Kitabı oku: «The Mind and the Brain», sayfa 4

We can, therefore, only deplore the error of all those who, to express the difference between mind and matter, have sought a contrast between sensation and physical facts. Physiologists, with hardly an exception, have fallen into this error; when contemplating in imagination the material working of the brain, they have thought that between the movement of cerebral matter and sensation there was a gulf fixed. The comparison, to have been correct, required to be presented in quite another way. A parallel, for instance, should have been drawn between a certain cerebral movement and the act of consciousness, and there should have been said: "The cerebral motion is the physical phenomenon, the act of consciousness the psychical." But this distinction has not been made. It is sensation en bloc which is compared to the cerebral movement, as witness a few passages I will quote as a matter of curiosity, which are borrowed from philosophers and, especially, from physiologists.

While philosophers take as a principle of idealism, that the mental can only know the mental, physiologists take, as a like principle, the heterogeneity existing, or supposed to exist, between the nerve impression and the sensation. "However much we may follow the excitement through the whole length of the nerve," writes Lotze,¹⁸ "or cause it to change its form a thousand times and to metamorphose itself into more and more delicate and subtle movements, we shall never succeed in showing that a movement thus produced can, by its very nature, cease to exist as movement and be reborn in the shape of sensation...." It will be seen that it is on the opposition between molecular movement and sensation, that Lotze insists. In like manner Ferrier: "But how is it that the molecular modifications in the cerebral cells coincide with the modifications of the consciousness; how, for instance, do luminous vibrations falling upon the retina excite the modification of consciousness called visual sensation? These are problems we cannot solve. We may succeed in determining the exact nature of the molecular changes which take place in the cerebral cells when a sensation is felt, but this will not bring us an inch nearer to the explanation of the fundamental nature of sensation." Finally, Du Bois Reymond, in his famous discussion in 1880, on the seven enigmas of the world, speaks somewhat as follows: "The astronomical knowledge of the encephalon, that is, the most intimate to which we can aspire, only reveals to us matter in motion. But no arrangement nor motion of material particles can act as a bridge by which we can cross over into the domain of intelligence.... What imaginable link is there between certain movements of certain molecules in my brain, on the one hand, and on the other hand primitive, undefinable, undeniable facts such as: I have the sensation of softness, I smell the odour of a rose, I hear the sound of an organ, I see a red colour, &c...."

These three quotations show very conclusively that their authors thought they could establish the heterogeneity of the two phenomena by opposing matter to sensation. It must be recognised that they have fallen into a singular error; for matter, whatever it may be, is for us nothing but sensation; matter in motion, I have often repeated, is only a quite special kind of sensation; the organic matter of the brain, with its whirling movements of atoms, is only sensation. Consequently, to oppose the molecular changes in the brain to the sensation of red, blue, green, or to an undefined sensation of any sort, is not crossing a gulf, and bringing together things which cannot be compared, it is simply comparing one sensation to another sensation.

There is evidently something equivocal in all this; and I pointed this out when outlining and discussing the different theories of matter. It consists in taking from among the whole body of sensations certain of them which are considered to be special, and which are then invested with the privilege of being more important than the rest and the causes of all the others. This is about as illegitimate as to choose among men a few individuals to whom is attributed the privilege of commanding others by divine right. These privileged sensations which belong to the sight, the touch, and the muscular sense, and which are of large extent, are indeed extensive. They have been unduly considered as objective and as representing matter because they are better known and measurable, while the other sensations, the unextensive sensations of the other senses, are considered as subjective for the reasons that they are less known and less measurable: and they are therefore looked on as connected with our sensibility, our Ego, and are used to form the moral world.

We cannot subscribe to this way of establishing the contrast between matter and thought, since it is simply a contrast between two categories of sensations, and I have already asserted that the partitioning-out of sensations into two groups having different objective values, is arbitrary.

CHAPTER III
DEFINITION OF THE IMAGE

Going on with our inventory, after sensations come images, ideas, and concepts; in fact, quite a collection of phenomena, which, are generally considered as essentially psychological.

So long as one does not carefully analyse the value of ideas, one remains under the impression that ideas form a world apart, which is sharply distinguished from the physical world, and behaves towards it as an antithesis. For is not conception the contrary of perception? and is not the ideal in opposition to reality?

