Abstract

This chapter discusses Stage 2 in the Socratic Picture of the order of inquiry, when we seek what a subject-kind is (i.e., its essence). The main focus is _Posterior Analytics_ 2.13. The chapter begins with a discussion of an important but difficult passage in which one can find the main outlines both of the Socratic Picture and of Aristotle’s account of how we acquire _nous_ of first principles (especially the definitions of subject-kinds). The chapter then discusses Aristotle’s account of how we discover by the method of division the causally simple essences of subordinate subject-kinds (i.e., species). These essences are made up of the species’ genus and a number of differentiae. Aristotle’s rules for the selection of differentiae are closely examined. The chapter ends with a discussion of Aristotle’s account of how we discover by induction the causally simple essences of primary subject-kinds (i.e., genera).