The idea that we have disengaged from the facts and confirmed by reasoning is that our body is an instrument of action, and of action only. In no degree, in no sense, under no aspect, does it serve to prepare, far less to explain, a representation. Consider external perception: there is only a difference of degree, not of kind, between the so-called perceptive faculties of the brain and the reflex functions of the spinal cord. While the spinal cord transforms the excitations received into movements which are more or less necessarily executed, the brain puts them into relation with motor mechanisms which are more or less freely chosen;
but that which the brain explains in our perception is action begun, prepared or suggested, it is not perception itself.
Consider memory. The body continues to have motor habits capable of acting the past over again; it can begin to have attitudes in which the past will insert itself; or, again, by the repetition of certain cerebral phenomena, which have prolonged former perceptions, it can furnish the action of remembering a point of attachment with the actual, a means of recovering its lost influence upon present reality: but in no case can the brain store up recollections or images. Thus,
neither in perception, nor in memory, nor a fortiori in the higher attainments of mind, does the body contribute directly to representation.
By developing this hypothesis under its manifold aspects and thus pushing dualism to an extreme, we appeared to divide body and soul by an impassable abyss. In truth, we were indicating the only possible means of bringing them together.
All the difficulties raised by this problem, either in ordinary dualism, or in materialism and idealism, come from considering, in the phenomena of perception and memory, the physical and the mental as duplicates of one another. Suppose I place myself at the materialist point of view of consciousness regarded as a byproduct of brain activity: I am quite unable to understand why certain cerebral phenomena are accompanied by consciousness, that is to say, of what use could the conscious repetition of the material universe I have begun by assuming it to be a fact, or how could it ever arise. Suppose I prefer idealism: I then allow myself only perceptions, and my body is one of them. But whereas observation shows me that the images I perceive are entirely changed by very slight alternatins of the image I call my body (since I have only to shut my eyes and my visual universe diassappears), science assures me that all phenomena must succeed and condition one another according to a determined order, in which effects are strictly proportioned to causes. I am obliged, therefore, to seek, in the image which I call my body, and which follows me everywhere, for changes which shall be the equivalents – but the well-regulated equivalents, now deducible from each other – of the images which succeed one another around my body: the cerebral movements, to which I am led back in this way again are the duplicates of my perceptions. It is true that these movements are still perceptions, “possible” perceptions – so that this second hypothesis is more intelligible than the first; but, on the other hand, it must suppose, in its turn, an inexplicable correspondence between my real perception of things and my possible perception of certain cerebral movements which do not in any way resemble these things. When we look at it closely, we shall see that this is the reef upon which all idealism is wrecked:
there is no possible transition from the order which is perceived by our senses to the order which we are to conceive for the sake of our science, – or, if we are dealing more particularly with the Kantian idealism, no possible transition from sense to understanding.
So my only refuge seems to be ordinary dualism. I place matter on this side, mind on that, and I suppose that cerebral movements are the cause or the occasion of my representation of objects. But if they are its cause, if they are enough to produce it, I must fall back, step-by-step, upon the materialistic hypothesis of a conciousness regarded as a byproduct of brain activity. If they are only its occasion, I thereby suppose that they do not resemble it in any way, and so, depriving matter of all the qualities which I conferred upon it in my representation, I come back to idealism. Idealism and materialism are then the two poles between which this kind of dualism will always oscillate; and when, in order to maintain the duality of substances, it decides to make them both of equal rank, it will be led to regard them as two translations of one and the same original, two parallel and predetermined developments of a single principle, and thus to deny their reciprocal influence, and, by an inevitable consequence, to sacrifice freedom.
