How should the “physical” in “physicalism” be understood? I here set out systematic criteria of adequacy, propose an account, and show how the account meets those criteria. The criteria of adequacy focus on the idea of rational management: to vindicate philosophical practice, the account must make it plausible that we can assess various questions about physicalism. The account on offer is dubbed the “Ideal Naturalist Physics” account, according to which the physical is that which appears in an ideal theory that (...) both meets the explanatory goals of physics and is naturalist in a sense to be explained. The combination of these two provides a satisfying account of the physical that meets the criteria of adequacy and can be used to predict puzzle cases as well. (shrink)