CHAPTER IV

             It is necessary for the student of these [parts of the soul] to discover what is the nature of each, and only then to investigate habits and other matters.§ 303

             But if one is to say what each of them is (namely the intellectual power or the sensitive or the vegetative) one must first say what it is to understand or perceive by sense; for actions and operations are prior to faculties in the order of thought. And if this is so, one ought first to consider the appropriate objects; which are prior even to the operations, and correspond to them; and thus to determine, in the first place, what these objects are--for instance, food and the sense-object and the intelligible.§§ 304-8