This book is about propositional attitudes – believing, saying, desiring, knowing, and so on – and how we talk about them. Its primary goal is to give an illuminating answer to questions like the following: When someone says

Maggie thinks that Odile is tired

or

Maggie said that Clark Kent is Superman

or

Maggie wishes that Greg would leave her alone

how do things have to stand with Maggie in order for what is said to be true? What makes sentences like these true or false?

This, then, is a book about the semantics of attitude ascription. But it would be difficult to say anything illuminating about the meaning of ‘believes’, ‘desires’, and their friends without saying something substantive about belief, desire, and the other propositional attitudes. And so this book addresses topics in the philosophy of mind, as well as ones in the philosophy of language. Discussed in the following pages are, for example, the nature of the psychological states that are beliefs and desires; the beliefs and desires (or lack thereof) of speechless nonhuman animals; the distinction between tacit and explicit belief; the idea that the sentences of a natural language play, for all its speakers, more or less the same cognitive or conceptual role.