 Kant’s political philosophy is a branch of practical philosophy, one-half of one of the broadest divisions in Kant’s thought between practical and theoretical philosophy. Political philosophy is also to be distinguished within practical philosophy from both empirically-based elements and from virtue proper. The separation from virtue is treated later in this section. Regarding the empirical elements, it is worth mentioning that practical philosophy, as a set of rules governing free behavior of rational beings, covers all human action in both its pure and applied (empirical, or “impure”) aspects. Pure practical philosophy, the rational elements of practical philosophy in abstraction from anything empirical, is called by Kant “metaphysics of morals” (4:388). Kant so emphasized the priority of the pure aspect of political philosophy that he wrote part of his essay “On the Common Saying: That May be Correct in Theory, but it is of No Use in Practice” in opposition to the view he associates with Hobbes that the politician need not be concerned with abstract right but only with pragmatic governance (8:289–306). Yet Kant also included the more pragmatic, impure, empirical study of human behavior as part of practical philosophy. For ethics in general, Kant called the empirical study of human beings as agents within particular cultures and with particular natural capacities “anthropology”. Some of Kant’s social philosophy fits into this rubric (see section 10). While Kant always based his claims about right on a priori principle, he was applying the a priori principles to actually existing beings, so he did at times include empirical claims in his analysis. Some of these empirical claims are quite general and uncontroversial (e.g. that there are a plurality of human beings living on the limited surface of a sphere) while others are more specific to Kant’s own time, place, and individual biases (e.g. his views on women).