Consequentialists Must Kill*

Many contemporary act consequentialists define facts about what we should do in terms of facts about what we should prefer. They claim that we should perform an action if and only if (and because) we should prefer its outcome to the outcome of any available alternative. Some of these theorists claim they can accommodate deontic constraints, such as a constraint against killing the innocent. I argue that they can't. If there's a constraint against killing, then when we can prevent five killings only by killing one, we shouldn't kill-but we should prefer the outcome where we do.