Chapter III

But let us come back to our tree or our ox. This ox can enter us in one of two ways. First, partly, but really, in the form of food. What we absorb of it in that way cannot, evidently, be known as ox. It reaches our knowledge only through its effects--strength, health, gaiety, activity, depression. Even were this absorption total in the case of a small animal, digestible in all its parts, the result, from the point of view of immediate knowledge, would be the same, since the object becomes resolved into elements which render its form unknowable.

The other manner--that which brings into play the external senses--will make us know the ox, in appearance as such, in reality as image of an ox. What is the true value of this knowledge? We must here return to this question, in order to enter more easily upon the second part of this essay.

Truth has been very seriously defined as conformity of the representation of an object with this object itself. But that solves nothing. What is the object itself, since we can know it only as representation? It is useless to carry the discussion further. We shall turn indefinitely around the fortress of idealism, without ever finding an opening, or any weak point. We shall enter it never, no argument serving as a bomb against its solid walls.

However, we must consider carefully. Having thoroughly reflected, we shall ask if this fortress be real, or if, on the contrary, it be not, perhaps, a representation without object, a pure phantom, like those sunken cities whose bells still ring for great festivals, but are heard only by those who believe in their mysterious life. This doubt will lead us to re-examine the reasoning of Berkeley and of Kant, and see if it be well constructed. Does it start from the senses to reach the mind? Or may it not, perchance, be one of those mental conceptions which fall back upon the senses like an avalanche, freezing and smothering them?

How have the senses been formed? Such is the question. Has there always been an opposition between the ego and the non-ego? There is nothing in the intelligence that has not first been in the senses. By intelligence, we must in this philosophic dictum, due to Locke, understand the psychologic consciousness. Let us leave aside the consciousness, which can only serve to complicate the problem. Consciousness is a phenomenon of secondary order and of an entirely sentimental utility, if it be restricted to man; commonplace and of pure reflex, if extended to all sensible matter. Let us consider this matter in perhaps its humblest manifestations, taking account only of the actions and reactions, exactly as we might observe the influence of heat, of light, or of cold on milk, wine or water. In living matter there will, however, be something more--the decomposition will be compensated by assimilation, and if the assimilation be abundant, there will be generation. Other forms, resembling the first, will detach themselves from the matrix form. This represents life essentially, a living being, a being limited in duration by the very fact of its growth, which constitutes an effort and a loss. Let us consider a being whose senses are not differentiated, and let us see how it gets on with the rest of the world, how it knows it.

The amoeba has no exterior senses. It is an almost homogeneous mass, and yet it is sensible to almost the same sensorial impressions as the highest mammal. It feeds (smell and taste); it moves (sense of space, touch); it is sensible to light, at least to certain rays (sight); its environment being in perpetual movement, ceaselessly traversed by sonorous waves, it doubtless reacts to these vibrations (hearing). Perhaps, even, it possesses, without special organs, senses which we lack, and which we recover only by study and analysis, such as the chemical sense, which judges the composition of a body, declares it assimilable or counsels its rejection. The exercise of all these senses denotes, first of all, a very long heredity. They have, doubtless, been acquired successively only, unless, the absence of one of them being capable of causing death, their presence is the strict consequence of the life of this humble beast. But it is useless to construct any hypotheses on the subject. It is enough to keep to the fact, and this fact is the existence of a being without differentiated organs, that is to say, a being all of whose parts are equally adapted to react against every external excitation.

Why these reactions? They are one of the conditions of life. But could not life be conceived without them? It is possible. It is a question of environment. If the amoeba's environment were homogeneous and calm, if it were of a constant temperature and luminosity, if it furnished an abundance of proper nourishment, if, in a word, the animal dwelt in an alimentary bath, no reactions would be necessary, and its only movement would be to open its pores for food, to reject the excess of this food, to divide itself, when swollen, into two amoebas. Why, then, does it possess all these senses which, though unorganized, are perfectly real? Because the environment obliges it to have them, because of its instability. The senses, whether differentiated, or spread over the entire surface of a living form, are the creation of the environment which--light, sound, material exteriority, odours, etc.--acts in accordance with different discontinuous manifestations. Constant or continuous, they would be without effect. Discontinuous, they make themselves felt. Discontinuous light has created the eye, just as the drop of water creates a hole in granite.

