 That reformulated focus requires a much stronger defense than does Baysan’s existential hypothesis interpretation of their identity theory. By it Polger and Shapiro are committed to arguing that identity theory provides “the best overall model” of psychology’s relationship to neuroscience. (Whether they succeed in making this argument is a separate issue.) And as far as a need to discuss metaphysical possibilities, and hence multiple realizability in the sense that some philosophers understand it, that depends on who one takes one’s audience to be. If one is concerned strictly about multiple realization as a part of the philosophy of the special sciences—as some discussants of multiple realization are—metaphysical possibilities and realizations of the mental in “metaphysically possible worlds” can strike one as philosophical jibber-jabber, the kind of discussions that give philosophy a bad name within broader twenty-first-century intellectual contexts. Curiously, however, Polger and Shapiro seem not to want to take that extreme a position. They locate their work squarely in the metaphysics of science, not strictly in philosophy of science or metascience. Does that leave them open to the charge of needing to consider at least some metaphysical possibilities, and so some kinds of multiple realizability? We will turn to this problem later in this section, in light of Polger and Shapiro’s replies to other criticisms.