Now, if we look beneath these three hypotheses, we find that they have a common basis: all three regard the elementary operations of the mind, perception and memory, as operations of pure knowledge. What they place at the origin of consciousness is either the useless duplicate of an external reality or the inert (lacking) material of an intellectual construction entirely disinterested (impartial): but they always neglect the relation of perception with action and of memory with the manner of its activity. Now, it is no doubt possible to conceive, as an ideal limit, a memory and a perception that are impartial; but, in fact, it is toward action that memory and perception are turned; it is action that the body prepares. Do we consider perception? The growing complexity of the nervous system push and pull the excitation received onto an ever larger variety of motor mechanisms and so sketches simultaneously an ever larger number of possible actions. Do we turn to memory? We note that its primary function is to evoke all those past perceptions which are analogous to the present perception, to recall to us what preceded and followed them, and so to suggest to us that decision which is the most useful. But this is not all. By allowing us to grasp in a single intuition multiple moments of duration, it frees us from movement of the flow of things, that is to say, from the rhythm of necessity. The more of the moments memory can contract into one, the firmer is the hold which it gives to us on matter: so the memory of a living being appears indeed to measure, above all, its powers of action upon things and to be only the intellectual reverberation of this power. Let us start, then, from this energy, as from the true principle: let us suppose that the body is a center of action, and only a center of action. We must see what consequences then result for perception, for memory, and for the relations between body and mind.
To take perception first. here is my body with its “perceptive centers.” These centers vibrate, and I have the representation of things. On the other hand, I have supposed that these vibrations can neither produce nor translate my perception. It is, then, outside them. Where is it? I cannot hesitate as to the answer: positing my body, I posit a certain image, but with it also the aggregate of the other images, since there is no material image which does not owe its qualities, its determinations, in short, its existence, to the place which it occupies in the totality of the universe. My perception can, then, only be some part of these objects themselves; it is in them rather than they in it. But what is it exactly within them? I see that my perception appears to follow all the vibratory detail of the so-called sensitive nerves; yet I know that the role of their vibrations is solely to prepare the reaction of my body on neighboring bodies, to sketch out my virtual actions. Perception, therefor, consists in detaching, from the totality of objects, the possible action of my body upon them. Perception appears, then, as only a choice. It creates nothing; its office, on the contrary, is to eliminate from the totality of images all those on which I can hove no hold, and then, from each of those which I retain, all that does not concern the needs of the image which I call my body, at least, much simplified, is the way we explain or describbe schematically what we have called pure perception. Let us mark out at once the intermediate place which we thus take up between realism and idealsm.
That every reality has a kinship, an analogy – in short, a relation with consciousness – this is what we concede to idealism by the very fact that we term things “images.” No philosophical doctrine, moreover, provided that it is consistent with itself, can escape from this conclusion. But, if we could assemble all the states of consciousness, past, present and possible, of all conscious beings, we should still only have gathered a very small part of material reality because images outrun perception on every side. It is just these images that science and metaphysic seek to reconstitute, thus restoring the whole of a chain of which our perception grasps only a few links. But, inorder thus to discover between perception and reality the relation of the part to the whole, it is necessary to leave to perception its true office, which is to prepare actions. This is what idealism fails to do. Why is it unable, as we said just now, to pass form the order manifested in perception to the order which is successful in science, that is to say, from the contingency with which our sensations appear to follow each other to the determinism which binds together the phenomena of nature? Precisely because it attributes to consciousness, in perception, a speculative role, so that it is impossible to see what interest this speculative role, so that it is impossible to see what interest this consciousness has in allowing to escape, between two sensations, for instance, the intermediate links through which the second might be deduced from the first. This intermediaries and their strict order thus remain obscure, whether, with Mill, we make the intermediaries into “possible sensations,” or, with Kant, hold the substructure of the order to be the work of an impersonal understanding. But suppose that my conscious perception has an entirely practical destination, simply indicating, in the aggregate of things, that which intereests my possible action upon them: I can then understand thatall the rest excapes me, and that, nevertheless, all the rest is o fhte same nature as what I perceive. My consciousness of matter is then no longer either subjective, as it is for English idealism, or relative, as it is for the kantian idealism. It is not subjective, for it is in things rather than in me. It is not relative, because between the “phenomenon” and the “thing” is not that of appearance to reality, but merely that of the part to the whole.