But before we go on to establish the precise rela tion between the personality and the images in which it dwells, let us briefly sum up, contrast ing it with the analyses of current psychology, the theory of pure perception which we have just sketched out.
We will return, for the sake of simplicity, to CHAP, i NATURAL EXTENSION OF IMAGES 65 the sense of sight, which we chose as our example. Psychology has accustomed us to assume The result of J &J positing sensa- the elementary sensations corresponding tions and J then con- to the impressions received by the rods strncting perception and cones of the retina. With these with them.
sensations it goes on to reconstitute visual perception. But, in the first place, there is not one retina, there are two; so that we have to explain how two sensations, held to be distinct, combine to form a single perception correspond ing to what we call a point in space.
Suppose this problem solved. The sensations in question are unextended; how will they ac quire extension? Whether we see in extensity a framework ready to receive sensations, or an effect of the mere simultaneity of sensations co existing in consciousness without coalescing, in either case something new is introduced with extensity, something unaccounted for; the process by which sensation arrives at extension, and the choice by each elementary sensation of a definite point in space, remain alike unexplained, We will leave this difficulty, and suppose visual extension constituted. How does it in its turn re unite with tactile extension? All that my vision perceives in space is verified by my touch. Shall we say that objects are constituted by just the co-operation of sight and touch, and that the agree ment of the two senses in perception may be explained by the fact that the object perceived is their common product? But how could there be anything common, in the matter of quality, between an elementary visual sensation and a tactile sensa tion, since they belong to two different genera? The correspondence between visual and tactile extension can only be explained, therefore, by the parallelism of the order of the visual sensations with the order of the tactile sensations. So we are now obliged to suppose, over and above visual sensations, over and above tactile sensations, a certain order which is common to both, and which consequently must be independent of either. We may go further: this order is independent of our individual perception, since it is the same for all men, and constitutes a material world in which effects are linked with causes, in which phenomena obey laws. We are thus led at last to the hypothesis of an objective order, independent of ourselves; that is to say, of a material world distinct from sensation.
We have had, as we advanced, to multiply our irreducible data, and to complicate more and more the simple hypothesis from which we started. But have we gained anything by it? Though the matter which we have been led to posit is indis pensable in order to account for the marvellous accord of sensations among themselves, we still know nothing of it, since we must refuse to.it all the qualities perceived, all the sensations of which it has only to explain the correspondence. It is not, then, it cannot be, anything of what we know, anything of what we imagine. It remains a mysterious entity.
CHAP. I NATURAL EXTENSION OF IMAGES 67 But our own nature, the office and the function of our personality, remain enveloped in equal mystery. For these elementary unextended sen sations which develop themselves in space, whence do they come, how are they born, what purpose do they serve? We must posit them as so many absolutes, of which we see neither the origin nor the end. And even supposing that we must distinguish, in each of us, between the spirit and the body, we can know nothing either of body or of spirit, nor of the relation between them.
Now in what does this hypothesis of ours consist, and at what precise point does it part company Action, not with, the other? Instead of starting from JnoSdbSthe affection, of which we can say nothing, starting point. since there is no reason why it should be what it is rather than anything else, we start from action, that is to say from our faculty of effecting changes in things, a faculty attested by consciousness and towards which all the powers of the organized body are seen to converge. So we place ourselves at once in the midst of extended images; and in this material universe we perceive centres of indetermination, characteristic of life. In order that actions may radiate from these centres, the move ments or influences of the other images must be on the one hand received and on the other utilized. Living matter, in its simplest form, and in a homogeneous state, accomplishes this function simultaneously with those of nourishment and repair. The progress of such matter consists in sharing this double labour between two categories of organs, the purpose of the first, called organs of nutrition, being to maintain the second: these last are made for action; they have as their simple type a chain of nervous elements, connect ing two extremities of which the one receives external impressions and the other executes move ments. Thus, to return to the example of visual perception, the office of the rods and cones is merely to receive excitations which will be subsequently elaborated into movements, either accomplished or nascent. No perception can result from this, and nowhere, in the nervous system, are there conscious centres; but perception arises from the same cause which has brought into being the chain of nervous elements, with the organs which sustain them and with life in general. It expresses and measures the power of action in the living being, the indetermination of the movement or of the action which will follow the receipt of the stimulus. This indetermination, as we have shown, will ex press itself in a reflexion upon themselves, or better in a division, of the images which surround our body; and, as the chain of nervous elements which receives, arrests, and transmits movements is the seat of this indetermination and gives its measure, our perception will follow all the detail and will appear to express all the variations of the nervous elements themselves. Perception, in its pure state, is then, in very truth, a part of things. And as for affective sensation, it does CHAP. 1 PURE PERCEPTION 69 not spring spontaneously from the depths of consciousness to extend itself, as it grows weaker, in space; it is one with the necessary modifi cations to which, in the midst of the surround ing images that influence it, the particular image that each one of us terms his body is subj ect.
