  Yet conventionalist views such as Glaucon's have real difficulties fitting with the common idea that the fundamental principles of morality are universal. Conventions, after all, are contingent creations that differ from place to place and come in to, and go out of, existence. Moreover, conventions seem liable to arbitrariness in ways that threaten to undermine their claim to authority unless they are recognized (at least implicitly) as satisfying some convention-independent standard. That some convention demands something seems to provide reason to conform to the demand only when the convention is, itself, just or reasonable, or in some other way good. And this suggests that, to whatever extent specific moral rules and principles are products of convention, their claim to authority relies on some standards that are not products of convention. 