SENSATION WILL FIRST HAVE TO BE EXAMINED.
Let us now examine to what beings sensation belongs, and whereby it operates. Let us see whether sensation can take place even without organs. Of what use to the earth could sensation be? For it does not serve the earth as means of knowledge; the knowledge which consists in wisdom suffices for the beings to whom sensation is of no use. This consideration might however be denied, for the knowledge of sense-objects offers, besides utility, some of the charms of the Muses. Such is, for example, the knowledge of the sun and the other stars, whose contemplation itself is agreeable. This problem will therefore demand solution.
RESTATEMENT OF PROBLEMS INVOLVED.
We must therefore first investigate if the earth possess senses, to what animals sensation naturally belongs, and how sensation operates. It will be necessary to begin by discussing the doubtful points that we have indicated, and to examine in general if sensation can operate without organs, and if the senses have been given for utility, admitting even that they can procure some other advantage.
CONCEPTIVE THOUGHT DEMANDS THE INTERMEDIARY PROCESS OF SENSATION.
23. Conception of sense-objects occurs when the soul or the living being experiences perceptions by grasping the bodies' inherent qualities, and by representing their forms to itself. The soul must therefore perceive sense-objects either with or without the body. How could the soul do so alone? Pure and isolated, she can conceive only what she has within herself; she can only think. But for conception of objects other than herself, she must previously have grasped them, either by becoming assimilated to them, or by finding herself united to something which may have become similar to them.
THE PURE SOUL WOULD REMAIN ISOLATED.
It is impossible for the soul to become similar to sense-objects (in order to grasp them), by remaining pure. How indeed could a point become similar to a line? The intelligible line itself could not become conformed to the sense-line, any more than intelligible fire to the sense-fire, or the intelligible man to the sense-man. Nature herself which begets man could not be identical with the begotten man. The isolated soul, even if she could grasp sense-objects, will finish by applying herself to the intuition of intelligible objects, because, having nothing by which to grasp the former, she will let them escape. Indeed, when the soul perceives from far a visible object, although only the form reaches her, nevertheless what first began by being for her indivisible, finally constitutes a subject, whether it be color or a figure, whose size is determined by the soul.
SENSATION DEPENDS ON THE SENSE-SHAPE, WHICH, LIKE TOOLS, IS INTERMEDIATE.
The soul and the exterior object do not therefore suffice (to explain sensation); for there would be nothing that suffers. There must therefore be a third term that suffers, that is, which receives the sense-form, or, shape. This third term must "sympathize," or, share the passion of the exterior object, it must also experience the same passion, and it must be of the same matter; and, on the other hand, its passion must be known by another principle; last, passion must keep something of the object which produces it, without however being identical with it. The organ which suffers must therefore be of a nature intermediary between the object which produces the passion and the soul, between the sensible and the intelligible, and thus play the part of a term intermediary between the two extremes, being receptive on one side, making announcements on the other, and becoming equally similar to both. The organ that is to become the instrument of knowledge must be identical neither with the subject that knows, nor with the object that is known. It must become similar to both of them; to the exterior object because it suffers, and to the cognizing soul because the passion which it experiences becomes a form. Speaking more accurately, the sensations operate by the organs. This results from the principle asserted above, that the soul isolated from the body can grasp nothing in the sense-world. As used here, the word "organ" either refers to the whole body, or to some part of the body fitted to fulfil some particular function; as in the case of touch or sight. Likewise, it is easy to see that tools of artisans play a part intermediary between the mind which judges, and the object which is judged; and that they serve to discover the properties of substances. For instance, a (foot) rule, which is equally conformed to the idea of straightness in the mind, and to the property of straightness in the wood, serves the artisan's mind as intermediary to judge if the wood he works be straight.