The contemporary methodological debate about justice has centered around a dispute about the value of so-called ideal theory. I argue that justice performs a social-guiding function, which explains how people should respond to their limited and fallible abilities to realize justice institutionally. My argument helps to re-orientate the contemporary methodological debate. The obvious disagreement between many prominent supporters and skeptics of ideal theory obscures the fact that they are united by a false assumption: the practical value of justice exclusively consists (...) of its institution-guiding function. To capture the overlooked social-guiding function, a richer normative theory of justice is required; I show how such a theory can be supplied by “ideal-transitional” principles. (shrink)