Natural Kinds

by

Alexander Bird

• LAST REVIEWED: 01 December 2022
• LAST MODIFIED: 27 October 2016
• DOI: 10.1093/obo/9780195396577-0322

Introduction

It appears to us that things in the natural world divide into different kinds. The most obvious examples come from biology. Cats are clearly distinct from mice; while both kinds show variation, all the cats are more similar to one another than they are to any mouse. We see different kinds of tree and different kinds of lichen. These are kinds that are apparent to any reasonably careful observer. Other kinds seem to be revealed by science. The chemical revolution gave us new ideas about what it is to be a chemical element, and in the subsequent decades many dozens of these different basic chemical kinds were revealed. The following century uncovered a multiplicity of different kinds of fundamental physical particle. While at a different set of scales, geologists distinguish different kinds of rock, meteorologists distinguish different kinds of weather system, and astronomers distinguish different kinds of galaxy. The philosophical questions that natural kinds generate can themselves be categorized into three types as they relate to metaphysics, philosophy of language, and philosophy of science. (It should be noted nonetheless that discussion of these questions quite rightly overlaps these fields. Consequently, works listed in this article may be relevant to further sections in addition to the ones they are listed under.) Here are examples of the philosophical questions surrounding natural kinds. Does the world itself genuinely have a structure of objective natural kinds, so that there are natural divisions of things by kinds? And do our actual natural classifications match those kinds? Or are what we take to be kinds merely the product of a particular non-objective perspective? How does a natural kind (or belonging to a natural kind) differ from other natural properties? In virtue of what do things group themselves into kinds? How is kind membership determined—for example, by necessary and sufficient conditions or by something else? Do, indeed, natural kinds have essences? Are there entities that are the natural kinds? Do our natural kind terms refer to such entities rather as names refer to objects? Is there a non-trivial way of spelling out the idea of rigid designation for natural kinds terms? Do the semantics of natural kind terms vindicate essentialism about kinds? Does what we discover about kinds in the special sciences (e.g., concerning chemical substances and biological species) support or undermine philosophical conceptions of kinds?

General Overviews, Monographs, and Edited Collections

For article-length introductions to the principal philosophical issues surrounding natural kinds, the reader is directed to Koslicki 2008 and Bird and Tobin 2015. Schwartz 1977 includes essential reading (e.g., Putnam, Kripke, and Quine) from the 1960s and 1970s, while Beebee and Sabbarton-Leary 2010 is a contemporary collection focused on natural kinds containing papers exemplifying the current state of research in the philosophy of natural kinds; Campbell, et al. 2011 is another collection of new research, focusing on the metaphysics of natural kinds. Monographs on natural kinds are surprisingly few. Wilkerson 1995 articulates a view of natural kinds that endorses a number of essentialist theses that one finds in the post-Kripke literature. LaPorte 2004 considers episodes of scientific and conceptual change and how these should make us think about natural kinds and essentialism. Khalidi 2013 provides the most comprehensive of recent monographic treatments of kinds.

• Beebee, Helen, and Nigel Sabbarton-Leary, eds. The Semantics and Metaphysics of Natural Kinds. New York: Routledge, 2010.

  An excellent collection of original essays on natural kinds in metaphysics and the philosophy of language, especially in relation to the sciences.

• Bird, Alexander, and Emma Tobin. “Natural Kinds.” In The Stanford Encyclopedia of Philosophy. Edited by Edward N. Zalta. Stanford, CA: Stanford University, 2015.

  This is a survey article covering the metaphysics of natural kinds, natural kinds in the philosophy of science, and natural kinds in the philosophy of language.

• Campbell, Joseph K., Michael O’Rourke, and Matthew H. Slater, eds. Carving Nature at Its Joints: Natural Kinds in Metaphysics and Science. Cambridge, MA: MIT, 2011.

  A wide-ranging collection of new essays, covering topics such as the relationship of kinds to laws, realism, essentialism, and species.

• Khalidi, Muhammad A. Natural Categories and Human Kinds: Classification in the Natural and Social Sciences. Cambridge, UK: Cambridge University Press, 2013.

  DOI: 10.1017/CBO9780511998553

  Khalidi opens with a general discussion of natural kinds and the traditional criteria for identifying them. He himself takes a naturalistic, epistemic, and causal approach, identifying kinds as nodes in causal networks. This approach, rejecting essentialism, accepts a greater range of kinds in the natural and human sciences.

• Koslicki, Kathrin. “Natural Kinds and Natural Kind Terms.” Philosophy Compass 3.4 (2008): 789–802.

  DOI: 10.1111/j.1747-9991.2008.00157.x

  A very helpful introduction to several of the central issues concerning natural kinds and natural kind terms, including the question of whether biological taxa are natural kinds.

• LaPorte, Joseph. Natural Kinds and Conceptual Change. Cambridge, UK: Cambridge University Press, 2004.

  A well-informed and stimulating discussion of natural kinds and their essences. LaPorte defends essentialism, but argues that it results from the decisions that arise in moments of conceptual change brought about by new discoveries.

• Schwartz, Stephen, ed. Naming, Necessity, and Natural Kinds. Ithaca, NY: Cornell University Press, 1977.

  The scope of this collection is broader than natural kinds alone. But it does contain crucial papers by Putnam, Kripke, and Quine, as well as several others discussing issues in the philosophy of language emerging from their work.

• Wilkerson, Terence E. Natural Kinds. Aldershot, UK: Avebury, 1995.

  A very clear exposition of a now-traditional view of natural kinds as characterized by real essences that are intrinsic properties.