Two Kinds of Completeness and the Uses (and Abuses) of Exclusion Principles

I argue that the completeness of physics is composed of two distinct claims. The first is the commonly made claim that, roughly, every physical event is completely causally determined by physical events. The second has rarely, if ever, been explicitly stated in the literature and is the claim that microphysics provides a complete inventory of the fundamental categories that constitute both the causal features and intrinsic nature of all the events that causally affect the physical universe. After showing that these claims are distinct, I argue that they can be used to solve a difficulty with existing responses to the exclusion problem—namely, that these existing responses also undermine the powerful causal argument for physicalism. Recognizing that there are two kinds of completeness opens up room for the nonreductive physicalist to solve the exclusion problem while also endorsing a modified, cogent causal argument for a kind of physicalism compatible with her position.