8. If, in any sense whatever, the soul were a body, we could not think. Here is the proof. If feeling is explained as the soul’s laying hold of perceptible things by making use of the body, thinking cannot also of making use of the body. Otherwise, thinking and feeling would be identical. Thus, thinking must consist in perceiving without the help of the body (as thought Aristotle). So much the more, the thinking principle cannot be corporeal. Since it is sensation that grasps sense-objects, it must likewise be thought, or intellection, that grasps intelligible objects. Though this should be denied, it will be admitted that we think certain intelligibles entities, and that we perceive entities that have no extension. How could an entity that had extension think one that had no extension? Or a divisible entity, think an indivisible one ? Could this take place by an indivisible part ? In this case, the thinking subject will not be corporeal; for there is no need that the whole subject be in contact with the object; it would suffice if one of its parts reached the object (as Aristotle said against Plato).
If then this truth be granted, that the highest thoughts must have incorporeal objects, the latter can be cognized only by a thinking principle that either is, or becomes independent of body. Even the objection that the object of thought is constituted by the forms inherent in matter, implies that these forces cannot be thought unless, by intelligence, they are separated from matter. It is not by means of the carnal mass of the body, nor generally by matter, that we can effect the abstraction of triangle, circle, line or point. To succeed in this abstraction, the soul must separate from the body, and consequently, the soul cannot be corporeal.
THE BODY CANNOT POSSESS VIRTUE.
Neither do beauty or justice possess extension, I suppose; and their conception must be similar. These things can be cognized or retained only by the indivisible part of the soul. If the latter were corporeal, where indeed could virtues, prudence, justice and courage exist? In this case, virtues (as Critias thought), would be no more than a certain disposition of the spirit, or blood (as Empédocles also thought). For instance, courage and temperance would respectively be no more than a certain irritability, and a fortunate temperament of the spirit; beauty would consist in the agreeable shape of outlines, which cause persons, in whom they occur, to be called elegant and handsome. Under this hypothesis, indeed, the types of spirit might possess vigor and beauty. But what need would it have of temperance ? On the contrary, the spirit would seek to be agreeably affected by the things it touches and embraces, to enjoy a moderate heat, a gentle coolness, and to be in contact only with sweet, tender, and smooth entities. What incentive would the spirit have to apportion rewards to those who had deserved them?.
IF VIRTUE WERE CORPOREAL IT WOULD BE PERISHABLE.
Are the notions of virtue, and other intelligible entities by the soul thought eternal, or does virtue arise and perish ? If so, by what being, and how will it be formed? It is the same problem that remains to be solved. Intelligible entities must therefore be eternal and immutable, like geometrical notions, and consequently cannot be corporeal. Further, the subject in whom they exist must be of a nature similar to theirs, and therefore not be corporeal; for the nature of body is not to remain immutable, but ta be in a perpetual flow.