The Anatomy of Primary Substance in Aristotle's Categories

This paper investigates two related aspects of Aristotle’s conception of primary substances in the Categories. In Section 1 I distinguish different interpretations of the relation between a primary substance and its accidental attributes: one (A) according to which a primary substance encompasses all of its attributes, including the accidental ones; another (B) according to which a primary substance encompasses only its essential attributes, whereas the accidental attributes are extrinsic to the substance, though related to it; and a third, intermediate one (C) according to which a primary substance encompasses neither all of its attributes nor only the essential ones, but all the necessary ones. I trace the history of all three interpretations and argue in favour of (B). In Section 2 I defend the view that a particular human being, their soul, and their body all count as primary substances, and that the relation between these three substances is that soul and body are parts of the substance. I show that this hypothesis harmonizes both with some views advanced in the Categories and with some passages from other Aristotelian works. I conclude by drawing a comparison between this view and Aristotle’s mature hylomorphic doctrine.