There is long-standing disagreement among systematists about how to divide biodiversity into species. Over twenty different species concepts are used to group organisms, according to criteria as diverse as morphological or molecular similarity, interbreeding and genealogical relationships. This, combined with the implications of evolutionary biology, raises the worry that either there is no single kind of species, or that species are not real.
The Species Problem surveys the history of thinking about species from Aristotle to modern systematics in order to understand the origin of the problem, and advocates a solution based on the idea of the division of conceptual labor, whereby species concepts function in different ways – theoretically and operationally. It also considers related topics such as individuality and the metaphysics of evolution, and how scientific terms get their meaning.
1. The species problem
2. The transformation of Aristotle
3. Linnaeus and the naturalists
4. Darwin and the proliferation of species concepts
5. The division of conceptual labor solution
6. Species and the metaphysics of evolution
7. Meaning, reference and conceptual change
Richard A. Richards is Associate Professor, Department of Philosophy, University of Alabama. He has published in major journals on a variety of topics in the philosophy of science and biology, including phylogenetic inference, theory of choice, taxonomy, and species concepts. He has also written extensively on Darwin's views about artificial selection and domestic breeding, and contributed to The Cambridge Companion to the Origins of Species (2009).