fit, caused a general rise of temperature, which rarely exceeded a degree Fahrenheit. The rise was in most cases more marked in the middle region of the head than elsewhere. Strange to say, it was greater in reciting poetry silently than in reciting it aloud. Dr. Lombard's explanation is that "in internal recitation an additional portion of energy, which in recitation aloud, was converted into nervous and muscular force, now appears as heat."[33] I should suggest rather, if we must have a theory, that the surplus of heat in recitation to one's self is due to inhibitory processes which are absent when we recite aloud. In the chapter on the Will we shall see that the simple central process is to speak when we think; to think silently involves a check in addition. In 1870 the indefatigable Schiff took up the subject, experimenting on live dogs and chickens, plunging thermo-electric needles into the substance of their brain, to eliminate possible errors from vascular changes in the skin when the thermometers were placed upon the scalp. After habituation was established, he tested the animals with various sensations, tactile, optic, olfactory, and auditory. He found very regularly an immediate deflection of the galvanometer, indicating an abrupt alteration of the intra-cerebral temperature. When, for instance, he presented an empty roll of paper to the nose of his dog as it lay motionless, there was a small deflection, but when a piece of meat was in the paper the deflection was much greater. Schiff concluded from these and other experiments that sensorial activity heats the brain-tissue, but he did not try to localize the increment of heat beyond finding that it was in both hemispheres, whatever might be the sensation applied.[34] Dr. R.W. Amidon in 1880 made a farther step forward, in localizing the heat produced by voluntary muscular contractions. Applying a number of delicate surface-thermometers simultaneously against the scalp, he found that when different muscles of the body were made to contract vigorously for ten minutes or more, different regions of the scalp rose in temperature, that the regions were well focalized, and that the rise of temperature was often considerably over a Fahrenheit degree. As a result of his investigations he gives a diagram in which numbered regions represent the centres of highest temperature for the various special movements which were investigated. To a large extent they correspond to the centres for the same movements assigned by Ferrier and others on other grounds; only they cover more of the skull.[35]

Phosphorus and Thought.

Chemical action must of course accompany brain-activity. But little definite is known of its exact nature. Cholesterin and creatin are both excrementitious products, and are both found in the brain. The subject belongs to chemistry rather than to psychology, and I only mention it here for the sake of saying a word about a wide-spread popular error about brain-activity and phosphorus. 'Ohme Phosphor, kein Gedanke,' was a noted war-cry of the 'materialists' during the excitement on that subject which filled Germany in the '60s. The brain, like every other organ of the body, contains phosphorus, and a score of other chemicals besides. Why the phosphorus should be picked out as its essence, no one knows. It would be equally true to say 'Ohne Wasser kein Gedanke,' or 'Ohne Kochsalz kein Gedanke'; for thought would stop as quickly if the brain should dry up or lose its NaCl as if it lost its phosphorus. In America the phosphorus-delusion has twined itself round a saying quoted (rightly or wrongly) from Professor L. Agassiz, to the effect that fishermen are more intelligent than farmers because they eat so much fish, which contains so much phosphorus. All the facts may be doubted.

The only straight way to ascertain the importance of phosphorus to thought would be to find whether more is excreted by the brain during mental activity than during rest. Unfortunately we cannot do this directly, but can only gauge the amount of PO5 in the urine, which represents other organs as well as the brain, and this procedure, as Dr. Edes says, is like measuring the rise of water at the mouth of the Mississippi to tell where there has been a thunder-storm in Minnesota.[36] It has been adopted, however, by a variety of observers, some of whom found the phosphates in the urine diminished, whilst others found them increased, by intellectual work. On the whole, it is impossible to trace any constant relation. In maniacal excitement less phosphorus than usual seems to be excreted. More is excreted during sleep. There are differences between the alkaline and earthy phosphates into which I will not enter, as my only aim is to show that the popular way of looking at the matter has no exact foundation.[37] The fact that phosphorous-preparations may do good in nervous exhaustion proves nothing as to the part played by phosphorus in mental activity. Like iron, arsenic, and other remedies it is a stimulant or tonic, of whose intimate workings in the system we know absolutely nothing, and which moreover does good in an extremely small number of the cases in which it is prescribed.

The phosphorous-philosophers have often compared thought to a secretion. "The brain secretes thought, as the kidneys secrete urine, or as the liver secretes bile," are phrases which one sometimes hears. The lame analogy need hardly be pointed out. The materials which the brain pours into the blood (cholesterin, creatin, xanthin, or whatever they may be) are the analogues of the urine and the bile, being in fact real material excreta. As far as these matters go, the brain is a ductless gland. But we know of nothing connected with liver-and kidney-activity which can be in the remotest degree compared with the stream of thought that accompanies the brain's material secretions.

There remains another feature of general brain-physiology, and indeed for psychological purposes the most important feature of all. I refer to the aptitude of the brain for acquiring habits. But I will treat of that in a chapter by itself.

Footnotes [1] I shall myself in later places indulge in much of this schematization. The reader will understand once for all that it is symbolic; and that the use of it is hardly more than to show what a deep congruity there is between mental processes and mechanical processes of some kind, not necessarily of the exact kind portrayed.

[2] Valentin: Archiv f. d. gesammt. Physiol., 1873, p.458. Stirling: Leipzig Acad. Berichte, 1875, p.372 (Journal of Physiol., 1875). J. Ward: Archiv f. (Anat. u.) Physiol., 1880, p.72. H. Sewall: Johns Hopkins Studies, 1880, p.30. Kronecker u. Nicolaides: Archiv f. (Anat.u.) Physiol., 1880, p.437. Exner: Archiv f. die ges. Physiol., Bd. 28, p.487 (1882). Eckhard: in Hermann's Hdbch. D. Physiol., Bd. I. Thl. II. p.31. Fran�ois-Franck: Le�ons sur les Fonctions motrices du Cerveau, p.51 ff., 339.-For the process of summation in nerves and muscles, cf. Hermann: ibid. Thl. I. p.109, and vol. I. p.40. Also Wundt: Physiol. Psych., I. 243 ff.; Richet: Travaux du Laboratoire de Marey, 1877, p.97; L'Homme et l'Intelligence, pp.24 ff., 468; Revue Philosophique, t.XXI. p. 564. Kronecker u. Hall: Archiv f. (Anat.u.) Physiol., 1879; Sch�nlein: ibid. 1882, p.357. Sertoli (Hofmann and Schwalbe's Jahresbericht, 1882. p.25. De Watteville: Neurologisches Centralblatt, 1883, No. 7. Gr�nhagen: Arch. f. d. ges. Physiol., Bd. 34, p.301(1884).

[3] Bubnoff und Heidenhain: Ueber Erregungs-und Hemmungsvorg�nge innerhalb der motorischen Hirncentren. Archiv f. d. ges. Physiol., Bd.26, p.156(1881).

[4] Archiv f. d. ges. Physiol., Bd.26, p.176(1881). Exner thinks (ibid. Bd.28, p.497(1882) that the summation here occurs in the spinal cord. It makes no difference where this particular summation occurs, so far as the general philosophy of summation goes.

[5] G.H. Lewes: Physical Basis of Mind, p.479, where many similar examples are given, 487-9.

[6] Romanes: Mental Evolution in Animals, p.163.

[7] See a similar instance in Mach: Beitr�ge zur Analyse der Empfindungen, p.36, a sparrow being the animal. My young children are afraid of their own pug-dog, if he enters their room after they are in bed and the lights are out. Compare this statement also: "The first question to a peasant seldom proves more than a flapper to rouse the torpid adjustments of his ears. The invariable answer of a Scottish peasant is, 'What's your wull?'-that of the English, a vacant stare. A second and even a third question may be required to elicit an answer." (R.Fowler: Some Observations on the Mental State of the Blind, and Deaf, and Dumb (Salisbury, 1843), p.14.)

[8] The reader will find a great deal about chronographic apparatus in J. Marey: La M�thode Graphique, pt. II. chap. II. One can make pretty fair measurements with no other instrument than a watch, by making a large number of reactions, each serving as a signal for the following one, and dividing the total time they take by their number. Dr. O. W. Holmes first suggested this method., which has been ingeniously elaborated and applied by Professor Jastrow. See Science' for September 10, 1886.

[9] See, for a few modifications, Cattell, Mind, XI. 220 ff.

[10] Physiol. Psych., II. 221-2. Cf. also the first edition, 728-9. I must confess to finding all Wundt's utterances about 'apperception' both vacillating and obscure. I see no use whatever for the word, as he employs it, in Psychology. Attention, perception, conception, volition, are its ample equivalents. Why we should need a single word to denote all these things by turns, Wundt fails to make clear. Consult, however, his pupil Staude's article, 'Uber den Begriff der Apperception,' etc., in Wundt's periodical Psychologische Studien, I. 149, which may be supposed official. For minute criticism of Wundt's 'apperception,' see Marty: Vierteljahrschrift f. wiss. Philos., X. 346.

[11] By Exner, for example, Pfl�ger's Archiv, VII. 628 ff.

[12] P.222. Cf. also Richet, Rev. Philos., VI. 395-6.

[13] For instance, if, on the previous day, one had resolved to act on a signal when it should come, and it now came whilst we were engaged in other things, and reminded us of the resolve.

[14] "I need hardly mention that success in these experiments depends in a high degree on our concentration of attention. If inattentive, one gets very discrepant figures...This concentration of the attention is in the highest degree exhausting. After some experiments in which I was concerned to get results as uniform as possible, I was covered with perspiration and excessively fatigued although I had as quietly in my chair all the while." (Exner, loc. cit. VII. 618.)

[15] Wundt, Physiol. Psych., II.226.

[16] Pfl�ger's Archiv, VII.616.

[17] In short, what M. Delboeuf calls an 'organe adventice.' The reaction-time, moreover, is quite compatible with the reaction itself being of a reflex order. Some reflexes (sneezing, e.g.) are very slow. The only time-measurement of a reflex act in the human subject with which I am acquainted is Exner's measurement of winking (in Pfl�ger's Archiv f. d. gesammt. Physiol., Bd. VIII. P.526, 1874). He found that when the stimulus was a flash of light it took the wink 0.2168 sec. to occur. A strong electric shock to the cornea shortened the time ot 0.0578 sec. The ordinary 'reaction-time' is midway between these values. Exner 'reduces' his times by eliminating the physiological process of conduction. His 'reduced winking-time' is then 0.471 as a minimum (ibid. 531), whilst his reduced reaction-time is 0.0828 (ibid. VII. 637). These figures have really no scientific value beyond that of showing, according to Exner's own belief (VII. 531) that reaction-time and reflex-time measure processes of essentially the same order. His description, moreover, of the process is an excellent description of a reflex act. "Every one," says he, "who makes reaction-time experiments for the first time is surprised to dind how little he is master of his own movements, so soon as it becomes a question of executing them with a maximum of speed. Not only does their energy lie, as it were, outside the field of choice, but even the time in which the movement occurs depends only partly upon ourselves. We jerk our arm, and we can afterwards tell with astonishing precision whether we have jerked it quicker or slower than another time, although we have no power to jerk it exactly at the wished-for moment."-Wundt himself admits that when we await a strong signal with tense preparation there is no consciousness of any duality of 'apperception' and motor response; the two are continuous (Physiol. Psych., II. 226).-Mr. Cattell's view is identical with the one I defend. "I think," he says, "that if the processes of perception and willing are present at all they are very rudimentary....The subject, by a voluntary effort[before the signal comes], puts the lines of communication between the centre for "the stimulus " and the centre for the co-ordination of motions...in a state of unstable equilibrium. When, therefore, a nervous impulse reaches the "former centre," it causes brain-changes in two directions; an impulse moves along to the cortex and calls forth there a perception corresponding to the stimulus, while at the same time an impulse follows a line of small resistance to the centre for the co-ordination of motions, and the proper nervous impulse, already prepared and waiting for the signal, is sent from the centre to the muscle of the hand. When the reaction has often been made the entire cerebral process becomes automatic, the impulse of itself takes the well-travelled way to the motor centre and releases the motor impulse." (Mind, XI. 232-3.) - Finally, Prof. Lipps has, in his elaborate way (Grundtatsachen, 179-188), made mince-meat of the view that stage 3 involves either conscious perception or conscious will.

[18] Physiol. Psych. 3d. edition (1887), vol. II p.266.

[19] Philosophische Studien, vol. IV. p.479 (1888).

[20] Loc. cit. p.488.

[21] Loc. cit. p.487.

[22] Loc. cit. p.489.

[23] Lange has an interesting hypothesis as to the brain-process concerned in the latter, for which I can only refer to his essay.

[24] The reader who wishes to know more about the matter will find a most faithful compilation of all that has been done, together with much original matter, in G. Buccola's 'Legge del Tempo.' etc. See also chapter XVI of Wundt's Physiol. Psychology; Exner in Hermann's Hdbch., Bd. 2, Thl. II. pp.252-280; also Ribot's Contemp. Germ. Psych., chap. VIII.

[25] The nature of the movement also seems to make it vary. Mr. B. I. Gilman and I reacted to the same signal by simply raising our hand, and again by carrying our hand towards our back. The moment registered was always that at which the hand broke and electric contact in starting to move. But it started one or two hundredths of a second later when the more extensive movement was the one to be made. Orchansky, on the other hand, experimenting on contractions of the masseter muscle, found (Archiv f. (Anat.u. ) Physiol., 1889, p.187) that the greater the amplitude of contraction intended, the shorter grew the time of reaction. He explains this by the fact that a more ample contraction makes a greater appeal to the attention, and this shortens the times.

[26] Physiol. Psych., II. 223.

[27] Fran�ois-Franck, Fonctions Motrices, Le�on XXII.

[28] La Paura (1884), p.117.

[29] Ueber den Kreislauf des Blutes im menschlichen Gehirn (1881), chap. II. The Introduction gives the history of our previous knowledge of the subject.

[30] In this conclusion M. Gley (Archives de Physiologie, 1881, p.742) agrees with Professor Mosso. Gley found his pulse rise 1-3 beats, his carotid dilate, and his radial artery contract during hard mental work.

[31] Address before Med. and Chirurg. Society of Maryland, 1879.

[32] See his book. "Experimental Researches on the Regional Temperature of the Head" (London, 1879).

[33] Loc. cit. p.195.

[34] The most convenient account of Schiff's experiments is by Prof. Herzen, in the Revue Philosophique, vol. III. p.36.

[35] A New Study of Cerebral Cortical Localization (N.Y., Putnam, 1880), pp.48-53.

[36] Archives of Medicine, vol. X, No. 1 (1883)

[37] Without multiplying references, I will simply cite Mendel (Archiv f. Psychiatrie, vol, III, 1871), Mairet (Archives de Neurologie, vol. IX, 1885), and Beaunis (Rech. Exp�rimentales sur l'Activit� C�r�brale, 1887). Richet gives a partial bibliography in the Revue Scientifique, vol. 38, p.788 (1886). Classics in the History of Psychology An internet resource developed by Christopher D. Green York University, Toronto, Ontario (Return to index)

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CHAPTER IV [1]. Habit

When we look at living creatures from an outward point of view, one of the first things that strike us is that they are bundles of habits. In wild animals, the usual round of daily behavior seems a necessity implanted at birth; in animals domesticated, and especially in man, it seems, to a great extent, to be the result of education. The habits to which there is an innate tendency are called instincts; some of those due to education would by most persons be called acts of reason. It thus appears that habit covers a very large part of life, and that one engaged in studying the objective manifestations of mind is bound at the very outset to define clearly just what its limits are.

The moment one tries to define what habit is, one is led to the fundamental properties of matter. The laws of Nature are nothing but the immutable habits which the different elementary sorts of matter follow in their actions and reactions upon each other. In the organic world, however, the habits are more variable than this. Even instincts vary from one individual to another of a kind; and are modified in the same individual, as we shall later see, to suit the exigencies of the case. The habits of an elementary particle of matter cannot change (on the principles of the atomistic philosophy), because the particle is itself an unchangeable thing; but those of a compound mass of matter can change, because they are in the last instance due to the structure of the compound, and either outward forces or inward tensions can, from one hour to another, turn that structure into something different from what it was. That is, they can do so if the body be plastic enough to maintain its integrity, and be not disrupted when its structure yields. The change of structure here spoken of need not involve the outward shape; it may be invisible and molecular, as when a bar of iron becomes magnetic or crystalline through the action of certain outward causes, or India-rubber becomes friable, or plaster 'sets.' All these changes are rather slow; the material in question opposes a certain resistance to the modifying cause, which it takes time to overcome, but the gradual yielding whereof often saves the material from being disintegrated altogether. When the structure has yielded, the same inertia becomes a condition of its comparative permanence in the new form, and of the new habits the body then manifests. Plasticity, then, in the wide sense of the word, means the possession of a structure weak enough to yield to an influence, but strong enough not to yield all at once. Each relatively stable phase of equilibrium in such a structure is marked by what we may call a new set of habits. Organic matter, especially nervous tissue, seems endowed with a very extraordinary degree of plasticity of this sort; so that we may without hesitation lay down as our first proposition the following, that the phenomena of habit in living beings are due to the plasticity [2] of the organic materials of which their bodies are composed.

But the philosophy of habit is thus, in the first instance, a chapter in physics rather than in physiology or psychology. That it is at bottom a physical principle is admitted by all good recent writers on the subject. They call attention to analogues of acquired habits exhibited by dead matter. Thus, M. L�on Dumont, whose essay on habit is perhaps the most philosophical account yet published, writes:

"Every one knows how a garment, after having been worn a certain time, clings to the shape of the body better than when it was new; there has been a change in the tissue, and this change is a new habit of cohesion. A lock works better after being used some time; at the outset more force was required to overcome certain roughnesses in the mechanism. The overcoming of their resistance is a phenomenon of habituation. It costs less trouble to fold a paper when it has been folded already. This saving of trouble is due to the essential nature of habit, which brings it about that, to reproduce the effect, a less amount of the outward cause is required. The sounds of a violin improve by use in the hands of an able artist, because the fibres of the wood at last contract habits of vibration conformed to harmonic relations. This is what gives such inestimable value to instruments that have belonged to great masters. Water, in flowing, hollows out for itself a channel, which grows broader and deeper; and, after having ceased to flow, it resumes, when it flows again, the path traced by itself before. Just so, the impressions of outer objects fashion for themselves in the nervous system more and more appropriate paths, and these vital phenomena recur under similar excitements from without, when they have been interrupted a certain time."[3]

Not in the nervous system alone. A scar anywhere is a locus minoris resistentioe, more liable to be abraded, inflamed, to suffer pain and cold, than are the neighboring parts. A sprained ankle, a dislocated arm, are in danger of being sprained or dislocated again; joints that have once been attacked by rheumatism or gout, mucous membranes that have been the seat of catarrh, are with each fresh recurrence more prone to a relapse, until often the morbid state chronically substitutes itself for the sound one. And if we ascend to the nervous system, we find how many so-called functional diseases seem to keep themselves going simply because they happen to have once begun; and how the forcible cutting short by medicine of a few attacks is often sufficient to enable the physiological forces to get possession of the field again, and to bring the organs back to functions of health. Epilepsies, neuralgias, convulsive affections of various sorts, insomnias, are so many cases in point. And, to take what are more obviously habits, the success with which a 'weaning' treatment can often be applied to the victims of unhealthy indulgence of passion, or of mere complaining or irascible disposition, shows us how much the morbid manifestations themselves were due to the mere inertia of the nervous organs, when once launched on a false career.

Can we now form a notion of what the inward physical changes may be like, in organs whose habits have thus struck into new paths? In other words, can we say just what mechanical facts the expression 'change of habit' covers when it is applied to a nervous system? Certainly we cannot in anything like a minute or definite way. But our usual scientific custom of interpreting hidden molecular events after the analogy of visible massive ones enables us to frame easily an abstract and general scheme of processes which the physical changes in question may be like. And when once the possibility of some kind of mechanical interpretation is established, Mechanical Science, in her present mood, will not hesitate to set her brand of ownership upon the matter, feeling sure that it is only a question of time when the exact mechanical explanation of the case shall be found out.

If habits are due to the plasticity of materials to outward agents, we can immediately see to what outward influences, if to any, the brain-matter is plastic. Not to mechanical pressures, not to thermal changes, not to any of the forces to which all the other organs of our body are exposed; for nature has carefully shut up our brain and spinal cord in bony boxes where no influences of this sort can get at them. She has floated them in fluid so that only the severest shocks can give them a concussion, and blanketed and wrapped them about in an altogether exceptional way. The only impressions that can be made upon them are through the blood, on the one hand, and through the sensory nerve-roots, on the other; and it is to the infinitely attenuated currents that pour in through these latter channels that the hemispherical cortex shows itself to be so peculiarly susceptible. The currents, once in, must find a way out. In getting out they leave their traces in the paths which they take. The only thing they can do, in short, is to deepen old paths or to make new ones; and the whole plasticity of the brain sums itself up in two words when we call it an organ in which currents pouring in from the sense-organs make with extreme facility paths which do not easily disappear. For, of course, a simple habit, like every other nervous event - the habit of snuffling, for example, or of putting one's hands into one's pockets, or of biting one's nails - is, mechanically, nothing but a reflex discharge; and its anatomical substratum must be a path in the system. The most complex habits, as we shall presently see more fully, are, from the same point of view, nothing but concatenated discharges in the nerve-centres, due to the presence there of systems of reflex paths, so organized as to wake each other up successively - the impression produced by one muscular contraction serving as a stimulus to provoke the next, until a final impression inhibits the process and closes the chain. The only difficult mechanical problem is to explain the formulation de novo of a simple reflex or path in a pre-existing nervous system. Here, as in so many other cases, it is only the premier pas qui co�te. For the entire nervous system is nothing but a system of paths between a sensory terminus a quo and a muscular, glandular, or other terminus ad quem. A path once traversed by a nerve-current might be expected to follow the law of most of the paths we know, and to be scooped out and made more permeable than before;[4] and this ought to be repeated with each new passage of the current. Whatever obstructions may have kept it at first from being a path should then, little by little, and more and more, be swept out of the way, until at last it might become a natural drainage-channel. This is what happens where either solids or liquids pass over a path; there seems no reason why is should not happen where the thing that passes is a mere wave of rearrangement in matter that does not displace itself, but merely changes chemically or turns itself round in place, or vibrates across the line. The most plausible views of the nerve-current make it out to be the passage of some such wave of rearrangement as this. If only a part of the matter of the path were to 'rearrange' itself, the neighboring parts remaining inert, it is easy to see how their inertness might oppose a friction which it would take many waves of rearrangement to break down and overcome. If we call the path itself the 'organ,' and the wave of rearrangement the 'function,' then it is obvi- ously a case for repeating the celebrated French formula of 'La fonction fait l'organe.'

So nothing is easier than to imagine how, when a current once has traversed a path, it should traverse it more readily still a second time. But what made it ever traverse it the first time?[5] In answering this question we can only fall back on our general conception of a nervous system as a mass of matter whose parts, constantly kept in states of different tension, are as constantly tending to equalize their states. The equalization between any two points occurs through whatever path may at the moment be most pervious. But, as a given point of the system may belong, actually or potentially, to many different paths, and, as the play of nutrition is subject to accidental changes, blocks may from time to time occur, and make currents shoot through unwonted lines. Such an unwonted line would be a new-created path, which if traversed repeatedly, would become the beginning of a new reflex arc. All this is vague to the last degree, and amounts to little more than saying that a new path may be formed by the sort of chances that in nervous material are likely to occur. But, vague as it is, it is really the last word of our wisdom in the matter.[6]

It must be noticed that the growth of structural modification in living matter may be more rapid than in any lifeless mass, because the incessant nutritive renovation of which the living matter is the seat tends often to corroborate and fix the impressed modification, rather than to counteract it by renewing the original constitution of the tissue that has been impressed. Thus,we notice after exercising our muscles or our brain in a new way, that we can do so no longer at that time; but after a day or two of rest, when we resume the discipline, our increase in skill not seldom surprises us. I have often noticed this in learning a tune; and it has led a German author to say that we learn to swim during the winter and to skate during the summer.

Dr. Carpenter writes:[7]

"It is a matter of universal experience that every kind of training for special aptitudes is both far more effective, and leaves a more permanent impress, when exerted on the growing organism than when brought to bear on the adult. The effect of such training is shown in the tendency of the organ to 'grow to' the mode in which it is habitually exercised; as is evidenced by the increased size and power of particular sets of muscles, and the extraordinary flexibility of joints, which are acquired by such as have been early exercised in gymnastic performances...There is no part of the organism of man in which the reconstructive activity is so great, during the whole period of life, as it is in the ganglionic substance of the brain. This is indicated by the enormous supply of blood which it receives....It is, moreover, a fact of great significance that the nerve-substance is specially distinguished by its reparative power. For while injuries of other tissues (such as the muscular) which are distinguished by the speciality of their structure and endowments, are repaired by substance of a lower or less specialized type, those of nerve-substance are repaired by a complete reproduction of the normal tissue; as is evidenced in the sensibility of the newly forming skin which is closing over an open wound, or in the recovery of the sensibility of a piece of 'transplanted' skin, which has for a time been rendered insensible by the complete interruption of the continuity of its nerves. The most remarkable example of this reproduction, however, is afforded by the results of M. Brown-S�quard's[8] experiments upon the gradual restoration of the functional activity of the spinal cord after its complete division; which takes place in way that indicates rather a reproduction of the whole, or the lower part of the cord and of the nerves proceeding from it, than a mere reunion of divided surfaces. This reproduction is but a special manifestation of the reconstructive change which is always taking place in the nervous system; it being not less obvious to the eye of reason that the 'waste' occasioned by its functional activity must be constantly repaired by the production of new tissue, than it is to the eye of sense that such reparation supplies an actual loss of substance by disease or injury.

"Now, in this constant and active reconstruction of the nervous system, we recognize a most marked conformity to the general plan manifested in the nutrition of the organism as a whole. For, in the first place, it is obvious that there is a tendency to the production of a determinate type of structure; which type is often not merely that of the species, but some special modification of it which characterized one or both of the progenitors. But this type is peculiarly liable to modification during the early period of life; in which the functional activity of the nervous system (and particularly of the brain) is extraordinarily great, and the reconstructive process proportionally active. And this modifiability expresses itself in the formation of the mechanism by which those secondarily automatic modes of movement come to be established, which, in man, take the place of those that are congenital in most of the animals beneath him; and those modes of sense-perception come to be acquired, which are elsewhere clearly instinctive. For there can be no reasonable doubt that, in both cases, a nervous mechanism is developed in the course of this self-education, corresponding with that which the lower animals inherit from their parents. The plan of that rebuilding process, which is necessary to maintain the integrity of the organism generally, and which goes on with peculiar activity in this portion of it, is thus being incessantly modified; and in this manner all that portion of it which ministers to the external life of sense and motion that is shared by man with the animal kingdom at large, becomes at adult age the expression of the habits which the individual has acquired during the period of growth and development. Of these habits, some are common to the race generally, while others are peculiar to the individual; those of the former kind (such as walking erect) being universally acquired, save where physical inability prevents; while for the latter a special training is needed, which is usually the more effective the earlier it is begun - as is remarkably seen in the case of such feats of dexterity as require a conjoint education of the perspective and of the motor powers. And when thus developed during the period of growth, so as to have become a part of the constitution of the adult, the acquired mechanism is thenceforth maintained in the ordinary course of the nutritive operations, so as to be ready for use when called upon, even after long inaction.

"What is so clearly true of the nervous apparatus of animal life can scarcely be otherwise than true of that which ministers to the automatic activity of the mind. For, as already shown, the study of psychology has evolved no more certain result than that there are uniformities of mental action which are so entirely conformable to those of bodily action as to indicate their intimate relation to a 'mechanism of thought and feeling,' acting under the like conditions with that of sense and motion. The psychical principles of association, indeed, and the physiological principles of nutrition, simply express - the former in terms of mind, the latter in terms of brain - the universally admitted fact that any sequence of mental action which has been frequently repeated tends to perpetuate itself; so that we find ourselves automatically prompted to think, feel, or do what we have been before accustomed to think, feel, or do, under like circumstances, without any consciously formed purpose, or anticipation of results. For there is no reason to regard the cerebrum as an exception to the general principle that, while each part of the organism tends to form itself in accordance with the mode in which it is habitually exercised, this tendency will be especially strong in the nervous apparatus, in virtue of that incessant regeneration which is the very condition of its functional activity. It scarcely, indeed, admits of doubt that every state of ideational consciousness which is either very strong or is habitually repeated leaves an organic impression on the cerebrum; in virtue of which that same state may be reproduced at any future time, in respondence to a suggestion fitted to excite it...... The 'strength of early association' is a fact so universally recognized that the expression of it has become proverbial; and this precisely accords with the physiological principle that, during the period of growth and development, the formative activity of the brain will be most amenable to directing influences. It is in this way that what is early 'learned by heart' becomes branded in (as it were) upon the cerebrum; so that its 'traces' are never lost, even though the conscious memory of it may have completely faded out. For, when the organic modification has been once fixed in the growing brain, it becomes a part of the normal fabric, and is regularly maintained by nutritive substitution; so that it may endure to the end of life, like the scar of a wound."

Dr. Carpenter's phrase that our nervous system grows to the modes in which it has been exercised expresses the philosophy of habit in a nutshell. We may now trace some of the practical applications of the principle to human life.

The first result of it is that habit simplifies the movements required to achieve a given result, makes them more accurate and diminishes fatigue.

"The beginner at the piano not only moves his finger up and down in order to depress the key, he moves the whole hand, the forearm and even the entire body, especially moving its least rigid part, the head, as if he would press down the key with that organ too. Often a contraction of the abdominal muscles occurs as well. Principally, however, the impulse is determined to the motion of the hand and of the single finger. This is, in the first place, because the movement of the finger is the movement thought of, and, in the second place, because its movement and that of the key are the movements we try to perceive, along with the results of the latter on the ear. The more often the process is repeated, the more easily the movement follows, on account of the increase in permeability of the nerves engaged.

