weighing reasons

What is involved in weighing normative reasons against each other? One attractive answer offers us the following Simple Picture: a fact is a reason for action when it bears to an action the normative relation of counting in its favour; this relation comes in different strengths or weights; the weights of the reasons for and against an action can be summed; the reasons for performing the action are sufficient when no other action is more strongly supported, overall; the reasons are decisive when it is most strongly supported; one ought to perform the action there is most reason to perform; rational deliberation is weighing reasons correctly; and acting rationally is doing what one has sufficient reasons to do. This chapter investigates various ways in which, on examination, this Simple Picture appears to require modification and refinement. It examines some of the ways in which talk of the weight of a reason may need improvement, looks more closely at the relationship between reasons and rationality, and asks whether there are ways in which a reason can be defeated which are not kinds of outweighing. The conclusion is that while in some respects the Simple Picture does need to be corrected, in others the jury is out