Western philosophy has a long-standing interest in the relationship between thought and language. This is not least because language-use and our mental capacities are so central to our human self-conception, as well as to the ways in which we have tried to think about other beings. Retrospectively, it is possible to identify certain broad traditions in the philosophical study of thought and language, traditions which also have their representatives in psychology and linguistics. In this introduction I shall focus on one such tradition, the one sometimes known as ‘lingualism’, in so far as it bears on the papers brought together in this volume.

In the Theaetetus, Plato has Socrates answer the question ‘What do you mean by “thinking”?’ by characterising thought as ‘A talk which the soul has with itself about the objects under its consideration’ (189e). On such a conception, there is a logical or ‘internal’ connection between thought and language: thought just is the discourse of the mind with itself (see also Plato's Sophist, 263e). While this is not the only Platonic account, it is perhaps the one which has borne the most fruit. Most accept that there is some kind of intimate (even necessary) connection between thought and language. But is it, as the lingualist supposes, that thought must always take place ‘in’ language?