This paper explores the isomorphism between two relationships. The first is that between reasons and requirements. Reasons for action (or for belief - but the focus here is action) differ from requirements, in that reasons are typically merely advisory while requirements are mandatory. We are rationally required to do that which there is most reason for us to do (and of course if we have most reason to do nothing, that is what reason requires). This way of understanding the relationship between reasons for action and what reasons require of an actor has been called the maximizing conception.
The second relationship is that between moral reasons (a subset of reasons generally, but not necessarily a proper subset) and moral requirements. It is natural to assume that moral reasons ripen into moral requirements in the same manner that reasons generally ripen into rational requirements: we are morally required to do what we have most reason, morally, to do. This transposition of the maximizing view from the realm of reasons generally to the moral realm can be traced to Moore.
The paper defends a version of Moore's view, despite its perhaps drastic consequences. Part of this defense consists of taking into account the putative incomparability between certain types of moral reasons. The paper argues that incomparability, far from undermining the maximizing view, helps it accommodate the possibility of moral options, and to that extent to avoid what has become commonly known as "the strenuousness objection," typically directed against consequentialistic species of the maximizing conception. But the larger part of this defense consists of criticism of alternative accounts of the relationship between moral reasons and moral requirements. Historically, a number of ideas have been invoked to close the gap between reasons and requirements, or (as the gap could also be described) between goodness and obligation. "Sanction" theories, voluntaristic theories, and rationalistic or universalization theories are examined and found wanting.
The paper concludes that the maximizing conception can be reconciled with whatever is defensible in each of these alternatives: a unary account of morality and rationality is available once moral reasoning is represented as an operation of maximization performed upon a "filtered" or "supplemented" set of reasons bearing upon the actor.