Natural Categories and Human Kinds: Classification in the Natural and Social Sciences, by Muhammad Ali Khalidi

Abstract

I have some sympathy with Ian Hacking’s recent view that the topic of natural kinds is one that has outlived its usefulness (Ian Hacking, ‘Natural Kinds: Rosy Dawn, Scholastic Twilight’, Royal Institute of Philosophy Supplement, 61 (2007), pp. 203–39), but Natural Categories and Human Kinds (hereafter NCHK ) makes a convincing case to the contrary. According to Hacking, the topic of natural kinds now comprises a great diversity of solutions to an equal diversity of problems, and the concept is a source of little more than confusion. NCHK , however, offers a comprehensive account of natural kinds and their role in science that ties together at least a good selection of the issues that Hacking distinguishes. Khalidi’s general thesis is that the members of a natural kind are the entities that occupy a node in the causal structures of nature. ‘Natural Kinds divide the world into individuals that share causal properties, enter into the same causal or similar causal relationships, and give rise to the same or similar causal processes’ (p. 222). Because of this central role of causality in the account, natural kinds indicate the properties of things that are projectable, sensu Nelson Goodman, and thus enable us to pursue the traditional scientific goals of prediction, explanation, and control.