Thoughts have some characteristics of fancy, of freedom, even of unreality, which are wanting to the prosaicness of heavy material things. Thoughts sport with the relations of time and space; they fly in a moment across the gulf between the most distant objects; they travel back up the course of time; they bring near to us events centuries away; they conceive objects which are unreal; they imagine combinations which upset all physical laws, and, further, these conceptions remain invisible to others as well as to ourselves. They are outside the grip of reality, and constitute a world which becomes, for any one with the smallest imagination, as great and as important as the world called real. One may call in evidence the poets, novelists, artists, and the dreamers of all kinds. When life becomes too hard for us, we fly to the ideal world, there to seek forgetfulness or compensation.

It is, therefore, easy to understand, that it should have been proposed to carry into ideation the dichotomy between the physical and the moral. Many excellent authors have made the domain of the mind begin in the ideal. Matter is that which does not think. Descartes, in his Discours de la Méthode (4th part), remarking that he may pretend "not to have a body, and that there is no world or place in which he exists, but that he cannot pretend that he does not think," concludes by saying that the mind is "a substance, all whose essence or nature is merely to think, and which has no need of either place or any other material thing, in order to exist;" in short, that "the soul is absolutely distinct from the body."¹⁹

Let us, then, examine in what measure this separation between perception and ideation can be legitimately established. If we accept this separation, we must abandon the distinction I proposed between acts and objects of cognition, or, at least, admit that this distinction does not correspond to that between the physical and the moral, since thoughts, images, recollections, and even the most abstract conceptions, all constitute, in a certain sense, objects of cognition. They are phenomena which, when analysed, are clearly composed of two parts, an object and a cognition. Their logical composition is, indeed, that of an external perception, and there is in ideation exactly the same duality as in sensation. Consequently, if we maintain the above distinction as a principle of classification for all knowable phenomena, we shall be obliged to assign the same position to ideas as to sensations.

The principal difference we notice between sensation and idea is, it would seem, the character of unreality in the last named; but this opposition has not the significance we imagine. Our mental vision only assumes this wholly special character of unreality under conditions in which it is unable to harmonise with the real vision. Taine has well described the phases of the reduction of the image by sensation: it is at the moment when it receives the shock of an image which contradicts it, that the image appears as illusory.²⁰ Let us suppose that we are sitting down dreaming and watching the passing by of our images. If, at this moment, a sudden noise calls us back to reality, the whole of our mental phantasmagoria disappears as if by the wave of a magic wand, and it is by thus vanishing that the image shows its falsity. It is false because it does not accord with the present reality.

But, when we do not notice a disagreement between these two modes of cognition, both alike give us the impression of reality. If I evoke a reminiscence and dwell attentively on the details, I have the impression that I am in face of the reality itself. "I feel as if I were there still," is a common saying; and, among the recollections I evoke, there are some which give me the same certitude as the perception of the moment. Certain witnesses would write their depositions with their blood. One does not see this every day; but still one does see it.

Further, there are thousands of circumstances where the ideation is neither in conflict with the perception nor isolated from it, but in logical continuity with it. This continuity must even be considered as the normal condition. We think in the direction of that which we perceive. The image seems to prepare the adaptation of the individual to his surroundings; it creates the foresight, the preparation of the means, and, in a word, everything which constitutes for us a final cause. Now, it is very necessary that the image appear real to be usefully the substitute of the sensation past or to come.

Let us establish one thing more. Acting as a substitute, the image not only appears as real as the sensation, it appears to be of the same nature; and the proof is that they are confounded one with the other, and that those who are not warned of the fact take one for the other. Every time a body is perceived, as I previously explained, there are images which affix themselves to the sensation unnoticed. We think we perceive when we are really remembering or imagining. This addition of the image to the sensation is not a petty and insignificant accessory; it forms the major part, perhaps nine-tenths, of perception. Hence arise the illusions of the senses, which are the result, not of sensations but of ideas. From this also comes the difficulty of knowing exactly what, under certain circumstances, is observation or perception, where the fact perceived ends, and where conjecture begins. Once acquainted with all these possibilities of errors, how can we suppose a radical separation between the sensation and the image?

Examined more closely, images appear to us to be divisible into as many kinds as sensations: visual images correspond to visual sensations, tactile to tactile, and so on with all the senses.

