ABSTRACT
There are beliefs which, were they true, would be knowledge. There are beliefs which it is permissible for you to get or allow yourself to start or go on having. Both kinds of beliefs are called justified. And both are called rational. ‘Justified belief’ and ‘rational belief’ are often used interchangeably. ‘Rational belief’ can however be taken in another way. This we can see if we consider what it is to call an action rational. To call an action rational can be to evaluate it. But it can also be to say no more than that it stands, or is believed by the agent to stand, in a certain relation to what are in fact the agent’s own ends. It can for example be to say no more than that the action is thought by the agent to be at least as conducive to what are in fact his own ends as any other action which he is able to perform instead. To call S’s belief that p rational can be to evaluate as rational an action of S’s which is suitably related to his believing that p. That makes ‘rational belief’ mean something not too different from what in the last chapter I labelled volitionally justified belief. But to call S’s belief that p rational can also be, not to make a value judgement, but just to say that an action suitably related to his believing that p is thought by S to stand in a certain relation to S’s own ends. Here we have a volitional but non-evaluative interpretation of ‘rational belief’. Volitional uses of ‘justified belief’ are always evaluative because to call an action justified is always to evaluate that action. Volitional uses of ‘rational belief’ are not always evaluative.
