Abstract

This article is an introduction to the Synthese Special Issue, Natural Kinds: Language, Science, and Metaphysics. The issue includes new contributions to some of the main questions involved in the present philosophical debates on natural kinds and on natural kind terms. Those debates are relevant to philosophy of language, philosophy of science, and metaphysics. In philosophy of language it is highly debated what the meaning of natural kind terms is, how their reference is determined, as well as whether there are differences and similarities between the semantics of natural kind terms and that of other sorts of kind terms. In philosophy of science, natural kinds are relevant because they are the basis for scientific classifications and play an explanatory role in scientific theories; thus one aim of science is to discover natural kinds and theorize about them. Natural kinds are also relevant in metaphysics, where many questions involving natural kinds are debated and especially those concerning the sort of entities we refer to when using natural kind terms, i.e., the ontological status of natural kinds; in this regard there are different views, such as conventionalism, realism and essentialism. Another metaphysical question is what it is that characterizes the naturalness of kind divisions. The introduction sketches the antecedents of some of the present views on natural kinds and natural kind terms, and indicates some of the topics dealt with in the articles that make up the issue, which can be classified in the following groups: the metaphysics and epistemology of natural kinds the semantics of natural kind terms and other kind terms questions on species and other related issues on natural kinds. However, many of the articles cover more than just one of these topics.