Non-reductive physicalists hold that mental properties are realized by physical properties. The realization relation is typically taken to be a metaphysical necessitation relation. Here, I explore how the metaphysical necessitation feature of realization can be explained by what is known as ‘the subset view’ of realization. The subset view holds that the causal powers that are associated with a realized property are a proper subset of the causal powers that are associated with the realizer property. I argue that the said (...) explanation of the metaphysical necessitation feature requires a careful treatment of the relationship between properties and causal powers. (shrink)

According to the subset view of realization, a property realizes another if the causal powers of the latter are a subset of those of the former. Against this view, some authors (in particular, Kevin Morris and Paul Audi) have argued that it has an untenable consequence that realizing properties are less fundamental than the properties they realize, because the subset view characterizes realized properties as parts (subsets) of their realizers whereas it is generally true that a part is prior to (...) its whole. This paper defends the subset view from this “part-whole” objection, by arguing that if we compare individual powers of realizer and realizee with particular attention to their manifestation conditions, it turns out that each power of a realizee is grounded in some power of its realizer. This grounding relation between powers, I shall argue, allows subset theorists to explain why a realizer is more fundamental than its realizee, even while having the latter as a part. (shrink)