Instrumental desires, instrumental rationality: II - Edward Harcourt

I argue that the incoherence Smith claims to identify in agents who desire that q, believe that p is a necessary means to q, but fail to desire that p is illusory, since it rests on the false assumption that every property I know to be possessed by an object of my desire is an object of my desire. Though the failure of Smith's account of the irrationality of this pattern of attitudes leaves it open that the pattern is indeed irrational, I argue that there are instances of it that are not irrational where the desires are desires for what the agent knows to be impossible for him. This conclusion casts doubt on the overall strategy - that of making a Humean theory of action explanation do duty as a theory of instrumental rationality - which implies that the norms of instrumental rationality apply to desires simply as such. I then try to criticise the strategy in such a way as to leave the Humean theory of action explanation unaffected.