AGAINST THE STOICS, SENSATIONS ARE NOT IMPRESSIONS OF A SEAL ON WAX. Besides, if the principle that feels were corporeal, it could feel only so long as exterior objects produced in the blood or in the air some impression similar to that of a seal on wax.[55] If they impressed their images on wet substances, as is no doubt supposed, these impressions would become confused as images in water, and memory would not occur. If, however, these impressions persisted, they would either form an obstacle to subsequent ones, and no further sensation would occur; or they would be effaced by the new ones, which would destroy memory. If then the soul is capable of recalling earlier sensations, and having new ones, to which the former would form no obstacle, it is because she is not corporeal. SENSATION CANNOT BE RELAYED FROM SENSE-ORGAN TO DIRECTING PRINCIPLE. 7. The same reflections may be made about pain, and one's feeling of it. When a man's finger is said to give him pain, this, no doubt, is a recognition that the seat of the pain is in the finger, and that the feeling of pain is experienced by the directing principle. Consequently, when a part of the spirit suffers, this suffering is felt by the directing principle, and shared by the whole soul.[56] How can this sympathy be explained? By relay transmission, (the Stoic) will answer; the sense-impression is felt first by the animal spirit that is in the finger, and then transmitted to the neighboring part, and so on till it reaches the directing part. Necessarily, if the pain is felt by the first part that experiences it, it will also be felt by the second part to which it is transmitted; then by the third, and so on, until the one pain would have caused an infinite number of sensations. Last the directing principle will perceive all these sensations, adding thereto its own sensation. Speaking strictly, however, each of these sensations will not transmit the suffering of the finger, but the suffering of one of the intermediate parts. For instance, the second sensation will relay the suffering of the hand. The third, that of the arm, and so on, until there will be an infinity of sensations. The directing principle, for its part, will not feel the pain of the finger, but its own; it will know none but that, it will pay no attention to the rest, because it will ignore the pain suffered by the finger. Therefore, relayed sensation is an impossibility, nor could one part of the body perceive the suffering felt by another part; for the body has extension, and, in every extension, parts are foreign to each other (the opposite of the opinion of Cleanthes, Nemesius).[57] Consequently, the principle that feels must everywhere be identical with itself; and among all beings, the body is that which is least suitable to this identity. THE BODY CANNOT THINK.