Such is our simplified, schematic theory of exter nal perception. It is the theory of pure percep tion. If we went no further, the part of con sciousness in perception would thus be confined to threading on the continuous string of memory an uninterrupted series of instantaneous visions, which would be a part of things rather than of ourselves. That this is the chief office of con sciousness in external perception is indeed what we may deduce a priori from the very defini tion of living bodies. For though the function of these bodies is to receive stimulations in order to elaborate them into unforeseen reactions, still the choice of the reaction cannot be the work of chance. This choice is likely to be inspired by past experience, and the reaction does not take place without an appeal to the memories which analogous situations may have left behind them. The indetermination of acts to be accomplished requires then, if it is not to be confounded with pure caprice, the preservation of the images per ceived. It may be said that we have no grasp of the future without an equal and corresponding outlook over the past, that the onrush of our activity makes a void behind it into which memories flow, and that memory is thus the reverbera tion, in the sphere of consciousness, of the indetermination of our will. — But the action of memory goes further and deeper than this superficial glance would suggest. The moment has come to reinstate memory in perception, to correct in this way the element of exaggeration in our conclusions, and so to determine with more precision the point of contact between con sciousness and things, between the body and the spirit.
We assert, at the outset, that if there be memory, that is, the survival of past images, these images must constantly mingle with our percep- Perception is. ° r.
less objective tion of the present, and may even take its in fact than in _.-.. -,..
theory because place. For if they have survived it is with it includes.
a share oi a view to utility: at every moment they memory...
complete our present experience, enrich ing it with experience already acquired; and, as the latter is ever increasing, it must end by covering up and submerging the former. It is indisputable that the basis of real, and so to speak instantaneous, intuition, on which our perception of the external world is developed, is a small matter compared with all that memory adds to it. Just because the recollection of earlier analogous intuitions is more useful than the intuition itself, being bound up in memory with the whole series of subsequent events, and capable thereby of throw- CHAP, i PURE PERCEPTION 71 ing a better light on our decision, it supplants the real intuition of which the office is then merely — we shall prove it later — to call up the recollection, to give it a body, to render it active and thereby actual. We had every right, then, to say that the coincidence of perception with the object perceived exists in theory rather than in fact. We must take into account that perception ends by being merely an occasion for remembering, that we measure in practice the degree of reality by the degree of utility, and, finally, that it is our interest to regard as mere signs of the real those immediate intuitions which are, in fact, part and parcel with reality. But here we discover the mistake of those who say that to perceive is to project externally unextended sensations which have been drawn from our own depths, and then to develop them in space. They have no difficulty in showing that our com plete perception is filled with images which belong to us personally, with exteriorized (that is to say recollected) images; but they forget that an impersonal basis remains in which perception coincides with the object perceived; and which is, in fact, externality itself.
