On the view I have proposed, the correctness of a judgment of political morality depends on the proper functioning of two different components of the human mental apparatus, the motivational disposition to make or seek concessions in cooperative contexts, and the extrapolative dispositions associated with the mastery of a socially provided set of normative and evaluative terms. The ultimate result is a body of cooperative motivation that has a particular, conceptually articulated structure. A properly functioning member of a polity will be able to employ the available terms to make valid claims against other members or against the polity as a whole. The available terms may also include some that identify certain social states of affairs as possessing a value that can sometimes justify the abridgment of claims. The understanding of appropriate concession embodied in a given member's judgments of political morality will constitute her sense of fairness.

In the previous chapter I argued that moral nominalism implies what I called localism. Different normative and evaluative concepts will be available to the members of different polities, with the result that judgments of political morality will differ somewhat from polity to polity. I explained this by noting that the set of available concepts is determined by an evolutionary process, and the histories of this process will be different in different polities. This has the consequence, however, that localism extends to the past.