 A second response to the challenge from evolutionary biology aims to draw metaphysical consequences from epistemic or semantic claims. Michael Thompson has argued that what he calls alternatively “the human life form” and “the human species” is an a priori category. Thompson substantiates this claim by examining forms of discourse touched on in  section 3.2,  forms of discourse that are generally taken to be of mere heuristic importance for amateur practices of identification, viz. field guides or animal documentaries. Statements such as “The domestic cat has four legs, two eyes, two ears and guts in its belly”, are, Thompson claims, instances of an important kind of predication that is neither tensed nor quantifiable. He calls these “natural historical descriptions” or “Aristotelian categoricals” (Thompson 2008: 64ff.). Such generic claims are not, he argues, made false where what is predicated is less than universal, or even statistically rare. Decisively, according to Thompson, our access to the notion of the human life form is non-empirical. It is, he claims, a presupposition of understanding ourselves from the first-person perspective as breathing, eating or feeling pain (Thompson 2004: 66ff.). Thus understood, the concept is independent of biology and therefore, if coherent, immune to problems raised by the Darwinian challenge.