Abstract

Metaphysics Θ treats potentiality (δύναμις) and actuality (ἐνέργεια), and many scholars think that Aristotle broaches these topics once he has answered his main questions in Ζ and Η. In Ζ he asked, what is primary being? After arguing in Ζ.1 that substance (οὐσία) is primary being—a being existentially, logically, and epistemologically prior to quantities and qualities and other categorial beings—he devotes the rest of the book to οὐσία itself, investigating what it is, to decide what entities count as primary substances. I differ from the leading interpretative consensus that ΖΗ adequately answer the questions about primary substance, and contend instead that Metaphysics Θ continues the same investigation as ΖΗ and, using δύναμις and ἐνέργεια as tools, arrives at a striking new conception of hylomorphism, different from that in ΖΗ, which enables Aristotle to defend the substantial primacy of living organisms consisting of matter and form.