Introduction

Normal adult human beings are good psychologists. They can explain and, to an extent, predict their own and other people's actions on the basis of a battery of psychological concepts: perception, desire, belief, fear, wonder, doubt, and so on. Let us call the seat of these psychological abilities the ‘psychology faculty’. The psychology faculty has been the focus of a great deal of research in experimental, theoretical and developmental cognitive psychology, as well as a fair amount of philosophy.

I believe that this investment of intellectual energy is well worthwhile, since the study of the psychology faculty relates in important ways to a variety of central interdisciplinary concerns. It intersects with questions in the philosophy of mind about eliminativism, knowledge of other minds and our conception of ourselves as human beings. It intersects in interesting and subtle ways with questions in philosophy of language about the semantics of sentences attributing propositional attitudes. And it relates to the most fundamental questions in psychology about concept acquisition and the structure of the mind. In this paper I'll address some aspects of the latter questions.

It is common practice among psychologists, linguists and some philosophers to talk of ‘modules’ of the mind. But there is a wide variety of quite different conceptions of modularity. In section 2, I will distinguish a few of these which I believe have a good chance of being genuine psychological, natural kinds.