In Evaluation and Legal Theory, Julie Dickson argues, against me and against Hart, that the beneficial moral consequences attaching to accepting one or another concept of law should have no place in deciding which concept of law is true. In response, I argue that a concept of law, as both Dickson and I acknowledge, is subject to change over time, and may vary across cultures. Yet once we recognize that the concept of law is contingent and variable, we can recognize that prescribing what the concept of law ought to be is no less plausible an enterprise than describing what our concept of law now is. And for the prescriptive enterprise, although plainly not for the descriptive one, the beneficial moral consequences flowing from accepting a particular concept of law are an unavoidable component of the task.