Concepts are Containers

In this paper, we propose and defend a theory of concepts. According to Machery (2009), psychologists and philosophers mean different things by ‘concept’. Psychologists mean bodies of knowledge used to categorise and infer; philosophers mean constituent of propositional thought. Machery’s conclusion would drive a wedge between contributions by psychologists and philosophers on concepts. Theories about the former would have no clear role to play in, and cast no light on, the latter, and vice versa. We argue that, on the contrary, ‘concept’ has a single core meaning: a container of stored knowledge pertaining to a single category. This single meaning satisfies both the theories of psychologists and philosophers. The divergence in use of the term ‘concept’ on which Machery focuses arises because words for containers are often used to refer to (a) what is contained by the container and (b) the label of a container. Our account explains what a concept is, and how one might be misled by Machery’s challenge.