In this paper, I will focus on the role that findings of the empirical sciences might play in justifying normative claims in political philosophy. In the first section, I will describe how political theory has become a discipline divorced from empirical sciences, against a strong current in post-war political philosophy. I then argue that Rawls’s idea of reflective equilibrium, rightly interpreted, leads to a perspective on the matter of justification that takes seriously empirical findings regarding currently held normative beliefs of (...) people. I will finally outline some functions that empirical studies might have in political philosophy. (shrink)