ABSTRACT
Scientific concepts play representational and heuristic roles in the acquisition of scientific knowledge. On the one hand, they represent entities, properties, and processes in nature. On the other hand, they facilitate, or even make possible, the investigation of those entities, properties, and processes. Concepts are supposed to be things in the head: mental representations of objects, properties, process and so on. In that sense, they are theoretical constructs of cognitive psychology. They are posited to account for various abilities that humans have, such as the ability to unify and to discriminate. The public character of scientific concepts, such as ‘electron’, ‘field’, ‘gene’, and so on, as opposed to their private mental counterparts, makes it possible for historians and philosophers of science to study them by examining the evolving representations associated with them; their uses, that is, the objects, properties, and processes to which they are applied; and their relations to other concepts.
