Killing, letting die, and normative inertia

According to commonsense and deontological ethics, it is impermissible to kill a person in order to save the life of another person, all else being equal. But why? This article suggests a justification of this restriction. It appeals to the idea of normative inertia—very roughly, to the idea that in practical decisions, changing course is harder to justify than staying on track. So, in a nutshell, the reason why we may not kill one person to save another is not that killing is worse than letting die, but that it is not better. Various arguments for, and various formulations of, principles of normative inertia are discussed. The article then argues for a specific principle that is not directly concerned with moral permissibility but with practical rationality in a general sense. When coupled with an independently motivated moral premise, this principle can be shown to vindicate intuitions about restrictions on killing. The resulting account is not only plausible and well-motivated. Further, it vindicates intuitions about cases of “withdrawing aid” that have long seemed puzzling. Finally, the account presented here fits particularly well into a contractualist moral theory, refuting the widely held view that contractualism cannot accommodate deontic restrictions.