Abstract: Among the many practical failures that threaten us, weakness of will or akrasia is often considered to be a paradigm of irrationality. The eleven new essays in this collection give a rich overview of the current debate over weakness of will and practical irrationality more generally. Issues covered include classical questions such as the distinction between weakness of will and compulsion, the connection between evaluative judgement and motivation, the role of emotions in akrasia, rational agency, and the existence of the will. They also include new topics, such as group akrasia, strength of will, the nature of correct choice, the structure of decision theory, the temporality of prudential reasons, and emotional rationality. The essays advance two central tasks: exploration of the implications of akrasia and other putatively irrational phenomena for the nature of practical reason and rationality; and consideration of possible explanations for such phenomena. The former intersects with recent theorizing about the nature of practical reason in general, and the latter with work in the philosophy of mind about the kinds of mental states and entities we need to posit in order adequately to understand human action.

Keywords: akrasia, desires, emotions, evaluation, internalism, irrationality, practical reason, reasons, weakness of will, will