Scientific Realism and Ontological Relativity

Abstract

The preeminent question of the metaphysics of classification is that of whether the world is itself naturally subdivided into kinds of things. Are kinds out there, so to speak, or are they rather artefacts of convention, existing only insofar as classificatory practices are brought to bear by creatures such as ourselves? In this paper, I examine this question from the point of view of the sciences, and more specifically, from the perspec tive of the most fulsome view of the epistemic credentials of the sciences regarding what's 'out there': scientific realism. As I hope to show, ap proaching the metaphysics of classification from the perspective of scientific realism has important consequences for one's very understanding of the perspective itself. Thus, by considering the nature of kinds from this per spective, I aim to shed light not only on the metaphysics of classification, but also on the nature of realism with respect to scientific knowledge. Scientific realism (simply 'realism', henceforth, unless otherwise indicated) is the view that our best scientific theories are true, or approx imately true, or to put it in terms other than truth, that they describe well, or to some significant degree of success, the ontology of parts of the world. There are explicit caveats built into this coarse definition ('best' theories, 'approximate' truth, 'significant degrees' of success), and I will make no attempt to expound these particular qualifications here. A further clarification of the definition, however, furnishes a central motivation for what follows. Realism is often explicated in terms of three sorts of com mitment: a metaphysical commitment to the existence of a mind-inde pendent reality; a semantic commitment to interpret scientific claims literally (or as it is often put, at face value); and an epistemological commitment to regard these claims as furnishing knowledge of both ob servable and unobservable entities and processes. After the demise of