Abstract

In this paper, I investigate how different views about the vertical and horizontal structure of reality affect the debate between reductive and nonreductive physicalism. This debate is commonly assumed to hinge on whether there are high-level, special-science properties that are distinct from low-level physical properties and whether the alleged multiple realizability of high-level properties establishes this. I defend a metaphysical interpretation of nonreductive physicalismin the absence of both of these assumptions. Adopting an independently motivated, discipline-relative account of natural properties and appealing to a phenomenon I call “multiple determinativity,” in which a single physical property simultaneously realizes different kinds of special-science properties, is sufficient to show that some special-science properties are irreducible to physical properties and that nonreductive physicalism is not merely a terminological variant of reductive physicalism.