Natural Kind Realism, Taxonomic Pluralism, and Relative Fundamentality

Abstract

I argue that in order to resolve the debate between taxonomic monism and taxonomic pluralism, we should construe the reality of natural kinds in terms of relative fundamentality: a natural kind is real if and only if it is more fundamental than its members, whose reality is taken for granted in the context of this debate. Taxonomic monism upholds that there is only one correct way of classifying entities into natural kinds within a given scientific domain; taxonomic pluralism maintains that there are different but equally correct ways of classifying entities into natural kinds within a given scientific domain, and these different ways disagree with each other. The monism/pluralism debate has reached a stalemate, as the two positions conceive the reality of natural kinds in different ways. While taxonomic monists characterize the distinction between natural and non-natural kinds in metaphysical terms, taxonomic pluralists approach this distinction in epistemic, viz., naturalist, terms. According to this approach, natural kinds are groupings that underwrite successful epistemic practices in the sciences, such as explanation and induction. As I argue in this dissertation, however, this naturalist approach alone does not secure taxonomic pluralism. First, it fails to provide the requisite realist commitment desired by taxonomic pluralists; second, it fails to ensure that the different ways of classifying entities in a given domain into natural kinds genuinely disagree with each other, as proclaimed by pluralists. In the face of these two problems, I argue that taxonomic pluralists should give up their anti-metaphysical stance and formulate the reality of natural kinds in terms of relative fundamentality. This formulation reorients the monism/pluralism debate so that different classifications of entities into natural kinds can be ranked by their degree of relative fundamentality, according to which membership in a kind posited by a more fundamental classification would account for membership in a kind posited by a less fundamental classification.