Utilitarianism is a theory about rightness, according to which the only good thing is welfare (well-being or ‘utility’). Welfare should, in some way, be maximized, and agents are to be neutral between their own welfare, and that of other people and of other sentient beings.
The roots of utilitarianism lie in ancient thought. Traditionally, welfare has been seen as the greatest balance of pleasure over pain, a view discussed in Plato. The notion of impartiality also has its roots in Plato, as well as in Stoicism and Christianity. In the modern period, utilitarianism grew out of the Enlightenment, its two major proponents being Jeremy Bentham and John Stuart Mill.
Hedonists, believing that pleasure is the good, have long been criticized for sensualism, a charge Mill attempted to answer with a distinction between higher and lower pleasures. He contended that welfare consists in the experiencing of pleasurable mental states, suggesting, in contrast to Bentham, that the quality, not simply the amount, of a pleasure is what matters. Others have doubted this conception, and developed desire accounts, according to which welfare lies in the satisfaction of desire. Ideal theorists suggest that certain things are just good or bad for people, independently of pleasure and desire.
Utilitarianism has usually focused on actions. The most common form is act-utilitarianism, according to which what makes an action right is its maximizing total or average utility. Some, however, have argued that constantly attempting to put utilitarianism into practice could be self-defeating, in that utility would not be maximized by so doing. Many utilitarians have therefore advocated nonutilitarian decision procedures, often based on common-sense morality. Some have felt the appeal of common-sense moral principles in themselves, and sought to reconcile utilitarianism with them. In particular, the extreme demandingness of act-utilitarianism has been found objectionable, since it rules out the giving of any special weight by the agent to their own interests or the interests of those close to them. This is one of the reasons for the development of rule-utilitarianism, according to which the right action is that which is consistent with those rules which would maximize utility if all accepted them.
There have been many arguments for utilitarianism, the most common being an appeal to reflective belief or ‘intuition’. One of the most interesting is Henry Sidgwick’s argument, which is ultimately intuitionist, and results from sustained reflection on common-sense morality. The most famous argument is Mill’s ‘proof’. In recent times, R. M. Hare has offered a logical argument for utilitarianism.
The main problems for utilitarianism emerge out of its conflict with common-sense morality, in particular justice, and its impartial conception of practical reasoning.
