Supervenience physicalism articulates only a necessary condition for physicalism, not a sufficient one

But the most influential objection to supervenience physicalism (and to modal formulations generally) is what might be called the sufficiency problem. This alleges that, while (1) articulates a necessary condition for physicalism it does not provide a sufficient condition. The underlying rationale is that, intuitively one thing can supervene on another and yet be of a completely different nature. To use Fine’s famous (1994) example, consider the difference between Socrates and his singleton set,