The capital error, the error which, passing over from psychology into metaphysic, shuts us out in the end from the knowledge both of tion and pure body and of spirit, is that which sees constantly only a difference of intensity, instead of a difference of nature, between pure perception and memory. Our perceptions are un doubtedly interlaced with memories, and inversely, a memory, as we shall show later, only becomes actual by borrowing the body of some perception into which it slips. These two acts, perception and recollection, always interpenetrate each other, are always exchanging something of their sub stance as by a process of endosmosis. The proper office of psychologists would be to dissociate them, to give back to each its natural purity; in this way many difficulties raised by psychology, and perhaps also by metaphysics, might be les sened. But they will have it that these mixed states, compounded, in unequal proportions, of pure perception and pure memory, are simple. And so we are condemned to an ignorance alike of pure memory and of pure perception; to knowing only a single kind of phenomenon which will be called now memory and now per ception, according to the predominance in it of one or other of the two aspects; and, con sequently, to finding between perception and memory only a difference in degree and not in kind. The first effect of this error, as we shall see in detail, is to vitiate profoundly the theory of memory; for if we make recollection merely a weakened perception we misunderstand the essential difference between the past and the present, we abandon all hope of understanding the phenomena of recognition, and, more gener ally, the mechanism of the unconscious. But, inversely, if recollection is regarded as a weakened perception, perception must be regarded as a stronger recollection. We are driven to argue as though it was given to us after the manner of a memory, as an internal state, a mere modification of our personality; and our eyes are closed to the primordial and fundamental act of perception, — the act, constituting pure perception, whereby we place ourselves in the very heart of things. And thus the same error, which manifests itself in psychology by a radical incapacity to explain the mechanism of memory, will in metaphysics pro foundly influence the idealistic and realistic conceptions of matter.
For realism, in fact, the invariable order of the phenomena of nature lies in a cause distinct from our perceptions, whether this cause must remain unknowable, or whether we can reach it by an effort (always more or less arbitrary) of meta physical construction. For the idealist, on the contrary, these perceptions are the whole of reality, and the invariable order of the phenomena of nature is but the symbol whereby we express, alongside of real perceptions, perceptions that are possible. But, for realism as for idealism, percep tions are ' veridical hallucinations/ states of the subject, projected outside himself; and the two doctrines differ merely in this: that in the one these states constitute reality, in the other they are sent forth to unite with it.
But behind this illusion lurks yet another that extends to the theory of knowledge in general. We have said that the material world is made philosophy up of objects, or, if you prefer it, of dissociate images, of which all the parts act and react upon each other by movements. And that which constitutes our pure perception is our dawning action, in so far as it is pre figured in those images. The actuality of our perception thus lies in its activity, in the movements which prolong it, and not in its greater intensity: the past is only idea, the present is ideo-motor. But this is what our opponents are determined not to see, because they regard perception as a kind of contempla tion, attribute to it always a purely speculative end, and maintain that it seeks some strange disinterested knowledge; as though, by isolating it from action, and thus severing its links with the real, they were not rendering it both inexplicable and useless. But thenceforward all difference between perception and recollection is abolished, since the past is essentially that which acts no longer, and since, by misunderstanding this characteristic of the past, they become incapable of making a real distinction between it and the present, i.e. that which is acting. No difference but that- of mere degree will remain between perception and memory; and neither in the one nor in the other will the subject be acknowledged to pass beyond himself. — Restore, on the contrary, the true char acter of perception; recognize in pure perception a system of nascent acts which plunges roots deep into the real; and at once perception is seen to be radically distinct from recollection; the reality of things is no more constructed or recon structed, but touched, penetrated, lived; and the problem at issue between realism and idealism, instead of giving rise to interminable metaphysical discussions, is solved, or rather dissolved by intuition.
