Reasons as Defaults

Much of the recent literature on reasons is focused on a common range of issues, concerning, for example, the relation between reasons and motivation, desires, and values, the issue of internalism versus externalism in the theory of reasons, or the objectivity or reasons. This paper is concerned with a different, and orthogonal, set of questions: What are reasons, and how do they support actions or conclusions? Given a collection of individual reasons, possibly suggesting conflicting actions or conclusions, how can we determine which course of action, or which conclusion, is supported by the collection as a whole? What is the mechanism of support? I begin by considering one possible line of response, which I refer to as the weighing conception, since it is based on the idea that reasons support actions or conclusions by contributing a kind of normative or epistemic weight, and that the goal is then to select those options whose overall weight is greatest. This general idea is almost certainly ancient, but we know that it goes back at least to 1772, where we can find a version of the weighing conception described with some elegance in a letter from Benjamin Franklin to his friend Joseph Priestley, the chemist. Priestley had written to Franklin for advice on a practical matter. In his reply, Franklin regrets that he has no help to offer on the specific matter at hand, since he is not sufficiently familiar with the facts, but recommends a general technique for reaching decisions in situations of the kind facing his friend: