 In restating his point “yet more perspicuously” (1035b4), Aristotle notes parenthetically another important aspect of his theory of substance. He reiterates the priority of form, and its parts, to the matter into which a compound is divided, and notes that “the soul of animals (for this is substance of the animate) is the substance that is in accord with the account and is the form and the essence” (1035b14–5). The idea recurs in Ζ.11, where he announces that “it is clear too that the soul is primary substance, whereas the body is matter” (1037a5). It is further developed, in the Metaphysics, in Ζ.17, as we will see below, and especially in De Anima. For more detail on this topic, see Section 3 of the entry on  Aristotle’s psychology.