Published online by Cambridge University Press: 21 June 2018
One view of practical reasoning is that it involves the weighing of reasons. It is not clear, however, how the weights of reasons combine, especially given the logical and substantive relations among different reasons. Nor is it clear how the weighing of reasons relates to decision theoretic maximization of expected value. This paper constructs a formal model of reasons and their weight in order to shed light on these issues. The model informs philosophical debates about reasons, such as the question of whether reasons or values are more fundamental and the opposing doctrines of atomism and holism about reasons.