In this way also we shall plainly see what position we ought to take up between idealism it might and realism, which are both condemned £kunggetan to see in matter only a construcnaSreo?8 ^on or a reconstruction executed by matter- the mind. For if we follow out to the end the principle according to which the subjectivity of our perception consists, above all, in the share taken by memory, we shall say that even the sensible qualities of matter would be known in themselves, from within and not from without, could we but disengage them from that particular rhythm of duration which characterizes our consciousness. Pure perception, in fact, however rapid we suppose it to be, occupies a certain depth of duration, so that our successive perceptions are never the real moments of things, as we have hitherto supposed, but are moments of our consciousness. Theoretically, we said, the part played by consciousness in external perception would be to join together, by the continuous thread of memory, instantaneous visions of the real. But, in fact, there is for us nothing that is instantaneous. In all that goes by that name there is already some work of our memory, and consequently of our consciousness, which prolongs into each other, so as to grasp them in one relatively simple intuition, an endless number of moments of an endlessly divisible time. Now what is, in truth, the difference between matter as the strictest realism might conceive it, and the per ception which we have of it? Our perception presents us with a series of pictorial, but discon tinuous, views of the universe; from our present perceptions we could not deduce subsequent perceptions, because there is nothing in an aggregate of sensible qualities which foretells the new qualities into which they will change. On the contrary, matter, as realism usually posits it, evolves in such a manner that we can pass from one moment to the next by a mathe matical deduction. It is true that, between this matter and this perception, scientific realism can find no point of contact, because it develops matter into homogeneous changes in space, while it contracts perception into unextended sensa tions within consciousness. But, if our hypo thesis is correct, we can easily see how perception and matter are distinguished, and how they coincide. The qualitative heterogeneity of our successive perceptions of the universe results from the fact that each, in itself, extends over a certain depth of duration, and that memory condenses in each an enormous multiplicity of vibrations which appear to us all at once, although they are successive. If we were only to divide, ideally, this undivided depth of time, to distinguish in it the necessary multiplicity of moments, in a word to eliminate all memory, we should pass thereby from perception to matter, from the subject to the object. Then matter, becoming more and more homo geneous as our extended sensations spread them selves over a greater number of moments, would tend more and more towards that system of homo geneous vibrations of which realism tells us, al though it would never coincide entirely with them. There would be no need to assume, on the one hand, space with unperceived movements, and, on the other, consciousness with unextended sensations. Subject and object would unite in an extended perception the subjective side of perception being the contraction effected by memory, and the objective reality of matter fusing with the multitudinous and successive vibrations into which this perception can be internally broken up. Such at least is the conclusion which, we hope, will issue clearly from the last part of this essay. Questions relating to subject and object, to their distinction and their union, should be put in terms of time rather than of space.
But our distinction between ' pure perception ' and 'pure memory' has yet another aim. Just as pure perception, by giving us hints as to the nature of matter, allows us to take an intermediate position between realism and idealism, so pure memory, on the other hand, by opening to us a view of what is called spirit, should enable us to decide between those other two doctrines, mater ialism and spiritualism.1 Indeed it is this aspect of the subject which will first occupy our atten tion in the two following chapters, because it is in this aspect that our hypothesis allows some degree of experimental verification.
For it is possible to sum up our conclusions as to pure perception by saying that there is in matter AS also of the something more than, but not something spirit. different from, that which is actually given. Undoubtedly conscious perception does not compass the whole of matter, since it consists, in as far as it is conscious, in the separation, or the ' discernment,' of that which, in matter, interests our various needs. But between this perception of matter and matter itself there is but a differ ence of degree and not of kind, pure perception standing towards matter in the relation of the part to the whole. This amounts to saying that matter cannot exercise powers of any kind other than those which we perceive. It has no mys terious virtue, it can conceal none. To take a definite example, one moreover which interests us most nearly, we may say that the nervous 1 The word ' spiritualism ' is used throughout this work to signify any philosophy that claims for spirit an existence of its own. (Translators' note.)
system, a material mass presenting certain quali ties of colour, resistance, cohesion, etc., may well possess unperceived physical properties, but physical properties only. And hence it can have no other office than to receive, inhibit, or transmit movement.
Now the essence of every form of materialism is to maintain the contrary, since it holds that consciousness, with all its functions, is born of the mere interplay of material elements. Hence it is led to consider even the perceived qualities of matter, — sensible, and consequently felt, quali ties, — as so many phosphorescences which follow the track of the cerebral phenomena in the act of perception. Matter, thus supposed capable of creating elementary facts of consciousness, might therefore just as well engender intellectual facts of the highest order. It is, then, of the essence of materialism to assert the perfect relativity of sensible qualities, and it is not without good reason that this thesis, which Democritus has formulated in precise terms, is as old as materialism.
But spiritualism has always followed mater ialism along this path. As if everything lost to matter must be gained by spirit, spiritualism has never hesitated to despoil matter of the qualities with which it is invested in our perception, and which, on this view, are subjective appearances. Matter has thus too often been reduced to a mysterious entity which, just because all we 8O MATTER AND MEMORY CHAP, i know of it is an empty show, might as well engender thought as any other phenomenon.
