Sometimes our intentions and beliefs exhibit a structure that proves us to be irrational. This dissertation is concerned with the question of whether we ought (or have at least good reason) to avoid such irrationality. The thesis defends the normativity of rationality by presenting a new solution to the problems that arise from the common assumption that we ought to be rational. The argument touches upon many other topics in the theory of normativity, such as the form and the content (...) of rational standards or requirements, the preconditions of criti¬cism, and the function of reasons in deliberation and advice. Over and above an exten¬sive assessment of the problems discussed in the literature, the thesis provides a detailed defence of a reason-response conception of rationality, a novel, evidence-relative account of reasons, and an explanation of structural irrationality in terms of these accounts. (shrink)