27O MATTER AND MEMORY CHAP, rv state of our consciousness and a reality independent of ourselves. This mixed character of our imme diate perception, this appearance of a realized contradiction, is the principal theoretical reason that we have for believing in an external world which does not coincide absolutely with our per ception. As it is overlooked in the doctrine that regards sensation as entirely heterogeneous with movements, of which sensation is then supposed to be only a translation into the language of consciousness, this doctrine ought, it would seem, to confine itself to sensations, which it had indeed begun by setting up as the actual data, and not add to them movements which, having no possible contact with them, are no longer any thing but their useless duplicate. Realism, so understood, is self-destructive. Indeed, we have no choice: if our belief in a more or less homo geneous substratum of sensible qualities has any ground, this can only be found in an act which makes us seize or divine, in quality itself, some thing which goes beyond sensation, as if this sensa tion itself were pregnant with details suspected yet unperceived. Its objectivity — that is to say, what it contains over and above what it yields upmust then consist, as we have foreshadowed, pre cisely in the immense multiplicity of the move ments which it executes, so to speak, within itself as a chrysalis. Motionless on the surface, in its very depth it lives and vibrates.
As a matter of fact, no one represents to himself the relation between quantity and quality in any whilst in other way. To believe in realities, distinct from that which is perceived, is above all to recognize that the order °f our perceptions depends on them an(^ no* on US- There must be, then, within the perceptions which fill a ou?own°f given moment, the reason of what will duration. happen in the following moment. And mechanism only formulates this belief with more precision when it affirms that the states of matter can be deduced one from the other. It is true that this deduction is possible only if we discover, beneath the apparent heterogeneity of sensible qualities, homogeneous elements which lend them selves to calculation. But, on the other hand, if these elements are external to the qualities of which they are meant to explain the regular order, they can no longer render the service de manded of them, because then the qualities must be supposed to come to overlie them by a kind of miracle, and cannot correspond to them unless we bring in some pre-established harmony. So, do what we will, we cannot avoid placing those movements within these qualities, in the form of internal vibrations, and then considering the vibra tions as less homogeneous, and the qualities as less heterogeneous, than they appear, and lastly attributing the difference of aspect in the two terms to the necessity which lies upon what may be called an endless multiplicity of contracting into a duration too narrow to permit of the separation of its moments.
We must insist on this last point, to which we have already alluded elsewhere, and which we Th«r« may regard as essential. The duration lived by our consciousness is a duration with *ts own [determined rhythm, a duration very different from the time of the phyn«w». sicist, which can store up, in a given in terval, as great a number of phenomena as we please. In the space of a second, red light, — the light which has the longest wave-length, and of which, consequently, the vibrations are the least frequent — accomplishes 400 billions of successive vibrations. If we would form some idea of this number, we should have to separ ate the vibrations sufficiently to allow our con sciousness to count them, or at least to record explicitly their succession; and we should then have to enquire how many days or months or years this succession would occupy. Now the smallest interval of empty time which we can detect equals, according to Exner, ^ of a second; and it is even doubtful whether we can per ceive in succession several intervals as short as this. Let us admit, however, that we can go on doing so indefinitely. Let us imagine, in a word, a consciousness which should watch the succession of 400 billions of vibrations, each instantaneous, and each separated from the next only by the sfa of a second necessary to distinguish them.
A very simple calculation shows that more than 25,000 years would elapse before the conclusion of the operation. Thus the sensation of red light, experienced by us in the course of a second, cor responds in itself to a succession of phenomena which, separately distinguished in our duration with the greatest possible economy of time, would occupy more than 250 centuries of our history. Is this conceivable? We must distinguish here between our own duration and time in general. In our duration, — the duration which our con sciousness perceives, — a given interval can only contain a limited number of phenomena of which we are aware. Do we conceive that this content can increase; and when we speak of an infi nitely divisible time, is it our own duration that we are thinking of?