The truth is that there is one, and only one, method of refuting materialism: it is to show that matter is precisely that which it appears to be. Thereby we eliminate all virtuality, all hidden power, from matter, and establish the phenomena of spirit as an independent reality. But to do this we must leave to matter those qualities which materialists and spiritualists alike strip from it: the latter that they may make of them representations of the spirit, the former that they may regard them only as the accidental garb of space.
This, indeed, is the attitude of common sense with regard to matter, and for this reason com mon sense believes in spirit. It seems to us that philosophy should here adopt the attitude of common sense, although correcting it in one respect. Memory, inseparable in practice from perception, imports the past into the present, contracts into a single intuition many moments of duration, and thus by a twofold operation compells us, de facto, to perceive matter in ourselves, whereas we, de jure, perceive matter within matter.
Hence the capital importance of the problem of memory. If it is memory above all that lends to perception its subjective character, cardinal " the philosophy of matter must aim t™ePpro'Sem0 in the first instance, we said, at elimina ting the contributions of memory. We CHAP, i THE PROBLEM OF MATTER 8l must now add that, as pure perception gives us the whole or at least the essential part of matter (since the rest comes from memory and is superadded to matter), it follows that memory must be, in principle, a power absolutely independent of matter. If, then, spirit is a reality, it is here, in the phenomenon of memory, that we may come into touch with it experimentally. And hence any attempt to derive pure memory from an operation of the brain should reveal on analysis a radical illusion.
Let us put the same statement in clearer lan guage. We maintain that matter has no occult or unknowable power, and that it coinseeing that a. \ ' true theory cides, in essentials, with pure perception, refutes mate- Thence we conclude that the living body rialism..
in general, and the nervous system in particular, are only channels for the transmission of movements, which, received in the form of stimulation, are transmitted in the form of action, reflex or voluntary. That is to say, it is vain to attribute to the cerebral substance the property of engendering representations. Now the pheno mena of memory, in which we believe that we can grasp spirit in its most tangible form, are pre cisely those of which a superficial psychology is most ready to find the origin in cerebral activity alone; just because they are at the point of con tact between consciousness and matter, and because even the adversaries of materialism have no objection to treating the brain as a storehouse of memories. But if it could be positively estab lished that the cerebral process answers only to a very small part of memory, that it is rather the effect than the cause, that matter is here as else where the vehicle of an action and not the sub stratum of a knowledge, then the thesis which we are maintaining would be demonstrated by the very example which is commonly supposed to be most unfavourable to it, and the necessity might arise of erecting spirit into an independent reality. In this way also, perhaps, some light would be thrown on the nature of what is called spirit, and on the possibility of the interaction of spirit and matter. For a demonstration of this kind could not be purely negative. Having shown what memory is not, we should have to try to discover what it is. Having attributed to the body the sole function of preparing actions, we are bound to enquire why memory appears to be one with this body, how bodily lesions influence it, and in what sense it may be said to mould itself upon the state of the brain matter. It is, more over, impossible that this enquiry should fail to give us some information as to the psychological mechanism of memory, and the various mental operations connected therewith. And, inversely, if the problems of pure psychology seem to ac quire some light from our hypothesis, this hypothesis itself will thereby gain in certainty and weight.
But we must present this same idea in yet a CHAP. I MEMORY 83 third form, so as to make it quite clear why the And might problem of memory is in our eyes a empiric!? privileged problem. From our analysis metap?y£cai °^ Pure perception issue two concluprobiems. sions which are in some sort divergent, one of them going beyond psychology in the direction of psycho-physiology, and the other in that of metaphysics, but neither allowing of immed iate verification. The first concerns the office of the brain in perception: we maintain that the brain is an instrument of action, and not of representation. We cannot demand from facts the direct confirmation of this thesis, because pure perception bears, by definition, upon present objects, acting on our organs and our nerve centres; and because everything always happens, in conse quence, as though our perceptions emanated from our cerebral state, and were subsequently pro jected upon an object which differs absolutely from them. In other words, with regard to external perception the thesis which we dispute and that which we substitute for it lead to pre cisely the same consequences, so that it is possible to invoke in favour of either the one or the other its greater intelligibility, but not the authority of experience. On the contrary, the empirical study of memory may and must decide between them.
