Abstract

[Michael Smith] The requirements of instrumental rationality are often thought to be normative conditions on choice or intention, but this is a mistake. Instrumental rationality is best understood as a requirement of coherence on an agent's non-instrumental desires and means-end beliefs. Since only a subset of an agent's means-end beliefs concern possible actions, the connection with intention is thus more oblique. This requirement of coherence can be satisfied either locally or more globally, it may be only one among a number of such requirements on an agent's total set of desires and beliefs, and it has no special connection with reasoning. An appreciation of these facts leads to a better understanding of both the nature and the significance of instrumental rationality. /// [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.