Supervenience does not fare better, though for different reasons: It seems to be too weak a notion to capture the idea that guided reduction-talk, although it surely is a necessary condition for reduction. In a sense, if mental states merely supervene on physiological states, they exist in a straightforward sense over and above the latter. Such supervenient states are dependent; but being dependent is not enough for reduction (Kim 1998). Note that this is, up to a certain point, a matter of stip