Abstract

This chapter begins with a putative puzzle between non-reductive physicalism according to which psychological properties are distinct from, yet metaphysically necessitated by, physical properties, and Hume's dictum according to which there are no necessary connections between distinct existences. However, the puzzle dissolves once care is taken to distinguish between distinct kinds of distinction: numerical distinctness, mereological distinctness, and what the chapter calls ‘weak modal distinctness’ and ‘strong modal distinctness’. For each of these notions, it turns out that either it makes no sense according to non-reductive physicalism or else it is unclear whether Hume's dictum is true. The chapter then deploys these distinctions to argue first that unlike the dualist, the non-reductive physicalist can reject the exclusion principle in the causal exclusion argument, and second that emergentism can be distinguished from non-reductive physicalism.