1. To what part of our nature do pleasure and grief, fear and boldness desire and aversion, and, last, pain, belong? Is it to the soul (herself),[271] or to the soul when she uses the body as an instrument,[272] or to some third (combination) of both? Even the latter might be conceived of in a double sense: it might be either the simple mixture of the soul and the body,[273] or some different product resulting therefrom.[274] The same uncertainty obtains about the products of the above mentioned experiences: namely, passions,[275] actions, and opinions. For example, we may ask whether ratiocination[276] and opinion both, belong to the same principle as the passions; or whether only one of them does; in which case the other would belong to some other principle. We should also inquire concerning the nature and classification of thought.[277] Last we should study the principle that undertakes this inquiry and which comes to some conclusion about it. But, first of all, who is the agent, who feels? This is the real starting point: for even passions are modes of feeling, or at least they do not exist without it.[278] THE SOUL AS A COMPOSITE AGGREGATE. 2. Let us first examine the soul (herself). Is there any difference between the soul and the soul-essence? If there be a difference, the soul must be a composite aggregate: and it should no longer be a matter of surprise that both she and her essence, at least so far as she admits thereof, together experience the above mentioned passions, and in general the habits, and better or worse dispositions. But, on the contrary, if, soul and soul-essence be identical, then the soul should be a form which would be unreceptive for all these energies of essence, which on the contrary she imparts to other things, possessing in herself a connate energy which our reason reveals in her. In this case we must acknowledge that she is immortal, inasmuch as the immortal and undecaying must be impassible, giving to others without receiving anything in return from them; or at least, deriving nothing but from the superior (or anterior) principles, from which she is not cut off, inasmuch as they are better. THE SOUL IS NOT ESSENCE.