 Inasmuch as the moral point of view is no different from the point of view that seeks our own happiness, Aquinas shares with ancient ethics the conviction that rational self-interest provides an adequate foundation for morality (Irwin 2007: ch. 19). But the weight Aquinas puts on our innate inclinations in shaping the moral law gives his account a distinctive character. Among its champions, this approach has been celebrated for the way it grounds traditional values in facts about human nature. To its critics, the view looks intellectually dubious twice over: on scientific grounds inasmuch as it makes false claims about the universality of various inclinations (Massey 1999); and philosophically inasmuch as it grounds  normativity in metaethics  on descriptive facts about human nature. Such criticisms, however, miss the philosophical sophistication of the overarching framework. To be sure, we now understand the diversity of human inclinations—for instance, regarding gender and sexuality—much better than we did even a century ago. Aquinas’s theory can survive when we update these assumptions, and indeed may generate surprisingly modern results (Oliva 2015). As for the complaint that the theory conflates normativity with nature, that would have real force only supposing that we had some better account of the basis of normative value. As things are, if there is a God, then it seems plausible to suppose that God would want us to be happy and would create our natures to guide us in seeking such happiness. On the other hand, if there is no God, then it is not clear what foundation for ethics there might be other than facts about the nature of human beings and how we best thrive in the world we live in. (The literature on the natural law in Aquinas is large and contentious. For a sample see Grisez 1965; Lisska 1996; Murphy 2001; Jensen 2015; Porter 2018. For an introduction to the variety of recent perspectives see Angier 2021. For a sense of the complexity of the contested issues see  Aquinas’ moral, political, and legal philosophy.)