Reasons for action, acting for reasons, and rationality

What kind of thing is a reason for action? What is it to act for a reason? And what is the connection between acting for a reason and rationality? There is controversy about the many issues raised by these questions. In this paper I shall answer the first question with a conception of practical reasons that I call ‘Factualism’, which says that all reasons are facts. I defend this conception against its main rival, Psychologism, which says that practical reasons are mental states or mental facts, and also against a variant of Factualism that says that some practical reasons are facts and others are false beliefs. I argue that the conception of practical reasons defended here provides plausible answers to the second and third questions above; and gives a more unified and satisfactory picture of practical reasons than those offered by its rivals.