Abstract

This is a response to Christie, Brusse, et al., ‘Are biological traits explained by their “selected effect” functions?’ The interest of their paper is that it draws our attention to those cases in which changes in a population that are brought about by natural selection in turn bring about changes in the environment that alter the selectionist pressures that were responsible for the original changes. Much of the paper, however, is an argument that the notion of a ‘proper function’ introduced in my Language, Thought, and Other Biological Categories (LTOBC), exhibits deep misunderstandings about the actual workings of natural selection. Very little that they say about ‘proper functions’ and related notions from LTOBC is correct, however. I will not list the errors but I will try to make my uses of ‘proper function’ and certain related terms clearer.