The Theory of Predication in Aquinas: Inherence or Identity?

The paper deals with Thomas Aquinas’s (1225–1274) theory of predication. Aquinas’s numerous works contain passages devoted to the issue of how predication works, usually in various theological or philosophical contexts. Assuming Aquinas’s account of predication was sufficiently uniform in relation to essential and accidental predications, there are several distinct interpretative models of predication possible in relation to the texts. They differ in ascribing different semantic roles to the copula. The first model sees the copula as expressing inherence of a form expressed by the predicate term in the entity denoted by the subject term. The second model interprets the copula as designating identity. The third model incorporates inherence with the fact that Aquinas combines predicative and existential functions of the copula. I argue that the identity model is closest to what Aquinas has in mind when speaking about predication as opposed to extensional truth conditions.