Examples of propositional attitudes include the belief that snow is white, the hope that Mt Rosea is twelve miles high, the desire that there should be snow at Christmas, the intention to go to the snow tomorrow, and the fear that one shall be killed in an avalanche. As these examples show, we can distinguish the kind of attitude – belief, desire, intention, fear and so on – from the content of the attitude – that snow is white, that there will be snow at Christmas, to go to the snow, and so forth. The term ‘propositional attitudes’ comes from Bertrand Russell and derives from the fact that we can think of the content of an attitude as the proposition the attitude is towards. It can be typically captured by a sentence prefixed by ‘that’, though sometimes at the cost of a certain linguistic awkwardness: it is more natural, for example, to talk of the intention to go to the snow rather than the intention that one go to the snow. The most frequently discussed kinds of propositional attitudes are belief, desire and intention, but there are countless others: hopes, fears, wishes, regrets, and so on.
Some sentences which contain the verbs of propositional attitude – believes, desires, intends, and so on – do not make ascriptions of propositional attitudes. For example: ‘Wendy believes me’, ‘John fears this dog’, and ‘He intends no harm’. However, while these sentences are not, as they stand, ascriptions of propositional attitudes, it is arguable – though not all philosophers agree – that they can always be analysed as propositional attitude ascriptions. So, for example, Wendy believes me just in case there is some p such that Wendy believes that p because I tell her that p; John fears this dog just in case there is some X such that John fears that this dog will do X and so on.
Discussions of propositional attitudes typically focus on belief and desire, and, sometimes, intention, because of the central roles these attitudes play in the explanation of rational behaviour. For example: Mary’s visit to the supermarket is explained by her desire to purchase some groceries, and her belief that she can purchase groceries at the supermarket; Bill’s flicking the switch is explained by his desire to illuminate the room, and his belief that he can illuminate the room by flicking the switch; and so on. It is plausible – though not uncontroversial – to hold that rational behaviour can always be explained as the outcome of a suitable belief together with a suitable desire.
Some philosophers (examples are Grice and Schiffer) have used the propositional attitudes to explain facts about meaning. They hold that the meanings of sentences somehow derive from the contents of relevantly related beliefs and intentions. Roughly, what I mean by a sentence S is captured by the content of, say, the belief that I express by saying S.
One fundamental question which divides philosophers turns on the ontological status of the propositional attitudes and of their contents. It is clear that we make heavy use of propositional attitude ascriptions in explaining and interpreting the actions of ourselves and others. But should we think that in producing such ascriptions, we attempt to speak the truth – that is should we think that propositional attitude ascriptions are truth-apt – or should we see some other purpose, such as dramatic projection, in this usage? Or, even more radically, should we think that there is nothing but error and confusion – exposed by modern science and neurophysiology – in propositional attitude talk?