"But the more easily the movement occurs, the slighter is the stimulus required to set it up; and the slighter the stimulus is, the more its effect is confined to the fingers alone.

"Thus, an impulse which originally spread its effects over the whole body, or at least over many of its movable parts, is gradually determined to a single definite organ, in which it effects the contraction of a few limited muscles. In this change the thoughts and perceptions which start the impulse acquire more and more intimate causal relations with a particular group of motor nerves.

"To recur to a simile, at least partially apt, imagine the nervous system to represent a drainage-system, inclining, on the whole, toward certain muscles, but with the escape thither somewhat clogged. Then streams of water will, on the whole, tend most to fill the drains that go towards these muscles and to wash out the escape. In case of a sudden 'flushing,' however, the whole system of channels will fill itself, and the water overflow everywhere before it escapes. But a moderate quantity of water invading the system will flow through the proper escape alone.

"Just so with the piano-player. As soon as his impulse, which has gradually learned to confine itself to single muscles, grows extreme, it overflows into larger muscular regions. He usually plays with his fingers, his body being at rest. But no sooner does he get excited than his whole body becomes 'animated,' and he moves his head and trunk, in particular, as if these also were organs with which he meant to belabor the keys."[9]

Man in born with a tendency to do more things than he has ready-made arrangements for in his nerve-centres. Most of the performances of other animals are automatic. But in him the number of them is so enormous, that most of them must be the fruit of painful study. If practice did not make perfect, nor habit economize the expense of nervous and muscular energy, he would therefore be in a sorry plight. As Dr. Maudsley says: [10]

:If an act became no easier after being done several times, if the careful direction of consciousness were necessary to its accomplishment on each occasion, it is evident that the whole activity of a lifetime might be confined to one or two deeds - that no progress could take place in development. A man might be occupied all day in dressing and un- dressing himself; the attitude of his body would absorb all his attention and energy; the washing of his hands or the fastening of a button would be as difficult to him on each occasion as to the child on its first trial; and he would, furthermore, be completely exhausted by his exertions. Think of the pains necessary to teach a child to stand, of the many efforts which it must make, and of the ease with which it at last stands, unconscious of any effort. For while secondarily automatic acts are accomplished with comparatively little weariness - in this regard approaching the organic movements, or the original reflex movements - the conscious effort of the will soon produces exhaustion. A spinal cord without... memory would simply be an idiotic spinal cord... It is impossible for an individual to realize how much he owes to its automatic agency until disease has impaired its functions."

The next result is that habit diminishes the conscious attention with which our acts are performed.

One may state this abstractly thus: If an act require for its execution a chain, A, B, C, D, E, F, G, etc., of successive nervous events, then in the first performances of the action the conscious will must choose each of these events from a number of wrong alternatives that tend to present themselves; but habit soon brings it about that each event calls up its own appropriate successor without any alternative offering itself, and without any reference to the conscious will, until at last the whole chain, A, B, C, D, E, F, G, rattles itself off as soon as A occurs, just as if A and the rest of the chain were fused into a continuous stream. When we are learning to walk, to ride, to swim, skate, fence, write, play, or sing, we interrupt ourselves at every step by unnecessary movements and false notes. When we are proficients, on the contrary, the results not only follow with the very minimum of muscular action requisite to bring them forth, they also follow from a single instantaneous 'cue.' The marksman sees the bird, and, before he knows it, he has aimed and shot. A gleam in his adversary's eye, a momentary pressure from his rapier, and the fencer finds that he has instantly made the right parry and return. A glance at the musical hieroglyphics, and the pianist's fingers have ripped through a cataract of notes. And not only is it the right thing at the right time that we thus involuntarily do, but the wrong thing also, if it be an habitual thing. Who is there that has never wound up his watch on taking off his waistcoat in the daytime, or taken his latchkey out on arriving at the door-step of a friend? Very absent-minded persons in going to their bedroom to dress for dinner have been known to take off one garment after another and finally to get into bed, merely because that was the habitual issue of the first few movements when performed at a later hour. The writer well remembers how, on revisiting Paris after ten years' absence, and, finding himself in the street in which for one winter he had attended school, he lost himself in a brown study, from which he was awakened by finding himself upon the stairs which led to the apartment in a house many streets away in which he had lived during that earlier time, and to which his steps from the school had then habitually led. We all of us have a definite routine manner of performing certain daily offices connected with the toilet, with the opening and shutting of familiar cupboards, and the like. Our lower centres know the order of these movements, and show their knowledge by their 'surprise' if the objects are altered so as to oblige the movement to be made in a different way. But our higher thought-centres know hardly anything about the matter. Few men can tell off-hand which sock, shoe, or trousers-leg they put on first. They must first mentally rehearse the act; and even that is often insufficient - the act must be performed. So of the questions, Which valve of my double door opens first? Which way does my door swing? etc. I cannot tell the answer; yet my hand never makes a mistake. No one can describe the order in which he brushes his hair or teeth; yet it is likely that the order is a pretty fixed one in all of us.

These results may be expressed as follows:

In action grown habitual, what instigates each new muscular contraction to take place in its appointed order is not a thought or a perception, but the sensation occasioned by the muscular contraction just finished. A strictly voluntary act has to be guided by idea, perception, and volition, throughout its whole course. In an habitual action, mere sensation is a sufficient guide, and the upper regions of brain and mind are set comparatively free. A diagram will make the matter clear: Let A, B, C, D, E, F, G represent an habitual chain of muscular contractions, and let a, b, c, d, e, f stand for the respective sensations which these contractions excite in us when they are successively performed. Such sensations will usually be of the muscles, skin, or joints of the parts moved, but they may also be effects of the movement upon the eye or the ear. Through them, and through them alone, we are made aware whether the contraction has or has not occurred. When the series, A, B, C, D, E, F, G, is being learned, each of these sensations becomes the object of a separate perception by the mind. By it we test each movement, to see if it be right before advancing to the next. We hesitate, compare, choose, revoke, reject, etc., by intellectual means; and the order by which the next movement is discharged is an express order from the ideational centres after this deliberation has been gone through.

In habitual action, on the contrary, the only impulse which the centres of idea or perception need send down is the initial impulse, the command to start. This is represented in the diagram by V; it may be a thought of the first movement or of the last result, or a mere perception of some of the habitual conditions of the chain, the presence, e.g., of the keyboard near the hand. In the present case, no sooner has the conscious thought or volition instigated movement A, than A, through the sensation a of its own occurrence, awakens B reflexly; B then excites C through b, and so on till the chain is ended when the intellect generally takes cognizance of the final result. The process, in fact, resembles the passage of a wave of 'peristaltic' motion down the bowels. The intellectual perception at the end is indicated in the diagram by the effect of G being represented, at G', in the ideational centres above the merely sensational line. The sensational impressions, a, b, c, d, e, f, are all supposed to have their seat below the ideational lines. That our ideational centres, if involved at all by a, b, c, d, e, f, are involved in a minimal degree, is shown by the fact that the attention may be wholly absorbed elsewhere. We may say our prayers, or repeat the alphabet, with our attention far away.

"A musical performer will play a piece which has become familiar by repetition while carrying on an animated conversation, or while continuously engrossed by some train of deeply interesting thought; the accustomed sequence of movements being directly prompted by the sight of the notes, or by the remembered succession of the sounds (if the piece is played from memory), aided in both cases by the guiding sensations derived from the muscles themselves. But, further, a higher degree of the same 'training' (acting on an organism specially fitted to profit by it) enables an accomplished pianist to play a difficult piece of music at sight; the movements of the hands and fingers following so immediately upon the sight of the notes that it seems impossible to believe that any but the very shortest and most direct track can be the channel of the nervous communication through which they are called forth. The following curious example of the same class of acquired aptitudes, which differ from instincts only in being prompted to action by the will, is furnished by Robert Houdin:

"'With a view of cultivating the rapidity of visual and tactile perception, and the precision of respondent movements, which are necessary for the success in every kind of prestidigitation, Houdin early practised the art of juggling with balls in the air; and having, after a month's practice, become thorough master of the art of keeping up four balls at once, he placed a book before him, and, while the balls were in the air, accustomed himself to read without hesitation. 'This,' he says, 'will probably seem to my readers very extraordinary; but I shall surprise them still more when I say that I have just amused myself with repeating this curious experiment. Though thirty years have elapsed since the time I was writing, and though I have scarcely once touched the balls during that period, I can still manage to read with ease while keeping three balls up.'" (Autobiography, p. 26.)[11]

We have called a, b, c, d, e, f, the antecedents of the successive muscular attractions, by the name of sensations. Some authors seem to deny that they are even this. If not even this, they can only be centripetal nerve-currents, not sufficient to arouse feeling, but sufficient to arouse motor response.[12] It may be at once admitted that they are not distinct volitions. The will, if any will be present, limits itself to a permission that they exert their motor effects, Dr. Carpenter writes:

"There may still be metaphysicians who maintain that actions which were originally prompted by the will with a distinct intention, and which are still entirely under its control, can never cease to be volitional; and that either an infinitesimally small amount of will is required to sustain them when they have been once set going, or that the will is in a sort of pendulum-like oscillation between the two actions - the maintenance of the train of thought, and the maintenance of the train of movement. But if only an infinitesimally small amount of will is necessary to sustain them, is not this tantamount to saying that they go on by a force of their own? And does not the experience of the perfect continuity of our train of thought during the performance of movements that have become habitual, entirely negative the hypothesis of oscillation? Besides, if such an oscillation existed, there must be intervals in which each action goes on of itself; so that its essentially automatic character is virtually admitted. The physiological explanation, that the mechanism of locomotion, as of other habitual movements, grows to the mode in which it is early exercised, and that it then works automatically under the general control and direction of the will, can scarcely be put down by any assumption of an hypothetical necessity, which rests only on the basis of ignorance of one side of our composite nature."[13]

But if not distinct acts of will, these immediate antecedents of each movement of the chain are at any rate accompanied by consciousness of some kind. They are sensations to which we are usually inattentive, but which immediately call out attention if they go wrong. Schneider's account of these sensations deserves to be quoted. In the act of walking, he says, even when our attention is entirely off,

"we are continuously aware of certain muscular feelings; and we have, moreover, a feeling of certain impulses to keep our equilibrium and to set down one leg after another. It is doubtful whether we could preserve equilibrium if no sensation of our body's attitude were there, and doubtful whether we should advance our leg if we had no sensation of its movements as executed, and not even a minimal feeling of impulse to set it down. Knitting appears altogether mechanical, and the knitter keeps up her knitting even while she reads or is engaged in lively talk. But if we ask her how this be possible, she will hardly reply that the knitting goes on of itself. She will rather say that she has a feeling of it, that she feels in her hands that she knits and how she must knit, and that therefore the movements of knitting are called forth and regulated by the sensations associated therewithal, even when the attention is called away.

"So of every one who practises, apparently automatically, a long-familiar handicraft. The smith turning his tongs as he smites the iron, the carpenter wielding his plane, the lace-maker with her bobbin, the weaver at his loom, all will answer the same question in the same way by saying that they have a feeling of the proper management of the implement in their hands.

"In these cases, the feelings which are conditions of the appropriate acts are very faint. But none the less are they necessary. Imagine your hands not feeling; your movements could then only be provoked by ideas, and if your ideas were then diverted away, the movements ought to come to a standstill, which is a consequence that seldom occurs."[14]

Again:

"An idea makes you take, for example, a violin into your left hand. But it is not necessary that your idea remain fixed on the contraction of the muscles of the left hand and fingers in order that the violin may continue to be held fast and not let fall. The sensations themselves which the holding of the instrument awakens in the hand, since they are associated with the motor impulse of grasping, are sufficient to cause this impulse, which then lasts as long as the feeling itself lasts, or until the impulse is inhibited by the idea of some antagonistic motion."

And the same may be said of the manner in which the right hand holds the bow:

"It sometimes happens, in beginning these simultaneous combinations, that one movement or impulse will cease if the consciousness turn particularly toward another, because at the outset the guiding sensations must all be strongly felt. The bow will perhaps slip from the fingers, because some of the muscles have relaxed. But the slipping is a cause of new sensations starting up in the hand, so that the attention is in a moment brought back to the grasping of the bow.

"The following experiment shows this well: When one begins to play on the violin, to keep him from raising his right elbow in playing a book is placed under his right armpit, which he is ordered to hold fast by keeping the upper arm tight against his body. The muscular feelings, and feelings of contact connected with the book, provoke an impulse to press it tight. But often it happens that the beginner, whose attention gets absorbed in the production of the notes, lets drop the book. Later, however, this never happens; the faintest sensations of contact suffice to awaken the impulse to keep it in its place, and the attention may be wholly absorbed by the notes and the fingering with the left hand. The simultaneous combination of movements is thus in the first instance conditioned by the facility with which in us, alongside of intellectual processes, processes of inattentive feeling may still go on."[15]

This brings us by a very natural transition to the ethical implications of the law of habit. They are numerous and momentous. Dr. Carpenter, from whose 'Mental Physiology' we have quoted, has so prominently enforced the principle that our organs grow to the way in which they have been exercised, and dwelt upon its consequences, that his book almost deserves to be called a work of edification, on this account alone. We need make no apology, then, for tracing a few of these consequences ourselves:

"Habit a second nature! Habit is ten times nature," the Duke of Wellington is said to have exclaimed; and the degree to which this is true no one can probably appreciate as well as one who is a veteran soldier himself. The daily drill and the years of discipline end by fashioning a man completely over again, as to most of the possibilities of his conduct.

"There is a story, which is credible enough, though it may not be true, of a practical joker, who, seeing a discharged veteran carrying home his dinner, suddenly called out, 'Attention!' whereupon the man instantly brought his hands down, and lost his mutton and potatoes in the gutter. The drill had been thorough, and its effects had become embodied in the man's nervous structure."[16]

Riderless cavalry-horses, at many a battle, have been seen to come together and go through their customary evolutions at the sound of the bugle-call. Most trained domestic animals, dogs and oxen, and omnibus- and car- horses, seem to be machines almost pure and simple, undoubtingly, unhesitatingly doing from minute to minute the duties they have been taught, and giving no sign that the possibility of an alternative ever suggests itself to their mind. Men grown old in prison have asked to be readmitted after being once set free. In a railroad accident to a travelling menagerie in the United States some time in 1884, a tiger, whose cage had broken open, is said to have emerged, but presently crept back again, as if too much bewildered by his new responsibilities, so that he was without difficulty secured.

Habit is thus the enormous fly-wheel of society, its most precious conservative agent. It alone is what keeps us all within the bounds of ordinance, and saves the children of fortune from the envious uprisings of the poor. It alone prevents the hardest and most repulsive walks of life from being deserted by those brought up to tread therein. It keeps the fisherman and the deck-hand at sea through the winter; it holds the miner in his darkness, and nails the countryman to his log-cabin and his lonely farm through all the months of snow; it protects us from invasion by the natives of the desert and the frozen zone. It dooms us all to fight out the battle of life upon the lines of our nurture or our early choice, and to make the best of a pursuit that disagrees, because there is no other for which we are fitted, and it is too late to begin again. It keeps different social strata from mixing. Already at the age of twenty-five you see the professional mannerism settling down on the young commercial traveller, on the young doctor, on the young minister, on the young counsellor-at-law. You see the little lines of cleavage running through the character, the tricks of thought, the prejudices, the ways of the 'shop,' in a word, from which the man can by-and-by no more escape than his coat-sleeve can suddenly fall into a new set of folds. On the whole, it is best he should not escape. It is well for the world that in most of us, by the age of thirty, the character has set like plaster, and will never soften again.

If the period between twenty and thirty is the critical one in the formation of intellectual and professional habits, the period below twenty is more important still for the fixing of personal habits, properly so called, such as vocalization and pronunciation, gesture, motion, and address. Hardly ever is a language learned after twenty spoken without a foreign accent; hardly ever can a youth transferred to the society of his betters unlearn the nasality and other vices of speech bred in him by the associations of his growing years. Hardly ever, indeed, no matter how much money there be in his pocket, can he even learn to dress like a gentleman-born. The merchants offer their wares as eagerly to him as to the veriest 'swell,' but he simply cannot buy the right things. An invisible law, as strong as gravitation, keeps him within his orbit, arrayed this year as he was the last; and how his better-bred acquaintances contrive to get the things they wear will be for him a mystery till his dying day.

The great thing, then, in all education, is to make our nervous system our ally instead of our enemy. It is to fund and capitalize our acquisitions, and live at ease upon the interest of the fund. For this we must make automatic and habitual, as early as possible, as many useful actions as we can, and guard against the growing into ways that are likely to be disadvantageous to us, as we should guard against the plague. The more of the details of our daily life we can hand over to the effortless custody of automatism, the more our higher powers of mind will be set free for their own proper work. There is no more miserable human being than one in whom nothing is habitual but indecision, and for whom the lighting of every cigar, the drinking of every cup, the time of rising and going to bed every day, and the beginning of every bit of work, are subjects of express volitional deliberation. Full half the time of such a man goes to the deciding, or regretting, of matters which ought to be so ingrained in him as practically not to exist for his consciousness at all. If there be such daily duties not yet ingrained in any one of my readers, let him begin this very hour to set the matter right.

In Professor Bain's chapter on 'The Moral Habits' there are some admirable practical remarks laid down. Two great maxims emerge from his treatment. The first is that in the acquisition of a new habit, or the leaving off of an old one, we must take care to launch ourselves with as strong and decided an initiative as possible. Accumulate all the possible circumstances which shall re-enforce the right motives; put yourself assiduously in conditions that encourage the new way; make engagements incompatible with the old; take a public pledge, if the case allows; in short, envelop your resolution with every aid you know. This will give your new beginning such a momentum that the temptation to break down will not occur as soon as it otherwise might; and every day during which a breakdown is postponed adds to the chances of its not occurring at all.

The second maxim is: Never suffer an exception to occur till the new habit is securely rooted in your life. Each lapse is like the letting fall of a ball of string which one is carefully winding up; a single slip undoes more than a great many turns will wind again. Continuity of training is the great means of making the nervous system act infallibly right. As Professor Bain says:

"The peculiarity of the moral habits, contradistinguishing them from the intellectual acquisitions, is the presence of two hostile powers, one to be gradually raised into the ascendant over the other. It is necessary, above all things, in such a situation, never to lose a battle. Every gain on the wrong side undoes the effect of many conquests on the right. The essential precaution, therefore, is so to regulate the two opposing powers that the one may have a series of uninterrupted successes, until repetition has fortified it to such a degree as to enable it to cope with the opposition, under any circumstances. This is the theoretically best career of mental progress."

The need of securing success at the outset is imperative. Failure at first is apt to dampen the energy of all future attempts, whereas past experience of success nerves one to future vigor. Goethe says to a man who consulted him about an enterprise but mistrusted his own powers: "Ach! you need only blow on your hands!" And the remark illustrates the effect on Goethe's spirits of his own habitually successful career. Prof. Baumann, from whom I borrow the anecdote,[17] says that the collapse of barbarian nations when Europeans come among them is due to their despair of ever succeeding as the new-comers do in the larger tasks of life. Old ways are broken and new ones not formed.

The question of 'tapering-off,' in abandoning such habits as drink and opium-indulgence, comes in here, and is a question about which experts differ within certain limits, and in regard to what may be best for an individual case. In the main, however, all expert opinion would agree that abrupt acquisition of the new habit is the best way, if there be a real possibility of carrying it out. We must be careful not to give the will so stiff a task as to insure its defeat at the very outset; but, provided one can stand it, a sharp period of suffering, and then a free time, is the best thing to aim at, whether in giving up a habit like that of opium, or in simply changing one's hours of rising or of work. It is surprising how soon a desire will die of inanition if it be never fed.

"One must first learn, unmoved, looking neither to the right nor left, to walk firmly on the straight and narrow path, before one can begin 'to make one's self over again.' He who every day makes a fresh resolve is like one who, arriving at the edge of the ditch he is to leap, forever stops and returns for a fresh run. Without unbroken advance there is no such thing as accumulation of the ethical forces possible, and to make this possible, and to exercise us and habituate us in it, is the sovereign blessing of regular work."[18]

A third maxim may be added to the preceding pair: Seize the very first possible opportunity to act on every resolution you make, and on every emotional prompting you may experience in the direction of the habits you aspire to gain. It is not in the moment of their forming, but in the moment of their producing motor effects, that resolves and aspirations communicate the new 'set' to the brain. As the author last quoted remarks:

"The actual presence of the practical opportunity alone furnishes the fulcrum upon which the lever can rest, by means of which the moral will may multiply its strength, and raise itself aloft. He who has no solid ground to press against will never get beyond the stage of empty gesture-making."

No matter how full a reservoir of maxims one may possess, and no matter how good one's sentiments may be, if one have not taken advantage of every concrete opportunity to act, one's character may remain entirely unaffected for the better. With mere good intentions, hell is proverbially paved. An this is an obvious consequence of the principles we have laid down. A 'character,' as J.S. Mill says, 'is a completely fashioned will'; and a will, in the sense in which he means it, is an aggregate of tendencies to act in a firm and prompt and definite way upon all the principal emergencies of life. A tendency to act only becomes effectively ingrained in us in proportion to the uninterrupted frequency with which the actions actually occur, and the brain 'grows' to their use. Every time a resolve or a fine glow of feeling evaporates without bearing practical fruit is worse than a chance lost; it works so as positively to hinder future resolutions and emotions from taking the normal path of discharge. There is no more contemptible type of human character than that of the nerveless sentimentalist and dreamer, who spends his life in a weltering sea of sensibility and emotion, but who never does a manly concrete deed. Rousseau, inflaming all the mothers of France, by his eloquence, to follow Nature and nurse their babies themselves, while he sends his own children to the foundling hospital, is the classical example of what I mean. But every one of us in his measure, whenever, after glowing for an abstractly formulated Good, he practically ignores some actual case, among the squalid 'other particulars' of which that same Good lurks disguised, treads straight on Rousseau's path. All Goods are disguised by the vulgarity of their concomitants, in this work-a-day world; but woe to him who can only recognize them when he thinks them in their pure and abstract form! The habit of excessive novel-reading and theatre-going will produce true monsters in this line. The weeping of a Russian lady over the fictitious personages in the play, while her coach-man is freezing to death on his seat outside, is the sort of thing that everywhere happens on a less glaring scale. Even the habit of excessive indulgence in music, for those who are neither performers themselves nor musically gifted enough to take it in a purely intellectual way, has probably a relaxing effect upon the character. One becomes filled with emotions which habitually pass without prompting to any deed, and so the inertly sentimental condition is kept up. The remedy would be, never to suffer one's self to have an emotion at a concert, without expressing it afterward in some active way.[19] Let the expression be the least thing in the world -speaking genially to one's aunt, or giving up one's seat in a horse-car, if nothing more heroic offers - but let it not fail to take place.

These latter cases make us aware that it is not simply particular lines of discharge, but also general forms of discharge, that seem to be grooved out by habit in the brain. Just as, if we let our emotions evaporate, they get into a way of evaporating; so there is reason to suppose that if we often flinch from making an effort, before we know it the effort-making capacity will be gone; and that, if we suffer the wandering of our attention, presently it will wander all the time. Attention and effort are, as we shall see later, but two names for the same psychic fact. To what brain-processes they correspond we do not know. The strongest reason for believing that they do depend on brain-processes at all, and are not pure acts of the spirit, is just this fact, that they seem in some degree subject to the law of habit, which is a material law. As a final practical maxim, relative to these habits of the will, we may, then, offer something like this: Keep the faculty of effort alive in you by a little gratuitous exercise every day. That is, be systematically ascetic or heroic in little unnecessary points, do every day or two something for no other reason than that you would rather not do it, so that when the hour of dire need draws nigh, it may find you not unnerved and untrained to stand the test. Asceticism of this sort is like the insurance which a man pays on his house and goods. The tax does him no good at the time, and possibly may never bring him a return. But if the fire does come, his having paid it will be his salvation from ruin. So with the man who has daily inured himself to habits of concentrated attention, energetic volition, and self-denial in unnecessary things. He will stand like a tower when everything rocks around him, and when his softer fellow-mortals are winnowed like chaff in the blast.

The physiological study of mental conditions is thus the most powerful ally of hortatory ethics. The hell to be endured hereafter, of which theology tells, is no worse than the hell we make for ourselves in this world by habitually fashioning our characters in the wrong way. Could the young but realize how soon they will become mere walking bundles of habits, they would give more heed to their conduct while in the plastic state. We are spinning our own fates, good or evil, and never to be undone. Every smallest stroke of virtue or of vice leaves its never so little scar. The drunken Rip Van Winkle, in Jefferson's play, excuses himself for every fresh dereliction by saying, 'I won't count this time!' Well! he may not count it, and a kind Heaven may not count it; but it is being counted none the less. Down among his nerve-cells and fibres the molecules are counting it, registering and storing it up to be used against him when the next temptation comes. Nothing we ever do is, in strict scientific literalness, wiped out. Of course, this has its good side as well as its bad one. As we become permanent drunkards by so many separate drinks, so we become saints in the moral, and authorities and experts in the practical and scientific spheres, by so many separate acts and hours of work. Let no youth have any anxiety about the upshot of his education, whatever the line of it may be. If he keep faithfully busy each hour of the working-day, he may safely leave the final result to itself. He can with perfect certainty count on waking up some fine morning, to find himself one of the competent ones of his generation, in whatever pursuit he may have singled out. Silently, between all the details of his business, the power of judging in all that class of matter will have built itself up within him as a possession that will never pass away. Young people should know this truth in advance. The ignorance of it has probably engendered more discouragement and faint-heartedness in youths embarking on arduous careers than all other causes put together.

Footnotes [1] This chapter has already appeared in the Popular Science Monthly for February 1887.

[2] In the sense above explained, which applies to inner structure as well as to outer form.

[3] Revue Philosophique, I, 324.

[4] Some paths, to be sure, are banked up by bodies moving through them under too great pressure, and made impervious. These special cases we disregard.

[5] We cannot say the will, for, though many, perhaps most, human habits were once voluntary actions, no action, as we shall see in a later chapter, can be primarily such. While an habitual action may once have been voluntary, the voluntary action must before that, at least once, have been impulsive or reflex. It is this very first occurrence of all that we consider in the text.

[6] Those who desire a more definite formulation may consult J. Fiske's 'Cosmic Philosophy,' vol. II. pp. 142-146 and Spencer's 'Principles of Biology,' sections 302 and 303, and the part entitled 'Physical Synthesis' of his 'Principles of Psychology.' Mr. Spencer there tries, not only to show how new actions may arise in nervous systems and form new reflex arcs therein, but even how nervous tissue may actually be born by the passage of new waves of isometric transformation through an originally indifferent mass. I cannot help thinking that Mr. Spencer's data, under a great show of precision, conceal vagueness and improbability, and even self-contradiction.

[7] 'Mental Physiology' (1874,) pp. 339-345.

[8] [See, later, Masius in Van Benedens' and Van Bambeke's 'Archives de Biologie,' vol. I (Li�ge, 1880). - W.J.]

[9] G. H. Schneider: 'Der menschliche Wille' (1882), pp. 417-419 (freely translated). For the drain-simile, see also Spencer's 'Psychology,' part V, chap. VIII.

[10] Physiology of Mind, p. 155.

[11] Carpenter's 'Mental Physiology' (1874), pp. 217, 218.

[12] Von Hartmann devotes a chapter of his 'Philosophy of the Unconscious' (English translation, vol. I. p. 72) to proving that they must be both ideas and unconscious.

[13] 'Mental Physiology,' p. 20.

[14] 'Der menschliche Willie,' pp. 447, 448.

[15] 'Der menschliche Wille,' p. 439. The last sentence is rather freely translated - the sense is unaltered.

[16] Huxley's 'Elementary Lessons in Physiology,' lesson XII.

[17] See the admirable passage about success at the outset, in his Handbuch der Moral (1878), pp. 38-43.

[18] J. Bahnsen: 'Beitr�ge zu Charakterologie' (1867), vol. I. p. 209.

[19] See for remarks on this subject a readable article by Miss V. Scudder on 'Musical Devotees and Morals,' in the Andover Review for January 1887. Classics in the History of Psychology An internet resource developed by Christopher D. Green York University, Toronto, Ontario (Return to index)

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CHAPTER V. The Automaton-Theory

In describing the functions of the hemispheres a short way back, we used language derived from both the bodily and the mental life, saying now that the animal made indeterminate and unforeseeable reactions, and anon that he was swayed by considerations of future good and evil; treating his hemispheres sometimes as the seat of memory and ideas in the psychic sense, and sometimes talking of them as simply a complicated addition to his reflex machinery. This sort of vacillation in the point of view is a fatal incident of all ordinary talk about these questions; but I must now settle my scores with those readers to whom I already dropped a word in passing (see page 24, note) and who have probably been dissatisfied with my conduct ever since.

Suppose we restrict our view to facts of one and the same plane, and let that be the bodily plane: cannot all the outward phenomena of intelligence still be exhaustively described? Those mental images, those 'considerations,' whereof we spoke, - presumably they do not arise without neural processes arising simultaneously with them, and presumably each consideration corresponds to a process sui generis, and unlike all the rest. In other words, however numerous and delicately differentiated the train of ideas may be, the train of brain-events that runs alongside of it must in both respects be exactly its match, and we must postulate a neural machinery that offers a living counterpart for every shading, however fine, of the history of its owner's mind. Whatever degree of complication the latter may reach, the complication of the machinery must be quite as extreme, otherwise we should have to admit that there may be mental events to which no brain-events correspond. But such an admission as this the physiologist is reluctant to make. It would violate all his beliefs. 'No psychosis without neurosis,' is one form which the principle of continuity takes in his mind.

