 The arguments that motivate the theory of intending as being embarked on intentional action are in any case inconclusive. As to the second, while it is a constraint on any theory of intention to show the unity of ‘naïve’ and ‘sophisticated’ rationalization, insofar as they are really unified, it would take much further argument to show that this cannot be done while thinking of intention as a mental state (cf. Setiya 2007a, pp. 51–2). Further demands for unity push towards that view. So, for instance, if we hope to bring out what is common to the explanations ‘He is doing A because he is doing B’ and ‘He is doing A because p’ where these entail, respectively, ‘He is doing A because he intends to do B’ and ‘He is doing A because he believes that p,’ we will have to relate intention to the mental state of belief. If intention is not itself a mental state, but a way of being in progress, such relations are more puzzling. They are taken up again in section 5.