That which we experience in the form of sensation, we can experience over again in the form of image, and the repetition, generally weaker in intensity and poorer in details, may, under certain favourable circumstances, acquire an exceptional intensity, and even equal reality: as is shown by hallucinations. Here, certainly, are very sound reasons for acknowledging that the images which are at the bottom of our thoughts, and form the object of them, are the repetition, the modification, the transposition, the analysis or the synthesis of sensations experienced in the past, and possessing, in consequence, all the characteristics of bodily states. I believe that there is neither more nor less spirituality in the idea than in the sensation. That which forms its spirituality is the implied act of cognition; but its object is material.

I foresee a final objection: I shall be told that even when the unreality of the image is not the rule, and appears only under certain circumstances, it nevertheless exists. This is an important fact. It has been argued from the unreality of dreams and hallucinations in which we give a body to our ideas, that we do not in reality perceive external bodies, but simply psychical states and modifications of our souls. If our ideas consist—according to the hypothesis I uphold—in physical impressions which are felt, we shall be told that these particular impressions must participate in the nature of everything physical; that they are real, and always real; that they cannot be unreal, fictitious, and mendacious, and that, consequently, the fictitious character of ideation becomes inexplicable.

Two words of answer are necessary to this curious argument, which is nothing less than an effort to define the mental by the unreal, and to suppose that an appearance cannot be physical. No doubt, we say, every image, fantastical as it may seem as signification, is real in a certain sense, since it is the perception of a physical impression; but this physical nature of images does not prevent our making a distinction between true and false images. To take an analogous example: we are given a sheet of proofs to correct, we delete certain redundant letters, and, although they are printed with the same type as the other letters, we have the right to say they are false. Again, in a musical air, we may hear a false note, though it is as real as the others, since it has been played. This distinction between reality and truth ought to be likewise applied to mental images. All are real, but some are false. They are false when they do not accord with the whole reality; they are true when they agree; and every image is partly false because, being an image, it does not wholly accord with the actual perceptions. It creates a belief in a perception which does not occur; and by developing these ideas we could easily demonstrate how many degrees of falsehood there are.

Physiologically, we may very easily reconcile the falsity of the image with the physical character of the impression on which it is based. The image results from a partial cerebral excitement, which sensation results from an excitement which also acts upon the peripheral sensory nerves, and corresponds to an external object—an excitant which the image does not possess. This difference explains how it is that the image, while resulting from a physical impression, may yet be in a great number of cases declared false—that is to say, may be recognised as in contradiction to the perceptions.

To other minds, perhaps, metaphysical reasoning will be more satisfactory. For those, we propose to make a distinction between two notions, Existence or Reality, on the one hand, and Truth, on the other.

Existence or Reality is that of which we have an immediate apprehension. This apprehension occurs in several ways. In perception, in the first place. I perceive the reality of my body, of a table, the sky, the earth, in proportion to my perception of them. They exist, for if they did not, I could not perceive them. Another way of understanding reality is conception or thought. However much I may represent a thing to myself as imaginary, it nevertheless exists in a certain manner, since I can represent it to myself. I therefore, in this case, say that it is real or it exists. It is of course understood, that in these definitions I am going against the ordinary acceptation of the terms; I am taking the liberty of proposing new meanings. This reality is, then, perceived in one case and conceived in the other. Perceptibility or conceivability are, then, the two forms which reality may assume. But reality is not synonymous with truth; notwithstanding the custom to the contrary, we may well introduce a difference between these two terms. Reality is that which is perceived or conceived; truth is that which accords with the whole of our knowledge. Reality is a function of the senses or of ideation; truth is a function of reasoning or of the reason.

For cognition to be complete, it requires the aid of all these functions. And, in fact, what does conception by itself give? It allows us to see if a thing is capable of representation. This is not a common-place thing, I will observe in passing; for many things we name are not capable of representation, and there is often a criticism to be made; we think we are representing, and we are not. What is capable of representation exists as a representation, but is it true? Some philosophers have imagined so, but they are mistaken; what we succeed in conceiving is alone possible.

Let us now take the Perceptible. Is what one perceives true? Yes, in most cases it is so in fact; but an isolated perception may be false, and disturbed by illusions of all kinds. It is all very well to say, "I see, I touch." There is no certainty through the senses alone in many circumstances that the truth has been grasped. If I am shown the spirit of a person I know to be dead, I shall not, notwithstanding the testimony of my eyes, believe it to be true, for this apparition would upset all my system of cognitions.

Truth is that which, being deemed conceivable, and being really perceived, has also the quality of finding its place, its relation, and its confirmation in the whole mass of cognitions previously acquired.