But this principle forces the physiologist to make still another step. If neural action is as complicated as mind; and if in the sympathetic system and lower spinal cord we see what, so far as we know, is unconscious neural action executing deeds that to all outward intent may be called intelligent; what is there to hinder us from supposing that even where we know consciousness to be there, the still more complicated neural action which we believe to be its inseparable companion is alone and of itself the real agent of whatever intelligent deeds may appear? "As actions of a certain degree of complexity are brought about by mere mechanism, why may not actions of a still greater degree of complexity be the result of a more refined mechanism?" The conception of reflex action is surely one of the best conquests of physiological theory; why not be radical with it? Why not say that just as the spinal cord is a machine with few reflexes, so the hemispheres are a machine with many, and that that is all the difference? The principle of continuity would press us to accept this view.

But what on this view could be the function of the consciousness itself? Mechanical function it would have none. The sense-organs would awaken the brain-cells; these would awaken each other in rational and orderly sequence, until the time for action came; and then the last brain-vibration would discharge downward into the motor tracts. But this would be a quite autonomous chain of occurrences, and whatever mind went with it would be there only as an 'epiphenomenon,' an inert spectator, a sort of 'foam, aura, or melody' as Mr. Hodgson says, whose opposition or whose furtherance would be alike powerless over the occurrences themselves. When talking, some time ago, we ought not, accordingly, as physiologists, to have said anything about 'considerations' as guiding the animal. We ought to have said 'paths left in the hemispherical cortex by former currents,' and nothing more.

Now so simple and attractive is this conception from the consistently physiological point of view, that it is quite wonderful to see how late it was stumbled on in philosophy, and how few people, even when it has been explained to them, fully and easily realize its import. Much of the polemic writing against it is by men who have as yet failed to take it into their imaginations. Since this has been the case, it seems worth while to devote a few more words to making it plausible, before criticising it ourselves.

To Descartes belongs the credit of having first been bold enough to conceive of a completely self-sufficing nervous mechanism which should be able to perform complicated and apparently intelligent acts. By a singularly arbitrary restriction, however, Descartes stopped short at man, and while contending that in beasts the nervous machinery was all, he held that the higher acts of man were the result of the agency of his rational soul. The opinion that beasts have no consciousness at all was of course too paradoxical to maintain itself long as anything more than a curious item in the history of philosophy. And with its abandonment the very notion that the nervous system per se might work the work of intelligence, which was an integral, though detachable part of the whole theory, seemed also to slip out of men's conception, until, in this century, the elaboration of the doctrine of reflex action made it possible and natural that it should again arise. But it was not till 1870, I believe, that Mr. Hodgson made the decisive step, by saying that feelings, no matter how intensely they may be present, can have no causal efficacy whatever, and comparing them to the colors laid on the surface of a mosaic, of which the events in the nervous system are represented by the stones.[1] Obviously the stones are held in place by each other and not by the several colors which they support.

About the same time Mr. Spalding, and a little later Messrs. Huxley and Clifford, gave great publicity to an identical doctrine, though in their case it was backed by less refined metaphysical considerations.[2]

A few sentences from Huxley and Clifford may be subjoined to make the matter entirely clear. Professor Huxley says:

"The consciousness of brutes would appear to be related to the mechanism of their body simply as a collateral product of its working, and to be as completely without any power of modifying that working as the steam-whistle which accompanies the work of a locomotive engine is without influence on its machinery. Their volition, if they have any, is an emotion indicative of physical changes, not a cause of such changes... The soul stands related to the body as the bell of a clock to the works, and consciousness answers to the sound which the bell gives out when it is struck... Thus far I have strictly confined myself to the automatism of brutes... It is quite true that, to the best of my judgment, the argumentation which applies to brutes holds equally good of men; and, therefore, that all states of consciousness in us, as in them, are immediately caused by molecular changes of the brain-substance. It seems to me that in men, as in brutes, there is no proof that any state of consciousness is the cause of change in the motion of the matter of the organism. If these positions are well based, it follows that our mental conditions are simply the symbols in consciousness of the changes which take place automatically in the organism; and that, to take an extreme illustration, the feeling we call volition is not the cause of a voluntary act, but the symbol of that state of the brain which is the immediate cause of that act. We are conscious automata."

Professor Clifford writes:

"All the evidence that we have goes to show that the physical world gets along entirely by itself, according to practically universal rules.... The train of physical facts between the stimulus sent into the eye, or to any one of our senses, and the exertion which follows it, and the train of physical facts which goes on in the brain, even when there is no stimulus and no exertion, - these are perfectly complete physical trains, and every step is fully accounted for by mechanical conditions.... The two things are on utterly different platforms - the physical facts go along by themselves, and the mental facts go along by themselves. There is a parallelism between them, but there is no interference of one with the other. Again, if anybody says that the will influences matter, the statement is not untrue, but it is nonsense. Such an assertion belongs to the crude materialism of the savage. The only thing which influences matter is the position of surrounding matter or the motion of surrounding matter.... The assertion that another man's volition, a feeling in his consciousness that I cannot perceive, is part of the train of physical facts which I may perceive, - this is neither true non untrue, but nonsense; it is a combination of words whose corresponding ideas will not go together.... Sometimes one series is known better, and sometimes the other; so that in telling a story we speak sometimes of mental and sometimes of material facts. A feeling of chill made a man run; strictly speaking, the nervous disturbance which coexisted with that feeling of chill made him run, if we want to talk about material facts; or the feeling of chill produced the form of sub-consciousness which coexists with the motion of legs, if we want to talk about mental facts....When, therefore, we ask: 'What is the physical link between the ingoing message from chilled skin and the outgoing message which moves the leg?' and the answer is, 'A man's will,' we have as much right to be amused as if we had asked our friend with the picture what pigment was used in painting the cannon in the foreground, and received the answer, 'Wrought iron.' It will be found excellent practice in the mental operations required by this doctrine to imagine a train, the fore part of which is an engine and three carriages linked with iron couplings, and the hind part three other carriages linked with iron couplings; the bond between the two parts being made up out of the sentiments of amity subsisting between the stoker and the guard."

To comprehend completely the consequences of the dogma so confidently enunciated, one should unflinchingly apply it to the most complicated examples. The movements of our tongues and pens, the flashings of our eyes in conversation, are of course events of a material order, and as such their causal antecedents must be exclusively material. If we knew thoroughly the nervous system of Shakespeare, and as thoroughly all his environing conditions, we should be able to show why at a certain period of his life his hand came to trace on certain sheets of paper those crabbed little black marks which we for shortness' sake call the manuscript of Hamlet. We should understand the rationale of every erasure and alteration therein, and we should understand all this without in the slightest degree acknowledging the existence of the thoughts in Shakespeare's mind. The words and sentences would be taken, not as signs of anything beyond themselves, but as little outward facts, pure and simple. In like manner we might exhaustively write the biography of those two hundred pounds, more or less, of warmish albuminoid matter called Martin Luther, without ever implying that it felt.

But, on the other hand, nothing in all this could prevent us from giving an equally complete account of either Luther's or Shakespeare's spiritual history, an account in which every gleam of thought and emotion should find its place. The mind-history would run alongside of the body-history of each man, and each point in the one would correspond to, but not react upon, a point in the other. So the melody floats from the harp-string, but neither checks nor quickens its vibrations; so the shadow runs alongside the pedestrian, but in no way influences his steps.

Another inference, apparently more paradoxical still, needs to be made, though, as far as I am aware, Dr. Hodgson is the only writer who has explicitly drawn it. That inference is that feelings, not causing nerve-actions, cannot even cause each other. To ordinary common sense, felt pain is, as such, not only the cause of outward tears and cries, but also the cause of such inward events as sorrow, compunction, desire, or inventive thought. So the consciousness of good news is the direct producer of the feeling of joy, the awareness of premises that of the belief in conclusions. But according to the automaton-theory, each of the feelings mentioned is only the correlate of some nerve-movement whose cause lay wholly in a previous nerve-movement. The first nerve-movement called up the second; whatever feeling was attached to the second consequently found itself following upon the feeling that was attached to the first. If, for example, good news was the consciousness correlated with the first movement, then joy turned out to be the correlate in consciousness of the second. But all the while the items of the nerve series were the only ones in causal continuity; the items of the conscious series, however inwardly rational their sequence, were simply juxtaposed.

REASONS FOR THE THEORY.

The 'conscious automaton-theory,' as this conception is generally called, is thus a radical and simple conception of the manner in which certain facts may possibly occur. But between conception and belief, proof ought to lie. And when we ask, 'What proves that all this is more than a mere conception of the possible?' it is not easy to get a sufficient reply. If we start from the frog's spinal cord and reason by continuity, saying, as that acts so intelligently, though unconscious, so the higher centres, though conscious, may have the intelligence they show quite as mechanically based; we are immediately met by the exact counter-argument from continuity, an argument actually urged by such writers as Pfl�ger and Lewes, which starts from the acts of the hemispheres, and says: "As these owe their intelligence to the consciousness which we know to be there, so the intelligence of the spinal cord's acts must really be due to the invisible presence of a consciousness lower in degree." All arguments from continuity work in two ways, you can either level up or level down by their means; and it is clear that such arguments as these can eat each other up to all eternity.

There remains a sort of philosophic faith, bred like most faiths from an aesthetic demand. Mental and physical events are, on all hands, admitted to present the strongest contrast in the entire field of being. The chasm which yawns between them is less easily bridged over by the mind than any interval we know. Why, then, not call it an absolute chasm, and say not only that the two worlds are different, but that they are independent? This gives us the comfort of all simple and absolute formulas, and it makes each chain homogeneous to our consideration. When talking of nervous tremors and bodily actions, we may feel secure against intrusion from an irrelevant mental world. When, on the other hand, we speak of feelings, we may with equal consistency use terms always of one denomination, and never be annoyed by what Aristotle calls 'slipping into another kind.' The desire on the part of men educated in laboratories not to have their physical reasonings mixed up with such incommensurable factors as feelings is certainly very strong. I have heard a most intelligent biologist say: "It is high time for scientific men to protest against the recognition of any such thing as consciousness in a scientific investigation." In a word, feeling constitutes the 'unscientific' half of existence, and any one who enjoys calling himself a 'scientist' will be too happy to purchase an untrammelled homogeneity of terms in the studies of his predilection, at the slight cost of admitting a dualism which, in the same breath that it allows to mind an independent status of being, banishes it to a limbo of causal inertness, from whence no intrusion or interruption on its part need ever be feared.

Over and above this great postulate that matters must be kept simple, there is, it must be confessed, still another highly abstract reason for denying causal efficacity to our feelings. We can form no positive image of the modus operandi of a volition or other thought affecting the cerebral molecules.

"Let us try to imagine an idea, say of food, producing a movement, say of carrying food to the mouth.... What is the method of its action? Does it assist the decomposition of the molecules of the gray matter, or does it retard the process, or does it alter the direction in which the shocks are distributed? Let us imagine the molecules of the gray matter combined in such a way that they will fall into simpler combinations on the impact of an incident force. Now suppose the incident force, in the shape of a shock from some other centre, to impinge upon these molecules. By hypothesis it will decompose them, and they will fall into the simpler combination. How is the idea of food to prevent this decomposition? Manifestly it can do so only by increasing the force which binds the molecules together. Good! Try to imagine the idea of a beefsteak binding two molecules together. It is impossible. Equally impossible is it to imagine a similar idea loosening the attractive force between two molecules."[3]

This passage from an exceedingly clever writer expresses admirably the difficulty to which I allude. Combined with a strong sense of the 'chasm' between the two worlds, and with a lively faith in reflex machinery, the sense of this difficulty can hardly fail to make one turn consciousness out of the door as a superfluity so far as one's explanations go. One may bow her out politely, allow her to remain as a 'concomitant,' but one insists that matter shall hold all the power.

"Having thoroughly recognized the fathomless abyss that separates mind from matter, and having so blended the very notion into his very nature that there is no chance of his ever forgetting it or failing to saturate with it all his meditations, the student of psychology has next to appreciate the association between these two orders of phenomena.... They are associated in a manner so intimate that some of the greatest thinkers consider them different aspects of the same process.... When the rearrangement of molecules takes place in the higher regions of the brain, a change of consciousness simultaneously occurs.... The change of consciousness never takes place without the change in the brain; the change in the brain never... without the change in consciousness. But why the two occur together, or what the link is which connects them, we do not know, and most authorities believe that we never shall and never can know. Having firmly and tenaciously grasped these two notions, of the absolute separateness of mind and matter, and of the invariable concomitance of a mental change with a bodily change, the student will enter on the study of psychology with half his difficulties surmounted."[4]

Half his difficulties ignored, I should prefer to say. For this 'concomitance' in the midst of 'absolute separateness' is an utterly irrational notion. It is to my mind quite inconceivable that consciousness should have nothing to do with a business which it so faithfully attends. And the question, 'What has it to do?' is one which psychology has no right to 'surmount,' for it is her plain duty to consider it. The fact is that the whole question of interaction and influence between things is a metaphysical question, and cannot be discussed at all by those who are unwilling to go into matters thoroughly. It is truly enough hard to imagine the 'idea of a beefsteak binding two molecules together;' but since Hume's time it has been equally hard to imagine anything binding them together. The whole notion of 'binding' is a mystery, the first step towards the solution of which is to clear scholastic rubbish out of the way. Popular science talks of 'forces,' 'attractions' or 'affinities' as binding the molecules; but clear science, though she may use such words to abbreviate discourse, has no use for the conceptions, and is satisfied when she can express in simple 'laws' the bare space-relations of the molecules as functions of each other and of time. To the more curiously inquiring mind, however, this simplified expression of the bare facts is not enough; there must be a 'reason' for them, and something must 'determine' the laws. And when one seriously sits down to consider what sort of a thing one means when one asks for a 'reason,' one is led so far afield, so far away from popular science and its scholasticism, as to see that even such a fact as the existence or non-existence in the universe of 'the idea of a beefsteak' may not be wholly indifferent to other facts in the same universe, and in particular may have something to do with determining the distance at which two molecules in that universe shall lie apart. If this is so, then common-sense, though the intimate nature of causality and of the connection of things in the universe lies beyond her pitifully bounded horizon, has the root and gist of the truth in her hands when she obstinately holds to it that feelings and ideas are causes. However inadequate our ideas of causal efficacy may be, we are less wide of the mark when we say that our ideas and feelings have it, than the Automatists are when they say they haven't it. As in the night all cats are gray, so in the darkness of metaphysical criticism all causes are obscure. But one has no right to pull the pall over the psychic half of the subject only, as the automatists do, and to say that that causation is unintelligible, whilst in the same breath one dogmatizes about material causation as if Hume, Kant, and Lotze had never been born. One cannot thus blow hot and cold. One must be impartially naif or impartially critical. If the latter, the reconstruction must be thorough-going or 'metaphysical,' and will probably preserve the common-sense view that ideas are forces, in some translated form. But Psychology is a mere natural science, accepting certain terms uncritically as her data, and stopping short of metaphysical reconstruction. Like physics, she must be na�ve; and if she finds that in her very peculiar field of study ideas seem to be causes, she had better continue to talk of them as such. She gains absolutely nothing by a breach with common-sense in this matter, and she loses, to say the least, all naturalness of speech. If feelings are causes, of course their effects must be furtherances and checkings of internal cerebral motions, of which in themselves we are entirely without knowledge. It is probable that for years to come we shall have to infer what happens in the brain either from our feelings or from motor effects which we observe. The organ will be for us a sort of vat in which feelings and motions somehow go on stewing together, and in which innumerable things happen of which we catch but the statistical result. Why, under these circumstances, we should be asked to forswear the language of our childhood I cannot well imagine, especially as it is perfectly compatible with the language of physiology. The feelings can produce nothing absolutely new, they can only reinforce and inhibit reflex currents, and the original organization by physiological forces of these in paths must always be the ground-work of the psychological scheme.

My conclusion is that to urge the automaton-theory upon us, as it is now urged, on purely a priori and quasi-metaphysical grounds, is an unwarrantable impertinence in the present state of psychology.

REASONS AGAINST THE THEORY.

But there are much more positive reasons than this why we ought to continue to talk in psychology as if consciousness had causal efficacy. The particulars of the distribution of consciousness, so far as we know them, point to its being efficacious. Let us trace some of them.

It is very generally admitted, though the point would be hard to prove, that consciousness grows the more complex and intense the higher we rise in the animal kingdom. That of a man must exceed that of an oyster. From this point of view it seems an organ, superadded to the other organs which maintain the animal in the struggle for existence; and the presumption of course is that is helps him in some way in the struggle, just as they do. But it cannot help him without being in some way efficacious and influencing the course of his bodily history. If now it could be shown in what way consciousness might help him, and if, moreover, the defects of his other organs (where consciousness is most developed) are such as to make them need just the kind of help that consciousness would bring provided it were efficacious; why, then the plausible infer- ence would be that it came just because of its efficacy - in other words, its efficacy would be inductively proved.

Now the study of the phenomena of consciousness which we shall make throughout the rest of this book will show us that consciousness is at all times primarily a selecting agency.[5] Whether we take it in the lowest sphere of sense, or in the highest of intellection, we find it always doing one thing, choosing one out of several of the materials so presented to its notice, emphasizing and accentuating that and suppressing as far as possible all the rest. The item emphasized is always in close connection with some interest felt by consciousness to be paramount at the time.

But what are now the defects of the nervous system in those animals whose consciousness seems most highly developed? Chief among them must be instability. The cerebral hemispheres are the characteristically 'high' nerve-centres, and we saw how indeterminate and unforeseeable their performances were in comparison with those of the basal ganglia and the cord. But this very vagueness constitutes their advantage. They allow their possessor to adapt his conduct to the minutest alterations in the environing circumstances, any one of which may be for him a sign, suggesting distant motives more powerful than any present solicitations of sense. It seems as if certain mechanical conclusions should be drawn from this state of things. An organ swayed by slight impressions is an organ whose natural state is one of unstable equilibrium. We may imagine the various lines of discharge in the cerebrum to be almost on a par in point of permeability - what discharge a given small impression will produce may be called accidental, in the sense in which we say it is a matter of accident whether a rain-drop falling on a mountain ridge descend the eastern or the western slope. It is in this sense that we may call it a matter of accident whether a child be a boy or a girl. The ovum is so unstable a body that certain causes too minute for our apprehension may at a certain moment tip it one way or the other. The natural law of an organ constituted after this fashion can be nothing but a law of caprice. I do not see how one could reasonably expect from it any certain pursuance of useful lines of reaction, such as the few and fatally determined performances of the lower centres constitute within their narrow sphere. The dilemma in regard to the nervous system seems, in short, to be of the following kind. We may construct one which will react infallibly and certainly, but it will then be capable of reacting to very few changes in the environment - it will fail to be adapted to all the rest. We may, on the other hand, construct a nervous system potentially adapted to respond to an infinite variety of minute features in the situation; but its fallibility will then be as great as its elaboration. We can never be sure that its equilibrium will be upset in the appropriate direction. In short, a high brain may do many things, and may do each of them at a very slight hint. But its hair-trigger organization makes of it a happy-go-lucky, hit-or-miss affair. It is as likely to do the crazy as the sane thing at any given moment. A low brain does few things, and in doing them perfectly forfeits all other use. The performances of a high brain are like dice thrown forever on a table. Unless they be loaded, what chance is there that the highest number will turn up oftener than the lowest?

All this is said of the brain as a physical machine pure and simple. Can consciousness increase its efficiency by loading its dice? Such is the problem.

Loading its dice would mean bringing a more or less constant pressure to bear in favor of those of its performances which make for the most permanent interests of the brain's owner; it would mean a constant inhibition of the tendencies to stray aside.

Well, just such pressure and such inhibition are what consciousness seems to be exerting all the while. And the interests in whose favor it seems to exert them are its interests and its alone, interests which it creates, and which, but for it, would have no status in the realm of being whatever. We talk, it is true, when we are darwinizing, as if the mere body that owns the brain had interests; we speak about the utilities of its various organs and how they help or hinder the body's survival; and we treat the survival as if it were an absolute end, existing as such in the physical world, a sort of actual should-be, presiding over the animal and judging his reactions, quite apart from the presence of any commenting intelligence outside. We forget that in the absence of some such superadded commenting intelligence (whether it be that of the animal itself, or only ours or Mr. Darwin's), the reactions cannot be properly talked of as 'useful' or 'hurtful' at all. Considered merely physically, all that can be said of them is that if they occur in a certain way survival will as a matter of fact prove to be their incidental consequence. The organs themselves, and all the rest of the physical world, will, however, all the time be quite indifferent to this consequence, and would quite as cheerfully, the circumstances changed, compass the animal's destruction. In a word, survival can enter into a purely physiological discussion only as an hypothesis made by an onlooker about the future. But the moment you bring a consciousness into the midst, survival ceases to be a mere hypothesis. No longer is it, "if survival is to occur, then so and so must brain and other organs work." It has now become an imperative decree: "Survival shall occur, and therefore organs must so work!" Real ends appear for the first time now upon the world's stage. The conception of consciousness as a purely cognitive form of being, which is the pet way of regarding it in many idealistic-modern as well as ancient schools, is thoroughly anti-psychological, as the remainder of this book will show. Every actually existing consciousness seems to itself at any rate to be a fighter for ends, of which many, but for its presence, would not be ends at all. Its powers of cognition are mainly subservient to these ends, discerning which facts further them and which do not.

Now let consciousness only be what it seems to itself, and it will help an instable brain to compass its proper ends. The movements of the brain per se yield the means of attaining these ends mechanically, but only out of a lot of other ends, if so they may be called, which are not the proper ones of the animal, but often quite opposed. The brain is an instrument of possibilities, but of no certainties. But the consciousness, with its own ends present to it, and knowing also well which possibilities lead thereto and which away, will, if endowed with causal efficacy, reinforce the favorable possibilities and repress the unfavorable or indifferent ones. The nerve-currents, coursing through the cells and fibres, must in this case be supposed strengthened by the fact of their awaking one consciousness and dampening by awakening another. How such reaction of the consciousness upon the currents may occur must remain at present unsolved: it is enough for my purpose to have shown that it may not uselessly exist, and that the matter is less simple than the brain-automatists hold.

All the facts of the natural history of consciousness lend color to this view. Consciousness, for example, is only intense when nerve-processes are hesitant. In rapid, automatic, habitual action it sinks to a minimum. Nothing could be more fitting than this, if consciousness have the teleological function we suppose; nothing more meaningless, if not. Habitual actions are certain, and being in no danger of going astray from their end, need no extraneous help. In hesitant action, there seem many alternative possibilities of final nervous discharge. The feeling awakened by the nascent excitement of each alternative nerve-tract seems by its attractive or repulsive quality to determine whether the excitement shall abort or shall become complete. Where indecision is great, as before a dangerous leap, consciousness is agonizingly intense. Feeling, from this point of view, may be likened to a cross-section of the chain of nervous discharge, ascertaining the links already laid down, and groping among the fresh ends presented to it for the one which seems best to fit the case.

The phenomena of 'vicarious function' which we studied in Chapter II seems to form another bit of circumstantial evidence. A machine in working order acts fatally in one way. Our consciousness calls this the right way. Take out a valve, throw a wheel out of gear or bend a pivot, and it becomes a different machine, acting just as fatally in another way which we call the wrong way. But the machine itself knows nothing of wrong or right: matter has no ideals to pursue. A locomotive will carry its train through an open drawbridge as cheerfully as to any other destination.

A brain with part of it scooped out is virtually a new machine, and during the first days after the operation functions in a thoroughly abnormal manner. As a matter of fact, however its performances become from day to day more normal, until at last a practised eye may be needed to suspect anything wrong. Some of the restoration is undoubtedly due to 'inhibitions' passing away. But if the consciousness which goes with the rest of the brain, be there not only in order to take cognizance of each functional error, but also to exert an efficient pressure to check it if it be a sin of commission, and to lend a strengthening hand if it be a weakness or sin of omission, - nothing seems more natural than that the remaining parts, assisted in this way, should by virtue of the principle of habit grow back to the old teleological modes of exercise for which they were at first incapacitated. Nothing, on the contrary, seems at first sight more unnatural than that they should vicariously take up the duties of a part now lost without those duties as such exerting any persuasive or coercive force. At the end of Chapter XXVI I shall return to this again.

There is yet another set of facts which seem explicable on the supposition that consciousness has causal efficacy. It is a well-known fact that pleasures are generally associated with beneficial, pains with detrimental, experiences. All the fundamental vital processes illustrate this law. Starvation, suffocation, privation of food, drink and sleep, work when exhausted, burns, wounds, inflammation, the effects of poison, are as disagreeable as filling the hungry stomach, enjoying rest and sleep after fatigue, exercise after rest, and a sound skin and unbroken bones at all times, are pleasant. Mr. Spencer and others have suggested that these coincidences are due, not to any pre-established harmony, but to the mere action of natural selection which would certainly kill off in the long-run any breed of creatures to whom the fundamentally noxious experience seemed enjoyable. An animal that should take pleasure in a feel- ling of suffocation would, if that pleasure were efficacious enough to make him immerse his head in water, enjoy a longevity of four or five minutes. But if pleasures and pains have no efficacy, one does not see (without some such � priori rational harmony as would be scouted by the 'scientific' champions of the automaton-theory) why the most noxious acts, such as burning, might not give thrills of delight, and the most necessary ones, such as breathing, cause agony. The exceptions to the law are, it is true, numerous, but relate to experiences that are either not vital or not universal. Drunkenness, for instance, which though noxious, is to many persons delightful, is a very exceptional experience. But, as the excellent physiologist Fick remarks, if all rivers and springs ran alcohol instead of water, either all men would now be born to hate it or our nerves would have been selected so as to drink it with impunity. The only considerable attempt, in fact, that has been made to explain the distribution of our feelings is that of Mr. Grant Allen in his suggestive little work Physiological Aesthetics; and his reasoning is based exclusively on that causal efficacy of pleasures and pains which the 'double-aspect' partisans so strenuously deny.

Thus, them, from every point of view the circumstantial evidence against that theory is strong. A priori analysis of both brain-action and conscious action shows us that if the latter were efficacious it would, by its selective emphasis, make amends for the indeterminateness of the former; whilst the study a posteriori of the distribution of consciousness shows it to be exactly such as we might expect in an organ added for the sake of steering a nervous system grown too complex to regulate itself. The conclusion that it is useful is, after all this, quite justifiable. But, if it is useful, it must be so through its causal efficaciousness, and the automaton-theory must succumb to the theory of commonsense. I, at any rate (pending metaphysical reconstructions not yet successfully achieved), shall have no hesitation in using the language of common-sense throughout this book.

Footnotes [1] The Theory of Practice, vol. , p. [sic]

[2] The present writer recalls how in 1869, when still a medical student, he began to write an essay showing how almost every one who speculated about brain-processes illicitly interpolated into his account of them links derived from the entirely heterogeneous universe of Feeling. Spencer, Hodgson (in his Time and Space), Maudsley, Lockhart Clarke, Bain, Dr. Carpenter, and other authors were cited as having been guilty of the confusion. The writing was soon stopped because he perceived that the view which he was upholding against these authors was a pure conception, with no proofs to be adduced of its reality. Later it seemed to him that whatever proofs existed really told in favor of their view.

[3] Chas. Mercier: The Nervous System and the Mind (1888). p. 9.

[4] Op. cit. p. 11.

[5] See in particular the end of Chapter IX.

Classics in the History of Psychology

An internet resource developed by Christopher D. Green York University, Toronto, Ontario (Return to index)

CHAPTER VI. The Mind-Stuff Theory

The reader who found himself swamped with too much metaphysics in the last chapter will have a still worse time of it in this one, which is exclusively metaphysical. Metaphysics means nothing but an unusually obstinate effort to think clearly. The fundamental conceptions of psychology are practically very clear to us, but theoretically they are very confused, and one easily makes the obscurest assumptions in this science without realizing, until challenged, what internal difficulties they involve. When these assumptions have once established themselves (as they have a way of doing in our very descriptions of the phenomenal facts) it is almost impossible to get rid of them afterwards or to make any one see that they are not essential features of the subject. The only way to prevent this disaster is to scrutinize them beforehand and make them give an articulate account of themselves before letting them pass. One of the obscurest of the assumptions of which I speak is the assumption that our mental states are composite in structure, made up of smaller states conjoined. This hypothesis has outward advantages which make it almost irresistibly attractive to the intellect, and yet it is inwardly quite unintelligible. Of its unintelligibility, however, half the writers on psychology seem unaware. As our own aim is to understand if possible, I make no apology for singling out this particular notion for very explicit treatment before taking up the descriptive part of our work. The theory of 'mind-stuff' is the theory that our mental states are compounds, expressed in its most radical form.

EVOLUTIONARY PSYCHOLOGY DEMANDS A MIND-DUST. In a general theory of evolution the inorganic comes first, then the lowest forms of animal and vegetable life, then forms of life that possess mentality, and finally those like ourselves that possess it in a high degree. As long as we keep to the consideration of purely outward facts, even the most complicated facts of biology, our task as evolutionists is comparatively easy. We are dealing all the time with matter and its aggregations and separations; and although our treatment must perforce be hypothetical, this does not prevent it from being continuous. The point which as evolutionists we are bound to hold fast to is that all the new forms of being that make their appearance are really nothing more than results of the redistribution of the original and unchanging materials. The self-same atoms which, chaotically dispersed, made the nebula, now, jammed and temporarily caught in peculiar positions, form our brains; and the 'evolution' of the brains, if understood, would be simply the account of how the atoms came to be so caught and jammed. In this story no new natures, no factors not present at the beginning, are introduced at any later stage.

But with the dawn of consciousness an entirely new nature seems to slip in, something whereof the potency was not given in the mere outward atoms of the original chaos.

The enemies of evolution have been quick to pounce upon this undeniable discontinuity in the data of the world, and many of them, from the failure of evolutionary explanations at this point, have inferred their general incapacity all along the line. Every one admits the entire incommensurability of feeling as such with material motion as such. "A motion became a feeling!" - no phrase that our lips can frame is so devoid of apprehensible meaning. Accordingly, even the vaguest of evolutionary enthusiasts, when deliberately comparing material with mental facts, have been as forward as any one else to emphasize the 'chasm' between the inner and the outer worlds.

