Inferential-role semantics: A theory of concepts for philosophy and psychology

Concepts are not sets of necessary and sufficient conditions. This fact has caused trouble for both psychologists and philosophers. The resultant psychological theories of concepts, which are primarily aimed at the functional role of concepts, are very specific but this specificity is at the expense of excluding some types of concepts. The resultant philosophical theories of concepts, which are primarily aimed at the content of concepts, are general but this generality is at the expense of understanding the role concepts play in the mind. My dissertation proposes a bridge between psychological and philosophical theories of concepts. This bridge has two parts: The first part is a general model of the functional role of concepts which is philosophically rigorous but can house existing psychological theories of concepts. The second part is a theory of the (narrow) content of concepts, which is informed by the mass of psychological evidence, but is general enough to encompass all concepts. The key in both parts is the role that concepts play in inference. I argue for the inferential model of concepts, which claims that the functional role of a concept is its inferential role. I also argue for inferential-role semantics which claims that the (narrow) content of a concept is determined by its inferential role. The overlooked advantage of this inferentialist position is the ability to draw on an account of reasoning to solve problems in developing a theory of concepts. My dissertation can then be seen as unifying philosophical and psychological work on concepts with philosophical and psychological work on reasoning. This is most obviously seen in the final chapter which offers an account of compositionality for inferential-role semantics