The dominant way to define physical entities is by appeal to ideal physics (as opposed to current physics). However, it has been worried that physicalism understood in terms of ideal physics would be too liberal to rule out “psychism”, the view that mentality exists at the fundamental metaphysical level. In this article, I argue that whereas physicalism is incompatible with some psychist cases, such as the case of “phenomenalism” in which ideal physics adopts mental concepts to denote fundamental entities, physicalism (...) should accommodate a certain type of psychist case in which fundamental mental entities are denoted by non-mental concepts in ideal physics. In so doing, I propose a distinctive account of physical entities, which asserts that physical entities are entities denoted by non-mental natural concepts in ideal physics. Physicalism thus understood is expected to be neither too liberal nor too demanding. (shrink)