The Journal of Philosophy

Volume 115, Issue 4, April 2018

Note on the Individuation of Biological Traits

Bence Nanay has argued that we must abandon the etiological theory of teleological function because this theory explains functions and functional categories in a circular manner. Paul Griffiths argued earlier that we should retain the etiological theory and instead prevent the circularity by making etiologies independent of functional categories. Karen Neander and Alex Rosenberg reply to Nanay similarly, and argue that we should analyze functions in terms of natural selection acting not on functional categories, but merely on lineages. Nanay replies that these lineages cannot be individuated except by reference to functional categories. Worryingly, Neander and Rosenberg themselves have previously argued persuasively that homology often depends on function. This article addresses their arguments and shows how to escape them: Regardless whether the arguments are right about long-term homological categories, they do not apply to generation-to-generation homology. The latter, moreover, is sufficient for individuating the lineages needed to explain teleological functions.