Does subset realization physicalism entail supervenience physicalism? Well, there is a problem here too having to do with (what is sometimes called) a causal theory of properties, that is, a theory according to which the causal powers or features that a property bestows on the things that have it are exhaustive of the nature of that property. Suppose that a causal theory is false. Then, in principle, one property might subset realize another and yet be quite different from it in nature. And this