Distinguishing Belief and Imagination

Some philosophers (including Urmson, Humberstone, Shah, and Velleman) hold that believing that p distinctively involves applying a norm according to which the truth of p is a criterion for the success or correctness of the attitude. On this view, imagining and assuming differ from believing in that no such norm is applied. I argue against this view with counterexamples showing that applying the norm of truth is neither necessary nor sufficient for distinguishing believing from imagining and assuming. Then I argue that the different functional properties of these mental states are enough to distinguish them, and that norm-application doesn't help us draw the functional distinctions