These distinctions,²¹ if developed, would readily demonstrate that the advantages of observation are not eclipsed by those of speculation; and that those of speculation, in their turn, do not interfere with those of observation. But we have not time to develop these rules of logic; it will be sufficient to point out their relation to the question of the reality of mental images. Here are my conclusions in two words. Physical phenomena and images are always real, since they are perceived or conceived; what is sometimes wanting to them, and makes them false, is that they do not accord with the rest of our cognitions.²²

Thus, then, are all objections overruled, in my opinion at least. We can now consider the world of ideas as a physical world; but it is one of a peculiar nature, which is not, like the other, accessible to all, and is subject to its own laws, which are laws of association. By these very different characteristics, it separates itself so sharply from the outer world that all endeavour to bring the two together seems shocking; and it is very easy to understand that many minds should wish to remain faithful to the conception that ideas form a mental or moral world. No metaphysical reasoning could prevail against this sentiment, and we must give up the idea of destroying it. But we think we have shown that idea, like sensation, comprises at the same time the physical and the mental.

CHAPTER IV
DEFINITION OF THE EMOTIONS

After sensations and images, we have to name among the phenomena of consciousness, the whole series of affective states—our pleasures and our pains, our joys and our griefs, our sentiments, our emotions, and our passions. It is universally admitted that these states are of a mental nature, for several reasons. (1) We never objectivate them as we do our sensations, but we constantly consider them as indwelling or subjective states. This rule, however, allows an exception for the pleasure and the pain termed physical, which are often localised in particular parts of our bodies, although the position attributed to them is less precise than with indifferent sensations. (2) We do not alienate them as we do our indifferent sensations. The sensations of weight, of colour, and of form serve us for the construction of bodies which appear to us as perceived by us, but as being other than ourselves. On the contrary, we constantly and without hesitation refer our emotional states to our Ego. It is I who suffer, we say, I who complain, I who hope. It is true that this attribution is not absolutely characteristic of mental phenomena, for it happens that we put a part of our Ego into material objects, such as our bodies, and even into objects separate from our bodies, and whose sole relation to us is that of a legal proprietorship. We must guard against the somewhat frequent error of identifying the Ego with the psychical.

These two reasons sufficiently explain the tendency to see only psychological states in the emotional ones; and, in fact, those authors who have sought to oppose mind to matter have not failed to introduce emotion into their parallel as representing the essence of mind. On this point I will recall the fine ironical image used by Tyndall, the illustrious English physicist, to show the abyss which separates thought from the molecular states of the brain. "Let us suppose," he says, "that the sentiment love, for example, corresponds to a right-hand spiral movement of the molecules of the brain and the sentiment hatred to a left-hand spiral movement. We should then know that when we love, a movement is produced in one direction, and when we hate, in another. But the Why would remain without an answer."

The question of knowing what place in our metaphysical theory we ought to secure for emotion seems difficult to resolve, and we even find some pleasure in leaving it in suspense, in order that it may be understood that a metaphysician is not compelled to explain everything. Besides, the difficulties which atop us here are peculiarly of a psychological order. They proceed from the fact that studies on the nature of the emotions are still very little advanced. The physical conditions of these states are pretty well known, and their psychical and social effects have been abundantly described; but very little is known as to what distinguishes an emotion from a thought.

Two principal opinions may be upheld in the actual state of our acquaintance with the psychology of the feelings. When we endeavour to penetrate their essential and final nature, we have a choice between two contrary theories.

The first and traditional one consists in seeing in emotion a phenomenon sui generis; this is very simple, and leaves nothing more to be said.

The second bears the name of the intellectualist theory. It consists in expunging the characteristic of the affective states. We consider them as derivative forms of particular modes of cognition, and they are only "confused intelligence." This intellectualist thesis is of early date; it will be found in Herbart, who, by-the-by, gave it a peculiar form, by causing the play of images to intervene in the formation of the feelings. However, this particular point is of slight Importance. The intellectualist theory is more vast than Herbartism; it exists in all doctrines in which the characteristic difference between thought and feeling is expunged and feeling is brought back to thought. One of the clearest means of so doing consists in only seeing in the feeling the fact of perceiving something. To perceive is, in fact, the property of intelligence; to reason, to imagine, to judge, to understand, is always, in a certain sense, to perceive. It has been imagined that emotion is nothing else than a perception of a certain kind, an intellectual act strictly comparable to the contemplation of a landscape. Only, in the place of a landscape with placid features you must put a storm, a cataclysm of nature; and, instead of supposing this storm outside us, let it burst within us, let it reach us, not by the outer senses of sight and condition, but by the inner senses. What we then perceive will be an emotion.

