Abstract

One strategy for providing an analysis of practical rationality is to start with the notion of a practical reason as primitive. Then it will be quite tempting to think that the rationality of an action can be defined rather simply in terms of ‘the balance of reasons’. But just as, for many philosophical purposes, it is extremely useful to identify the meaning of a word in terms of the systematic contribution the word makes to the meanings of whole sentences, this paper argues that it is extremely useful to explain the nature of practical reasons in terms of the systematic contributions that such reasons make to the wholesale rational statuses of actions. This strategy gives us a clear view of two logically distinct normative roles for practical reasons – justifying and requiring – that are often conflated, and it allows us to give clear definitions of what ‘the strength of a reason’ means within each of these roles. The final section of the paper explores some implications of the resulting view for the internalism/externalism debate about practical reasons, and for the practical significance of moral theory.