ABSTRACT
Morality is often said to be relative or, even more seriously, incommensurable in a number of respects. First, it is said to be relative in the sense that it differs from culture to culture, meaning that something which may be a moral wrong in one cultural may not be in another. Second, it is said to be incommensurable in the sense that within any single moral system, the values identified by that system cannot be translated into one another or otherwise assessed according to some single, universal moral value. In this chapter, I argue that things are actually more complicated than this. Personal morality, which is often assumed to be culturally relative, is actually not, or not to any significant extent. Within any system of personal morality, however, the values identified in that system are incommensurable, and must be, for morality as we know it to exist. But political morality is different. Political morality is not merely relative in the way that personal morality may be, it is incommensurable, and not only at the applied level, but at the most fundamental level as well. There are two great families of political theories, and they begin with such different fundamental presuppositions that reasoned argument between members of one family and the other turns out to be impossible.