A being, whatever it may be, whether vague and almost amorphous or clearly defined, is not isolated in the universal vital environment. It is the molecule of a diapason. It vibrates, not of its own accord, but in obedience to a general movement. The living cell, itself in internal movement and subjected to all the reactions of external movement, perceives this movement doubtless as an unique impression only. But when several cells come together and live in permanent contact, the impressions of external movement begin to be perceived as differentiated. Is this then necessary? Do there then already exist luminous vibrations, different from sonorous vibrations? Assuredly, since otherwise the sensorial differentiation would be inexplicable, being useless. The union of several cells permits the animal to divide its work of perception, and to present to each perceptible manifestation an organ or, at least, the sketch of an organ, appropriate to receive it.

It would be possible, it is true, from the idealistic point of view, to suppose that the senses are a creation of the individual, an enhancement of his own life, and that he differentiates, on his own initiative, his cinematic impression. This would be a phenomenon of spontaneous analytic creation, the analyzing instrument existing prior to the matter analyzed, or even, for exasperated idealists, creating this matter according to determinate needs, once and for all, by its own physiology. It would then be a property of organized living matter to fabricate senses for itself, and to diversify, by this means, its own life. This point of view is not easy to admit for several reasons, purely physical.

First, if this sensorial differentiation were a faculty of living matter, it would not be observed to be limited in its powers, as it is. Even admitting certain senses unknown to man, such as the chemical sense, the electric sense, the sense of orientation (extremely doubtful), it is still seen that the number of senses is very limited. But, far more important, the fundamental senses are found to be identical among the majority of the higher species, vertebrates and insects, with very few exceptions. The moment the animal arrives at sensorial differentiation, this differentiation occurs in response to the manifestations of matter.

The senses should, then, correspond to external realities. They have been created, not by the perceiving being, but by the perceptible environment. It is the light that has created the eye, just as, in our houses, it has created the windows. Where there is no light, fish become blind. This is perhaps the direct proof, for if light is the creation of the eye, this creation can occur at the bottom of the sea quite as well as on the surface of the earth. Another proof: these same fish, having become blind, but still requiring a luminous habitat, create for themselves in the night of the abysses, not eyes, but apparatus directly productive of light; and this artificial light creates anew the atrophied eye. The senses are then clearly the product of the environment. That is all they can do, moreover, their utility being nil, if the environment is not perceptible. It might still be objected that it is the nervous system which, having intuition of an environment to be perceived, creates for itself organs adapted to this perception. But this is merely begging the question; for, either the nervous system has knowledge of the external environment, which means that it already has senses, or else it has no senses, and thus can have no knowledge. A more serious objection would be that, sensorial aptitude being a property of the nervous system, it would afterwards create for itself organs in order to perceive more distinctly, and clearly differentiated, the various natural phenomena. This view would explain up to a certain point the creation of sensorial organs, but not the existence of the senses themselves as sensitive power. It is, moreover, certain that the nervous system acts rather by tyrannizing the organs at its disposal, than by seeking to modify these organs or to create new ones. It is a power which evidently exceeds the limits of its capacity. It has, on the contrary, devolved upon the external phenomena which, in acting mechanically on the living matter, produce in it local modifications. The organs of the senses seem to be nothing other than surfaces sensitized by the very agents which, once their work is done, will reflect in them their particular physiognomy. The eye--let us take once more this example, and repeat it--is a creation of light.

Since they are themselves the work of the principal general phenomena, the senses ought then to agree exactly--allowing for approximation--with the very nature which has created them. The luminous environment is not, in this case, a dream, but a reality, and a reality existing prior to the eye which perceives it; and, since the eye is the very product of light, objects situated in this luminous environment should be perceived by it as an exact image, just as the drill which creates a hole, creates it strictly to its size, its form, its image. Bacon said that the senses are holes. Here this is only a metaphor.