Aquinas and Kripke on the Genealogy of Essential Properties

The aim of this article is to reassess the similarity between Kripke’s metaphysics and Aquinas’ thought on truth, a similarity affirmed in Schultz-Aldrich’s Heythrop Journal article from 20091 and denied by Klima and Kerr in their analysis of Kripkean and Thomist accounts of essence.2 My claim is that this similarity has been insufficiently understood and its misunderstanding has closed off ways by means of which Aquinas’ thought can provide Kripkean epistemology with a component that it lacks. Despite the significance of Kripke’s thought to analytic metaphysics and growing work in so-called ‘Analytical Thomism,’3 only a few thinkers have attempted to examine Aquinas’ thought in relation to that of Kripke’s. While some scholars have argued for a constructive application of Kripkean notions to Thomistic and/or Aristotelian metaphysics,4 the predominant scholarly view has concluded that Kripke’s and Aquinas’s metaphysical frameworks, especially with regards to grounding essentialism in possible-world semantics, are deeply incompatible and that all methodological similarities between them result purely from a superficial interpretation. Notwithstanding the risk of a superficial reading, there are prima facie two reasons why these similarities are worth investigating. The first is that Kripke’s Naming and Necessity (1970)5 and its subsequent elaboration in his recently-published John Locke Lectures from 1973,6 can in broad terms be read as attempting to close the methodological gap between metaphysics, epistemology and language, a gap opened by developments in early 20th-century analytic philosophy, and inconceivable for Aquinas in the first place. Secondly, Kripke is by many considered to have ushered into analytic philosophy an unprecedented revival of Aristotelian essentialism. Since essentialism lies at the core of Aquinas’ thought on truth, it is not surprising that the idea of potential comparisons between the two systems arose as early as eight years after the publication of Naming and Necessity.7 Pursuing this line of inquiry, Schultz-Aldrich has briefly suggested that Aquinas’ relation between the truth of things and the truths of the intellect is structurally equivalent to Kripke’s epistemological and metaphysical apparatus from Naming and Necessity.8 This article aims to pick up where Schultz-Aldrich left off. I argue that the vast majority of objections against a fusion of Thomist and Kripkean frameworks in the recent treatments, while based on a careful reading of Aquinas, receive their force from a lack of appreciation of a very specific account of possible worlds in Kripke; although these critiques provide accurate accounts of ‘essence’ in the context of Aquinas’s metaphysics, they fail to do so in the context of Kripke’s epistemology. From the outset, this project requires three preliminary clarifications: