 Supervenience claims, by themselves, do nothing more than state that certain patterns of property (or fact) variation hold. They are silent about why those patterns hold, and about the precise nature of the dependency involved (see Kim 1993, 167; 1998, 9–15; Blackburn 1984, 186; Schiffer 1987, 153–154; and McGinn 1993, 57). But few supervenience theses are plausibly brute, that is, unexplainable. It is natural to look further, and to try to explain why A-properties supervene on B-properties. When such supervenience is explainable, there is ‘superdupervenience’ (a term coined by William Lycan; see also Schiffer 1987; Horgan 1993; and Wilson 1999).