As long as we are dealing with space, we may carry the division as far as we please; we change in no way, thereby, the nature of what is divided. This is because space, by definition, is outside us; it is because a part of space appears to us to sub sist even when we cease to be concerned with it; so that, even when we leave it undivided, we know that it can wait, and that a new effort of our imagination may decompose it when we choose. As, moreover, it never ceases to be space, it always implies juxtaposition and consequently possible division. Abstract space is, indeed, at bottom, no thing but the mental diagram of infinite divisibility. But with duration it is quite otherwise. The parts of our duration are one with the successive moments of the act which divides it; if we distinguish in it so many instants, so many parts it indeed possesses; and if our consciousness can only distinguish in a given interval a definite number of elementary acts, if it terminates the division at a given point, there also terminates the divisibility. In vain does our imagination endeavour to go on, to carry division further still, and to quicken, so to speak, the circulation of our inner phenomena: the very effort by which we are trying to effect this further division of our duration lengthens that duration by just so much. And yet we know that millions of phenomena succeed each other while we hardly succeed in counting a few. We know this not from physics alone; the crude experience of the senses allows us to divine it; we are dimly aware of successions in nature much more rapid than those of our internal states. How are we to conceive them, and what is this duration of which the capacity goes beyond all our imagination?
It is not ours, assuredly; but neither is it that homogeneous and impersonal duration, the same for everything and for every one, which flows onward, indifferent and void, external to all that endures. This imaginary homogeneous time is, as we have endeavoured to show elsewhere,1 an idol of language, a fiction of which the origin is 1 H. i^ergson, Time and Free Will. Sonnenschein & Co.
easy to discover. In reality there is no one rhythm of duration; it is possible to imagine many different rhythms which, slower or faster, measure the degree of tension or relaxation of different kinds of consciousness, and thereby fix their respective places in the scale of being. To conceive of durations of different tensions is per haps both difficult and strange to our mind, be cause we have acquired the useful habit of sub stituting for the true duration, lived by conscious ness, an homogeneous and independent Time; but, in the first place, it is easy, as we have shown, to detect the illusion which renders such a thought foreign to us, and, secondly, this idea has in its favour, at bottom, the tacit agreement of our consciousness. Do we not sometimes per ceive in ourselves, in sleep, two contemporaneous and distinct persons of whom one sleeps a few minutes, while the other's dream fills days and weeks? And would not the whole of history be contained in a very short time for a conscious ness at a higher degree of tension than our own, which should watch the development of human ity while contracting it, so to speak, into the great phases of its evolution? In short, then, to perceive consists in condensing enormous periods of an infinitely diluted existence into a few more differentiated moments of an intenser life, and in thus summing up a very long history. To perceive means to immobilize.
To say this is to say that we seize, in the act of perception, something which outruns per- Om ception itself, although the material nessscsums"up universe is not essentially different or 5ho?e periods distinct from the representation which we have of it. In one sense, my perception is indeed truly within me, since it contracts into a single moment of my duration that which, taken in itself, spreads over an incalculable number of moments. But, if you abolish my consciousness, the material universe subsists exactly as it was; only, since you have removed that particular rhythm of duration which was the condition of my action upon things, these things draw back into themselves, mark as many moments in their own existence as science distinguishes in it; and sensible qualities, with out vanishing, are spread and diluted in an in comparably more divided duration. Matter thus resolves itself into numberless vibrations, all linked together in uninterrupted continuity, all bound up with each other, and travelling in every direction like shivers through an immense body. — In short, try first to connect together the dis continuous objects of daily experience; then resolve the motionless continuity of their qualities into vibrations on the spot; finally fix your at tention on these movements, by abstracting from the divisible space which underlies them' and considering only their mobility (that undivided act which our consciousness becomes aware of in our own movements): you will thus obtain a vision of matter, fatiguing perhaps for your ima gination, but pure, and freed from all that the exigencies of life compel you to add to it in external perception. — Now bring back conscious ness, and with it the exigencies of life: at long, very long, intervals, and by as many leaps over enormous periods of the inner history of things, quasi-instantaneous views will be taken, views which this time are bound to be pictorial, and of which the more vivid colours will condense an infinity of elementary repetitions and changes. In just the same way the multitudinous successive positions of a runner are contracted into a single symbolic attitude, which our eyes perceive, which art reproduces, and which becomes for us all the image of a man running. The glance which falls at any moment on the things about us only takes in the effects of a multiplicity of inner repetitions and evolutions, effects which are, for that very reason, discontinuous, and into which we bring back continuity by the relative movements that we attribute to 'objects ' in space. The change is everywhere, but inward; we localize it here and there, but outwardly; and thus we consti tute bodies which are both stable as to their qualities and mobile as to their positions, a mere change of place summing up in itself, to our eyes, the universal transformation.
