 In any case, regardless of how the categories were derived, Aristotle’s approach to categories is generally taken to be in the spirit of what Brian Carr calls “categorial realism” – an approach conceiving of a system of categories as a list of the highest genera of beings (not merely of language or thought – even if those may be used in deriving the metaphysical categories). As Studtmann (2007) puts it, Aristotle “ assumes rather than defends a posture of realism with respect to the metaphysical structures of the world”. Given this approach, a complete system of categories would offer a systematic inventory of what there is, considered at the most abstract level (although it is not clear whether Aristotle intended his categories to be exhaustive). Thus on a categorial realist approach, providing a system of categories can be seen as one, or even the central task of metaphysics (cf. Grossman 1983, 3). Such a system of categories may also play a central role in answering individual questions of nature, providing the most general sort of answer to questions of the form “What is this?”, and providing the basis for definitions of narrower sorts of things by specifying the most general category (genus) under which things of this sort fall, and the differentia that distinguishes them from other things of the same category. This has endured as the paradigmatic approach to categories, and several recent authors have offered new theories of categories in this spirit of Aristotelian realism (see §1.4 below).