Compared to other philosophies of special sciences, the scope, object, and definition of the philosophy of political science remain vague. This article traces this vagueness to the changing subject matter of political science throughout its history, but argues that all social sciences are subject to radical changes in what count as their defining characteristics. Accordingly, the only legitimate definition of “philosophy of political science” is “the philosophical study of whatever happens to conventionally fall within the scope of political science at (...) a given moment.” Moving from this assumption, this article makes the case for a unified philosophy of social science. (shrink)