This book contains a collection of new papers on the topic of reasons for belief, sometimes referred to in the literature as ‘theoretical reasons’. The papers in this volume address two broad themes: the nature of reasons for belief and the application of reasons for belief to other traditional problems in epistemology. The choice of these two themes reflects the rationale for putting together this volume.

For a period of roughly 35 years, practical philosophers have been appealing to reasons to do ever more work in their theorizing. Early debates in practical philosophy posed the question of whether one could have normative reasons for action – considerations that count in favour of an agent's performing a particular action or actions – that were disconnected from an agent's own motivations. Soon the value of thinking of broader problems in ethics in terms of reasons became apparent, and now appeals to reasons populate debates across normative ethics and metaethics alike. Reasons became a kind of common currency for consideration of the normative issues in practical philosophy.

Like those in ethics and other areas of practical philosophy, many of the problems studied in epistemology are also normative. Epistemologists have traditionally examined these problems through discussions of justification and warrant. Increasingly, however, philosophers interested in the problems of normative epistemology have appealed to reasons both to help explicate justification, warrant, and related concepts, and to address independently other concerns in epistemology.

Over the last three decades, practical philosophy has increasingly looked at, and become dependent upon, the concept of normative reasons for actions, and action-related propositional attitudes. The concept gradually came into prominence in a series of classic treatments in the late seventies and early eighties and has since then become the focal point and organizing concept for a vast array of work in both ethics and the philosophy of mind and action. The core of the concept is a simple one: normative reasons are facts that count in favor of some action or attitude; they are the facts that determine whether or not an agent ought to do something, or adopt some attitude. As such, normative reasons are often thought to be the most fundamental concept relevant to understanding rationality, which, on this view, is the capacity to recognize and respond to reasons in appropriate ways. The link to rationality means that normative reasons not only determine what ought to be done; at least sometimes, they also play the role of explaining why an agent in fact acted or thought as she did.

Even if there is broad agreement among philosophers on these fundamental features of reasons, a detailed understanding of reasons is still subject to controversy. What kinds of facts can act as reasons? Are they restricted to representational states such as beliefs or desires, or can non-mental states of affairs act as reasons as well?