When the subject of belief is proposed for philosophical discussion, one may tend to think of such things as religious and moral beliefs, belief in the sense of conviction of an ideological or practical character. Indeed, many of the most interesting questions in the philosophy of belief are concerned with beliefs of this type. However, this is not in fact what I shall be talking about, though what I say will, I hope, have some relevance to issues that arise in those areas. I wish to start with the question of what it is to believe something, and then go on from that to discuss (rather briefly) how far, if at all, believing something can be related to decision and will. In order to discuss this, I am not going to take religious and moral beliefs, but cases of more straightforward factual belief; the sort of belief one has when one just believes that it is raining, or believes that somebody over there is one's father, or believes that the substance in front of one is salt.

I shall be talking about belief as a psychological state. The word ‘belief’, of course, can stand equally for the state of somebody who believes something, and for what he believes. And we can talk about beliefs in an impersonal way, when we talk about certain propositions which people believe or might believe.