The Utility of the Proximate‐Ultimate Dichotomy in Ethology

Abstract
We defend the organizing principle that there are fundamentally different levels of analysis in biology, notably proximate and ultimate. Despite recent claims to the contrary, the proximate‐ultimate distinction is a true dichotomy, not an artificial division of a continuum. Acceptance of this dichotomy does not imply that ultimate questions are of greater importance than those dealing with proximate mechanisms, nor does it result in confusion of current reproductive consequences with evolutionary causes.