"Can the oscillations of a molecule," says Mr. Spencer, "be represented side by side with a nervous shock [he means a mental shock], and the two be recognized as one? No effort enables us to assimilate them. That a unit of feeling has nothing in common with a unit of motion becomes more than ever manifest when we bring the two into juxtaposition." [1]

And again:

"Suppose it to have become quite clear that a shock in consciousness and a molecular motion are the subjective and objective faces of the same thing; we continue utterly incapable of uniting the two, so as to conceive that reality of which they are the opposite faces." [2]

In other words, incapable of perceiving in them any common character. So Tyndall, in that lucky paragraph which has been quoted so often that every one knows it by heart:

"The passage from the physics of the brain to the corresponding facts of consciousness is unthinkable. Granted that a definite thought and a definite molecular action in the brain occur simultaneously; we do not possess the intellectual organ, nor apparently any rudiment of the organ, which would enable us to pass, by a process of reasoning, from one to the other." [3]

Or in this other passage:

"We can trace the development of a nervous system and correlate with it the parallel phenomena of sensation and thought. We see with undoubting certainty that they go hand in hand. But we try to soar in a vacuum the moment we seek to comprehend the connection between them... There is no fusion possible between the two classes of facts - no motor energy in the intellect of man to carry it without logical rupture from the one to the other." [4]

None the less easily, however, when the evolutionary afflatus is upon them, do the very same writers leap over the breach whose flagrancy they are the foremost to announce, and talk as if mind grew out of body in a continuous way. Mr. Spencer, looking back on his review of mental evolution, tells us how "in tracing up the increase we found ourselves passing without break from the phenomena of bodily life to the phenomena of mental life." [5] And Mr. Tyndall, in the same Belfast Address from which we just quoted, delivers his other famous passage:

"Abandoning all disguise, the confession that I feel bound to make before you is that I prolong the vision backward across the boundary of the experimental evidence, and discern in that matter which we, in our ignorance and notwithstanding our professed reverence for its Creator, have hitherto covered with opprobrium the promise and potency of every form and quality of life." [6] - mental life included, as a matter of course.

So strong a postulate is continuity! Now this book will tend to show that mental postulates are on the whole to be respected. The demand for continuity has, over large tracts of science, proved itself to possess true prophetic power. We ought therefore ourselves sincerely to try every possible mode of conceiving the dawn of consciousness so that it may not appear equivalent to the irruption into the universe of a new nature, non-existent until then.

Merely to call the consciousness 'nascent' will not serve our turn.[7] It is true that the word signifies not yet quite born, and so seems to form a sort of bridge between existence and nonentity. But that is a verbal quibble. The fact is that discontinuity comes in if a new nature comes in at all. The quantity of the latter is quite immaterial. The girl in 'Midshipman Easy' could not excuse the illegitimacy of her child by saying, 'it was a very small one.' And Consciousness, however small, is an illegitimate birth in any philosophy that starts without it, and yet professes to explain all facts by continuous evolution.

If evolution is to work smoothly, consciousness in some shape must have been present at the very origin of things. Accordingly we find that the more clear-sighted evolutionary philosophers are beginning to posit it there. Each atom of the nebula, they suppose, must have had an aboriginal atom of consciousness linked with it; and, just as the material atoms have formed bodies and brains by massing themselves together, so the mental atoms, by an analogous process of aggregation, have fused into those larger consciousnesses which we know in ourselves and suppose to exist in our fellow-animals. Some such doctrine of atomistic hylozoism as this is an indispensable part of a thorough-going philosophy of evolution. According to it there must be an infinite number of degrees of conscious- ness, following the degrees of complication and aggregation of the primordial mind-dust. To prove the separate existence of these degrees of consciousness by indirect evidence, since direct intuition of them is not to be had, becomes therefore the first duty of psychological evolutionism.

SOME ALLEGED PROOFS THAT MIND-DUST EXISTS. Some of this duty we find already performed by a number of philosophers who, though not interested at all in evolution, have nevertheless on independent grounds convinced themselves of the existence of a vast amount of sub-conscious mental life. The criticism of this general opinion and its grounds will have to be postponed for a while. At present let us merely deal with the arguments assumed to prove aggregation of bits of mind-stuff into distinctly sensible feelings. They are clear and admit of a clear reply.

The German physiologist A. Fick, in 1862, was, so far as I know, the first to use them. He made experiments on the discrimination of the feelings of warmth and of touch, when only a very small portion of the skin was excited through a hole in a card, the surrounding parts being protected by the card. He found that under these circumstances mistakes were frequently made by the patient,[8] and concluded that this must be because the number of sensations from the elementary nerve-tips affected was too small to sum itself distinctly into either of the qualities of feeling in question. He tried to show how a different manner of the summation might give rise in one case to the heat and in another to the touch.

" A feeling of temperatures," he says," arises when the intensities of the units of feeling are evenly gradated, so that between two elements a and b no other unit can spatially intervene whose intensity is not also between that of a and b. A feeling of contact perhaps arises when this condition is not fulfilled. Both kinds of feeling, however, are composed of the same units."

But it is obviously far clearer to interpret such a gradation of intensities as a brain-fact than as a mind-fact. If in the brain a tract were first excited in one of the ways suggested by Prof. Fick, and then again in the other, it might very well happen, for aught we can say to the contrary, that the psychic accompaniment in the one case would be heat, and in the other pain. The pain and the heat would, however, not be composed of psychic units, but would each be the direct result of one total brain-process. So long as this latter interpretation remains open, Fick cannot be held to have proved psychic summation.

Later, both Spencer and Taine, independently of each other, took up the same line of thought. Mr. Spencer's reasoning is worth quoting in extenso. He writes:

"Although the individual sensations and emotions, real or ideal, of which consciousness is built up, appear to be severally simple, homogeneous, unanalyzable, or of inscrutable natures, yet they are not so. There is at least one kind of feeling which, as ordinarily experienced, seems elementary, that is demonstrably not elementary. And after resolving it into its proximate components, we can scarcely help suspecting that other apparently-elementary feelings are also compound, and may have proximate components like those which we can in this one instance identify.

"Musical sound is the name we give to this seemingly simple feeling which is clearly resolvable into simpler feelings. Well known experiments prove that when equal blows or taps are made one after another at a rate not exceeding some sixteen per second, the effect of each is perceived as a separate noise; but when the rapidity with which the blows follow one another exceeds this, the noises are no longer identified in separate states of consciousness, and there arises in place of them a continuous state of consciousness, called a tone. In further increasing the rapidity of the blows, the tone undergoes the change of quality distinguished as rise in pitch; and it continues to rise in pitch as the blows continue to increase in rapidity, until it reaches an acuteness beyond which it is no longer appreciable as a tone. So that out of units of feeling of the same kind, many feelings distinguishable from one another in quality result, according as the units are more or less integrated.

"This is not all. The inquiries of Professor Helmholtz have shown that when, along with one series of these rapidly-recurring noises, there is generated another series in which the noises are more rapid though not so loud, the effect is a change in that quality known as its timbre. As various musical instruments show us, tones which are alike in pitch and strength are distinguishable by their harshness or sweetness, their ringing or their liquid characters; and all their specific peculiarities are proved to arise from the combination of one, two, three, or more, supplementary series of recurrent noises with the chief series of recurrent noises. So that while the unlikenesses of feeling known as differences of pitch in tones are due to differences of integration among the recurrent noises of one series, the unlikenesses of feeling known as differences of timbre, are due to the simultaneous integration with this series of other series having other degrees of integration. And thus an enormous number of qualitatively-contrasted kinds of consciousness that seem severally elementary prove to be composed of one simple kind of consciousness, combined and recombined with itself in multitudinous ways.

"Can we stop short here? If the different sensations known as sounds are built out of a common unit, is it not to be rationally inferred that so likewise are the different sensations known as tastes, and the different sensations known as odors, and the different sensations known as colors? Nay, shall we not regard it as probable that there is a unit common to all these strongly-contrasted classes of sensations? If the unlikenesses among the sensations of each class may be due to unlikenesses among the modes of aggregation of a unit of consciousness common to them all; so too may the much greater unlikenesses between the sensations of each class and those of other classes. There may be a single primordial element of consciousness, and the countless kinds of consciousness may be produced by the compounding of this element with itself and the recompounding of its compounds with one another in higher and higher degrees; so producing increased multiplicity, variety, and complexity.

"Have we any clue to this primordial element? I think we have. That simple mental impression which proves to be the unit of composition of the sensation of musical tone, is allied to certain other simple mental impressions differently originated. The subjective effect produced by a crack or noise that has no appreciable duration is little else than a nervous shock. Though we distinguish such a nervous shock as belonging to what we call sounds, yet it does not differ very much from nervous shocks of other kinds. An electric discharge sent through the body causes a feeling akin to that which a sudden loud report causes. A strong unexpected impression made through the eyes, as by a flash of lightning, similarly gives rise to a start or shock; and though the feeling so named seems, like the electric shock, to have the body at large for its seat, and may therefore be regarded as the correlative rather of the efferent than of the afferent disturbance yet on remembering the mental change that results from the instantaneous transit of an object across the field of vision, I think it may be perceived that the feeling accompanying the efferent disturbance is itself reduced very nearly to the same form. The state of consciousness so generated is, in fact, comparable in quality to the initial state of consciousness caused by a blow (distinguishing it from the pain or other feeling that commences the instant after); which state of consciousness caused by a blow may be taken as the primitive and typical form of the nervous shock. The fact that sudden brief disturbances thus set up by different stimuli through different sets of nerves cause feelings scarcely distinguishable in quality will not appear strange when we recollect that distinguishableness of feeling implies appreciable duration; and that when the duration is greatly abridged, nothing more is known than that some mental change has occurred and ceased. To have a sensation of redness, to know a tone as acute or grave, to be conscious of a taste as sweet, implies in each case a considerable continuity of state. If the state does not last long enough to admit of its being contemplated, it cannot be classed as of this or that kind; and becomes a momentary modification very similar to momentary modifications otherwise caused.

"It is possible, then - may we not even say probable? - that something of the same order as that which we call nervous shock is the ultimate unit of consciousness, and that all the unlikenesses among our feelings result from unlike modes of integration of this ultimate unit. I say of the same order, because there are discernible differences among nervous shocks that are differently caused; and the primitive nervous shock probably differs somewhat form each of them. And I say of the same order, for the further reason that while we may ascribe to them a general likeness in nature, we must suppose a great unlikeness in degree. The nervous shocks recognized as such are violent - must be violent before they can be perceived amid the procession of multitudinous vivid feelings suddenly interrupted by them. But the rapidly-recurring nervous shocks of which the different forms of feeling consist, we must assume to be of comparatively moderate, or even of very slight intensity. Were our various sensations and emotions composed of rapidly-recurring shocks as strong as those ordinarily called shocks, they would be unbearable; indeed life would cease at once. We must think of them rather as successive faint pulses of subjective change, each having the same quality as the strong pulse of subjective change distinguished as a nervous shock." [9]

REFUTATION OF THESE PROOFS. Convincing as this argument of Mr. Spencer's may appear on a first reading, it is singular how weak it really is.[10] We do, it is true, when we study the connection between a musical note and its outward cause, find the note simple and continuous while the cause is multiple and discrete. Somewhere, then, there is a transformation, reduction, or fusion. The question is, Where - in the nerve-world or in the mind-world? Really we have no experimental proof by which to decide; and if decide we must, analogy and a priori probability can alone guide us. Mr. Spencer assumes that the fusion must come to pass in the mental world, and that the physical processes get through air and ear, auditory nerve and medulla, lower brain and hemispheres, without their number being reduced. Figure 25, on the previous page, will make the point clear.

Let the line a - b represent the threshold of consciousness: then everything drawn below that line will symbolize a physical process, everything above it will mean a fact of mind. Let the crosses stand for the physical blows, the circles for the events in successively higher orders of nerve-cells, and the horizontal marks for the facts of feeling. Spencer's argument implies that each order of cells transmits just as many impulses as it receives to the cells above it; so that if the blows come at the rate of 20,000 in a second the cortical cells discharge at the same rate, and one unit of feeling corresponds to each one of the 20,000 discharges. Then, and only then, does 'integration' occur, by the 20,000 units of feeling 'compounding with themselves' into the 'continuous state of consciousness' represented by the short line at the top of the figure.

Now such an interpretation as this flies in the face of physical analogy, no less than of logical intelligibility. Consider physical analogy first.

A pendulum may be deflected by a single blow, and swing back. Will it swing back the more often the more we multiply the blows? No; for it they rain upon the pendulum too fast, it will not swing at all but remain deflected in a sensibly stationary state. In other words, increasing the cause numerically need not equally increase numerically the effect. Blow through a tube: you get a certain musical note; and increasing the blowing increases for a certain time the loudness of the note. Will this be true indefinitely? No; for when a certain force is reached, the note, instead of growing louder, suddenly disappears and is replaced by its higher octave. Turn on the gas slightly and light it: you get a tiny flame. Turn on more gas, and the breadth of the flame increases. Will this relation increase indefinitely? No, again; for at a certain moment up shoots the flame into a ragged streamer and begins to hiss. Send slowly through the nerve of a frog's gastrocnemius muscle a succession of galvanic shocks: you get a succession of twitches. Increasing the number of shocks does not increase the twitching; on the contrary, it stops it, and we have the muscle in the apparently stationary state of contraction called tetanus. This last fact is the true analogue of what must happen between the nerve-cell and the sensory fibre. It is certain that cells are more inert than fibres, and that rapid vibrations in the latter can only arouse relatively simple processes or states in the former. The higher cells may have even a slower rate of explosion than the lower, and so the twenty thousand supposed blows of the outer air may be 'integrated' in the cortex into a very small number of cell-discharges in a second. This other diagram will serve to contrast this supposition with Spencer's. In Fig. 26 all 'integration' occurs below the threshold of consciousness. The frequency of cell-events becomes more and more reduced as we approach the cells to which feeling is most directly attached, until at last we come to a condition of things symbolized by the larger ellipse, which may be taken to stand for some rather massive and slow process of tension and discharge in the cortical centres, to which, as a whole, the feeling of musical tone symbolized by the line at the top of the diagram simply and totally corresponds. It is as if a long file of men were to start one after the other to reach a distant point. The road at first is good and they keep their original distance apart. Presently it is intersected by bogs each worse than the last, so that the front men get so retarded that the hinder ones catch up with them before the journey is done, and all arrive together at the goal.[11]

On this supposition there are no unperceived units of mind-stuff preceding and composing the full consciousness. The latter is itself an immediate psychic fact and bears an immediate relation to the neural state which is its unconditional accompaniment. Did each neural shock give rise to its own psychic shock, and the psychic shocks then combine, it would be impossible to understand why severing one part of the central nervous system from another should break up the integrity of the consciousness. The cut has nothing to do with the psychic world. The atoms of mind-stuff ought to float off from the nerve-matter on either side of it, and come together over it and fuse, just as well as if it had not been made. We know, however, that they do not; that severance of the paths of conduction between a man's left auditory centre or optical centre and the rest of his cortex will sever all communication between the words which he hears or sees written and the rest of his ideas.

Moreover, if feelings can mix into a tertium quid, why do we not take a feeling of greenness and a feeling of redness, and make a feeling of yellowness out of them? Why has optics neglected the open road to truth, and wasted centuries in disputing about theories of color-composition which two minutes of introspection would have settled forever?[12] We cannot mix feelings as such, though we may mix the objects we feel, and from their mixture get new feelings. We cannot even (as we shall later see) have two feelings in our mind at once. At most we can compare together objects previously presented to us in distinct feelings; but then we find each object stubbornly maintaining its separate identity before consciousness, whatever the verdict of the comparison may be.[13]

SELF-COMPOUNDING OF MENTAL FACTS IS INADMISSIBLE. But there is a still more fatal objection to the theory of mental units 'compounding with themselves' or 'integrating.' It is logically unintelligible; it leaves out the essential feature of all the 'combinations' we actually know.

All the 'combinations' which we actually know are EFFECTS, wrought by the units said to be 'combined,' UPON SOME ENTITY OTHER THAN THEMSELVES. Without this feature of a medium or vehicle, the notion of combination has no sense.

"A multitude of contractile units, by joint action, and by being all connected, for instance, with a single tendon, will pull at the same, and will bring about a dynamical effect which is undoubtedly the resultant of their combined individual energies.... On the whole, tendons are to muscular fibres, and bones are to tendons, combining recipients of mechanical energies. A medium of composition is indispensable to the summation of energies. To realize the complete dependence of mechanical resultants on a combining substratum, one may fancy for a moment all the individually contracting muscular elements severed from their attachments. They might then still be capable of contracting with the same energy as before, yet no co-operative result would be accomplished. The medium of dynamical combination would be wanting. The multiple energies, singly exerted on no common recipient, would lose themselves on entirely isolated and disconnected efforts."[14]

In other words, no possible number of entities (call them as you like, whether forces, material particles, or mental elements) can sum themselves together. Each remains, in the sum, what it always was; and the sum itself exists only for a bystander who happens to overlook the units and to apprehend the sum as such; or else it exists in the shape of some other effect on an entity external to the sum itself. Let it not be objected that H2 and O combine of themselves into 'water,' and thenceforward exhibit new properties. They do not. The 'water' is just the old atoms in the new position, H-O-H; the 'new properties' are just their combined effects, when in this position, upon external media, such as our sense-organs and the various reagents on which water may exert its properties and be known.

"Aggregations are organized wholes only when they behave as such in the presence of other things. A statue is an aggregation of particles of marble; but as such it has no unity. For the spectator it is one; in itself it is an aggregate; just as, to the consciousness of an ant crawling over it, it may again appear a mere aggregate. No summing up of parts can make an unity of a mass of discrete constituents, unless this unity exist for some other subject, not for the mass itself."[15]

Just so, in the parallelogram of forces, the 'forces' themselves do not combine into the diagonal resultant; a body is needed on which they may impinge, to exhibit their resultant effect. No more do musical sounds combine per se into concords or discords. Concord and discord are names for their combined effects on that external medium, the ear.

Where the elemental units are supposed to be feelings, the case is in no wise altered. Take a hundred of them, shuffle them and pack them as close together as you can (whatever that may mean); still each remains the same feeling it always was, shut in its own skin, windowless, ignorant of what the other feelings are and mean. There would be a hundred-and-first feeling there, if, when a group or series of such feelings were set up, a consciousness belonging to the group as such should emerge. And this 101st feeling would be a totally new fact; the 100 original feelings might, by a curious physical law, be a signal for its creation, when they came together; but they would have no substantial identity with it, nor it with them, and one could never deduce the one from the others, or (in any intelligible sense) say that they evolved it.

Take a sentence of a dozen words, and take twelve men and tell to each one word. Then stand the men in a row or jam them in a bunch, and let each think of his word as intently as he will; nowhere will there be a consciousness of the whole sentence.[16] We talk of the 'spirit of the age,' and the 'sentiment of the people,' and in various ways we hypostatize 'public opinion.' But we know this to be symbolic speech, and never dream that the spirit, opinion, sentiment, etc., constitute a consciousness other than, and additional to, that of the several individuals whom the words 'age,' 'people,' or 'public' denote. The private minds do not agglomerate into a higher compound mind. This has always been the invincible contention of the spiritualists against the associationists in Psychology, - a contention which we shall take up at greater length in Chapter X. The associationists say the mind is constituted by a multiplicity of distinct 'ideas' associated into a unity. There is, they say, an idea of a, and also an idea of b. Therefore, they say, there is an idea of a + b, or of a and b together. Which is like saying that the mathematical square of a plus that of b is equal to the square of a + b, a palpable untruth. Idea of a + idea of b is not identical with idea of (a + b). It is one, they are two; in it, what knows a also knows b; in them, what knows a is expressly posited as not knowing b; etc. In short, the two separate ideas can never by any logic be made to figure as one and the same thing as the 'associated' idea.

This is what the spiritualists keep saying; and since we do, as a matter of fact, have the 'compounded' idea, and do know a and b together, they adopt a farther hypothesis to explain that fact. The separate ideas exist, they say, but affect a third entity, the soul. This has the 'compounded' idea, if you please so to call it; and the compounded idea is an altogether new psychic fact to which the separate ideas stand in the relation, not of constituents, but of occasions of production.

This argument of the spiritualists against the associationists has never been answered by the latter. It holds good against any talk about self-compounding amongst feelings, against any 'blending,' or 'complication,' or 'mental chemistry,' or 'psychic synthesis,' which supposes a resultant consciousness to float off from the constituents per se, in the absence of a supernumerary principle of consciousness which they may affect. The mind-stuff theory, in short, is unintelligible. Atoms of feeling cannot compose higher feelings, any more than atoms of matter can compose physical things! The 'things,' for a clear-headed atomistic evolutionist, are not. Nothing is but the everlasting atoms. When grouped in a certain way, we name them this 'thing' or that; but the thing we name has no existence out of our mind. So of the states of mind which are supposed to be compound because they know many different things together. Since indubitably such states do exist, they must exist as single new facts, effects, possibly, as the spiritualists say, on the Soul (we will not decide that point here), but at any rate independent and integral, and not compounded of psychic atoms.[17]

CAN STATES OF MIND BE UNCONSCIOUS? The passion for unity and smoothness is in some minds so insatiate that, in spite of the logical clearness of these reasonings and conclusions, many will fail to be influenced by them. They establish a sort of disjointedness in things which in certain quarters will appear intolerable. They sweep away all chance of 'passing without break' either from the material to the mental, or from the lower to the higher mental; and they thrust us back into a pluralism of consciousness - each arising discontinuity in the midst of two disconnected worlds, material and mental - which is even worse than the old notion of the separate creation of each particular soul. But the malcontents will hardly try to refute our reasonings by direct attack. It is more probable that, turning their back upon them altogether, they will devote themselves to sapping and mining the region roundabout until it is a bog of logical liquefaction, into the midst of which all definite conclusions of any sort may be trusted ere long to sink and disappear.

Our reasonings have assumed that the 'integration' of a thousand psychic units must be either just the units over again, simply rebaptized, or else something real, but then other than and additional to those units; that if a certain existing fact is that of a thousand feelings, it cannot at the same time be that of ONE feeling; for the essence of feeling is to be felt, and as a psychic existent feels, so it must be. If the one feeling feels like no one of the thousand, in what sense can it be said to be the thousand? These assumptions are what the monists will seek to undermine. The Hegelizers amongst them will take high ground at once, and say that the glory and beauty of the psychic life is that in it all contradictions find their reconciliation; and that it is just because the facts we are considering are facts of the self that they are both one and many at the same time. With this intellectual temper I confess that I cannot contend. As in striking at some unresisting gossamer with a club, one but overreaches one's self, and the thing one aims at gets no harm. So I leave this school to its devices.

The other monists are of less deliquescent frame, and try to break down distinctness among metal states by making a distinction. This sounds paradoxical, but it is only ingenious. The distinction is that between the unconscious and the conscious being of the mental state. It is the sovereign means for believing what one likes in psychology, and of turning what might become a science into a tumbling-ground for whimsies. It has numerous champions, and elaborate reasons to give for itself. We must therefore accord it due consideration. In discussing the question:

DO UNCONSCIOUS MENTAL STATES EXIST? it will be best to give the list of so-called proofs as briefly as possible, and to follow each by its objection, as in scholastic books.[18]

First Proof. The minimum visible, the minimum audible, are objects composed of parts. How can the whole affect the sense unless each part does? And yet each part does so without being separately sensible. Leibnitz calls the total consciousness an 'aperception,' the supposed insensible consciousness by the name of 'petites perceptions.'

"To judge of the latter," he says, "I am accustomed to use the example of the roaring of the sea with which one is assailed when near the shore. To hear this noise as one does, on must hear the parts which compose its totality, that is, the noise of each wave,... although this noise would not be noticed if its wave were alone. One must be affected a little by the movement of one wave, one must have some perception of each several noise, however small it be. Otherwise one would not hear that of 100,000 waves, for of 100,000 zeros one can never make a quantity."[19]

Reply. This is an excellent example of the so-called 'fallacy of division,' or predicating what is true only of a collection, of each member of the collection distributively. It no more follows that if a thousand things together cause sensation, one thing alone must cause it, than it follows that if one pound weight moves a balance, then one ounce weight must move it too, in less degree. One ounce weight does not move it at all; its movement begins with the pound. At most we can say that each ounce affects it in some way which helps the advent of that movement. And so each infra-sensible stimulus to a nerve no doubt affects the nerve and helps the birth of sensation when the other stimuli come. But this affection is a nerve-affection, and there is not the slightest ground for supposing it to be a 'perception' unconscious of itself. "A certain quantity of the cause may be a necessary condition to the production of any of the effect,"[20] when the latter is a mental state.

Second Proof. In all acquired dexterities and habits, secondarily automatic performances as they are called, we do what originally required a chain of deliberately conscious perceptions and volitions. As the actions still keep their intelligent character, intelligence must still preside over their execution. But since our consciousness seems all the while elsewhere engaged, such intelligence must consist of unconscious perceptions, inferences, and volitions.

Reply. There is more than one alternative explanation in accordance with larger bodies of fact. One is that the perceptions and volitions in habitual actions may be performed consciously, only so quickly and inattentively that no memory of them remains. Another is that the consciousness of these actions exists, but is split-off from the rest of the consciousness of the hemispheres. We shall find in Chapter X numerous proofs of the reality of this split-off condition of portions of consciousness. Since in man the hemispheres indubitably co-operate in these secondarily automatic acts, it will not do to say either that they occur without consciousness or that their consciousness is that of the lower centres, which we know nothing about. But either lack of memory or split-off cortical consciousness will certainly account for all of the facts.[21]

Third Proof. Thinking of A, we presently find ourselves thinking of C. Now B is the natural logical link between A and C, but we have no consciousness of having thought of B. It must have been in our mind 'uncon- sciously,' and in that state affected the sequence of our ideas.

Reply. Here again we have a choice between more plausible explanations. Either B was consciously there, but the next instant forgotten, or its brain-tract alone was adequate to do the whole work of coupling A with C, without the idea B being aroused at all, whether consciously or 'unconsciously.'

Fourth Proof. Problems unsolved when we go to bed are found solved in the morning when we wake. Somnambulists do rational things. We awaken punctually at an hour predetermined overnight, etc. Unconscious thinking, volition, time-registration, etc., must have presided over these acts.

Reply. Consciousness forgotten, as in the hypnotic trance.

Fifth Proof. Some patients will often, in an attack of epileptiform unconsciousness, go through complicated processes, such as eating a dinner in a restaurant and paying for it, or making a violent homicidal attack. In trance, artificial or pathological, long and complex performances, involving the use of the reasoning powers, are executed, of which the patient is wholly unaware on coming to.

Reply. Rapid and complete oblivescence is certainly the explanation here. The analogue again is hypnoticism. Tell the subject of an hypnotic trance, during his trance, that he will remember, and he may remember everything perfectly when he awakes, though without your telling him no memory would have remained. The extremely rapid oblivescence of common dreams is a familiar fact.

Sixth Proof. In a musical concord the vibrations of the several notes are in relatively simple ratios. The mind must unconsciously count the vibrations, and be pleased by the simplicity which it finds.

Reply. The brain-process produced by the simple ratios may be as directly agreeable as the conscious process of comparing them would be. No counting, either conscious or 'unconscious,' is required.

Seventh Proof. Every hour we make theoretic judgments and emotional reactions, and exhibit practical tendencies, for which we can give no explicit logical justification, but which are good inferences from certain premises. We know more than we can say. Our conclusions run ahead of our power to analyze their grounds. A child, ignorant of the axiom that two things equal to the same are equal to each other, applies it nevertheless in his concrete judgments unerringly. A boor will use the dictum de omni et nullo who is unable to understand it in abstract terms.

"We seldom consciously think how our house is painted, what the shade of it is, what the pattern of our furniture is, or whether the door opens to the right or left, or out or in. But how quickly should we notice a change in any of these things! Think of the door you have most often opened, and tell, if you can, whether it opens to the right or left, out or in. Yet when you open the door you never put the hand on the wrong side to find the latch, nor try to push it when it opens with a pull.... What is the precise characteristic in your friend's step that enables you to recognize it when he is coming? Did you ever consciously think the idea, 'if I run into a solid piece of matter I shall get hurt, or be hindered in my progress'? and do you avoid running into obstacles because you ever distinctly conceived, or consciously acquired and thought, that idea?"[22]

Most of our knowledge is at all times potential. We act in accordance with the whole drift of what we have learned, but few items rise into consciousness at the time. Many of them, however, we may recall at will. All this co-operation of unrealized principles and facts, of potential knowledge, with our actual thought is quite inexplicable unless we suppose the perpetual existence of an immense mass of ideas in an unconscious state, all of them exerting a steady pressure and influence upon our conscious thinking, and many of them in such continuity with it as ever and anon to become conscious themselves.

Reply. No such mass of ideas is supposable. But there are all kinds of short-cuts in the brain; and processes not aroused strongly enough to give any 'idea' distinct enough to be a premise, may, nevertheless, help to determine just that resultant process of whose psychic accompaniment the said idea would be a premise, if the idea existed at all. A certain overtone may be a feature of my friend's voice, and may conspire with the other tones thereof to arouse in my brain the process which suggests to my consciousness his name. And yet I may be ignorant of the overtone per se, and unable, even when he speaks, to tell whether it be there or no. It leads me to the idea of the name; but it produces in me no such cerebral process as that to which the idea of the overtone would correspond. And similarly of our learning. Each subject we learn leaves behind it a modification of the brain, which makes it impossible for the latter to react upon things just as it did before; and the result of the difference may be a tendency to act, though with no idea, much as we should if we were consciously thinking about the subject. The becoming conscious of the latter at will is equally readily explained as a result of the brain-modification. This, as Wundt phrases it, is a 'predisposition' to bring forth the conscious idea of the original subject, a predisposition which other stimuli and brain-processes may convert into an actual result. But such a predisposition is no 'unconscious idea;' it is only a particular collocation of the molecules in certain tracts of the brain.

