ANA GABRIELA VILHENA DE MELLO SANTOS

This work investigates the concept of οὐσία in Aristotle's Metaphysics and Categories, focusing on two central problems. First, it examines how the relationship between ὑποκείμενον (substratum) and τόδε τι reveals a discontinuity in the concept of substance between the two works, contributing to a deeper understanding of Aristotelian ontology. In the Categories, the substratum is essential to substance but does not fully align with the οὐσία ἑκάστου (ousia of X) presented in Book Z of the Metaphysics, creating a significant conceptual tension. The second problem explores the substantiality of substance, aiming to reflect on its ontological stability. In the Categories, substance is primarily identified with concrete particulars. However, in Metaphysics Z, Aristotle introduces matter and form, redefining these particulars as composites, adding complexity to the concept of substance. By comparing passages from both works, this study highlights the conceptual differences and challenges that arise, demonstrating how these analyses deepen the understanding of Aristotelian ontology.