"Rational Animal" in Heidegger and Aquinas

Martin Heidegger rejects the traditional definition of the human being as the “rational animal” in part because he thinks it fits us into a genus that obscures our difference in kind. Thomas Aquinas shares with Heidegger the concern about the human difference, and yet he appropriates the definition, “rational animal” by conceiving animality in terms of the specifically human power of understanding being. Humans are not just distinct in their openness to being, but, thanks to that openness, they are distinct in their animality, a distinction that changes the very significance of animality itself. Heidegger also thinks the traditional definition closes us to the experience of our essence, but again Aquinas has resources for bringing out the experiential character of rational animality. Aquinas’ inclusion of animation has significance for what Heidegger calls fundamental ontology; by virtue of the human animate body, particular beings can be pointed out and designated as such.