Essence and Natural Kinds

Abstract

The work of Kripke and Putnam motivated the thesis that some propositions are a posteriori and yet metaphysically necessary. Among these propositions are the so-called theoretical identifications, which are taken to express the essences of natural kinds, thereby laying the foundation of Natural Kind Essentialism. This dissertation examines one of the main criticisms of that thesis: the suspicion that theoretical identifications are metaphysically contingent, a concern sometimes referred to as “the intuition of contingency.” I interpret this intuition by means of a Neo-Aristotelian perspective on essence and metaphysical modality, where notions such as metaphysical necessity, possibility, contingency, and impossibility acquire a distinctive meaning. I argue that, when adopting this perspective, the intuition of contingency poses a serious threat to the metaphysical necessity of theoretical identifications and, consequently, to Natural Kind Essentialism—a challenge that the standard strategies for addressing the intuition fail to overcome. I maintain that a successful response to this threat demands endorsing a view according to which the natural kind at issue is distinct from its associated properties. On this basis, I challenge a prevalent approach for justifying theoretical identifications, which I call Explanatory Essentialism: the thesis that a property is essential to a kind because it explains the various properties associated with that kind. I show that this approach lacks the theoretical resources to counter the intuition of contingency, since it relies on a view on which natural kinds are identified with their associated properties. On these grounds, I advance a proposal concerning the relation between Natural Kind Essentialism and the ontology of natural kinds: the former is at odds with the widespread ontological view that natural kinds are collections of natural properties and requires a perspective according to which kinds and properties are distinct.

Date of Award	4 Feb 2025
Original language	English
Awarding Institution	University of Bristol
Supervisor	Tuomas Tahko (Supervisor) & Samir Okasha (Supervisor)