That there are, in a sense, multiple objects, that one man is distinct from another man, tree from tree, stone from stone, is an indisputable 278 MATTER AND MEMORY CHAP. iv.
fact; for each of these beings, each of these Necessity things, has characteristic properties and be°nidthatea obeys a determined law of evolution, therbythm oi But *ne separation between a thing and $emaTtn"°n its environment cannot be absolutely fhyat°duSong definite and clear cut; there is a passage £J°cJSiSrit by insensible gradations from the one to necessity, trig other: the close solidarity which binds all the obj ects of the material universe, the perpetu ity of their reciprocal actions and reactions, is suffi cient to prove that they have not the precise limits which we attribute to them. Our per ception outlines, so to speak, the form of their nucleus; it terminates them at the point where our possible action upon them ceases, where, consequently, they cease to interest our needs.
Such is the primary and the most apparent opera tion of the perceiving mind: it marks out divi sions in the continuity of the extended, simply following the suggestions of our requirement and the needs of practical life. But, in order to divide the real in this manner, we must first persuade ourselves that the real is divisible at will. Conse quently we must throw beneath the continuity of sensible qualities, that is to say, beneath con crete extensity, a network, of which the meshes may be altered to any shape whatsoever and become as small as we please: this substra tum which is merely conceived, this wholly ideal diagram of arbitrary and infinite divisi bility, is homogeneous space. — Now, at the same time that our actual and so to speak instan taneous perception effects this division of matter into independent objects, our memory solidifies into sensible qualities the continuous flow of things. It prolongs the past into the present, because our action will dispose of the future in the exact proportion in which our perception, enlarged by memory, has contracted the past. To reply, to an action received, by an immediate reaction which adopts the rhythm of the first and continues it in the same duration, to be in the present and in a present which is always beginning again, — this is the fundamental law of matter: herein consists necessity. If there are actions that are really free, or at least partly in determinate, they can only belong to beings able to fix, at long intervals, that becoming to which their own becoming clings, able to solidify it into distinct moments, and so to condense matter and, by assimilating it, to digest it into movements of reaction which will pass through the meshes of natural necessity. The greater or less ten sion of their duration, which expresses, at bottom, their greater or less intensity of life, thus deter mines both the degree of the concentrating power of their perception and the measure of their liberty. The independence of their action upon surround ing matter becomes more and more assured in the degree that they free themselves from the par ticular rhythm which governs the flow of this matter. So that sensible qualities, as they are found in our memory-shot perception, are in fact the successive moments obtained by a solidi fication of the real. But, in order to distinguish these moments, and also to bind them together by a thread which shall be common alike to our own existence and to that of things, we are bound to imagine a diagrammatic design of succes sion in general, an homogeneous and indifferent medium, which is to the flow of matter in the sense of length as space is to it in the sense of breadth: herein consists homogeneous time.
