The argument we have presented above presupposes that Sally and Sally* and Bill and Bill* are numerically distinct but qualitatively indiscernible pairs of objects. Although many find this to be a genuine possibility, thanks in large part to Max Black (1952) and Robert Adams (1979), there is a long tradition that subscribes to the Identity of Indiscernibles (PII), according to which, for any objects x and y, if, for every quality F, x is F if and only if y is F (i.e., if x and y are qualitativel