For pure recollection is, by hypothesis, the repre sentation of an absent object. If the necessary and sufficient cause of perception lies in a certain activity of the brain, this same cerebral activity, repeating itself more or less completely in the absence of the object, will suffice to reproduce perception: memory will be entirely explicable by the brain. But if we find that the cerebral mechanism does indeed in some sort condition memories, but is in no way sufficient to ensure their survival; if it concerns, in remembered perception, our action rather than our repre sentation; we shall be able to infer that it plays an analogous part in perception itself, and that its office is merely to ensure our effective action on the object present. Our first conclusion may thus find its verification. — There would still remain this second conclusion, which is of a more metaphysical order, — viz.: that in pure per ception we are actually placed outside ourselves, we touch the reality of the object in an immediate intuition. Here also an experimental verifica tion is impossible, since the practical results are absolutely the same whether the reality of the object is intuitively perceived or whether it is rationally constructed. But here again a study of memory may decide between the two hypotheses. For, in the second, there is only a difference of intensity, or more generally, of degree, between perception and recollection, since they are both self-sufficient phenomena of representation. But if, on the contrary, we find that the difference between perception and recollection is not merely in degree, but is a radical difference in kind, the presumption will CHAP, i MEMORY 85 CHAP, i MEMORY 85 be in favour of the hypothesis which finds in per ception something which is entirely absent from memory, a reality intuitively grasped. Thus the problem of memory is in very truth a privi leged problem, in that it must lead to the psycho logical verification of two theses which appear to be insusceptible of proof, and of which the second, being of a metaphysical order, appears to go far beyond the borders of psychology.
The road which we have to follow, then, lies clear before us. We shall first pass in review evidences of various kinds borrowed from normal and from pathological psychology, by which philosophers might hold themselves justified in maintaining a physical explanation of memory. This examination must needs be minute or it would be useless. Keeping as close as possible to facts, we must seek to discover where, in the operations of memory, the office of the body begins, and where it ends. And should we, in the course of this enquiry, find confirmation of our own hypo thesis, we shall not hesitate to go further and, considering in itself the elementary work of the mind, complete the theory thereby sketched out, of the relation of spirit with matter.
CHAPTER II .s - 1 OF THE RECOGNITION OF IMAGEsJ MEMORY AND THE BRAIN.
WE pass now to the consideration of the conse quences for the theory of memory, which might The two ensue from the acceptance of the prinmemory: the ciples we have laid down. We have as a bodily said that the body, placed between the an indepen- objects which act upon it and those lection. which it influences, is only a conductor, the office of which is to receive movements, and to transmit them (when it does not arrest them) to certain motor mechanisms, determined if the action is reflex, chosen if the action is volun tary. Everything, then, must happen as it an independent memory gathered images as they successively occur along the course of time; and as if our body, together with its surround ings, was never more than one among these images, the last, that which we obtain at any mo ment by making an instantaneous section in the general stream of becoming. In this section our body occupies the centre. The things which surround it act upon it, and it reacts upon them. Its reactions are more or less complex, more or CHAP, ii THE TWO FORMS OF MEMORY 87 less varied, according to the number and nature ot the apparatus which experience has set up within it. Therefore in the form of motor contri vances, and of motor contrivances only, it can store up the action of the past. Whence it results that past images, properly so called, must be otherwise preserved; and we may formulate this first hypothesis: I. The past survives under two distinct forms: first, in motor mechanisms; secondly, in indepenpendent recollections.
But then the practical, and consequently the usual function of memory, the utilizing of past experience for present action, — recognition, in short, — must take place in two different ways. Sometimes it lies in the action itself, and in the automatic setting in motion of a mechanism adapted to the circumstances; at other times it implies an effort of the mind which seeks in the past, in order to apply them to the present, those representations which are best able to enter into the present situation. Whence our second pro position: II. The recognition of a present object is effected by movements when it proceeds from the object, by representations when it issues from the subject.