Eighth Proof. Instincts, as pursuits of ends by appropriate means, are manifestations of intelligence; but as the ends are not foreseen, the intelligence must be unconscious.

Reply. Chapter XXIV will show that all the phenomena of instinct are explicable as actions of the nervous system, mechanically discharged by stimuli to the senses.

Ninth Proof. In sense-perception we have results in abundance, which can only be explained as conclusions drawn by a process of unconscious inference from data given to sense. A small human image on the retina is referred, not to a pygmy, but to a distant man of normal size. A certain gray patch is inferred to be a white object seen in a dim light. Often the inference leads us astray: e.g., pale gray against pale green looks red, because we take a wrong premise to argue from. We think a green film is spread over everything; and knowing that under such a film a red thing would look gray, we wrongly infer from the gray appearance that a red thing must be there. Our study of space-perception in Chapter XVIII will give abundant additional examples both of the truthful and illu- sory percepts which have been explained to result from unconscious logic operations.

Reply. That chapter will also in many cases refute this explanation. Color- and light-contrast are certainly purely sensational affairs, in which inference plays no part. This has been satisfactorily proved by Hering,[23] and shall be treated of again in Chapter XVII. Our rapid judgments of size, shape, distance, and the like, are best explained as processes of simple cerebral association. Certain sense-impressions directly stimulate brain-tracts, of whose activity ready-made conscious percepts are the immediate psychic counterparts. They do this by a mechanism either connate or acquired by habit. It is to be remarked that Wundt and Helmholtz, who in their earlier writings did more than any one to give vogue to the notion that unconscious inference is a vital factor in sense-perception, have seen fit on later occasions to modify their views and to admit that results like those of reasoning may accrue without any actual reasoning process unconsciously taking place.[24] Maybe the excessive and riotous applications made by Hartmann of their principle have led them to this change. It would be natural to feel towards him as the sailor in the story felt towards the horse who got his foot into the stirrup, - "If you're going to get on, I must get off."

Hartmann fairly boxes the compass of the universe with the principle of unconscious thought. For him there is no namable thing that does not exemplify it. But his logic is so lax and his failure to consider the most obvious alternatives so complete that it would, on the whole, be a waste of time to look at his arguments in detail. The same is true of Schopenhauer, in whom the mythology reaches its climax. The visual perception, for example, of an object in space results, according to him, from the intellect performing the following operations, all unconscious. First, it apprehends the inverted retinal image and turns it right side up, constructing flat space as a preliminary operation; then it computes from the angle of convergence of the eyeballs that the two retinal images must be the projection of but a single object; thirdly, it constructs the third dimension and sees this object solid; fourthly, it assigns its distance; and fifthly, in each and all of these operations it gets the objective character of what it 'constructs' by unconsciously inferring it as the only possible cause of some sensation which it unconsciously feels.[25] Comment on this seems hardly called for. It is, as I said, pure mythology.

None of these facts, then, appealed to so confidently in proof of the existence of ideas in an unconscious state, prove anything of the sort. They prove either that conscious ideas were present which the next instant were forgotten; or they prove that certain results, similar to results of reasoning, may be wrought out by rapid brain-processes to which no ideation seems attached. But there is one more argument to be alleged, less obviously insufficient than those which we have reviewed, and demanding a new sort of reply.

Tenth Proof. There is a great class of experiences in our mental life which may be described as discoveries that a subjective condition which we have been having is really something different from what we had supposed. We suddenly find ourselves bored by a thing which we thought we were enjoying well enough; or in love with a person whom we imagined we only liked. Or else we deliberately analyze our motives, and find that at bottom they contain jealousies and cupidities which we little suspected to be there. Our feelings towards people are perfect wells of motivation, unconscious of itself, which introspection brings to light. And our sensations likewise: we constantly discover new elements in sensations which we have been in the habit of receiving all our days, elements, too, which have been there from the first, since otherwise we should have been unable to distinguish the sensations containing them from others nearly allied. The elements must exist, for we use them to discriminate by; but they must exist in an unconscious state, since we so completely fail to single them out.[26] The books of the analytic school of psychology abound in examples of the kind. Who knows the countless associations that mingle with his each and every thought? Who can pick apart all the nameless feelings that stream in at every moment from his various internal organs, muscles, heart, glands, lungs, etc., and compose in their totality his sense of bodily life? Who is aware of the part played by feelings of innervation and suggestions of possible muscular exertion in all his judgments of distance, shape, and size? Consider, too, the difference between a sensation which we simply have and one which we attend to. Attention gives results that seem like fresh creations; and yet the feelings and elements of feeling which it reveals must have been already there - in an unconscious state. We all know practically the difference between the so-called sonant and the so-called surd consonants, between D, B, Z, G, V, and T, P, S, K, F, respectively. But comparatively few persons know the difference theoretically, until their attention has been called to what it is, when they perceive it readily enough. The sonants are nothing but the surds plus a certain element, which is alike in all, superadded. That element is the laryngeal sound with which they are uttered, surds having no such accompaniment. When we hear the sonant letter, both its component elements must really be in our mind; but we remain unconscious of what they really are, and mistake the letter for a simple quality of sound until an effort of attention teaches us its two components. There exist a host of sensations which most men pass through life and never attend to, and consequently have only in an unconscious way. The feelings of opening and closing the glottis, of making tense the tympanic membrane, of accommodating for near vision, of intercepting the passage from the nostrils to the throat, are instances of what I mean. Every one gets these feelings many times an hour; but few readers, probably, are conscious of exactly what sensations are meant by the names I have just used. All these facts, and an enormous number more, seem to prove conclusively that, in addition to the fully conscious way in which an idea may exist in the mind, there is also an unconscious way; that it is unquestionably the same identical idea which exists in these two ways; and that therefore any arguments against the mind-stuff theory, based on the notion that esse in our mental life is sentiri, and that an idea must consciously be felt as what it is, fall to the ground.

Objection. These reasonings are one tissue of confusion. Two states of mind which refer to the same external reality, or two states of mind the later one of which refers to the earlier, are described as the same state of mind, or 'idea,' published as it were in two editions; and then whatever qualities of the second edition are found openly lacking in the first are explained as having really been there, only in an 'unconscious' way. It would be difficult to believe that intelligent men could be guilty of so patent a fallacy, were not the history of psychology there to give the proof. The psychological stock-in-trade of some authors is the belief that two thoughts about one thing are virtually the same thought, and that this same thought may in subsequent reflections become more and more conscious of what it really was all along from the first. But once make the distinction between simply having an idea at the moment of its presence and subsequently knowing all sorts of things about it; make moreover that between a state of mind itself, taken as a subjective fact, on the one hand, and the objective thing it knows, on the other, and one has no difficulty in escaping from the labyrinth.

Take the latter distinction first: Immediately all the arguments based on sensations and the new features in them which attention brings to light fall to the ground. The sensations of the B and the V when we attend to these sounds and analyze out the laryngeal contribution which makes them differ from P and F respectively, are different sensations from those of the B and the V taken in a simple way. They stand, it is true, for the same letters, and thus mean the same outer realities; but they are different mental affections, and certainly depend on widely different processes of cerebral activity. It is unbelievable that two mental states so different as the passive reception of a sound as a whole, and the analysis of that whole into distinct ingredients by voluntary attention, should be due to processes at all similar. And the subjective difference does not consist in that the first-named state is the second in an 'unconscious' form. It is an absolute psychic difference, even greater than that between the states to which two different surds will give rise. The same is true of the other sensations chosen as examples. The man who learns for the first time how the closure of his glottis feels, experiences in this discovery an absolutely new psychic modification, the like of which he never had before. He had another feeling before, a feeling incessantly renewed, and of which the same glottis was the organic starting point; but that was not the later feeling in an 'unconscious' state; it was a feeling sui generis altogether, although it took cognizance of the same bodily part, the glottis. We shall see, hereafter, that the same reality can be cognized by an endless number of psychic states, which may differ toto coelo among themselves, without ceasing on that account to refer to the reality in question. Each of them is a conscious fact; none of them has any mode of being whatever except a certain way of being felt at the moment of being present. It is simply unintelligible and fantastical to say, because they point to the same outer reality, that they must therefore be so many editions of the same 'idea,' now in conscious and now in an 'unconscious' phase. There is only one 'phase' in which an idea can be, and that is a fully conscious condition. If it is not in that condition, then it is not at all. Something else is, in its place. The something else may be a merely physical brain-process, or it may be another conscious idea. Either of these things may perform much the same function as the first idea, refer to the same object, and roughly stand in the same relations to the upshot of our thought. But that is no reason why we should throw away the logical principle of identity in psychology, and say that, however it may fare in the outer world, the mind at any rate is a place in which a thing can be all kinds of other things without ceasing to be itself as well.

Now take the other cases alleged, and the other distinc- tion, that namely between having a mental state and knowing all about it. The truth is here even simpler to unravel. When I decide that I have, without knowing it, been for several weeks in love, I am simply giving a name to a state which previously I have not named, but which was fully conscious; which had no residual mode of being except the manner in which it was conscious; and which, though it was a feeling towards the same person for whom I now have much more inflamed feeling, and though it continuously led into the latter, and is similar enough to be called by the same name, is yet in no sense identical with the latter, and least of all in an 'unconscious' way. Again, the feelings from our viscera and other dimly-felt organs, the feelings of innervation (if such there be), and those of muscular exertion which, in our spatial judgments, are supposed unconsciously to determine what we shall perceive, are just exactly what we feel them, perfectly determinate conscious states, not vague editions of other conscious states. They may be faint and weak; they may be very vague cognizers of the same realities which other conscious states cognize and name exactly; they may be unconscious of much in the reality which the other states are conscious of. But that does not make them in themselves a whit dim or vague or unconscious. They are eternally as they feel when they exist, and can, neither actually nor potentially, be identified with anything else than their own faint selves. A faint feeling may be looked back upon and classified and understood in its relations to what went before or after it in the stream of thought. But it, on the one hand, and the later state of mind which knows all these things about it, on the other, are surely not two conditions, one conscious and the other 'unconscious,' of the same identical psychic fact. It is the destiny of thought that, on the whole, our early ideas are superseded by later ones, giving fuller accounts of the same realities. But none the less do the earlier and the later ideas preserve their own several substantive identities as so many several successive states of mind. To believe the contrary would make any definite science of psychology impossible. The only identity to be found among our successive ideas is their similarity of cognitive or representa- tive function as dealing with the same objects. Identity of being, there is none; and I believe that throughout the rest of this volume the reader will reap the advantages of the simpler way of formulating the facts which is here begun.[27]

So we seem not only to have ascertained the unintelligibility of the notion that a mental fact can be two things at once, and that what seems like one feeling, of blueness for example, or of hatred, may really and 'unconsciously' be ten thousand elementary feelings which do not resemble blueness or hatred at all, but we find that we can express all the observed facts in other ways. The mind- stuff theory, however, though scotched, is, we may be sure, not killed. If we ascribe consciousness to unicellular animalcules, then single cells can have it, and analogy should make us ascribe it to the several cells of the brain, each individually taken. And what a convenience would it not be for the psychologist if, by the adding together of various doses of this separate-cell-consciousness, he could treat thought as a kind of stuff or material, to be measured out in great or small amount, increased and subtracted from and baled about at will! He feels an imperious craving to be allowed to construct synthetically the successive mental states which he describes. The mind-stuff theory so easily admits of the construction being made, that it seems certain that 'man's unconquerable mind' will devote much future pertinacity and ingenuity to setting it on its legs again and getting it into some sort of plausible working-order. I will therefore conclude the chapter with some consideration of the remaining difficulties which beset the matter as it at present stands.

DIFFICULTY OF STATING THE CONNECTION BETWEEN MIND AND BRAIN. It will be remembered that in our criticism of the theory of the integration of successive conscious units into a feeling of musical pitch, we decided that whatever integration there was was that of the air-pulses into a simpler and simpler sort of physical effect, as the propagations of material change got higher and higher in the nervous system. At last, we said (p. 23), there results some simple and massive process in the auditory centres of the hemispherical cortex, to which, as a whole, the feeling of musical pitch directly corresponds. Already, in discussing the localization of functions in the brain, I had said (pp.158-9) that consciousness accompanies the stream of innervation through that organ and varies in quality with the character of the currents, being mainly of things seen if the occipital lobes are much involved, of things heard if the action is focalized in the temporal lobes, etc., etc.; and I had added that a vague formula like this was as much as one could safely venture on in the actual state of physiology. The facts of mental deafness and blindness, of auditory and optical aphasia, show us that the whole brain must act together if certain thoughts are to occur. The consciousness, which is itself an integral thing not made of parts, 'corresponds' to the entire activity of the brain, whatever that may be, at the moment. This is a way of expressing the relation of mind and brain from which I shall not depart during the remainder of the book, because it expresses the bare phenomenal fact with no hypothesis, and is exposed to no such logical objections as we have found to cling to the theory of ideas in combination.

Nevertheless, this formula which is so unobjectionable if taken vaguely, positivistically, or scientifically, as a mere empirical law of concomitance between our thoughts and our brain, tumbles to pieces entirely if we assume to represent anything more intimate or ultimate by it. The ultimate of ultimate problems, of course, in the study of the relations of thought and brain, is to understand why and how such disparate things are connected at all. But before that problem is solved (if it ever is solved) there is a less ultimate problem which must first be settled. Before the connection of thought and brain can be explained, it must at least be stated in an elementary form; and there are great difficulties about so stating it. To state it in elementary form one must reduce it to its lowest terms and know which mental fact and which cerebral fact are, so to speak, in immediate juxtaposition. We must find the minimal mental fact whose being reposes directly on a brain-fact; and we must similarly find the minimal brain-event which will have a mental counterpart at all. Between the mental and the physical minima thus found there will be an immediate relation, the expression of which, if we had it, would be the elementary psycho-physic law.

Our own formula escapes the unintelligibility of psychic atoms by taking the entire thought (even of a complex object) as the minimum with which it deals on the mental side. But in taking the entire brain-process as its minimal fact on the material side it confronts other difficulties almost as bad.

In the first place, it ignores analogies on which certain critics will insist, those, namely, between the composition of the total brain-process and that of the object of the thought. The total brain-process is composed of parts, of simultaneous processes in the seeing, the hearing, the feeling, and other centres. The object thought of is also composed of parts, some of which are seen, others heard, others perceived by touch and muscular manipulation. "How then," these critics will say, "should the thought not itself be composed of parts, each the counterpart of a part of the object and of a part of the brain-process?" So natural is this way of looking at the matter that it has given rise to what is on the whole the most flourishing of all psychological systems - that of the Lockian school of associated ideas - of which school the mind-stuff theory is nothing but the last and subtlest offshoot.

The second difficulty is deeper still. The 'entire brain-process' is not a physical fact at all. It is the appearance to an onlooking mind of a multitude of physical facts. 'Entire brain' is nothing but our name for the way in which a million of molecules arranged in certain positions may affect our sense. On the principles of the corpuscular or mechanical philosophy, the only realities are the separate molecules, or at most the cells. Their aggregation into a 'brain' is a fiction of popular speech. Such a fiction cannot serve as the objectively real counterpart to any psychic state whatever. Only a genuinely physical fact can so serve. But the molecular fact is the only genuine physical fact - whereupon we seem, if we are to have an elementary psycho-physic law at all, thrust right back upon something like the mind-stuff theory, for the molecular fact, being an element of the 'brain,' would seem naturally to correspond, not to the total thoughts, but to elements in the thought.

What shall we do? Many would find relief at this point in celebrating the mystery of the Unknowable and the 'awe' which we should feel at having such a principle to take final charge of our perplexities. Others would rejoice that the finite and separatist view of things with which we started had at last developed its contradictions, and was about to lead us dialectically upwards to some 'higher synthesis' in which inconsistencies cease from troubling and logic is at rest. It may be a constitutional infirmity, but I can take no comfort in such devices for making a luxury of intellectual defeat. They are but spiritual chloroform. Better live on the ragged edge, better gnaw the file forever!

THE MATERIAL - MONAD THEORY. The most rational thing to do is to suspect that there may be a third possibility, an alternative supposition which we have not considered. Now there is an alternative supposition - a supposition moreover which has been frequently made in the history of philosophy, and which is freer from logical objections than either of the views we have ourselves discussed. It may be called the theory of polyzoism or multiple monadism; and it conceives the matter thus:

Every brain-cell has its own individual consciousness, which no other cell knows anything about, all individual consciousness being 'ejective' to each other. There is, however, among the cells one central or pontifical one to which our consciousness is attached. But the events of all the other cells physically influence this arch-cell; and through producing their joint effects on it, these other cells may be said to 'combine.' The arch-cell is, in fact, one of those 'external media' without which we saw that no fusion or integration of a number of things can occur. The physical modifications of the arch-cell thus form a sequence of results in the production whereof every other cell has a share, so that, as one might say, every other cell is represented therein. And similarly, the conscious correlates to these physical modifications form a sequence of thoughts or feelings, each one of which is, as to its substantive being, an integral and uncompounded psychic thing, but each one of which may (in the exercise of its cognitive function) be aware of THINGS many and complicated in proportion to the number of other cells that have helped to modify the central cell.

By a conception of this sort, one incurs neither of the internal contradictions which we found to beset the other two theories. One has no unintelligible self-combining of psychic units to account for on the one hand; and on the other hand, one need not treat as the physical counterpart of the stream of consciousness under observation, a 'total brain-activity' which is non-existent as a genuinely physiological fact. But, to offset these advantages, one has physiological difficulties and improbabilities. There is no cell or group of cells in the brain of such anatomical or functional pre-eminence as to appear to be the keystone or centre of gravity of the whole system. And even if there were such a cell, the theory of multiple monadism would, in strictness of thought, have no right to stop at it and treat it as a unit. The cell is no more a unit, materially considered, than the total brain is a unit. It is a compound of molecules, just as the brain is a compound of cells and fibres. And the molecules, according to the prevalent physical theories, are in turn compounds of atoms. The theory in question, therefore, if radically carried out, must set up for its elementary and irreducible psycho-physic couple, not the cell and its consciousness, but the primordial and eternal atom and its consciousness. We are back at Leibnitzian monadism, and therewith leave physiology behind us and dive into regions inaccessible to experience and verification; and our doctrine, although not self-contradictory, becomes so remote and unreal as to be almost as bad as if it were. Speculative minds alone will take an interest in it; and metaphysics, not psychology, will be responsible for its career. That the career may be a successful one must be admitted as a possibility - a theory which Leibnitz, Herbart, and Lotze have taken under their protection must have some sort of a destiny.

THE SOUL - THEORY. But is this my last word? By no means. Many readers have certainly been saying to themselves for the last few pages: "Why on earth doesn't the poor man say the Soul and have done with it?" Other readers, of antispiritualistic training and prepossessions, advanced thinkers, or popular evolutionists, will perhaps be a little sur- prised to find this much-despised word now sprung upon them at the end of so physiological a train of thought. But the plain fact is that all the arguments for a 'pontifical cell' or an 'arch-monad' are also arguments for that well-known spiritual agent in which scholastic psychology and common-sense have always believed. And my only reason for beating the bushes so, and not bringing it in earlier as a possible solution of our difficulties, has been that by this procedure I might perhaps force some of these materialistic minds to feel the more strongly the logical respectability of the spiritualistic position. The fact is that one cannot afford to despise any of these great traditional objects of belief. Whether we realize it or not, there is always a great drift of reasons, positive and negative, towing us in their direction. If there be such entities as Souls in the universe, they may possibly be affected by the manifold occurrences that go on in the nervous centres. To the state of the entire brain at a given moment they may respond by inward modifications of their own. These changes of state may be pulses of consciousness, cognitive of objects few or many, simple or complex. The soul would be thus a medium upon which (to use our earlier phraseology) the manifold brain-processes combine their effects. Not needing to consider it as the 'inner aspect' of any arch-molecule or brain-cell, we escape that physiological improbability; and as its pulses of consciousness are unitary and integral affairs from the outset, we escape the absurdity of supposing feelings which exist separately and then 'fuse together' by themselves. The separateness is in the brain-world, on this theory, and the unity in the soul-world; and the only trouble that remains to haunt us is the metaphysical one of understanding how one sort of world or existent thing can affect or influence another at all. This trouble, however, since it also exists inside of both worlds, and involves neither physical improbability nor logical contradiction, is relatively small.

I confess, therefore, that to posit a soul influenced in some mysterious way by the brain-states and responding to them by conscious affections of its own, seems to me the line of least logical resistance, so far as we yet have attained.

If it does not strictly explain anything, it is at any rate less positively objectionable than either mind-stuff or a material-monad creed. The bare PHENOMENON, however, the IMMEDIATELY KNOWN thing which on the mental side is in apposition with the entire brain-process is the state of consciousness and not the soul itself. Many of the stanchest believers in the soul admit that we know it only as an inference from experiencing its states. In Chapter X, accordingly, we must return to its consideration again, and ask ourselves whether, after all, the ascertainment of a blank unmediated correspondence, term for term, of the succession of states of consciousness with the succession of total brain-processes, be not the simplest psycho-physic formula, and the last word of a psychology which contents itself with verifiable laws, and seeks only to be clear, and to avoid unsafe hypotheses. Such a mere admission of the empirical parallelism will there appear the wisest course. By keeping to it, our psychology will remain positivistic and non-metaphysical; and although this is certainly only a provisional halting-place, and things must some day be more thoroughly thought out, we shall abide there in this book, and just as we have rejected mind-dust, we shall take no account of the soul. The spiritualistic reader may nevertheless believe in the soul if he will; whilst the positivistic one who wishes to give a tinge of mystery to the expression of his positivism can continue to say that nature in her unfathomable designs has mixed us of clay and flame, of brain and mind, that the two things hang indubitably together and determine each other's being, but how or why, no mortal may ever know.

Footnotes [1] Psychol. � 62.

[2] Ibid. � 272.

[3] Fragments of Science, 5th ed., p. 420.

[4] Belfast Address, 'Nature,' August 20, 1874, p. 318. I cannot help remarking that the disparity between motions and feelings on which these authors lay so much stress, is somewhat less absolute than at first sight it seems. There are categories common to the two worlds. Not only temporal succession (as Helmholtz admits, Physiol. Optik, p. 445), but such attributes as intensity, volume, simplicity or complication, smooth or impeded change, rest or agitation, are habitually predicated of both physical facts and mental facts. Where such analogies obtain, the things do have something in common.

[5] Psychology, � 131.

[6] 'Nature,' as above, 317-8.

[7] 'Nascent' is Mr. Spencer's great word. In showing how at a certain point consciousness must appear upon the evolving scene this author fairly outdoes himself in vagueness. "In its higher forms, Instinct is probably accompanied by a rudimentary consciousness. There cannot be co-ordination of many stimuli without some ganglion through which they are all brought into relation. In the process of bringing them into relation, this ganglion must be subject to the influence of each - must undergo many changes. And the quick succession of changes in a ganglion, implying as it does perpetual experiences of differences and likenesses, constitutes the raw material of consciousness. The implication is that as fast as Instinct is developed, some kind of consciousness becomes nascent." (Psychology, � 195.) The words 'raw material' and 'implication' which I have italicized are the words which do the evolving. They are supposed to have all the rigor which the 'synthetic philosophy' requires. In the following passage, when 'impressions' pass through a common 'centre of communication' in succession (much as people might pass into a theatre through a turnstile) consciousness, non-existent until then, is supposed to result: "Separate impressions are received by the senses - by different parts of the body. If they go no further than the places at which they are received, they are useless. Or if only some of them are brought into relation with one another, they are useless. That an effectual adjustment may be made, they must be all brought into relation with one another. But this implies some centre of communication common to them all, through which they severally pass; and as they cannot pass through it simultaneously, they must pass through it in succession. So that as the external phenomena responded to become greater in number and more complicated in kind, the variety and rapidity of the changes to which this common centre of communication is subject must increase - there must result an unbroken series of these changes - there must arise a consciousness. "Hence the progress of the correspondence between the organism and its environment necessitates a gradual reduction of the sensorial changes to a succession; and by so doing evolves a distinct consciousness - a consciousness that becomes higher as the succession becomes more rapid and the correspondence more complete." (Ibid. � 179.) It is true that in the Fortnightly Review (vol. XIV. p. 716) Mr. Spencer denies that he means by this passage to tell us anything about the origin of consciousness at all. It resembles, however, too many other places in his Psychology (e.g. �� 43, 110, 244) not to be taken as a serious attempt to explain how consciousness must at a certain point be 'evolved.' That, when a critic calls his attention to the inanity of his words, Mr. Spencer should say he never meant anything particular by them, is simply an example of the scandalous vagueness with which this sort of 'chromo-philosophy' is carried on.

[8] His own words are: "Mistakes are made in the sense that he admits having been touched, when in reality it was radiant heat that affected his skin. In our own before-mentioned experiments there was never any deception on the entire palmar side of the hand or on the face. On the back of the hand in one case in a series of 60 stimulations 4 mistakes occurred, in another case 2 mistakes in 45 stimulations. On the extensor side of the upper arm 3 deceptions out of 48 stimulations were noticed, and in the case of another individual, 1 out of 31. In one case over the spine 3 deceptions in a series of 11 excitations were observed; in another, 4 out of 19. On the lumbar spine 6 deceptions came among 29 stimulations, and again 4 out of 7. There is certainly not yet enough material on which to rest a calculation of probabilities, but any one can easily convince himself that on the back there is no question of even a moderately accurate discrimination between warmth and a light pressure so far as but small portions of skin come into play. It has been as yet impossible to make corresponding experiments with regard to sensibility to cold." (Lehrb. d. Anat. u. Physiol. d. Sinnesorgane (1862), p. 29.)

[9] Principles of Psychology, � 60.

[10] Oddly enough, Mr. Spencer seems quite unaware of the general function of the theory of elementary units of mind-stuff in the evolutionary philosophy. We have seen it to be absolutely indispensable, if that philosophy is to work, to postulate consciousness in the nebula, - the simplest way being, of course, to suppose every atom animated. Mr. Spencer, however, will have it (e.g. First Principles, � 71) that consciousness is only the occasional result of the 'transformation' of a certain amount of 'physical force' to which it is 'equivalent.' Presumably a brain must already be there before any such 'transformation' can take place; and so the argument quoted in the text stands as a mere local detail, without general bearings.

[11] The compounding of colors may be dealt with in an identical way. Helmholtz has shown that if green light and red light fall simultaneously on the retina, we see the color yellow. The mind-stuff theory would interpret this as a case where the feeling green and the feeling red 'combine' into the tertium quid of feeling, yellow. What really occurs is no doubt that a third kind of nerve-process is set up when the combined lights impinge on the retina, - not simply the process of red plus the process of green, but something quite different from both or either. Of course, then, there are no feelings, either of red or of green, present to the mind at all; but the feeling of yellow which is there, answers as directly to the nerve-process which momentarily then exists, as the feelings of green and red would answer to their respective nerve-processes did the latter happen to be taking place.

[12] Cf. Mill's Logic, book VI. chap. IV. � 3.

[13] I find in my students an almost invincible tendency to think that we can immediately perceive that feelings do combine. "What!" they say, "is not the taste of lemonade composed of that of lemon plus that of sugar?" This is taking the combining of objects for that of feelings. The physical lemonade contains both the lemon and the sugar, but its taste does not contain their tastes, for if there are any two things which are certainly not present in the taste of lemonade, those are the lemon-sour on the one hand and the sugar-sweet on the other. These tastes are absent utterly. The entirely new taste which is present resembles, it is true, both those tastes; but in Chapter XIII we shall see that resemblance can not always be held to involve partial identity.

[14] E. Montgomery, in 'Mind,' V. 18-19. See also pp. 24-5.

[15] J. Royce, 'Mind,' VI. p. 376. Lotze has set forth the truth of this law more clearly and copiously than any other writer. Unfortunately he is too lengthy to quote. See his Microcosmus, bk. II. ch. I. � 5; Metaphysik, �� 242, 260; Outlines of Metaphysics, part II. chap. I. �� 3, 4, 5. Compare also Reid's Intellectual Powers, essay V, chap. III ad fin.; Bowne's Metaphysics, pp. 361-76; St. J. Mivart: Nature and Thought, pp. 98-101; E. Gurney: 'Monism,' in 'Mind,' VI. 153; and the article by Prof. Royce, just quoted, on 'Mind-stuff and Reality.' In defence of the mind-stuff view, see W. K. Clifford: 'Mind,' III. 57 (reprinted in his 'Lectures and Essays,' II. 71); G. T. Fechner, Psychophysik, Bd. II. cap. XLV; H. Taine: on Intelligence, bk. III; E. Haeckel. 'Zellseelen u. Seelenzellen ' in Gesammelte pop. Vortr�ge, Bd. I. p. 143; W. S. Duncan. Conscious Matter, passim; H. Zollner; Natur d. Cometen, pp. 320 ff.; Alfred Barratt: 'Physical Ethic' and Physical Metempiric,' passum' J. Soury: 'Hylozoismus,' in Kosmos,' V. Jahrg., Heft X. p. 241; A. Main: 'Mind,' I. 292, 431, 566; II. 129, 402; Id. Revue Philos., II. 86, 88, 419; III. 51, 502; IV. 402; F. W. Frankland: 'Mind,' VI. 116; Whittaker: 'Mind,' VI. 498 (historical); Morton Prince: The Nature of Mind and Human Automatism (1885); A. Riehl: Der philosophische Kriticismus, Bd. II. Theil 2, 2ter Abschnitt, 2tes Cap. (1887). The clearest of all these statements is, as far as it goes, that of Prince.

[16] "Someone might say that although it is true that neither a blind man nor a deaf man by himself can compare sounds with colors, yet since one hears and the other sees they might do so both together.... But whether they are apart or close together makes no difference; not even if they permanently keep house together; no, not if they were Siamese twins, or more than Siamese twins, and were inseparably grown together, would it make the assumption any more possible. Only when sound and color are represented in the same reality is it thinkable that they should be compared." (Brentano; Psychologie, p. 209.)