Homogeneous space and homogeneous time are then neither properties of things nor essential Homogeneous COnditi°nS °f OUr faulty of knowing t?meearedthe tnem: they express, in an abstract form> the double work of solidification and of division which we effect on propertfesnot ^ne moving continuity of the real in of things. order to obtain there a fulcrum for our action, in order to fix within it starting-points for our operation, in short, to introduce into it real changes. They are the diagrammatic design of our eventual action upon matter. The first mistake, that which consists in viewing this homogeneous time and space as properties of things, leads to the insurmountable difficulties of metaphysical dogmatism, — whether mechan istic or dynamistic, — dynamism erecting 'into so many absolutes the successive cross-cuts which we make in the course of the universe as it flows along, and then endeavouring vainly CHAP; iv EXTENSITY AND EXTENSION 28 1 to bind them together by a kind of qualitative deduction; mechanism attaching itself rather, in any one of these cross-cuts, to the divisions made in its breadth, that is to say, to instantaneous differences in magnitude and position, and striv ing no less vainly to produce, by the variation of these differences, the succession of sensible qualities.
Shall we then seek refuge in the other hypothesis, and maintain, with Kant, that space and time are forms of our sensibility? If we do, we shall have to look upon matter and spirit as equally unknow able. Now, if we compare these two hypotheses, we discover in them a common basis: by setting up homogeneous time and homogeneous space either as realities that are contemplated or as forms of contemplation, they both attribute to space and time an interest which is speculative rather than vital. Hence there is room, between meta physical dogmatism on the one hand and critical philosophy on the other, for a doctrine which regards homogeneous space and time as princi ples of division and of solidification introduced into the real with a view to action and not with a view to knowledge, which attributes to things a real duration and a real extensity, and which, in the end, sees the source of all difficulty no longer in that duration and in that extensity (which really belong to things and are directly manifest to the mind), but in the homogeneous space and time which we stretch out beneath them in order to divide the continuous, to fix the becoming, and provide our activity with points to which it can be applied.
But erroneous conceptions about sensible quality and about space are so deeply rooted in the mind that it is important to attack them Qualities of, • j TTT J.T.
different from every side. We may say then, in extensity, to reveal yet another aspect, that they though In. J. J, different imply this double postulate, accepted equally by realism and by idealism: first, that between different kinds of qualities there is nothing common; second, that neither is there anything common between extensity and pure quality. We maintain, on the contrary, that there is something common between qualities of different orders, that they all share in extensity, though in different degrees, and that it is im possible to overlook these two truths without entangling in a thousand difficulties the metaphysic of matter, the.psychology of perception and, more generally, the problem of the relation of consciousness with matter. Without insisting on these consequences, let us content ourselves for the moment with showing, at the bottom of the various theories of matter, the two postulates which we dispute and the illusion from which they proceed.
The essence of English idealism is to regard extensity as a property of tactile perceptions. As it sees nothing in sensible qualities but sen sations, and in sensations themselves nothing but mental states, it finds in the different qualities CHAP, rv EXTENSITY AND EXTENSION 283 nothing on which to base the parallelism of idealism and their phenomena. It is therefore conregard the strained to account for this parallelism orders of by a habit which makes the actual persensation as...,.
discontinuous, ceptions of sight, lor instance, suggest and so miss ~. 0<:> the true to us potential sensations of touch. If nature of.,.. „ perception, the impressions of two different senses resemble each other no more than the words of two languages, we shall seek in vain to de duce the data of the one from the data of the other. They have no common element; and consequently, there is nothing common between extensity, which is always tactile, and the data of the senses other than that of touch, which must then be supposed to be in no way extended. But neither can atomistic realism, which locates movements in space and sensations in conscious ness, discover anything in common between the modifications or phenomena of extensity and the sensations which correspond to them. Sensations are supposed to issue from the modifications as a kind of phosphorescence, or, again, to translate into the language of the soul the manifestations of matter; but in neither case do they re flect, we are told, the image of their causes. No doubt they may all be traced to a common origin, which is movement in space; but, just because they develop outside of space, they must forego, qua sensations, the kinship which binds their causes together. In breaking with space they break also their connexion with each other; they 284 MATTER AND MEMORY CHAP, nr have nothing in common between them, nor with extensity.
