Aristotle on Substance and Predication: A Mediaeval View

Abstract

In the "posterior analytics" aristotle distinguishes four ways in which something can be "in itself" (kath' auto). the third way was characterized by some mediaeval commentators as a "modus essendi", rather than a "modus praedicandi". this distinction has an analogue in contemporary discussions of aristotle's theory of predication. what is the connection between primary substances, which are kath' auto or exist "in themselves" and kath' auto predications? some contemporary commentators hold that, for aristotle, all valid predications are made concerning primary substances or reducible to those concerning primary substances. this involves a "category mistake" which the mediaeval commentators did not make, giving them more satisfactory reading of aristotle's theory of predication.