[17] The reader must observe that we are reasoning altogether about the logic of the mind-stuff theory, about whether it can explain the constitution of higher mental states by viewing them as identical with lower ones summed together. We say the two sorts of fact are not identical: a higher state is not a lot of lower states; it is itself. When, however, a lot of lower states have come together, or when certain brain-conditions occur together which, if they occurred separately, would produce a lot of lower states, we have not for a moment pretended that a higher state may not emerge. In fact it does emerge under those conditions; and our Chapter IX will be mainly devoted to the proof of this fact. But such emergence is that of a new psychic entity, and is toto coelo different from such an 'integration' of the lower states as the mind-stuff theory affirms. It may seem strange to suppose that anyone should mistake criticism of a certain theory about a fact for doubt of the fact itself. And yet the confusion is made in high quarters enough to justify our remarks. Mr. J. Ward, in his article Psychology in the Encyclopaedia Britannica, speaking of the hypothesis that "a series of feelings can be aware of itself as a series," says (p. 39): "Paradox is too mild a word for it, even contradiction will hardly suffice." Whereupon, Professor Bain takes him thus to task: "As to 'a series of states being aware of itself, I confess I see no insurmountable difficulty. It may be a fact, or not a fact; it may be a very clumsy expression for what it is applied to; but it is neither paradox nor contradiction. A series merely contradicts an individual, or it may be two or more individuals as coexisting; but that is too general to exclude the possibility of self-knowledge. It certainly does not bring the property of self-knowledge into the foreground, which, however, is not the same as denying it. An algebraic series might know itself, without any contradiction: the only thing against it is the want of evidence of the fact." ('Mind,' XI, 459). Prof. Bain thinks, then, that all the bother is about the difficulty of seeing how a series of feelings can have the knowledge of itself added to it!!! As if anybody ever was troubled about that. That, notoriously enough, is a fact: our consciousness is a series of feelings to which every now and then is added a retrospective consciousness that they have come and gone. What Mr. Ward and I are troubled about is merely the silliness of the mind-stuffists and associationists continuing to say that the 'series of states' is the 'awareness of itself;' that if the states be posited severally, their collective consciousness is eo ipso given; and that we need no farther explanation, or 'evidence of the fact.'

[18] The writers about 'unconscious cerebration' seem sometimes to mean that and sometimes unconscious thought. The arguments which follow are culled from various quarters. The reader will find them most systematically urged by E. von Hartmann: Philosophy of the Unconscious, vol. I, and by E. Colsenet: La vie Inconsciente de l'Esprit (1880). Consult also T. Laycock: Mind and Brain, vol, I. chap. V (1860); W. B. Carpenter: Mental Physiology, chap. XIII; F. P. Cobbe: Darwinism in Morals and other Essays, essay XI, Unconscious Cerebration (1872); F. Bowen: Modern Philosophy, pp. 428-480; R. H. Hutton: Contemporary Review, vol. XXIV. p. 201; J. S. Mill: Exam. of Hamilton, chap. XV; G. H. Lewes; Problems of life and Mind, 3d series, Prob. II. chap. X, and also Prob. III. chap. II; D. G. Thompson: A System of Psychology, chap. XXXIII; J. M. Baldwin, Hand-book of Psychology, chap. IV.

[19] Nouveaux Essais, Avant-propos.

[20] J. S. Mill, Exam of Hamilton, chap. XV.

[21] Cf. Dugald Stewart, Elements, chap. II.

[22] J. E. Maude: 'The Unconscious in Education,' in 'Education' vol. I. p. 401 (1882).

[23] Zur Lehre vom Lichtsinne (1878).

[24] Cf. Wundt: Ueber den Einfluss der Philosophie, etc. - Antrittsrede (1876), pp. 10-11; - Helmholtz: Die Thatsachen in der Wahrnehmung, (1879), p. 27.

[25] Cf. Satz vom Grunde, pp. 59-65. Compare also F. Z�llner's Natur der Kometen, pp. 342 ff., and 425.

[26] Cf. the statements from Helmholtz to be found later in Chapter XIII.

[27] The text was written before Professor Lipps's Grundtatsachen des Seelenlebens (1883) came into my hands. In Chapter III of that book the notion of unconscious thought is subjected to the clearest and most searching criticism which it has yet received, [sic] Some passages are so similar to what I have myself written that I must quote them in a note. After proving that dimness and clearness, incompleteness and completeness do not pertain to a state of mind as such - since every state of mind must be exactly what it is, and nothing else - but only pertain to the way in which states of mind stand for objects, which they more or less dimly, more or less clearly, represent; Lipps takes the case of those sensations which attention is said to make more clear. "I perceive an object," he says, "now in clear daylight, and again at night. Call the content of the day-perception a, and that of the evening-perception a1. There will probably be a considerable difference between a and a1. The colors of a will be varied and intense, and will be sharply bounded by each other; those of a1 will be less luminous, and less strongly contrasted, and will approach a common gray or brown, and merge more into each other. Both percepts, however, as such, are completely determinate and distinct from all others. The colors of a1 appear before my eye neither neither more nor less decidedly dark and blurred than the colors of a appear bright and sharply bounded. But now I know, or believe I know, that one and the same real Object A corresponds to both a and a1. I am convinced, moreover, that a represents A better than does a1. Instead, however, of giving to my conviction this, its only correct, expression, and keeping the content of the consciousness, and the real object, the representation and what it means, distinct from each other, I substitute the real object for the content of the consciousness, and talk of the experience as if it consisted in one and the same object (namely, the surreptitiously introduced real one), constituting twice over the content of my consciousness, once in a clear and distinct, the other time in an obscure and vague fashion. I talk now of a distincter and of a less distinct consciousness of A, whereas I am only justified in talking of two consciousnesses, a and a1, equally distinct in se, but to which the supposed external object A corresponds with different degrees of distinctness." (P. 38-9.) Classics in the History of Psychology

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CHAPTER VII. The Methods and Snares of Psychology

We have now finished the physiological preliminaries of our subject and must in the remaining chapters study the mental states themselves whose cerebral conditions and concomitants we have been considering hitherto. Beyond the brain, however, there is an outer world to which the brain-states themselves 'correspond.' And it will be well, ere we advance farther, to say a word about the relation of the mind to this larger sphere of physical fact.

PSYCHOLOGY IS A NATURAL SCIENCE. That is, the mind which the psychologist studies is the mind of distinct individuals inhabiting definite portions of a real space and of a real time. With any other sort of mind, absolute Intelligence, Mind unattached to a particular body, or Mind not subject to the course of time, the psychologist as such has nothing to do. 'Mind,' in his mouth, is only a class name for minds. Fortunate will it be if his more modest inquiry result in any generalizations which the philosopher devoted to absolute Intelligence as such can use.

To the psychologist, then, the minds he studies are objects, in a world of other objects. Even when he introspectively analyzes his own mind, and tells what he finds there, he talks about it in an objective way. He says, for instance, that under certain circumstances the color gray appears to him green, and calls the appearance an illusion. This implies that he compares two objects, a real color seen under conditions, and a mental perception which he believes to represent it, and that he declares the relation between them to be of a certain kind. In making this critical judgment, the psychologist stands as much outside of the perception which he criticises as he does of the color. Both are his objects. And if this is true of him when he reflects on his own conscious states, how much truer is it when he treats of those of others! In German philosophy since Kant the word Erkenntnisstheorie, criticism of the faculty of knowledge, plays a great part. Now the psychologist necessarily becomes such an Erkenntnisstheoretiker. But the knowledge he theorizes about is not the bare function of knowledge which Kant criticises - he does not inquire into the possibility of knowledge �berhaupt. He assumes it to be possible, he does not doubt its presence in himself at the moment he speaks. The knowledge he criticises is the knowledge of particular men about the particular things that surround them. This he may, upon occasion, in the light of his own unquestioned knowledge, pronounce true or false, and trace the reasons by which it has become one or the other.

It is highly important that this natural-science point of view should be understood at the outset. Otherwise more may be demanded of the psychologist than he ought to be expected to perform.

A diagram will exhibit more emphatically what the assumptions of Psychology must be: 1 The Psychologist 2 The Thought Studied 3 The Thought's Object 4 The Psycholo- gist's Reality

These four squares contain the irreducible data of psychology. No. 1, the psychologist, believes Nos. 2, 3, and 4, which together form his total object, to be realities, and reports them and their mutual relations as truly as he can without troubling himself with the puzzle of how he can report them at all. About such ultimate puzzles he in the main need trouble himself no more than the geometer, the chemist, or the botanist do, who make precisely the same assumptions as he.[1]

Of certain fallacies to which the psychologist is exposed by reason of his peculiar point of view - that of being a reporter of subjective as well as of objective facts, we must presently speak. But not until we have considered the methods he uses for ascertaining what the facts in question are.

THE METHODS OF INVESTIGATION. Introspective Observation is what we have to rely on first and foremost and always. The word introspection need hardly be defined - it means, of course, the looking into our own minds and reporting what we there discover. Every one agrees that we there discover states of consciousness. So far as I know, the existence of such states has never been doubted by any critic, however sceptical in other respects he may have been. That we have cogitations of some sort is the inconcussum in a world most of whose other facts have at some time tottered in the breath of philosophic doubt. All people unhesitatingly believe that they feel themselves thinking, and that they distinguish the mental state as an inward activity or passion, from all the objects with which it may cognitively deal. I regard this belief as the most fundamental of all the postulates of Psychology, and shall discard all curious inquiries about its certainty as too metaphysical for the scope of this book.

A Question of Nomenclature. We ought to have some general term by which to designate all states of consciousness merely as such, and apart from their particular quality or cognitive function. Unfortunately most of the terms in use have grave objections. 'Mental state,' 'state of consciousness,' 'conscious modification,' are cumbrous and have no kindred verbs. The same is true of 'subjective condition.' 'Feeling' has the verb 'to feel,' both active and neuter, and such derivatives as 'feelingly,' 'felt,' 'feltness,' etc., which make it extremely convenient. But on the other hand it has specific meanings as well as its generic one, sometimes standing for pleasure and pain, and being sometimes a synonym of 'sensation' as opposed to thought ; whereas we wish a term to cover sensation and thought indifferently. Moreover, 'feeling' has acquired in the hearts of platonizing thinkers a very opprobrious set of implications ; and since one of the greatest obstacles to mutual understanding in philosophy is the use of words eulogistically and disparagingly, impartial terms ought always, if possible, to be preferred. The word psychosis has been proposed by Mr. Huxley. It has the advantage of being correlative to neurosis (the name applied by the same author to the corresponding nerve-process), and is moreover technical and devoid of partial implications. But it has no verb or other grammatical form allied to it. The expressions 'affection of the soul,' 'modification of the ego,' are clumsy, like 'state of consciousness,' and they implicitly assert theories which it is not well to embody in terminology before they have been openly discussed and approved. 'Idea' is a good vague neutral word, and was by Locke employed in the broadest generic way ; but notwithstanding his authority it has not domesticated itself in the language so as to cover bodily sensations. It has no opprobrious connotation such as 'feeling' has, and it immediately suggests the omnipresence of cognition (or reference to an object other than the mental state itself), which we shall soon see to be of the mental life's essence. But can the expression 'thought of a toothache' ever suggest to the reader the actual present pain itself? It is hardly possible ; and we thus seem about to be forced back on some pair of terms like Hume's 'impression and idea,' or Hamilton's 'presentation and representation,' or the ordinary 'feeling and thought,' if we wish to cover the whole ground.

In this quandary we can make no definitive choice, but must, according to the convenience of the context, use sometimes one, sometimes another of the synonyms that have been mentioned. My own partiality is for either FEELING or THOUGHT. I shall probably often use both words in a wider sense than usual, and alternately startle two classes of readers by their unusual sound ; but if the connection makes it clear that mental states at large, irrespec- tive of their kind, are meant, this will do no harm, and may even do some good.[2]

The inaccuracy of introspective observation has been made a subject of debate. It is important to gain some fixed ideas on this point before we proceed.

The commonest spiritualistic opinion is that the Soul or Subject of the mental life is a metaphysical entity, inaccessible to direct knowledge, and that the various mental states and operations of which we reflectively become aware are objects of an inner sense which does not lay hold of the real agent in itself, any more than sight or hearing gives us direct knowledge of matter in itself. From this point of view introspection is, of course, incompetent to lay hold of anything more than the Soul's phenomena. But even then the question remains, How well can it know the phenomena themselves?

Some authors take high ground here and claim for it a sort of infallibility. Thus Ueberweg:

"When a mental image, as such, is the object of my apprehension, there is no meaning in seeking to distinguish its existence in my consciousness (in me) from its existence out of my consciousness (in itself) ; for the object apprehended is, in this case, one which does not even exist, as the objects of external perception do, in itself outside of my consciousness. It exists only within me."[3]

And Brentano:

"The phenomena inwardly apprehended are true in themselves. As they appear - of this the evidence with which they are apprehended is a warrant - so they are in reality. Who, then, can deny that in this a great superiority of Psychology over the physical sciences comes to light?"

And again:

"No one can doubt whether the psychic condition he apprehends in himself be, and be so, as he apprehends it. Whoever should doubt this would have reached that finished doubt which destroys itself in destroying every fixed point from which to make an attack upon knowledge."[4]

Others have gone to the opposite extreme, and maintained that we can have no introspective cognition of our own minds at all. A deliverance of Auguste Comte to this effect has been so often quoted as to be almost classical ; and some reference to it seems therefore indispensable here.

Philosophers, says Comte,[5] have

"in these latter days imagined themselves able to distinguish, by a very singular subtlety, two sorts of observation of equal importance, one external, the other internal, the latter being solely destined for the study of intellectual phenomena.... I limit myself to pointing out the principal consideration which proves clearly that this pretended direct contemplation of the mind by itself is a pure illusion.... It is in fact evident that, by an invincible neccessity, [sic] the human mind can observe directly all phenomena except its own proper states. For by whom shall the observation of these be made? It is conceivable that a man might observe himself with respect to the passions that animate him, for the anatomical organs of passion are distinct from those whose function is observation. Though we have all made such observations on ourselves, they can never have much scientific value, and the best mode of knowing the passions will always be that of observing them from without ; for every strong state of passion... is necessarily incompatible with the state of observation. But, as for observing in the same way intellectual phenomena at the time of their actual presence, that is a manifest impossibility. The thinker cannot divide himself into two, of whom one reasons whilst the other observes him reason. The organ observed and the organ observing being, in this case, identical, how could observation take place? This pretended psychological method is then radically null and void. On the one hand, they advise you to isolate yourself, as far as possible, from every external sensation, especially every intellectual work, - for if you were to busy yourself even with the simplest calculation, what would become of internal observation? - on the other hand, after having with the utmost care attained this state of intellectual slumber, you must begin to contemplate the operations going on in your mind, when nothing there takes place! Our descendants will doubtless see such pretensions some day ridiculed upon the stage. The results of so strange a procedure harmonize entirely with its principle. For all the two thousand years during which metaphysicians have thus cultivated psychology, they are not agreed about one intelligible and established proposition. 'Internal observation' gives almost as many divergent results as there are individuals who think they practise it."

Comte hardly could have known anything of the English, and nothing of the German, empirical psychology. The 'results' which he had in mind when writing were probably scholastic ones, such as principles of internal activity, the faculties, the ego, the liberum arbitrium indifferentioe, etc. John Mill, in replying to him,[6] says:

"It might have occurred to M. Comte that a fact may be studied through the medium of memory, not at the very moment of our perceiving it, but the moment after : and this is really the mode in which our best knowledge of our intellectual acts is generally acquired. We reflect on what we have been doing when the act is past, but when its impression in the memory is still fresh. Unless in one of these ways, we could not have acquired the knowledge which nobody denies us to have, of what passes in our minds. M. Comte would scarcely have affirmed that we are not aware of our own intellectual operations. We know of our observings and our reasonings, either at the very time, or by memory the moment after ; in either case, by direct knowledge, and not (like things done by us in a state of somnambulism) merely by their results. This simple fact destroys the whole of M. Comte's argument. Whatever we are directly aware of, we can directly observe."

Where now does the truth lie? Our quotation from Mill is obviously the one which expresses the most of practical truth about the matter. Even the writers who insist upon the absolute veracity of our immediate inner apprehension of a conscious state have to contrast with this the fallibility of our memory or observation of it, a moment later. No one has emphasized more sharply than Brentano himself the difference between the immediate feltness of a feeling, and its perception by a subsequent reflective act. But which mode of consciousness of it is that which the psychologist must depend on? If to have feelings or thoughts in their immediacy were enough, babies in the cradle would be psychologists, and infallible ones. But the psychologist must not only have his mental states in their absolute veritableness, he must report them and write about them, name them, classify and compare them and trace their relations to other things. Whilst alive they are their own property ; it is only post-mortem that they become his prey.[7] And as in the naming, classing, and know- ing of things in general we are notoriously fallible, why not also here? Comte is quite right in laying stress on the fact that a feeling, to be named, judged, or perceived, must be already past. No subjective state, whilst present, is its own object ; its object is always something else. There are, it is true, cases in which we appear to be naming our present feeling, and so to be experiencing and observing the same inner fact at a single stroke, as when we say 'I feel tired,' 'I am angry,' etc. But these are illusory, and a little attention unmasks the illusion. The present conscious state, when I say 'I feel tired,' is not the direct state of tire ; when I say "I feel angry,' it is not the direct state of anger. It is the state of saying-I-feel-tired, of saying-I-feel-angry, - entirely different matters, so different that the fatigue and anger apparently included in them are considerable modifications of the fatigue and anger directly felt in the previous instant. The act of naming them has momentarily detracted from their force.[8]

The only sound grounds on which the infallible veracity of the introspective judgment might be maintained are empirical. If we had reason to think it has never yet deceived us, we might continue to trust it. This is the ground actually maintained by Herr Mohr.

"The illusions of our senses." says this author," have undermined our belief in the reality of the outer world ; but in the sphere of inner observation our confidence is intact, for we have never found ourselves to be in error about the reality of an act of thought or feeling. We have never been misled into thinking we were not in doubt or in anger when these conditions were really states of our consciousness."[9]

But sound as the reasoning here would be, were the premises correct, I fear the latter cannot pass. However it may be with such strong feelings as doubt or anger, about weaker feelings, and about the relations to each other of all feelings, we find ourselves in continual error and uncertainty so soon as we are called on to name and class, and not merely to feel. Who can be sure of the exact order of his feelings when they are excessively rapid? Who can be sure, in his sensible perception of a chair, how much comes from the eye and how much is supplied out of the previous knowledge of the mind? Who can compare with precision the quantities of disparate feelings even where the feelings are very much alike. For instance, where an object is felt now against the back and now against the cheek, which feeling is most extensive? Who can be sure that two given feelings are or are not exactly the same? Who can tell which is briefer or longer than the other when both occupy but an instant of time? Who knows, of many actions, for what motive they were done, or if for any motive at all? Who can enumerate all the distinct ingredients of such a complicated feeling as anger? and who can tell offhand whether or no a perception of distance be a compound or a simple state of mind. The whole mind-stuff controversy would stop if we could decide conclusively by introspection that what seem to us elementary feelings are really elementary and not compound.

Mr. Sully, in his work on Illusions, has a chapter on those of Introspection from which we might now quote. But, since the rest of this volume will be little more than a collection of illustrations of the difficulty of discovering by direct introspection exactly what our feelings and their relations are, we need not anticipate our own future details, but just state our general conclusion that introspection is difficult and fallible ; and that the difficulty is simply that of all observation of whatever kind. Something is before us ; we do our best to tell what it is, but in spite of our good will we may go astray, and give a description more applicable to some other sort of thing. The only safeguard is in the final consensus of our farther knowledge about the thing in question, later views correcting earlier ones, until at last the harmony of a consistent system is reached. Such a system, gradually worked out, is the best guarantee the psychologist can give for the soundness of any particular psychologic observation which he may report. Such a system we ourselves must strive, as far as may be, to attain.

The English writers on psychology, and the school of Herbart in Germany, have in the main contented themselves with such results as the immediate introspection of single individuals gave, and shown what a body of doctrine they may make. The works of Locke, Hume, Reid, Hartley, Stewart Brown, the Mills, will always be classics in this line ; and in Professor Brain's Treatises we have probably the last word of what this method taken mainly by itself can do - the last monument of the youth of our science, still untechnical and generally intelligible, like the Chemistry of Lavoisier, or Anatomy before the microscope was used.

The Experimental Method. But psychology is passing into a less simple phase. Within a few years what one may call a microscopic psychology has arisen in Germany, carried on by experimental methods, asking of course every moment for introspective data, but eliminating their uncertainty by operating on a large scale and taking statistical means. This method taxes patience to the utmost, and could hardly have arisen in a country whose natives could be bored. Such Germans as Weber, Fechner, Vierordt, and Wundt obviously cannot ; and their success has brought into the field an array of younger experimental psychologists, bent on studying the elements of the mental life, dissecting them out from the gross results in which they are embedded, and as far as possible reducing them to quantitative scales. The simple and open method of attack having done what it can, the method of patience, starving out, and harassing to death is tried ; the Mind must submit to a regular siege, in which minute advantages gained night and day by the forces that hem her in must sum themselves up at last into her overthrow. There is little of the grand style about these new prism, pendulum, and chronograph-philosophers. They mean business, not chivalry. What generous divination, and that superiority in virtue which was thought by Cicero to give a man the best insight into nature, have failed to do, their spying and scraping, their deadly tenacity and almost diabolic cunning, will doubtless some day bring about.

No general description of the methods of experimental psychology would be instructive to one unfamiliar with the instances of their application, so we will waste no words upon the attempt. The principal fields of experimentation so far have been : 1) the connection of conscious states with their physical conditions, including the whole of brain-physiology, and the recent minutely cultivated physiology of the sense-organs, together with what is technically known as 'psycho-physics,' or the laws of correlation between sensations and the outward stimuli by which they are aroused ; 2) the analysis of space-perception into its sensational elements ; 3) the measurement of the duration of the simplest mental processes ; 4) that of the accuracy of reproduction in the memory of sensible experiences and of intervals of space and time ; 5) that of the manner in which simple mental states influence each other, call each other up, or inhibit each other's reproduction ; 6) that of the number of facts which consciousness can simultaneously discern ; finally, 7) that of the elementary laws of oblivescence and retention. It must be said that in some of these fields the results have as yet borne little theoretic fruit commensurate with the great labor expended in their acquisition. But facts are facts, and if we only get enough of them they are sure to combine. New ground will from year to year be broken, and theoretic results will grow. Meanwhile the experimental method has quite changed the face of the science so far as the latter is a record of mere work done.

The comparative method, finally, supplements the intro- spective and experimental methods. This method presupposes a normal psychology of introspection to be established in its main features. But where the origin of these features, or their dependence upon one another, is in question, it is of the utmost importance to trace the phenomenon considered through all its possible variations of type and combination. So it has come to pass that instincts of animals are ransacked to throw light on our own ; and that the reasoning faculties of bees and ants, the minds of savages, infants, madmen, idiots, the deaf and blind, criminals, and eccentrics, are all invoked in support of this or that special theory about some part of our own mental life. The history of sciences, moral and political institutions, and languages, as types of mental product, are pressed into the same service. Messrs. Darwin and Galton have set the example of circulars of questions sent out by the hundred to those supposed able to reply. The custom has spread, and it will be well for us in the next generation if such circulars be not ranked among the common pests of life. Meanwhile information grows, and results emerge. There are great sources of error in the comparative method. The interpretation of the 'psychoses' of animals, savages, and infants is necessarily wild work, in which the personal equation of the investigator has things very much its own way. A savage will be reported to have no moral or religious feeling if his actions shock the observer unduly. A child will be assumed without self-consciousness because he talks of himself in the third person, etc., etc. No rules can be laid down in advance. Comparative observations, to be definite, must usually be made to test some pre-existing hypothesis ; and the only thing then is to use as much sagacity as you possess, and to be as candid as you can.

THE SOURCES OF ERROR IN PSYCHOLOGY. The first of them arises from the Misleading Influence of Speech. Language was originally made by men who were not psychologists, and most men to-day employ almost exclusively the vocabulary of outward things. The cardinal passions of our life, anger, love, fear, hate, hope, and the most comprehensive divisions of our intellectual activity, to remember, expect, think, know, dream, with the broadest genera of aesthetic feeling, joy, sorrow, pleasure, pain, are the only facts of a subjective order which this vocabulary deigns to note by special words. The elementary qualities of sensation, bright, loud, red, blue, hot, cold, are, it is true, susceptible of being used in both an objective and a subjective sense. They stand for outer qualities and for the feelings which these arouse. But the objective sense is the original sense ; and still to-day we have to describe a large number of sensations by the name of the object from which they have most frequently been got. An orange color, an odor of violets, a cheesy taste, a thunderous sound, a fiery smart, etc., will recall what I mean. This absence of a special vocabulary for subjective facts hinders the study of all but the very coarsest of them. Empiricist writers are very fond of emphasizing one great set of delusions which language inflicts on the mind. Whenever we have made a word, they say, to denote a certain group of phenomena, we are prone to suppose a substantive entity existing beyond the phenomena, of which the word shall be the name. But the lack of a word quite as often leads to the directly opposite error. We are then prone to suppose that no entity can be there ; and so we come to overlook phenomena whose existence would be patent to us all, had we only grown up to hear it familiarly recognized in speech.[10] It is hard to focus our attention on the nameless, and so there results a certain vacuousness in the descriptive parts of most psychologies.

But a worse defect than vacuousness comes from the dependence of psychology on common speech. Naming our thought by its own objects, we almost all of us assume that as the objects are, so the thought must be. The thought of several distinct things can only consist of several distinct bits of thought, or 'ideas ;' that of an abstract or universal object can only be an abstract or universal idea. As each object may come and go, be forgotten and then thought of again, it is held that the thought of it has a precisely similar independence, self-identity, and mobility. The thought of the object's recurrent identity is regarded as the identity of its recurrent thought ; and the perceptions of multiplicity, of coexistence, of succession, are severally conceived to be brought about only through a multiplicity, a coexistence, a succession, of perceptions. The continuous flow of the mental stream is sacrificed, and in its place an atomism, a brickbat plan of construction, is preached, for the existence of which no good introspective grounds can be brought forward, and out of which presently grow all sorts of paradoxes and contradictions, the heritage of woe of students of the mind.

These words are meant to impeach the entire English psychology derived from Locke and Hume, and the entire German psychology derived from Herbart, so far as they both treat 'ideas' as separate subjective entities that come and go. Examples will soon make the matter clearer. Meanwhile our psychologic insight is vitiated by still other snares.

'The Psychologist's Fallacy.' The great snare of the psychologist is the confusion of his own standpoint with that of the mental fact about which he is making his report. I shall hereafter call this the 'psychologist's fallacy' par excellence. For some of the mischief, here too, language is to blame. The psychologist, as we remarked above (p. 183), stands outside of the mental state he speaks of. Both itself and its object are objects for him. Now when it is a cognitive state (percept, thought, concept, etc.), he ordinarily has no other way of naming it than as the thought, percept, etc., of that object. He himself, meanwhile, knowing the self-same object in his way, gets easily led to suppose that the thought, which is of it, knows it in the same way in which he knows it, although this is often very far from being the case.[11] The most fictitious puzzles have been introduced into our science by this means. The so-called question of presentative or representative perception, of whether an object is present to the thought that thinks it by a counterfeit image of itself, or directly and without any intervening image at all ; the question of nominalism and conceptualism, of the shape in which things are present when only a general notion of them is before the mind ; are comparatively easy questions when once the psychologist's fallacy is eliminated from their treatment, - as we shall ere long see (in Chapter XII).

Another variety of the psychologist' fallacy is the assumption that the mental state studied must be conscious of itself as the psychologist is conscious of it. The mental state is aware of itself only from within ; it grasps what we call its own content, and nothing more. The psychologist, on the contrary, is aware of it from without, and knows its relations with all sorts of other things. What the thought sees is only its own object ; what the psychologist sees is the thought's object, plus the thought itself, plus possibly all the rest of the world. We must be very careful therefore, in discussing a state of mind from the psychologist's point of view, to avoid foisting into its own ken matters that are only there for ours. We must avoid substituting what we know the consciousness is, for what it is a consciousness of, and counting its outward, and so to speak physical, relations with other facts of the world, in among the objects of which we set it down as aware. Crude as such a confusion of standpoints seems to be when abstractly stated, it is nevertheless a snare into which no psychologist has kept himself at all times from falling, and which forms almost the entire stock-in-trade of certain schools. We cannot be too watchful against its subtly corrupting influence.

Summary. To sum up the chapter, Psychology assumes that thoughts successively occur, and that they know objects in a world which the psychologist also knows. These thoughts are the subjective data of which he treats, and their relations to their objects, to the brain, and to the rest of the world constitute the subject-matter of psychologic science. Its methods are introspection, experimentation, and comparison. But introspection is no sure guide to truths about our mental states ; and in particular the poverty of the psychological vocabu. [sic] lary leads us to drop out certain states from our consideration, and to treat others as if they knew themselves and their objects as the psychologist knows both, which is a disastrous fallacy in the science.

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Footnotes [1] On the relation between Psychology and General Philosophy, see G. C. Robertson, 'Mind,' vol. VIII. p. 1, and J. Ward, ibid. p. 153 ; J. Dewey, ibid. vol. IX. p. 1.

[2] Compare some remarks in Mill's Logic, bk. I. chap. III. �� 2, 3.

[3] Logic, � 40.

[4] Psychologie, bk. II. chap. III. �� 1, 2.

[5] Cours de Philosophie Positive, I. 34-8.

[6] Auguste Comte and Positivism, 3d edition (1882), p. 64.

[7] Wundt says: "The first rule for utilizing inward observation consists in taking, as far as possible, experiences that are accidental, unexpected, and not intentionally brought about.... First it is best as far as possible to rely on Memory and not on immediate Apprehension.... Second, internal observation is better fitted to grasp clearly conscious states, especially voluntary mental acts: such inner processes as are obscurely conscious and involuntary will almost entirely elude it, because the effort to observe interferes with them, and because they seldom abide in memory." (Logik, II. 432.)