Idealism and realism, then, only differ in that the first relegates extensity to tactile perception, of which it becomes the exclusive property, while the second thrusts extensity yet further back, outside of all perception. But the two doctrines are agreed in maintaining the discon tinuity of the different orders of sensible qualities, and also the abrupt transition from that which is purely extended to that which is not extended at all. Now the principal difficulties which they both encounter in the theory of perception arise from this common postulate.
For suppose, to begin with, as Berkeley did, that all perception of extensity is to be referred to the sense of touch. We may, indeed, if you will have it so, deny extension to the data of hearing, smell and taste; but we must at least explain the genesis of a visual space that corre sponds to tactile space. It is alleged, indeed, that sight ends by becoming symbolic of touch, and that there is nothing more in the visual per ception of the order of things in space than a suggestion of tactile perception. But we fail to understand how the visual perception of relief, for instance, a perception which makes upon us an impress sui generis, and indeed indescribable, could ever be one with the mere remembrance of a sensation of touch. The association of a mem ory with a present perception may complicate this perception by enriching it with an element already known, but it cannot create a new kind of impress, a new quality of perception: now the visual perception of relief presents an abso lutely original character. It may be urged that it is possible to give the illusion of relief with a plane surface. This only proves that a surface, on which the play of light and shadow on an object in relief is more or less well imitated, is enough to remind us of relief; but how could we be reminded of relief if relief had not been, at first, actually perceived? We have already said, but we cannot repeat too often, that our theories of perception are entirely vitiated by the idea that if a certain arrangement produces, at a given moment, the illusion of a certain perception, it must always have been able to produce the perception itself; — as if the veryfunction of memory were not to make the complexity of the effect survive the simplifica tion of the cause! Again, it may be urged that the retina itself is a plane surface, and that if we perceive by sight something that is extended, it can only be the image on the retina. But is it not true, as we have shown at the beginning of this book, that in the visual perception of an object the brain, nerves, retina and the object itself form a connected whole, a continuous process in which the image on the retina is only an episode? By what right, then, do we isolate this image to sum up in it the whole of perception? And then, as we have also shown,1 how could a surface be perceived as a surface otherwise than,in a space that has recovered its three dimensions? Berkeley, at least, carried out his theory to its conclusion; he denied to sight any perception of extensity. But the ob jections which we raised only acquire the more force from this, since it is impossible to understand the spontaneous creation, by a mere association of memories, of all that is original in our visual perceptions of line, surface and volume, per ceptions so distinct that the mathematician does not go beyond them and works with a space that is purely visual. But we will not insist on these various points, nor on the disputable argu ments drawn from the observation of those, born blind, whose sight has been surgically restored: the theory of the acquired perceptions of sight, classical since Berkeley's day, does not seem likely to resist the multiplied attacks of contemporary psychology.2 Passing over the difficulties of a psychological order, we will content ourselves with drawing attention to another point, in our opinion essential. Suppose for a moment that 1 Time and Free Will. Sonnenschein & Co., 1910.
8 See on this subject: Paul Janet, La perception visuelle de la distance, Revue philosophique, 1879, vol. vii, p. I et seq. — William James, Principles of Psychology, vol.ii, chap. xxii. — Cf. on the subject of the visual perception of extensity: Dunan, L'espace visuel et I'espace tactile (Revue philosophique, Feb. and Apr. 1888, Jan. 1889).
CHAP iv. EXTENSITY AND EXTENSION 287 the eye does not, at the outset, give us any informa tion as to any of the relations of space. Visual form, visual relief, visual distance, then become the symbols of tactile perceptions. But how is it, then, that this symbolism succeeds? Here are objects which change their shape and move. Vision takes note of definite changes which touch afterwards verifies. There is, then, in the two series, visual and tactile, or in their causes, something which makes them correspond one to another and ensures the constancy of their parallelism. What is the principle of this con nexion?
