 There are two connected features of moral norms that seem particularly significant in this connection. First, they are intuitively understood to represent agent-relative reasons for action (Nagel 1978). Thus, if I have promised that I will take you to the airport tomorrow afternoon, this consideration has a significance for me that it does not necessarily have for other agents. In particular, the importance to me of keeping my promise seems to be independent from the impersonal end of promissory fidelity. This shows itself in the fact that my reason to keep the promise I have made would be unaffected if I found myself in a scenario in which breaking my promise would lead five other agents to keep promises they would otherwise have flouted. Second, these agent-relative considerations have a distinctive function within practical deliberation. They are not merely considerations that speak in favor of the actions they recommend, but operate rather as practical requirements that presumptively constrain the agent’s activities. The fact that I have promised to take you to the airport tomorrow, for instance, is ordinarily a decisive basis for concluding that that is to be done. I do not need to weigh this consideration against other values that might be pursued under the circumstances; rather, the promissory commitment enters the deliberative field from the start in the deontic guise of an obligation. 