Introduction

There are words in the language we speak and concepts in our minds. For present purposes, we can use a relatively common-sense, unsophisticated notion of a linguistic word. A bit more needs to be said, now and later, about what we mean by a concept. We assume that mental representations have a structure not wholly unlike that of a sentence, and combine elements from a mental repertoire not wholly unlike a lexicon. These elements are mental concepts: so to speak, ‘words of mentalese’. Mental concepts are relatively stable and distinct structures in the mind, comparable to entries in an encyclopaedia or permanent files in a data-base. Their occurrence in a mental representation may determine matching causal and formal (semantic or logical) relationships. On the one hand, there are relationships between the mind and the world. The activation of a concept may play a major role in causal interactions between the organism and external objects that fall under that concept. On the other hand, there are relationships among representations within the mind. The occurrence of a concept in a mental representation may play a causal role in the derivation of further representations, and may also contribute to the justification of this derivation.

Three types of mapping

What kind of mapping is there (if any) between mental concepts and public words? One extreme view is that natural languages such as English or Swahili are the sole medium of thought. In this case, there is obviously a genuine one-to-one correspondence between public words and mental concepts. An opposite extreme view is that there are no such things as individual mental concepts at all, and therefore no conceptual counterparts to public words. We will ignore these extreme views. We assume that there are mental concepts, and that they are not simply internalisations of public words, so that the kind and degree of correspondence between concepts and words is a genuine and interesting empirical issue.