The Importance of Homology for Biology and Philosophy

Homology is one of the most important concepts in biology (de Beer 1971; Donoghue 1992). Having been introduced in pre-Darwinian comparative biology, it continues to be fundamental to taxonomy, phylogeny, and evolutionary biology. In recent times it has come to play an important role in molecular and developmental biology. In addition to figuring prominently in biological practice, the notion of homology is the subject of extensive theoretical reflection among biologists (Bock and Cardew 1999; Hall 1994; Wagner 2001b). Curiously though, homology has been discussed only sparsely by philosophers. The contributions to this special issue attempt to highlight the importance of homology for philosophy as well as biology. Homology is germane to such philosophical issues as the individuation of biological natural kinds, and the patterns of inductive reasoning in the life sciences. Given the possibility of individuating cognitive kinds and mental phenomena in terms of homology (rather than their evolutionary function), the idea of homology has implications for the philosophy of mind and cognitive science, implications that are explored in the contributions of Marc Ereshefsky and Mohan Matthen.