This paper examines the efforts of contractualists to develop an alternative to aggregation to govern our duty not to harm (duty to rescue) others. I conclude that many of the moral principles articulated in the literature seem to reduce to aggregation by a different name. Those that do not are viable only as long as they are limited to a handful of oddball cases at the margins of social life. If extended to run‐of‐the‐mill conduct that accounts for virtually all unintended (in the sense undesired) harm to others - noncriminal activities that impose some risk of harm on others - they would rule out all action. Moreover, because such conduct poses an irreducible conflict between freedom of action and freedom from expected harm, it can be regulated only by principles that accept the necessity of making precisely the sorts of interpersonal trade-offs that contractualism is foundationally committed to reject: trade-offs in which the numbers count, such that a risk of serious harm to one person can be justified by small benefits to the many.