Philospher Ed Feser showed that Black or White racism is anti-Thomist and anti-Catholic: Those features that are essential to a thing comprise what Aristotelians call its substantial form – the form that makes a thing the kind of substance or thing that it is, its essence. Being round is part of the substantial form or essence of a ball; being blue is not. Being a rational animal is (according to Aristotelians) the essence or substantial form of a human being; having black or white skin is not part of this essence; since someone can be a rational animal , and thus a human being, whatever his skin color. As with actualities, forms come in a kind of hierarchy. There is the substantial form or essence of a thing (e.g. being a rational animal in the case of human beings); there are various properties of a thing that are not part of its essence per se but which necessarily flow from its essence (e.g. having the capacity for humor, which follows from being a rational animal)...