 Supervenience gives us less than some philosophers have thought. Even logically or metaphysically necessary supervenience is compatible with there being no B-properties that entail any A-properties. Supervenience is not itself explanatory, and does not guarantee that the A-properties either reduce to, ontologically depend upon, or are grounded by the B-properties. It might provide a way to capture the thought that A-properties or facts are not a further ontological commitment over and above the B-properties or facts, but this is controversial. At heart, all a supervenience claim says is that A-properties covary with B-properties. Nevertheless, as we shall see in  Section 5,  supervenience has a variety of philosophical uses.