Evaluative judgement has a decidedly Janus-faced character.

On the one hand, when an agent judges her performance of some action to be desirable it seems that she thereby conveys her normative perspective on the world, her assessment of the importance of acting in the way in question. This assessment is one in which she might have more or less confidence, and for which she might have more or less justification. In this respect an agent's evaluative judgements seem to give expression to her beliefs. On the other hand, however, when an agent judges that some action is desirable she also appears to be in a state that has the potential to lead her all the way to action, at least in so far as she is rational. No additional desire to (say) do whatever it is that she happens to value doing is needed. In this respect an agent's evaluative judgements seem to give expression to her desires.

The Janus-faced character of evaluative judgement sets the agenda for much contemporary meta-ethics. Cognitivists take it as read that they can accommodate the belief-like features of evaluative judgement, and then confront the problem of trying to account for the potential to lead all the way to action that beliefs with that sort of content must have (Brink 1989; Scanlon 1998). Non-cognitivists do the reverse (Gibbard 1990; Blackburn 1998).