 By way of illustration, both Mill and Sidgwick recognize that desert, of both reward and punishment, is a key component of common understandings of justice, but they argue that if we remain at the level of common sense when we try to analyse it, we run into irresolvable contradictions. For instance, we are inclined to think that a person’s deserts should depend on what they have actually achieved – say the economic value of what they have produced – but also, because achievement will depend on factors for which the person in question can claim no credit, such as inborn talent, that their deserts should depend only on factors for which they are directly responsible, such as the amount of effort they expend. Each of these conceptions, when put into practice, would lead to a quite different schedule of rewards, and the only means to escape the impasse, these utilitarians claim, is to ask which schedule will generate most utility by directing people’s choices and efforts in the most socially productive way. Similar reasoning applies to the principles of punishment: the rules we should follow are the rules that are most conducive to the ends for which punishment is instituted, such as deterring crime.