Role of Essence in Substance: A Philosophical Interpretation of Aristotle’s Metaphysics

Abstract

This article argues that essence is the intelligible principle that defines a substance as the kind of thing it is. It examines the philosophical role of essence in Aristotle’s theory of substance, focusing on Books Zeta, Eta, and Theta of the Metaphysics. Aristotle’s inquiry into substance is closely connected to his analysis of to ti ēn einai, or “essence” and “what-it-is-to-be.” The article maintains that Aristotle’s account of essence operates at the intersection of ontology, definition, form, actuality, causation, and individuation. Although Aristotle considers several candidates for substance—including underlying subject, matter, composite, form, essence, universal, and genus—he ultimately prioritizes form and essence, as they explain a substance’s identity, intelligibility, unity, and actuality. Essence is not simply a conceptual description; it expresses what a thing is in itself and serves as the explanatory principle of its being. The relationship between essence and substance remains philosophically complex. Aristotle does not equate essence with an abstract universal, nor does he reduce substance to matter or a collection of accidental properties. Instead, essence is linked to substantial form and to the actuality that gives matter determinate being. The article thoroughly analyses Aristotle’s theory through the work of contemporary scholars, including David Charles, Frank A. Lewis, Kathrin Koslicki, Michael Loux, and Charlotte Witt. It argues that the Aristotelian concept of essence should be understood as a dynamic ontological principle that addresses not only “What properties does a thing possess?” but also “What makes this thing the kind of being that it is?” The article concludes that essence plays a constitutive and interpretive role in substance. It provides intelligible identity, grounds definition, explains unity, determines characteristic activities, and distinguishes essential being from accidental predication. Aristotle’s metaphysics thus presents substance as an intelligible unity whose essence expresses its fundamental mode of being.