[8] In cases like this, where the state outlasts the act of naming it, exists before it, and recurs when it is past, we probably run little practical risk of error when we talk as if the state knew itself. The state of feeling and the state of naming the feeling are continuous, and the infallibility of such prompt introspective judgments is probably great. But even here the certainty of our knowledge ought not to be argued on the a priori ground that percipi and esse are in psychology the same. The states are really two ; the naming state and the named state are apart ; percipi is esse' is not the principle that applies.

[9] J. Mohr : Grundlage der Empirischen Psychologie (Leipzig, 1882), p. 47.

[10] In English we have not even the generic distinction between the-thing-thought-of and the-thought-thinking-it, which in German is expressed by the opposition between Gedachtes and Gedanke, in Latin by that between cogitatum and cogitatio.

[11] Compare B. P. Bowne's Metaphysics (1882), p. 408.

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CHAPTER VIII. The Relations Of Minds To Other Things.

Since, for psychology, a mind is an object in a world of other objects, its relation to those other objects must next be surveyed. First of all, to its

TIME-RELATIONS. Minds, as we know them, are temporary existences. Whether my mind had a being prior to the birth of my body, whether it shall have one after the latter's decease, are questions to be decided by my general philosophy or theology rather than by what we call 'scientific facts' - I leave out the facts of so-called spiritualism, as being still in dispute. Psychology, as a natural science, confines itself to the present life, in which every mind appears yoked to a body through which its manifestations appear. In the present world, then, minds precede, succeed, and coexist with each other in the common receptacle of time, and of their collective relations to the latter nothing more can be said. The life of the individual consciousness in time seems, however, to be an interrupted one, so that the question:

Are we ever wholly unconscious? becomes one which must be discussed. Sleep, fainting, coma, epilepsy, and other 'unconscious' conditions are apt to break in upon and occupy large durations of what we nevertheless consider the mental history of a single man. And, the fact of interruption being admitted, is it not possible that it may exist where we do not suspect it, and even perhaps in an incessant and fine-grained form?

This might happen, and yet the subject himself never know it. We often take ether and have operations performed without a suspicion that our consciousness has suf- fered a breach. The two ends join each other smoothly over the gap; and only the sight of our wound assures us that we must have been living through a time which for our immediate consciousness was non-existent. Even in sleep this sometimes happens: We think we have had no nap, and it takes the clock to assure us that we are wrong.[1] We thus may live through a real outward time, a time known by the psychologist who studies us, and yet not feel the time, or infer it from any inward sign. The question is, how often does this happen? Is consciousness really discontinuous, incessantly interrupted and recommencing (from the psychologist's point of view)? and does it only seem continuous to itself by an illusion analogous to that of the zoetrope? Or is it at most times as continuous outwardly as it inwardly seems?

It must be confessed that we can give no rigorous answer to this question. Cartesians, who hold that the essence of the soul is to think, can of course solve it a priori, and explain the appearance of thoughtless intervals either by lapses in our ordinary memory, or by the sinking of consciousness to a minimal state, in which perhaps all that it feels is a bare existence which leaves no particulars behind to be recalled. If, however, one have no doctrine about the soul or its essence, one is free to take the appearances for what they seem to be, and to admit that the mind, as well as the body, may go to sleep.

Locke was the first prominent champion of this latter view, and the pages in which he attacks the Cartesian belief are as spirited as any in his Essay. "Every drowsy nod shakes their doctrine who teach that their soul is always thinking." He will not believe that men so easily forget. M. Jouffroy and Sir W. Hamilton, attacking the question in the same empirical way, are led to an opposite conclusion. Their reasons, briefly stated, are these:

In somnambulism, natural or induced, there is often a great display of intellectual activity, followed by complete oblivion of all that has passed.[2]

On being suddenly awakened from a sleep, however profound, we always catch ourselves in the middle of a dream. Common dreams are often remembered for a few minutes after waking, and then irretrievably lost.

Frequently, when awake and absent-minded, we are visited by thoughts and images which the next instant we cannot recall.

Our insensibility to habitual noises, etc., whilst awake, proves that we can neglect to attend to that which we nevertheless feel. Similarly in sleep, we grow inured, and sleep soundly in presence of sensations of sound, cold, contact, etc., which at first prevented our complete repose. We have learned to neglect them whilst asleep as we should whilst awake. The mere sense-impressions are the same when the sleep is deep as when it is light; the difference must lie in a judgment on the part of the apparently slumbering mind that they are not worth noticing.

This discrimination is equally shown by nurses of the sick and mothers of infants, who will sleep through much noise of an irrelevant sort, but waken at the slightest stirring of the patient or the babe. This last fact shows the sense-organ to be pervious for sounds.

Many people have a remarkable faculty of registering when asleep the flight of time. They will habitually wake up at the same minute day after day, or will wake punctually at an unusual hour determined upon overnight. How can this knowledge of the hour (more accurate often than anything the waking consciousness shows) be possible without mental activity during the interval?

Such are what we may call the classical reasons for admitting that the mind is active even when the person afterwards ignores the fact.[3] Of late years, or rather, one may say, of late months, they have been reinforced by a lot of curious observations made on hysterical and hypnotic subjects, which prove the existence of a highly developed consciousness in places where it has hitherto not been suspected at all. These observations throw such a novel light upon human nature that I must give them in some detail. That at least four different and in a certain sense rival observers should agree in the same conclusion justifies us in accepting the conclusion as true.

'Unconsciousness' in Hysterics. One of the most constant symptoms in persons suffering from hysteric disease in its extreme forms consists in alterations of the natural sensibility of various parts and organs of the body. Usually the alteration is in the direction of defect, or anaesthesia. One or both eyes are blind, or color-blind, or there is hemianopsia (blindness to one half the field of view), or the field is contracted. Hearing, taste, smell may similarly disappear, in part or in totality. Still more striking are the cutaneous anaesthesias. The old witch-finders looking for the 'devil's seals' learned well the existence of those insensible patches on the skin of their victims, to which the minute physical examinations of recent medicine have but recently attracted attention again. They may be scattered anywhere, but are very apt to affect one side of the body. Not infrequently they affect an entire lateral half, from head to foot; and the insensible skin of, say, the left side will then be found separated from the naturally sensitive skin of the right by a perfectly sharp line of demarcation down the middle of the front and back. Sometimes, most remarkable of all, the entire skin, hands, feet, face, everything, and the mucous membranes, muscles and joints so far as they can be ex- plored, become completely insensible without the other vital functions becoming gravely disturbed.

These hysterical anaesthesias can be made to disappear more or less completely by various odd processes. It has been recently found that magnets, plates of metal, or the electrodes of a battery, placed against the skin, have this peculiar power. And when one side is relieved in this way, the anaesthesia is often found to have transferred itself to the opposite side, which until then was well. Whether these strange effects of magnets and metals be due to their direct physiological action, or to a prior effect on the patient's mind ('expectant attention' or 'suggestion') is still a mooted question. A still better awakener of sensibility is the hypnotic trance, into which many of these patients can be very easily placed, and in which their lost sensibility not infrequently becomes entirely restored. Such returns of sensibility succeed the times of insensibility and alternate with them. But Messrs. Pierre Janet[4] and A. Binet[5] have shown that during the times of anaesthesia, and coexisting with it, sensibility to the anaesthetic parts is also there, in the form of a secondary consciousness entirely cut off from the primary or normal one, but susceptible of being tapped and made to testify to its existence in various odd ways.

Chief amongst these is what M. Janet calls 'the method of distraction.' These hysterics are apt to possess a very narrow field of attention, and to be unable to think of more than one thing at a time. When talking with any person they forget everything else. "When Lucie talked directly with any one," says M. Janet, "she ceased to be able to hear any other person. You may stand behind her, call her by name, shout abuse into her ears, without making her turn round; or place yourself before her, show her objects, touch her, etc., without attracting her notice. When finally she becomes aware of you, she thinks you have just come into the room again, and greets you accordingly. This singular forgetfulness makes her liable to tell all her secrets aloud, unrestrained by the presence of unsuitable auditors."

Now M. Janet found in several subjects like this that if he came up behind them whilst they were plunged in conversation with a third party, and addressed them in a whisper, telling them to raise their hand or perform other simple acts, they would obey the order given, although their talking intelligence was quite unconscious of receiving it. Leading them from one thing to another, he made them reply by signs to his whispered questions, and finally made them answer in writing, if a pencil were placed in their hand. The primary consciousness meanwhile went on with the conversation, entirely unaware of these performances on the hand's part. The consciousness which presided over these latter appeared in its turn to be quite as little disturbed by the upper consciousness's concerns. This proof by 'automatic' writing, of a secondary consciousness's existence, is the most cogent and striking one; but a crowd of other facts prove the same thing. If I run through them rapidly, the reader will probably be convinced.

The apparently anaesthetic hand of these subjects, for one thing, will often adapt itself discriminatingly to whatever object may be put into it. With a pencil it will make writing movements; into a pair of scissors it will put its fingers and will open and shut them, etc., etc. The primary consciousness, so to call it, is meanwhile unable to say whether or no anything is in the hand, if the latter be hidden from sight. "I put a pair of eyeglasses into L�onie's anaesthetic hand, this hand opens it and raises it towards the nose, but half way thither it enters the field of vision of L�onie, who sees it and stops stupefied: 'Why,' says she, 'I have an eyeglass in my left hand!'" M. Binet found a very curious sort of connection between the apparently anaesthetic skin and the mind in some Salp�tri�re-subjects. Things placed in the hand were not felt, but thought of (apparently in visual terms) and in no wise referred by the subject to their starting point in the hand's sensation. A key, a knife, placed in the hand occasioned ideas of a key or a knife, but the hand felt nothing. Similarly the subject thought of the number 3, 6, etc., if the hand or finger was bent three or six times by the operator, or if he stroked it three, six, etc., times.

In certain individuals there was found a still odder phenomenon, which reminds one of that curious idiosyncrasy of 'colored hearing' of which a few cases have been lately described with great care by foreign writers. These individuals, namely, saw the impression received by the hand, but could not feel it; and the thing seen appeared by no means associated with the hand, but more like an independent vision, which usually interested and surprised the patient. Her hand being hidden by a screen, she was ordered to look at another screen and to tell of any visual image which might project itself thereon. Numbers would then come, corresponding to the number of times the insensible member was raised, touched, etc. Colored lines and figures would come, corresponding to similar ones traced on the palm; the hand itself or its fingers would come when manipulated; and finally objects placed in it would come; but on the hand itself nothing would ever be felt. Of course simulation would not be hard here; but M. Binet disbelieves this (usually very shallow) explanation to be a probable one in cases in question.[6]

The usual way in which doctors measure the delicacy of our touch is by the compass-points. Two points are normally felt as one whenever they are too close together for discrimination; but what is 'too close' on one part of the skin may seem very far apart on another. In the middle of the back or on the thigh, less than 3 inches may be too close; on the finger-tip a tenth of an inch is far enough apart. Now, as tested in this way, with the appeal made to the primary consciousness, which talks through the mouth and seems to hold the field alone, a certain person's skin may be entirely anaesthetic and not feel the compass-points at all; and yet this same skin will prove to have a perfectly normal sensibility if the appeal be made to that other secondary or sub-consciousness, which expresses itself automatically by writing or by movements of the hand. M. Binet, M. Pierre Janet, and M. Jules Janet have all found this. The subject, whenever touched, wonld [sic] signify 'one point' or 'two points,' as accurately as if she were a normal person. She would signify it only by these movements; and of the movements themselves her primary self would be as unconscious as of the facts they signified, for what the submerged consciousness makes the hand do automatically is unknown to the consciousness which uses the mouth.

Messrs. Bernheim and Pitres have also proved, by observations too complicated to be given in this spot, that the hysterical blindness is no real blindness at all. The eye of an hysteric which is totally blind when the other or seeing eye is shut, will do its share of vision perfectly well when both eyes are open together. But even where both eyes are semi-blind from hysterical disease, the method of automatic writing proves that their perceptions exist, only cut off from communication with the upper consciousness. M. Binet has found the hand of his patients unconsciously writing down words which their eyes were vainly endeavoring to 'see,' i.e., to bring to the upper consciousness. Their submerged consciousness was of course seeing them, or the hand could not have written as it did. Colors are similarly perceived by the sub-conscious self, which the hysterically color-blind eyes cannot bring to the normal consciousness. Pricks, burns, and pinches on the anaesthetic skin, all unnoticed by the upper self, are recollected to have been suffered, and complained of, as soon as the under self gets a chance to express itself by the passage of the subject into hypnotic trance.

It must be admitted, therefore, that in certain persons, at least, the total possible consciousness may be split into parts which coexist but mutually ignore each other, and share the objects of knowledge between them. More remarkable still, they are complementary. Give an object to one of the consciousnesses, and by that fact you remove it from the other or others. Barring a certain common fund of information, like the command of language, etc., what the upper self knows the under self is ignorant of, and vice versa. M. Janet has proved this beautifully in his subject Lucie. The following experiment will serve as the type of the rest: In her trance he covered her lap with cards, each bearing a number. He then told her that on waking she should not see any card whose number was a multiple of three. This is the ordinary so-called 'post-hypnotic suggestion,' now well known, and for which Lucie was a well-adapted subject. Accordingly, when she was awakened and asked about the papers on her lap, she counted and said she saw those only whose number was not a multiple of 3. To the 12, 18, 9, etc., she was blind. But the hand, when the sub-conscious self was interrogated by the usual method of engrossing the upper self in another conversation, wrote that the only cards in Lucie's lap were those numbered 12, 18, 9, etc., and on being asked to pick up all the cards which were there, picked up these and let the others lie. Similarly when the sight of certain things was suggested to the sub-conscious Lucie, the normal Lucie suddenly became partially or totally blind. "What is the matter? I can't see!" the normal personage suddenly cried out in the midst of her conversation, when M. Janet whispered to the secondary personage to make use of her eyes. The anaesthesias, paralyses, contractions and other irregularities from which hysterics suffer seem then to be due to the fact that their secondary personage has enriched itself by robbing the primary one of a function which the latter ought to have retained. The curative indication is evident: get at the secondary personage, by hypnotization or in whatever other way, and make her give up the eye, the skin, the arm, or whatever the affected part may be. The normal self thereupon regains possession, sees, feels, or is able to move again. In this way M. Jules Janet easily cured the well-known subject of the Salp�tri�re, Wit., of all sorts of afflictions which, until he discovered the secret of her deeper trance, it had been difficult to subdue. "Cessez cette mauvaise plaisanterie," he said to the secondary self - and the latter obeyed. The way in which the various personages share the stock of possible sensations between them seems to be amusingly illustrated in this young woman. When awake, her skin is insensible everywhere except on a zone about the arm where she habitually wears a gold bracelet. This zone has feeling; but in the deepest trance, when all the rest of her body feels, this particular zone becomes absolutely anaesthetic.

Sometimes the mutual ignorance of the selves leads to incidents which are strange enough. The acts and movements performed by the sub-conscious self are withdrawn from the conscious one, and the subject will do all sorts of incongruous things of which he remains quite unaware. "I order Lucie [by the method of distraction] to make a pied de nez, and her hands go forthwith to the end of her nose. Asked what she is doing, she replies that she is doing nothing, and continues for a long time talking, with no apparent suspicion that her fingers are moving in front of her nose. I make her walk about the room; she continues to speak and believes herself sitting down."

M. Janet observed similar acts in a man in alcoholic delirium. Whilst the doctor was questioning him, M. J. made him by whispered suggestion walk, sit, kneel, and even lie down on his face on the floor, he all the while believing himself to be standing beside his bed. Such bizarreries sound incredible, until one has seen their like. Long ago, without understanding it, I myself saw a small example of the way in which a person's knowledge may be shared by the two selves. A young woman who had been writing automatically was sitting with a pencil in her hand, trying to recall at my request the name of a gentleman whom she had once seen. She could only recollect the first syllable. Her hand meanwhile, without her knowledge, wrote down the last two syllables. In a perfectly healthy young man who can write with the planchette, I lately found the hand to be entirely anaesthetic during the writing act; I could prick it severely without the Subject knowing the fact. The writing on the planchette, however, accused me in strong terms of hurting the hand. Pricks on the other (non-writing) hand, meanwhile, which awakened strong protest from the young man's vocal organs, were denied to exist by the self which made the planchette go.[7]

We get exactly similar results in the so-called post-hypnotic suggestion. It is a familiar fact that certain subjects, when told during a trance to perform an act or to experience an hallucination after waking, will when the time comes, obey the command. How is the command registered? How is its performance so accurately timed? These problems were long a mystery, for the primary personality remembers nothing of the trance or the suggestion, and will often trump up an improvised pretext for yielding to the unaccountable impulse which possesses the man so suddenly and which he cannot resist. Edmund Gurney was the first to discover, by means of automatic writing, that the secondary self is awake, keeping its attention constantly fixed on the command and watching for the signal of its execution. Certain trance-subjects who were also automatic writers, when roused from trance and put to the planchette, - not knowing then what they wrote, and having their upper attention fully engrossed by reading aloud, talking, or solving problems in mental arithmetic, - would inscribe the orders which they had received, together with notes relative to the time elapsed and the time yet to run before the execution.[8] It is therefore to no 'automatism' in the mechanical sense that such acts are due: a self presides over them, a split-off, limited and buried, but yet a fully conscious, self. More than this, the buried self often comes to the surface and drives out the other self whilst the acts are performing. In other words, the subject lapses into trance again when the moment arrives for execution, and has no subsequent recollection of the act which he has done. Gurney and Beaunis established this fact, which has since been verified on a large scale; and Gurney also showed that the patient became suggestible again during the brief time of the performance. M. Janet's observations, in their turn, well illustrate the phenomenon.

"I tell Lucie to keep her arms raised after she shall have awakened. Hardly is she in the normal state, when up go her arms above her head, but she pays no attention to them. She goes, comes, converses, holding her arms high in the air. If asked what her arms are doing, she is surprised at such a question, and says very sincerely: 'My hands are doing nothing; they are just like yours.'... I com- mand her to weep, and when awake she really sobs, but continues in the midst of her tears to talk of very gay matters. The sobbing over, there remained no trace of this grief, which seemed to have been quite sub-conscious."

The primary self often has to invent an hallucination by which to mask and hide from its own view the deeds which the other self is enacting. L�onie 3 [9] writes real letters, whilst L�onie 1 believes that she is knitting; or Lucie 3 really comes to the doctor's office, whilst Lucie 1 believes herself to be at home. This is a sort of delirium. The alphabet, or the series of numbers, when handed over to the attention of the secondary personage may for the time be lost to the normal self. Whilst the hand writes the alphabet, obediently to command, the 'subject,' to her great stupefaction, finds herself unable to recall it, etc. Few things are more curious than these relations of mutual exclusion, of which all gradations exist between the several partial consciousnesses.

How far this splitting up of the mind into separate consciousnesses may exist in each one of us is a problem. M. Janet holds that it is only possible where there is abnormal weakness, and consequently a defect of unifying or co-ordinating power. An hysterical woman abandons part of her consciousness because she is too weak nervously to hold it together. The abandoned part meanwhile may solidify into a secondary or sub-conscious self. In a perfectly sound subject, on the other hand, what is dropped out of mind at one moment keeps coming back at the next. The whole fund of experiences and knowledges remains integrated, and no split-off portions of it can get organized stably enough to form subordinate selves. The stability, monotony, and stupidity of these latter is often very striking. The post-hypnotic sub-consciousness seems to think of nothing but the order which it last received; the cataleptic sub-consciousness, of nothing but the last position imprinted on the limb. M. Janet could cause definitely circumscribed reddening and tumefaction of the skin on two of his subjects, by suggesting to them in hypnotism the hallucination of a mustard-poultice of any special shape. "J'ai tout le temps pens� � votre sinapisme," says the subject, when put back into trance after the suggestion has taken effect. A man N.,... whom M. Janet operated on at long intervals, was betweenwhiles tampered with by another operator, and when put to sleep again by M. Janet, said he was 'too far away to receive orders, being in Algiers.' The other operator, having suggested that hallucination, had forgotten to remove it before waking the subject from his trance, and the poor passive trance-personality had stuck for weeks in the stagnant dream. L�onie's sub-conscious performances having been illustrated to a caller, by a 'pied de nez' executed with her left hand in the course of conversation, when, a year later, she meets him again, up goes the same hand to her nose again, without L�onie's normal self suspecting the fact.

All these facts, taken together, form unquestionably the beginning of an inquiry which is destined to throw a new light into the very abysses of our nature. It is for that reason that I have cited them at such length in this early chapter of the book. They prove one thing conclusively, namely, that we must never take a person's testimony, however sincere, that he has felt nothing, as proof positive that no feeling has been there. It may have been there as part of the consciousness of a 'secondary personage,' of whose experiences the primary one whom we are consulting can naturally give no account. In hypnotic subjects (as we shall see in a later chapter) just as it is the easiest thing in the world to paralyze a movement or member by simple suggestion, so it is easy to produce what is called a systematized anaesthesia by word of command. A systematized anaesthesia means an insensibility, not to any one element of things, but to some one concrete thing or class of things. The subject is made blind or deaf to a certain person in the room and to no one else, and thereupon denies that that person is present, or has spoken, etc. M. P. Janet's Lucie, blind to some of the numbered cards in her lap (p. 207 above), is a case in point. Now when the object is simple, like a red wafer or a black cross, the subject, although he denies that he sees it when he looks straight at it, nevertheless gets a 'negative after-image' of it when he looks away again, showing that the optical impression of it has been received. Moreover reflection shows that such a subject must distinguish the object from others like it in order to be blind to it. Make him blind to one person in the room, set all the persons in a row, and tell him to count them. He will count all but that one. But how can he tell which one not to count without recognizing who he is? In like manner, make a stroke on paper or blackboard, and tell him it is not there, and he will see nothing but the clean paper or board. Next (he not looking) surround the original stroke with other strokes exactly like it, and ask him what he sees. He will point out one by one all the new strokes, and omit the original one every time, no matter how numerous the new strokes may be, or in what order they are arranged. Similarly, if the original single stroke to which he is blind be doubled by a prism of some sixteen degrees placed before one of his eyes (both being kept open), he will say that he now sees one stroke, and point in the direction in which the image seen through the prism lies, ignoring still the original stroke.

Obviously, then, he is not blind to the kind of stroke in the least. He is blind only to one individual stroke of that kind in a particular position on the board or paper - that is to a particular complex object; and, paradoxical as it may seem to say so, he must distinguish it with great accuracy from others like it, in order to remain blind to it when the others are brought near. He discriminates it, as a preliminary to not seeing it at all.

Again, when by a prism before one eye a previously invisible line has been made visible to that eye, and the other eye is thereupon closed or screened, its closure makes no difference; the line still remains visible. But if then the prism be removed, the line will disappear even to the eye which a moment ago saw it, and both eyes will revert to their original blind state.

We have, then, to deal in these cases neither with a blindness of the eye itself, nor with a mere failure to notice, but with something much more complex; namely, an active counting out and positive exclusion of certain objects. It is as when one 'cuts' an acquaintance, 'ignores' a claim, or 'refuses to be influenced' by a consideration. But the perceptive activity which works to this result is disconnected from the consciousness which is personal, so to speak, to the subject, and makes of the object concerning which the suggestion is made, its own private possession and prey.[10]

The mother who is asleep to every sound but the stirrings of her babe, evidently has the babe-portion of her auditory sensibility systematically awake. Relatively to that, the rest of her mind is in a state of systematized anaesthesia. That department, split off and disconnected from the sleeping part, can none the less wake the latter up in case of need. So that on the whole the quarrel between Descartes and Locke as to whether the mind ever sleeps is less near to solution than ever. On a priori speculative grounds Locke's view that thought and feeling may at times wholly disappear seems the more plausible. As glands cease to secrete and muscles to contract, so the brain should sometimes cease to carry currents, and with this minimum of its activity might well coexist a minimum of consciousness. On the other hand, we see how deceptive are appearances, and are forced to admit that a part of consciousness may sever its connections with other parts and yet continue to be. On the whole it is best to abstain from a conclusion. The science of the near future will doubtless answer this question more wisely than we can now.

Let us turn now to consider the

RELATIONS OF CONSCIOUSNESS TO SPACE. This is the problem known in the history of philosophy as the question of the seat of the soul. It has given rise to much literature, but we must ourselves treat it very briefly. Everything depends on what we conceive the soul to be, an extended or an inextended entity. If the former, it may occupy a seat. If the latter, it may not; though it has been thought that even then it might still have a position. Much hair-splitting has arisen about the possibility of an inextended thing nevertheless being present throughout a certain amount of extension. We must distinguish the kinds of presence. In some manner our consciousness is 'present' to everything with which it is in relation. I am cognitively present to Orion whenever I perceive that constellation, but I am not dynamically present there, I work no effects. To my brain, however, I am dynamically present, inasmuch as my thought and feelings seem to react upon the processes thereof. If, then, by the seat of the mind is meant nothing more than the locality with which it stands in immediate dynamic relations, we are certain to be right in saying that its seat is somewhere in the cortex of the brain. Descartes, as is well known, thought that the inextended soul was immediately present to the pineal gland. Others, as Lotze in his earlier days, and W. Volkmann, think its position must be at some point of the structureless matrix of the anatomical brain-elements, at which point they suppose that all nerve-currents may cross and combine. The scholastic doctrine is that the soul is totally present, both in the whole and in each and every part of the body. This mode of presence is said to be due to the soul's inextended nature and to its simplicity. Two extended entities could only correspond in space with one another, part to part, - but not so does the soul, which has no parts, correspond with the body. Sir Wm. Hamilton and Professor Bowen defend something like this view. I. H. Fichte, Ulrici, and, among American philosophers, Mr. J. E. Walter,[11] maintain the soul to be a space-filling prin- ciple. Fichte calls it the inner body, Ulrici likens it to a fluid of non-molecular composition. These theories remind us of the 'theosophic' doctrines of the present day, and carry us back to times when the soul as vehicle of consciousness was not discriminated , as it now is, from the vital principle presiding over the formation of the body. Plato gave head, breast, and abdomen to the immortal reason, the courage, and the appetites, as their seats respectively. Aristotle argues that the heart is the sole seat. Elsewhere we find the blood, the brain, the lungs, the liver the kidneys even, in turn assigned as seat of the whole or part of the soul.[12]

The truth is that if the thinking principle is extended we neither know its form nor its seat; whilst if unextended, it is absurd to speak of its having any space-relations at all. Space-relations we shall see hereafter to be sensible things. The only objects that can have mutual relations of position are objects that are perceived coexisting in the same felt space. A thing not perceived at all, such as the inextended soul must be, cannot coexist with any perceived objects in this way. No lines can be felt stretching from it to the other objects. It can form no terminus to any space-interval. It can therefore in no intelligible sense enjoy position. Its relations cannot be spatial, but must be exclusively cognitive or dynamic, as we have seen. So far as they are dynamic to talk of the soul being 'present' is only a figure of speech. Hamilton's doctrine that the soul is present to the whole body is at any rate false: for cognitively its presence extends far beyond the body, and dynamically it does not extent beyond the brain.[13]

THE RELATIONS OF MINDS TO OTHER OBJECTS are either relations to other minds, or to material things. The material things are either the mind's own brain, on the one hand, or anything else, on the other. The relations of a mind to its own brain are of a unique and utterly mysterious sort; we discussed them in the last two chapters, and can add nothing to that account.

The mind's relations to other objects than the brain are cognitive and emotional relations exclusively, so far as we know. It knows them, and it inwardly welcomes or rejects them, but it has no other dealings with them. When it seems to act upon them, it only does so through the intermediary of its own body, so that not it but the body is what acts on them, and the brain must first act upon the body. The same is true when other things seem to act on it - they only act on its body, and through that on its brain.[14] All that it can do directly is to know other things, misknow or ignore them, and to find that they interest it, in this fashion or in that.

Now the relation of knowing is the most mysterious thing in the world. If we ask how one thing can know another we are led into the heart of Erkenntnisstheorie and metaphysics. The psychologist, for his part, does not consider the matter so curiously as this. Finding a world before him which he cannot but believe that he knows, and setting himself to study his own past thoughts, or someone else's thoughts, of what he believes to be that same world; he cannot but conclude that those other thoughts know it after their fashion even as he knows it after his. Knowledge becomes for him an ultimate relation that must be admitted, whether it be explained or not, just like difference or resemblance, which no one seeks to explain.

Were our topic Absolute Mind instead of being the concrete minds of individuals dwelling in the natural world, we could not tell whether that Mind had the function of knowing or not, as knowing is commonly understood. We might learn the complexion of its thoughts; but, as we should have no realities outside of it to compare them with, - for if we had, the Mind would not be Absolute, - we could not criticise them, and find them either right or wrong; and we should have to call them simply the thoughts, and not the knowledge, of the Absolute Mind. Finite minds, however, can be judged in a different way, because the psychologist himself can go bail for the independent reality of the objects of which they think. He knows these to exist outside as well as inside the minds in question; he thus knows whether the minds think and know, or only think; and though his knowledge is of course that of a fallible mortal, there is nothing in the conditions that should make it more likely to wrong in this case than in any other.

Now by what tests does the psychologist decide whether the state of mind he is studying is a bit of knowledge, or only a subjective fact not referring to anything outside itself?

He uses the tests we all practically use. If the state of mind resembles his own idea of a certain reality; or if without resembling his idea of it, it seems to imply that reality and refer to it by operating upon it through the bodily organs; or even if it resembles and operates on some other reality that implies, and leads up to, and terminates in, the first one, - in either or all of these cases the psychologist admits that the state of mind takes cognizance, directly or remotely, distinctly or vaguely, truly or falsely, of the reality's nature and position in the world. If, on the other hand, the mental state under examination neither resembles nor operates on any of the realities known to the psychologist, he calls it a subjective state pure and simple, possessed of no cognitive worth. If, again, it resemble a reality or a set of realities as he knows them, but altogether fail to operate on them or modify their course by producing bodily motions which the psychologist sees, then the psychologist, like all of us, may be in doubt. Let the mental state, for example, occur during the sleep of its subject. Let the latter dream of the death of a certain man, and let the man simultaneously die. Is the dream a mere coincidence, or a veritable cognition of the death? Such puzzling cases are what the Societies for 'Psychical Research' are collecting and trying to interpret in the most reasonable way.

