Abstract
How should scientists carve up cognition to generate good predictions, explanations, and models of cognition? This chapter argues that cognitive categories should be constructed the same way that biological categories are: in terms of homology. The chapter adapts a developmental account of trait identity from evolutionary-developmental biology to make sense of the notion of “cognitive homology.” The consequence is that both brain structures and the organism’s ongoing interactions with the environment are crucial for individuating cognitive homologies, and thus for cognitive ontology.