Abstract

This chapter considers various views about the precise nature of possible worlds, but each view is compatible with this initial characterization. It considers modality, particularly focusing on metaphysical possibility, necessity, and impossibility, that broadest kind of modality. The chapter offers an example of why one might care about this issue, an example of why the study of modality matters to philosophy more generally. It is plausible that modality is importantly connected to understanding. The chapter focuses on two contrasting views about the nature of possible worlds, Concretism and Abstractionism. The fundamental difference between Concretism and Abstractionism is whether possible worlds are concrete or abstract. Concretism is the view that possible worlds are like parallel universes. Concretism requires Modal Indexicalism and denies Modal Anti‐Indexicalism. The chapter describes the ways that the Concretism carries out its reduction of possibility and actuality.