Sergio Tenenbaum

This paper argues that the principles of instrumental rationality apply primarily to extended action through time. Most philosophers assume that rational requirements and principles govern in the first instance momentary mental states, as opposed to governing extended intentional actions directly. In the case of instrumental rationality, the relevant mental states or attitudes would typically be preferences, decisions, or intentions. In fact, even those who recognize the extended nature of our agency still assume that rational requirements apply primarily to mental states at a moment in time. Such views try to do justice to the extended nature of our agency by postulating rational requirements that apply in the first instance to plans, policies, and intentions more generally. The paper focuses on the central case of requirements and reasons governing the reconsideration of intentions and argues that these requirements or reasons are either superfluous or invalid.I argue that a proper conception of instrumental reasoning that applies directly to actions turn out to have surprising consequences. In fact, this conception allows us to see that policies, projects and the like are best understood as instances of extended actions, and that the instrumental requirements that apply to projects and policies are exactly the same as the instrumental requirements that apply to ordinary extended actions. Finally, I argue that the resulting theory of instrumental rationality is a significant improvement over theories that rely on principles governing intentions.