As the nature of the body is composite, reason convinces us that it cannot last perpetually, and our senses show it to us dissolved, destroyed, and decayed, because the elements that compose it return to join the elements of the same nature, altering, destroying them and each other, especially when this chaos is abandoned to the soul, which alone keeps her parts combined. Even if a body were taken alone, it would not be a unity; it may be analyzed into form and matter, principles that are necessary to the constitution of all bodies, even of those that are simple.[32] Besides, as they contain extension, the bodies can be cut, divided into infinitely small parts, and thus perish.[33] Therefore if our body is a part of ourselves,[34] not all of us is immortal; if the body is only the instrument of the soul, as the body is given to the soul only for a definite period, it still is by nature perishable. THE SOUL IS THE INDIVIDUALITY, AS ITS FORM, AND AS A SKILLED WORKMAN. The soul, which is the principal part of man, and which constitutes man himself,[35] should bear to the body the relation of form to matter, or of a workman to his tool;[36] in both cases the soul is the man himself. IF THE SOUL IS INCORPOREAL, WE MUST STUDY INCORPOREALITY. 2. What then is the nature of the soul? If she is a body, she can be decomposed, as every body is a composite. If, on the contrary, she is not a body, if hers is a different nature, the latter must be examined; either in the same way that we have examined the body, or in some other way. A.--THE SOUL IS NOT CORPOREAL (AS THE STOICS THOUGHT). (a.) (Neither a material molecule, nor a material aggregation of material atoms could possess life and intelligence.) First, let us consider the nature of this alleged soul-body. As every soul necessarily possesses life, and as the body, considered as being the soul, must obtain at least two molecules, if not more (there are three possibilities): either only one of them possesses life, or all of them possess it, or none of them. If one molecule alone possesses life, it alone will be the soul. Of what nature will be that molecule supposed to possess life by itself? Will it be water (Hippo), air (Anaximenes, Archelaus, and Diogenes), earth, or fire (Heraclitus, Stobaeus?[37]) But those are elements that are inanimate by themselves, and which, even when they are animated, possess but a borrowed life. Still there is no other kind of body. Even those (philosophers, like the Pythagoreans) who posited elements other (than water, air, earth and fire) still considered them to be bodies, and not souls, not even attributing souls to them. The theory that life results from the union of molecules of which, nevertheless, none by itself possesses life, is an absurd hypothesis. If further any molecule possesses life, then a single one would be sufficient. NEITHER MIXTURE NOR ITS PRINCIPLE WILL EXPLAIN LIFE AS A BODY.