Abstract
Wedin discusses Aristotle's claims in Metaphysics Zeta 6 that the essence of a thing is to be sought among its per se attributes, and that each thing that is primary and spoken of per se, e.g. primary substance, is the same as its essence. Wedin argues that the Zeta 6 Thesis, i.e. that the essence of a thing is the thing's immediate essence, is a crucial requirement of the explanatory role of essence as the substance of c‐substances. According to Wedin, Aristotle introduces this requirement in order to establish that a thing's essence cannot depend on another essence. Form must be the essence; if form cannot explain the nature of the thing of which it is the form, there would be the threat of a regress of explanatory forms. At the end of the chapter, Wedin considers the problem that the identity of a thing and its essence is a requirement that can be met by non‐substance items, but he denies that this leads to a dilution of the conception of substance.