 Aristotle makes both claims in very different theoretical contexts, on the one hand, in his zoological writings and, on the other, in his ethical and political works. This fact, together with the fact that Aristotle’s philosophy of nature and his practical philosophy are united by a teleological metaphysics, may make it appear obvious that the slogans are biological claims that provide a foundation for normative claims in ethics and politics. The slogans do indeed function as foundations in the Politics and the Nicomachean Ethics respectively (on the latter, see  section 5  of this entry). It is, however, unclear whether they are to be understood as biological claims. Let us focus on the slogan that has traditionally dominated discussions of human nature in Western philosophy, that humans are “rational animals”.