On the nature of certain philosophical entities: Set theoretic constructionalism in the metaphysics of David Lewis

Viewed from a suitable distance, David Lewis’s ontological scheme is simplicity itself. Absolutely everything that exists, according to Lewis, is either a spatiotemporal particular, or a set theoretic construction from such particulars, or a mereological aggregate of such items. Set theoretic constructionalism is not an incidental feature of Lewis’s system. The master argument of On the Plurality of Worlds is that a pluriverse composed of infinitely many concrete universes constitutes a “paradise for philosophers. Given his other views, his account of classes has profound implications for general metaphysics, implying as it does an account of the nature of properties and instantiation, propositions and propositional truth, the nature of events, and so on. But Lewis does not consider those implications. The aim of this chapter is to close the circle by bringing Lewis’s mature account of sets into contact with his larger ontological scheme.