Abstract
Drawing upon a distinction between epistemically and metaphysically motivated notions of a concept, I consider the insurmountable problems of theories that appeal to our epistemic capacities to address the problem of the nature of concepts satisfactorily. Prominent theories of concepts hold that primitive concepts must have
internal structure if they are to account for the explanatory functions that cognitive scientists have attributed to such constructs as prototypes, exemplars, and theories. Vindicating the role of non-experimental philosophy in the critical examination of empirical theories, I argue that the explanatory effectiveness of those constructs is orthogonal to an argument concerning the structure of primitive concepts. Conceptual atomism provides an alternative approach to individuating primitive concepts the precise formulation of which has yet to be worked out. Despite its unpopularity, the atomist alternative is still in a better position to face the question of what concepts are than its competitors.