 Acceptance or rejection of Mayr's proximate-ultimate distinction may lie at the centre of several major debates within contemporary biology, concerning evo devo (evolutionary developmental biology), niche construction, cultural evolution, human cooperation, and the evolution of language.According to some biologists and philosophers, these disputes share a common pattern.On one side are researchers who consider that interaction and feedback processes traditionally characterized as ‘proximate’ have explanatory value for ‘ultimate’ evolutionary questions.