 Anstey (2000: 52) maintains that qualities have a reductive structure: MAs are not powers and qualities, which are powers, are reduced to their respective MAs. The quality is, then, explained by its constituents: the congruent mechanical affections of a pair of bodies explain what happens when one is duly applied to the other in terms that are intelligible and familiar from our understanding of machines. Boyle repeatedly claims that in the bodies that constitute qualities, there is nothing distinct from their MAs, but often remarks that qualities derive from or depend upon the MAs of bodies. Anstey is one of several scholars who find a tension between these two claims. The worry is that “nothing distinct from” expresses ontological reduction; that the dependence in view is asymmetric; and a thing cannot have an asymmetric relation to itself.