Such is the theory that two authors—W. James and Lange—happened to discover almost at the same time, Lange treating it as a physiologist and W. James as a philosopher. Their theory, at first sight, appears singular, like everything which runs counter to our mental habits. It lays down that the symptoms which we all till now have considered as the physiological consequence, the translation, and the distant effects of the emotions, constitute their essential base. These effects are: the expression of the physiognomy, the gesture, the cry, and the speech; or the reflex action on the circulation, the pallor or blushing, the heat mounting to the head, or the cold of the shiver which passes over the body. Or it is the heart, which hastens or slackens its beats, or makes them irregular, or enfeebles, or augments them. Or the respiration, which changes its rhythm, or increases, or is suspended. Or else it is the secretion of the saliva or of the sweat, which flows in abundance or dries up. Or the muscular force, which is increased or decays. Or the almost undefinable organic troubles revealed to us by the singing in the ears, constriction of the epigastrium, the jerks, the trembling, vertigo, or nausea—all this collection of organic troubles which comes more or less confusedly to our consciousness under the form of tactile, muscular, thermal, and other sensations. Until now this category of phenomena has been somewhat neglected, because we saw in it effects and consequences of which the rôle in emotion itself seemed slight, since, if they could have been suppressed, it was supposed that emotion would still remain. The new theory commences by changing the order of events. It places the physical symptoms of the emotions at the very beginning, and considers them the direct effects of the external excitant, which is expressed by this elegant formula: "It used to be said, 'I perceive a danger; I am frightened, I tremble.' Now we must say, 'I tremble before a danger, first, and it is after having trembled that I am frightened.'" This is not a change in order only; it is something much more serious. The change is directed to the nature of emotion. It is considered to exist in the organic derangements indicated above. These derangements are the basis of emotion, its physical basis, and to be moved is to perceive them. Take away from the consciousness this physical reflex, and emotion ceases. It is no longer anything but an idea.

This theory has at least the merit of originality. It also pleases one by its great clearness—an entirely intellectual clearness, we may say; for it renders emotion comprehensible by enunciating it in terms of cognition. It eliminates all difference which may exist between a perception and an emotion. Emotion is no longer anything but a certain kind of perception, the perception of the organic sensations.

This reduction, if admitted, would much facilitate the introduction of emotion into our system, which, being founded on the distinction between the consciousness and the object, is likewise an intellectualist system. The definition of emotion, as it is taught by W. James, seems expressly made for us who are seeking to resolve all intellectual states into physical impressions accompanied by consciousness.

By the side of emotion we may place, as demanding the same analytical study, the feeling of effort. We ought to inquire with effort, as has been done with emotion, what is the psychological nature of this phenomenon; and in the same way that there exists an intellectualist theory of the emotions, viz. that of James, who reduces all the history of the emotions to intelligence, so there exists an intellectualist theory of effort, which likewise tends to bring back, all will to intelligence. It is again the same author, that true genius, W. James, who has attempted this reduction. I do not know whether he has taken into account the parallelism of the two theories, but it is nevertheless evident. Effort, that basis of activity, that state of consciousness which so many psychologists have described as something sui generis, becomes to James a phenomenon of perception. It is the perception of sensations proceeding from the muscles, the tendons, the articulations, the skin, and from all the organs directly or indirectly concerned in the execution of movement. To be conscious of an effort would then be nothing else than to receive all these centripetal sensations; and what proves this is, that the consciousness of effort when most clearly manifested is accompanied by some muscular energy, some strong contraction, or some respiratory trouble, and yields if we render the respiration again regular and put the muscles back into repose.

To my great regret I can state nothing very clear regarding these problems. The attempt to intellectualise all psychical problems is infinitely interesting, and leads to a fairly clear conception, by which everything is explained by a mechanism reflected in a mirror, which is the consciousness. But we remain perplexed, and we ask ourselves whether this clearness of perception is not somewhat artificial, whether affectivity, emotivity, tendency, will, are really all reduced to perceptions, or whether they are not rather irreducible elements which should be added to the consciousness. Does not, for instance, desire represent a complement of the consciousness? Do not desire and consciousness together represent a something which does not belong to the physical domain and which forms the moral world? This question I leave unanswered.