If the dream were the only one of the kind the subject ever had in his life, if the context of the death in the dream differed in many particulars from the real death's context, and if the dream led to no action about the death, unquestionably we should all call it a strange coincidence, and naught besides. But if the death in the dream had a long context, agreeing point for point with every feature that attended the real death; if the subject were constantly having such dreams, all equally perfect, and if on awaking he had a habit of acting immediately as if they were true and so getting 'the start' of his more tardily informed neighbors, - we should probably all have to admit that he had some mysterious kind of clairvoyant power, that his dreams in an inscrutable way knew just those realities which they figured, and that the word 'coincidence' failed to touch the root of the matter. And whatever doubts any one preserved would completely vanish if it should appear that from the midst of his dream he had the power of interfering with the course of the reality, and making the events in it turn this way or that, according as he dreamed they should. Then at least it would be certain that he and the psychologist were dealing with the same. It is by such tests as these that we are convinced that the waking minds of our fellows and our own minds know the same external world.

The psychologist's attitude towards cognition will be so important in the sequel that we must not leave it until it is made perfectly clear. It is a thoroughgoing dualism. It supposes two elements, mind knowing and thing known, and treats them as irreducible. Neither gets out of itself or into the other, neither in any way is the other, neither makes the other. They just stand face to face in a common world, and one simply knows, or is known unto, its counterpart. This singular relation is not to be expressed in any lower terms, or translated into any more intelligible name. Some sort of signal must be given by the thing to the mind's brain, or the knowing will not occur - we find as a matter of fact that the mere existence of a thing outside the brain is not a sufficient cause for our knowing it: it must strike the brain in some way, as well as be there, to be known. But the brain being struck, the knowledge is constituted by a new construction that occurs altogether in the mind. The thing remains the same whether known or not.[15] And when once there, the knowledge may remain there, whatever becomes of the thing.

By the ancients, and by unreflecting people perhaps today, knowledge is explained as the passage of something from without into the mind - the latter, so far, at least, as its sensible affections go, being passive and receptive. But even in mere sense-impression the duplication of the object by an inner construction must take place. Consider, with Professor Bowne, what happens when two people converse together and know each other's mind.

"No thoughts leave the mind of one and cross into the mind of the other. When we speak of an exchange of thought, even the crudest mind knows that this is a mere figure of speech.... To perceive another's thought, we must construct his thought within ourselves;... this thought is our own and is strictly original with us. At the same time we owe it to the other; and if it had not originated with him, it would probably not have originated with us. But what has the other done?... This: by an entirely mysterious world-order, the speaker is enabled to produce a series of signs which are totally unlike [the] thought, but which, by virtue of the same mysterious order, act as a series of incitements upon the hearer, so that he constructs within himself the corresponding mental state. The act of the speaker consists in availing himself of the proper incitements. The act of the hearer is immediately only the reaction of the soul against the incitement.... All communication between finite minds is of this sort.... Probably no reflecting person would deny this conclusion, but when we say that what is thus true of perception of another's thought is equally true of the perception of the outer world in general, many minds will be disposed to question, and not a few will deny it outright. Yet there is no alternative but to affirm that to perceive the universe we must construct it in thought, and that our knowledge of the universe is but the unfolding of the mind's inner nature.... By describing the mind as a waxen tablet, and things as impressing themselves upon it, we seem to get great insight until we think to ask where this extended tablet is, and how things stamp themselves on it, and how the percep- tive act would be explained even if they did.... The immediate antecedents of sensation and perception are a series of nervous changes in the brain. Whatever we know of the outer world is revealed only in and through these nervous changes. But these are totally unlike the objects assumed to exist as their causes. If we might conceive the mind as in the light, and in direct contact with its objects, the imagination at least would be comforted; but when we conceive the mind as coming in contact with the outer world only in the dark chamber of the skull, and then not in contact with the objects perceived, but only with a series of nerve-changes of which, moreover, it knows nothing, it is plain that the object is a long way off. All talk of pictures, impressions, etc., ceases because of the lack of all the conditions to give such figures any meaning. It is not even clear that we shall ever find our way out of the darkness into the world of light and reality again. We begin with complete trust in physics and the senses, and are forthwith led away from the object into a nervous labyrinth, where the object is entirely displaced by a set of nervous changes which are totally unlike anything but themselves. Finally, we land in the dark chamber of the skull. The object has gone completely, and knowledge has not yet appeared. Nervous signs are the raw material of all knowledge of the outer world according to the most decided realism. But in order to pass beyond these signs into a knowledge of the outer world, we must posit an interpreter who shall read back these signs into their objective meaning. But that interpreter, again, must implicitly contain the meaning of the universe within itself; and these signs are really but excitations which cause the soul to unfold what is within itself. Inasmuch as by common consent the soul communicates with the outer world only through these signs, and never comes nearer to the object than such signs can bring it, it follows that the principles of interpretation must be in the mind itself, and that the resulting construction is primarily only an expression of the mind's own nature. All reaction is of this sort; it expresses the nature of the reacting agent, and knowledge comes under the same head. this [sic] fact makes it necessary for us either to admit a pre-established harmony between the laws and nature of thought and the laws and nature of things, or else to allow that the objects of perception, the universe as it appears, are purely phenomenal, being but the way in which the mind reacts against the ground of its sensations."[16]

The dualism of Object and Subject and their pre-established harmony are what the psychologist as such must assume, whatever ulterior monistic philosophy he may, as an individual who has the right also to be a metaphysician, have in reserve. I hope that this general point is now made clear, so that we may leave it, and descend to some distinctions of detail.

There are two kinds of knowledge broadly and practically distinguishable: we may call them respectively knowledge of acquaintance and knowledge-about. Most languages express the distinction; thus, g n v n a i , e i d e n a i; noscere, scire; kennen, wissen; conna�tre, savoir.[17] I am acquainted with many people and things, which I know very little about, except their presence in the places where I have met them. I know the color blue when I see it, and the flavor of a pear when I taste it; I know an inch when I move my finger through it; a second of time, when I feel it pass; an effort of attention when I make it; a difference between two things when I notice it; but about the inner nature of these facts or what makes them what they are, I can say nothing at all. I cannot impart acquaintance with them to any one who has not already made it himself. I cannot describe them, make a blind man guess what blue is like, define to a child a syllogism, or tell a philosopher in just what respect distance is just what it is, and differs from other forms of relation. At most, I can say to my friends, Go to certain places and act in certain ways, and these objects will probably come. All the elementary natures of the world, its highest genera, the simple qualities of matter and mind, together with the kinds of relation that subsist between them, must either not be known at all, or known in this dumb way of acquaintance without knowledge-about. In minds able to speak at all there is, it is true, some knowledge about everything. Things can at least be classed, and the times of their appearance told. But in general, the less we analyze a thing, and the fewer of its relations we perceive, the less we know about it and the more our familiarity with it is of the acquaintance-type. The two kinds of knowledge are, therefore, as the human mind practically exerts them, relative terms. That is, the same thought of a thing may be called knowledge-about it in comparison with a simpler thought, or acquaintance with it in compari- son with a thought of it that is more articulate and explicit still.

The grammatical sentence expresses this. Its 'subject' stands for an object of acquaintance which, by the addition of the predicate, is to get something known about it. We may already know a good deal, when we hear the subject named - its name may have rich connotations. But, know we much or little then, we know more still when the sentence is done. We can relapse at will into a mere condition of acquaintance with an object by scattering our attention and staring at it in a vacuous trance-like way. We can ascend to knowledge about it by rallying our wits and proceeding to notice and analyze and think. What we are only acquainted with is only present to our minds; we have it, or the idea of it. But when we know about it, we do more than merely have it; we seem, as we think over its relations, to subject it to a sort of treatment and to operate upon it with our thought. The words feeling and thought give voice to the antithesis. Through feelings we become acquainted with things, but only by our thoughts do we know about them. Feelings are the germ and starting point of cognition, thoughts the developed tree. The minimum of grammatical subject, of objective presence, of reality known about, the mere beginning of knowledge, must be named by the word that says the least. Such a word is the interjection, as lo! there! ecco! voil�! or the article or demonstrative pronoun introducing the sentence, as the, it, that. In Chapter XII we shall see a little deeper into what this distinction, between the mere mental having or feeling of an object and the thinking of it, portends.

The mental states usually distinguished as feelings are the emotions, and the sensations we get from skin, muscle, viscus, eye, ear, nose, and palate. The 'thoughts,' as recognized in popular parlance, are the conceptions and judgments. When we treat of these mental states in particular we shall have to say a word about the cognitive function and value of each. It may perhaps be well to notice now that our senses only give us acquaintance with facts of body, and that of the mental states of other persons we only have conceptual knowledge. Of our own past states of mind we take cognizance in a peculiar way. They are 'objects of memory,' and appear to us endowed with a sort of warmth and intimacy that makes the perception of them seem more like a process of sensation than like a thought.

-------------------------------------------------------------------------------- Footnotes [1] Messrs. Payton-Spence (Journal of Spec. Phil., X. 338, XIV. 286) and M. M. Garver (Amer. Jour. of Science, 3d series, XX. 189) argue, the one from speculative, the other from experimental grounds, that, the physical condition of consciousness being neural vibration, the consciousness must itself be incessantly interrupted by unconsciousness - about fifty times a second, according to Garver.

[2] That the appearance of mental activity here is real can be proved by suggesting to the 'hypnotized' somnambulist that he shall remember when he awakes. He will then often do so.

[3] For more details, cf. Malebranche, Rech. de la Verit�, bk. III. chap. I; J. Locke, Essay conc. H. U., book II. ch. I; C. Wolf, Psychol. rationalis, � 59; Sir W. Hamilton, Lectures on Metaph., lecture XVII; J. Bascom, Science of Mind, � 12; Th. Jouffroy, M�langes Philos., 'du Sommeil'; H. Holland, Chapters on Mental Physiol., p. 80; B. Brodie, Psychol. Researches, p. 147; E. M. Chesley, Journ. of Spec. Phil., vol. XI. p. 72; Th. Ribot, Maladies de la Personnalit�, pp. 8-10; H. Lotze, Metaphysics, � 533.

[4] L'Automatisme Psychologique, Paris, 1889, passim.

[5] See his articles in the Chicago Open Court, for July, August and November, 1889. Also in the Revue Philosophique for 1889 and '90.

[6] This whole phenomena shows how an idea which remains itself below the threshold of a certain conscious self may occasion associative effects therein. The skin-sensations unfelt by the patient's primary consciousness awaken nevertheless their usual visual associates therein.

[7] See Proceedings of American Soc. for Psych. Research, vol. I. p. 548.

[8] Proceedings of the (London) Soc. for Psych. Research, May 1887, p. 268 ff.

[9] M. Janet designates by numbers the different personalities which the subject may display.

[10] How to conceive of this state of mind is not easy. It would be much simpler to understand the process, if adding new strokes made the first one visible. There would then be two different objects apperceived as totals, - paper with one stroke, paper with many strokes; and, blind to the former, he would see all that was in the latter, because he would have apperceived it as a different total in the first instance.

A process of this sort occurs sometimes (not always) when the new strokes, instead of being mere repetitions of the original one, are lines which combine with it into a total object, say a human face. The subject of the trance then may regain his sight of the line to which he had previously been blind, by seeing it as part of the face.

[11] Perception of Space and Matter, 1879, part II. chap. 3.

[12] For a very good condensed history of the various opinions, see W. Volkmann von Volkmar, Lehrbuch d. Psychologie, � 16. Anm. Complete references to Sir W. Hamilton are given in J. E. Walter, Perception of Space and Matter, pp. 65-6.

[13] Most contemporary writers ignore the question of the soul's seat. Lotze is the only one who seems to have been much concerned about it, and his views have varied. Cf. Medicinische Psychol., � 10. Microcosmus, bk. III. ch. 2. Metaphysic, bk. III. ch. 5. Outlines of Psychol., part II. ch. 3. See also G. T. Fechner, Psychophysik, chap. XXXVII.

[14] I purposely ignore 'clairvoyance' and action upon distant things by 'mediums,' as not yet matters of common consent.

[15] I disregard consequences which may later come to the thing from the fact that it is known. The knowing per se in no wise affects the thing.

[16] B. P. Bowne: Metaphysics, pp. 407-10. Cf. also Lotze: Logik, �� 308, 326-7.

[17] Cf. John Grote: Exploratio Philosophica, p. 60; H. Helmholtz, Popular Scientific Lectures, London, p. 308-9.

CHAPTER IX.[1] The Stream of Thought.

We now begin our study of the mind from within. Most books start with sensations, as the simplest mental facts, and proceed synthetically, constructing each higher stage from those below it. But this is abandoning the empirical method of investigation. No one ever had a simple sensation by itself. Consciousness, from our natal day, is of a teeming multiplicity of objects and relations, and what we call simple sensations are results of discriminative attention, pushed often to a very high degree. It is astonishing what havoc is wrought in psychology by admitting at the outset apparently innocent suppositions, that nevertheless contain a flaw. The bad consequences develop themselves later on, and are irremediable, being woven through the whole texture of the work. The notion that sensations, being the simplest things, are the first things to take up in psychology is one of these suppositions. The only thing which psychology has a right to postulate at the outset is the fact of thinking itself, and that must first be taken up and analyzed. If sensations then prove to be amongst the elements of the thinking, we shall be no worse off as respects them than if we had taken them for granted at the start.

The first fact for us, then, as psychologists, is that thinking of some sort goes on. I use the word thinking, in accordance with what was said on p. 186, for every form of consciousness indiscriminately. If we could say in English 'it thinks,' as we say 'it rains' or 'it blows,' we should be stating the fact most simply and with the minimum of assumption. As we cannot, we must simply say that thought goes on.

  

FIVE CHARACTERS IN THOUGHT.
How does it go on? We notice immediately five important characters in the process, of which it shall be the duty of the present chapter to treat in a general way: 
1) Every thought tends to be part of a personal consciousness. 
2) Within each personal consciousness thought is always changing. 
3) Within each personal consciousness thought is sensibly continuous. 
4) It always appears to deal with objects independent of itself. 
5) It is interested in some parts of these objects to the exclusion of others, and welcomes or rejects - chooses from 
among them, in a word - all the while.

In considering these five points successively, we shall have to plunge in medias res as regards our vocabulary, and use psychological terms which can only be adequately defined in later chapters of the book. But every one knows what the terms mean in a rough way; and it is only in a rough way that we are now to take them. This chapter is like a painter's first charcoal sketch upon his canvas, in which no niceties appear.

1) Thought tends to Personal Form. When I say every thought is part of a personal consciousness, 'personal consciousness' is one of the terms in question, Its meaning we know so long as no one asks us to define it, but to give an accurate account of it is the most difficult of philosophic tasks. This task we must confront in the next chapter; here a preliminary word will suffice.

In this room - this lecture-room, say - there are a multitude of thoughts, yours and mine, some of which cohere mutually, and some not. They are as little each-for-itself and reciprocally independent as they are all-belonging- together. They are neither: no one of them is separate, but each belongs with certain others and with none beside. My thought belongs with my other thoughts, and your thought with your other thoughts. Whether anywhere in the room there be a mere thought, which is nobody's thought, we have no means of ascertaining, for we have no experience of its like. The only states of consciousness that we naturally deal with are found in personal consciousnesses, minds, selves, concrete particular I's and you's.

Each of these minds keeps its own thoughts to itself. There is no giving or bartering between them. No thought even comes into direct sight of a thought in another personal consciousness than its own. Absolute insulation, irreducible pluralism, is the law. It seems as if the elementary psychic fact were not thought or this thought or that thought, but my thought, every thought being owned. Neither contemporaneity, nor proximity in space, nor similarity of quality and content are able to fuse thoughts together which are sundered by this barrier of belonging to different personal minds. The breaches between such thoughts are the most absolute breaches in nature. Everyone will recognize this to be true, so long as the existence of something corresponding to the term 'personal mind' is all that is insisted on, without any particular view of its nature being implied. On these terms the personal self rather than the thought might be treated as the immediate datum in psychology. The universal conscious fact is not 'feelings and thoughts exist,' but 'I think' and 'I feel.'[2] No psychology, at any rate, can question the existence of personal selves. The worst a psychology can do is so to interpret the nature of these selves as to rob them of their worth. A French writer, speaking of our ideas, says somewhere in a fit of anti-spiritualistic excitement that, misled by certain peculiaritities which they display, we 'end by personifying' the procession which they make, - such personification being regarded by him as a great philosophic blunder on our part. It could only be a blunder if the notion of personality meant something essentially different from anything to be found in the mental procession. But if that procession be itself the very 'original' of the notion of personality, to personify it cannot possibly be wrong. It is already personified. There are no marks of personality to be gathered aliunde, and then found lacking in the train of thought. It has them all already; so that to whatever farther analysis we may subject that form of personal selfhood under which thoughts appear, it is, and must remain, true that the thoughts which psychology studies do continually tend to appear as parts of personal selves.

I say 'tend to appear' rather than 'appear,' on account of those facts of sub-conscious personality, automatic writing, etc., of which we studied a few in the last chapter. The buried feelings and thoughts proved now to exist in hysterical an�sthetics, in recipients of post-hypnotic suggestion, etc.,themselves are parts of secondary personal selves. These selves are for the most part very stupid and contracted, and are cut off at ordinary times from communication with the regular and normal self of the individual; but still they form conscious unities, have continuous memories, speak, write, invent distinct names for themselves, or adopt names that are suggested; and, in short, are entirely worthy of that title of secondary personalities which is now commonly given them. According to M. Janet these secondary personalities are always abnormal, and result from the splitting of what ought to be a single complete self into two parts, of which one lurks in the background whilst the other appears on the surface as the only self the man or woman has. For our present purpose it is unimportant whether this account of the origin of secondary selves is applicable to all possible cases of them or not, for it certainly is true of a large number of them. Now although the size of a secondary self thus formed will depend on the number of thoughts that are thus split-off from the main consciousness, the form, of it tends to personality, and the later thoughts pertaining to it remember the earlier ones and adopt them as their own. M. Janet caught the actual moment of inspissation (so to speak) of one of these secondary personalities in his an�sthetic somnambulist Lucie. He found that when this young woman's attention was absorbed in conversation with a third party, her an�sthetic hand would write simple answers to questions whispered to her by himself. "Do you hear?" he asked. "No," was the unconsciously written reply. "But to answer you must hear." "Yes, quite so." "Then how do you manage?" "I don't know." "There must be some one who hears me." "Yes." "Who?" "Someone other than Lucie." "Ah! another person. Shall we give her a name?" "No." "Yes, it will be more convenient." "Well, Adrienne, then." "Once baptized, the subconscious personage," M. Janet continues, "grows more definitely outlined and displays better her psychological characters. In particular she shows us that she is conscious of the feelings excluded from the consciousness of the primary or normal personage. She it is who tells us that I am pinching the arm or touching the little finger in which Lucie for so long has had no tactile sensations."[3]

In other cases the adoption of the name by the secondary self is more spontaneous. I have seen a number of incipient automatic writers and mediums as yet imperfectly 'developed,' who immediately and of their own accord write and speak in the name of departed spirits. These may be public characters, as Mozart, Faraday, or real persons formerly known to the subject, or altogether imaginary beings. Without prejudicing the question of real 'spirit-control' in the more developed sorts of trance- utterance, I incline to think that these (often deplorably unintelligent) rudimentary utterances are the work of an inferior fraction of the subject's own natural mind, set free from control by the rest, and working after a set pattern fixed by the prejudices of the social environment. In a spiritualistic community we get optimistic messages, whilst in an ignorant Catholic village the secondary personage calls itself by the name of a demon, and proffers blasphemies and obscenities, instead of telling us how happy it is in the summer-land.[4]

Beneath these tracts of thought, which, however rudimentary, are still organized selves with a memory, habits, and sense of their own identity, M. Janet thinks that the facts of catalepsy in hysteric patients drive us to suppose that there are thoughts quite unorganized and impersonal. A patient in cataleptic trance (which can be produced artificially in certain hypnotized subjects) is without memory on waking, and seems insensible and unconscious as long as the cataleptic condition lasts. If, however, one raises the arm of such a subject it stays in that position, and the whole body can thus be moulded like wax under the hands of the operator, retaining for a considerable time whatever attitude he communicates to it. In hysterics whose arm, for example, is an�sthetic, the same thing may happen. The an�sthetic arm may remain passively in positions which it is made to assume; or if the hand be taken and made to hold a pencil and trace a certain letter, it will continue tracing that letter indefinitely on the paper. These acts, until recently, were supposed to be accompanied by no consciousness at all: they were physiological reflexes. M. Janet considers with much more plausibility that feeling escorts them. The feeling is probably merely that of the position or movement of the limb, and it produces no more than its natural effects when it discharges into the motor centres which keep the position maintained, or the movement incessantly renewed.[5] Such thoughts as these, says M. Janet, "are known by no one, for disaggregated sensations reduced to a state of mental dust are not synthetized in any personality."[6] He admits, however, that these very same unutterably stupid thoughts tend to develop memory, - the cataleptic ere long moves her arm at a bare hint; so that they form no important exception to the law that all thought tends to assume the form of personal consciousness.

2) Thought is in Constant Change. I do not mean necessarily that no one state of mind has any duration - even if true, that would be hard to establish.

The change which I have more particularly in view is that which takes place in sensible intervals of time; and the result on which I wish to lay stress is this, that no state once gone can recur and be identical with what it was before. Let us begin with Mr. Shadworth Hodgson's description:

"I go straight to the facts, without saying I go to perception, or sensation, or thought, or any special mode at all. What I find when I look at my consciousness at all is that what I cannot divest myself of, or not have in consciousness, if I have any consciousness at all, is a sequence of different feelings. I may shut my eyes and keep perfectly still, and try not to contribute anything of my own will; but whether I think or do not think, whether I perceive external things or not, I always have a succession of different feelings. Anything else that I may have also, of a more special character, comes in as parts of this succession. Not to have the succession of different feelings is not to be conscious at all� The chain of consciousness is a sequence of differents."[7]

Such a description as this can awaken no possible protest from any one. We all recognize as different great classes of our conscious states. Now we are seeing, now hearing; now reasoning, now willing; now recollecting, now expecting; now loving, now hating; and in a hundred other ways we know our minds to be alternately engaged. But all these are complex states. The aim of science is always to reduce complexity to simplicity; and in psychological science we have the celebrated 'theory of ideas' which, admitting the great difference among each other of what may be called concrete conditions of mind, seeks to show how this is all the resultant effect of variations in the combination of certain simple elements of consciousness that always remain the same. These mental atoms or molecules are what Locke called 'simple ideas.' Some of Locke's successors made out that the only simple ideas were the sensations strictly so called. Which ideas the simple ones may be does not, however, now concern us. It is enough that certain philosophers have thought they could see under the dissolving-view-appearance of the mind elementary facts of any sort that remained unchanged amid the flow.

And the view of these philosophers has been called little into question, for our common experience seems at first sight to corroborate it entirely. Are not the sensations we get from the same object, for example, always the same? Does not the same piano-key, struck with the same force, make us hear in the same way? Does not the same grass give us the same feeling of green, the same sky the same feeling of blue, and do we not get the same olfactory sensation no matter how many times we put our nose to the same flask of cologne? It seems a piece of metaphysical sophistry to suggest that we do not; and yet a close attention to the matter shows that there is no proof that the same bodily sensation is ever got by us twice.

What is got twice is the same OBJECT. We hear the same note over and over again; we see the same quality of green, or smell the same objective perfume, or experience the same species of pain. The realities, concrete and abstract, physical and ideal, whose permanent existence we believe in, seem to be constantly coming up again before our thought, and lead us, in our carelessness, to suppose that our 'ideas' of them are the same ideas. When we come, some time later, to the chapter on Perception, we shall see how inveterate is our habit of not attending to sensations as subjective facts, but of simply using them as stepping-stones to pass over to the recognition of the realities whose presence they reveal. The grass out of the window now looks to me of the same green in the sun as in the shade, and yet a painter would have to paint one part of it dark brown, another part bright yellow, to give its real sensational effect. We take no heed, as a rule, of the different way in which the same things look and sound and smell at different distances and under different circumstances. The sameness of the things is what we are concerned to ascertain; and any sensations that assure us of that will probably be considered in a rough way to be the same with each other. This is what makes off-hand testimony about the subjective identity of different sensations well-nigh worthless as a proof of the fact. The entire history of Sensation is a commentary on our inability to tell whether two sensations received apart are exactly alike. What appeals to our attention far more than the absolute quality or quantity of a given sensation is its ratio to whatever other sensations we may have at the same time. When everything is dark a somewhat less dark sensation makes us see an object white. Helmholtz calculates that the white marble painted in a picture representing an architectural view by moonlight is, when seen by daylight, from ten to twenty thousand times brighter than the real moonlit marble would be.[8]

Such a difference as this could never have been sensibly learned; it had to be inferred from a series of indirect considerations. There are facts which make us believe that our sensibility is altering all the time, so that the same object cannot easily give us the same sensation over again. The eye's sensibility to light is at its maximum when the eye is first exposed, and blunts itself with surprising rapidity. A long night's sleep will make it see things twice as brightly on wakening, as simple rest by closure will make it see them later in the day.[9] We feel things differently according as we are sleepy or awake, hungry or full, fresh or tired; differently at night and in the morning, differently in summer and in winter, and above all things differently in childhood, manhood, and old age. Yet we never doubt that our feelings reveal the same world, with the same sensible qualities and the same sensible things occupying it. The difference of the sensibility is shown best by the difference of our emotion about the things from one age to another, or when we are in different organic moods. What was bright and exciting becomes weary, flat, and unprofitable. The bird's song is tedious, the breeze is mournful, the sky is sad.

To these indirect presumptions that our sensations, following the mutations of our capacity for feeling, are always undergoing an essential change, must be added another presumption, based on what must happen in the brain. Every sensation corresponds to some cerebral action. For an identical sensation to recur it would have to occur the second time in an unmodified brain. But as this, strictly speaking, is a physiological impossibility, so is an unmodified feeling an impossibility; for to every brain-modification, however small, must correspond a change of equal amount in the feeling which the brain subserves.

All this would be true if even sensations came to us pure and single and not combined into 'things.' Even then we should have to confess that, however we might in ordinary conversation speak of getting the same sensation again, we never in strict theoretic accuracy could do so; and that whatever was true of the river of life, of the river of elementary feeling, it would certainly be true to say, like Heraclitus, that we never descend twice into the same stream.

But if the assumption of 'simple ideas of sensation' recurring in immutable shape is so easily shown to be baseless, how much more baseless is the assumption of immutability in the larger masses of our thought!

For there it is obvious and palpable that our state of mind is never precisely the same. Every thought we have of a given fact is, strictly speaking, unique, and only bears a resemblance of kind with our other thoughts of the same fact. When the identical fact recurs, we must think of it in a fresh manner, see it under a somewhat different angle, apprehend it in different relations from those in which it last appeared. And the thought by which we cognize it is the thought of it-in-those-relations, a thought suffused with the consciousness of all that dim context. Often we are ourselves struck at the strange differences in our successive views of the same thing. We wonder how we ever could have opined as we did last month about a certain matter. We have outgrown the possibility of that state of mind, we know not how. From one year to another we see things in new lights. What was unreal has grown real, and what was exciting is insipid. The friends we used to care the world for are shrunken to shadows; the women, once so divine, the stars, the woods, and the waters, how now so dull and common; the young girls that brought an aura, of infinity, at present hardly distinguishable existences; the pictures so empty; and as for the books, what was there to find so mysteriously significant in Goethe, or in John Mill so full of weight? Instead of all this, more zestful than ever is the work, the work; and fuller and deeper the import of common duties and of common goods.

But what here strikes us so forcibly on the flagrant scale exists on every scale, down to the imperceptible transition from one hour's outlook to that of the next. Experience is remoulding us every moment, and our mental reaction on every given thing is really a resultant of our experience of the whole world up to that date. The analogies of brain-physiology must again be appealed to to corroborate our view.

Our earlier chapters have taught us to believe that, whilst we think, our brain changes, and that, like the aurora borealis, its whole internal equilibrium shifts with every pulse of change. The precise nature of the shifting at a given moment is a product of many factors. The accidental state of local nutrition or blood-supply may be among them. But just as one of them certainly is the influence of outward objects on the sense-organs during the moment, so is another certainly the very special susceptibility in which the organ has been left at that moment by all it has gone through in the past. Every brain-state is partly determined by the nature of this entire past succession. Alter the latter in any part, and the brain-state must be somewhat different. Each present brain-state is a record in which the eye of Omniscience might read all the foregone history of its owner. It is out of the question, then, that any total brain-state should identically recur. Something like it may recur; but to suppose it to recur would be equivalent to the absurd admission that all the states that had intervened between its two appearances had been pure nonentities, and that the organ after their passage was exactly as it was before. And (to consider shorter periods) just as, in the senses, an impression feels very differently according to what has preceded it; as one color succeeding another is modified by the contrast, silence sounds delicious after noise, and a note, when the scale is sung up, sounds unlike itself when the scale is sung down; as the presence of certain lines in a figure changes the apparent form of the other lines, and as in music the whole �sthetic effect comes from the manner in which one set of sounds alters our feeling of another; so, in thought, we must admit that those portions of the brain that have just been maximally excited retain a kind of soreness which is a condition of our present consciousness, a codeterminant of how and what we now shall feel.[10]

Ever some tracts are waning in tension, some waxing, whilst others actively discharge. The states of tension have as positive an influence as any in determining the total condition, and in deciding what the psychosis shall be. All we know of submaximal nerve-irritations, and of the summation of apparently ineffective s

The Principles of Psychology

William James