For English idealism, it can only be some deus ex machina, and we are confronted with a mys tery again. For ordinary realism, it is in a space distinct from the sensations themselves that the principle of the correspondence of sensations one with another lies; but this doctrine only throws the difficulty further back and even aggravates it, for we shall now want to know how a system of homogeneous movements in space evokes various sensations which have no resemblance whatever with them. Just now the genesis of visual perception of space by a mere association of images appeared to us to imply a real creation ex nihilo; here all the sen sations are born of nothing, or at least have no resemblance with the movement that occasions them. In the main, this second theory differs much less from the first than is commonly believed.
Amorphous space, atoms jostling against each other, are only our tactile perceptions made ob jective, set apart from all our other perceptions on account of the special importance which we attribute to them, and made into independent realities, — thus contrasting with the other sensa tions which are then supposed to be only the symbols of these. Indeed, in the course of this operation, we have emptied these tactile sensa tions of a part of their content; after having reduced all other senses to being mere appen dages of the sense of touch, touch itself we mu tilate, leaving out everything in it that is not a mere abstract or diagrammatic design of tac tile perception: with this design we then go on to construct the external world. Can we wonder that between this abstraction on the one hand, and sensations on the other, no possible link is to be found? But the truth is that space is no more without us than within us, and that it does not belong to a privileged group of sensations. All sensations partake of extensity; all are more or less deeply rooted in it; and the difficulties of ordinary realism arise from the fact that, the kinship of the sensations one with another having been extracted and placed apart under the form of an indefinite and empty space, we no longer see either how these sensations can partake of extensity or how they can corre spond with each other.
Contemporary psychology is more and more impressed with the idea that all our sensations But modem are in some degree extensive. It is psychology..,., has a tendency maintained, not without an appearance to regard all.,.
sensation as of reason, that there is no sensation extensive. without cxtensity l or without a feel ing 'of volume.' 2 English idealism sought to reserve to tactile perception a monopoly of the extended, the other senses dealing with space only in so far as they remind us of the data of touch. A more attentive psychology reveals to us, on the contrary, and no doubt will hereafter reveal still more clearly, the need of regarding all sensa tions as primarily extensive, their extensity fading and disappearing before the higher intensity and usefulness of tactile, and also, no doubt, of visual, extensity.
So understood, space is indeed the symbol of fixity and of infinite divisibility. Concrete we invert extensity, that is to say the diversity of wewlaSSst sensible qualities, is not within space; interior*"! rather is it space that we thrust into S°?he'neoe£ extensity. Space is not a ground on which St totece" real motion is posited; rather is it real movements. motiOn that deposits space beneath it self. But our imagination, which is preoccu- 1 Ward, Article Psychology in the Encycl. Britannica.
2 W. James, Principles of Psychology, vol. ii, p. 134 et seq. — We may note in passing that we might, in strictness, attribute this opinion to Kant, since The Transcendental /Esthetic allows no difference between the data of the different senses as far as their extension in space is concerned. But it must not be forgotten that the point of view of the Critique is other than u 29O MATTER AND MEMORY CHAP, iv pied above all by the convenience of expression and the exigencies of material life, prefers to invert the natural order of the terms. Accus tomed to seek its fulcrum in a world of readymade motionless images, of which the apparent fixity is hardly anything else but the outward reflexion of the stability of our lower needs, it cannot help believing that rest is anterior to motion, cannot avoid taking rest as its point of reference and its abiding place, so that it comes to see movement as only a variation of distance, space being thus supposed to precede motion. Then, in a space which is homo geneous and infinitely divisible, we draw, in imagination, a trajectory and fix positions: after wards, applying the movement to the trajectory, we see it divisible like the line we have drawn, and equally denuded of quality. Can we wonder that our understanding, working thenceforward on this idea, which represents precisely the reverse of the truth, discovers in it nothing but contra dictions? Having assimilated movements to space, we find these movements homogeneous like space; and since we no longer see in them anything but calculable differences of direction and velocity, all relation between movement and quality is for us destroyed. So that all we have to do is to shut up motion in space, qualities in consciousness, and