Utilitarianism is a theory in normative ethics holding that the proper course of action is the one that maximizes overall happiness. It is now generally taken to be a form of consequentialism, although when Anscombe first introduced that term it was to distinguish between "old-fashioned Utilitarianism" and consequentialism. According to utilitarianism the moral worth of an action is determined only by its resulting outcome although there is debate over how much consideration should be given to actual consequences, foreseen consequences and intended consequences. Two influential contributors to this theory are Jeremy Bentham and John Stuart Mill. In A Fragment on Government Bentham says ‘it is the greatest happiness of the greatest number that is the measure of right and wrong’ and describes this as a fundamental axiom. In An Introduction to the Principles of Morals and Legislation he talks of ‘the principle of utility’ but later prefers “the greatest happiness principle". Utilitarianism can be characterized as a quantitative and reductionist approach to ethics. It is a type of naturalism. It can be contrasted with deontological ethics, which does not regard the consequences of an act as a determinant of its moral worth; virtue ethics, which primarily focuses on acts and habits leading to happiness; pragmatic ethics; as well as with ethical egoism and other varieties of consequentialism. Utilitarianism has often been considered the natural ethic of a democracy operating by simple majority without protection of individual rights.
The importance of happiness as an end for humans has long been recognized. Forms of hedonism were put forward by Aristippus and Epicurus; Aristotle argued that eudaimonia is the highest human good and Augustine wrote that "all men agree in desiring the last end, which is happiness." Happiness was also explored in depth by Aquinas However, utilitarianism as a distinct ethical position only emerged in the eighteenth century. Although utilitarianism is usually thought to start with Jeremy Bentham there were earlier writers who presented theories that were strikingly similar. In An Enquiry Concerning the Principles of Morals David Hume writes: In all determinations of morality, this circumstance of public utility is ever principally in view; and wherever disputes arise, either in philosophy or common life, concerning the bounds of duty, the question cannot, by any means, be decided with greater certainty, than by ascertaining, on any side, the true interests of mankind. Hume had studied under Francis Hutcheson and it was he who first introduced a key utilitarian phrase. In An Inquiry into the Original of Our Ideas of Beauty and Virtue (1725) Hutcheson writes, In comparing the moral qualitys of actions, in order to regulate our election among various actions proposed, or to find which of them has the greatest moral excellency, we are led by our moral sense of virtue to judge thus; that in equal degrees of happiness, expected to proceed from the action, the virtue is in proportion to the number of persons to whom the happiness shall extend (and here the dignity, or moral importance of persons, may compensate numbers); and in equal numbers, the virtue is as the quantity of the happiness, or natural good; or that the virtue is in a compound ratio of the quantity of good, and number of enjoyers. In the same manner, the moral evil, or vice, is as the degree of misery, and number of sufferers; so that, that action is best, which procures the greatest happiness for the greatest numbers; and that, worst, which, in like manner, occasions misery. In the first three editions of the book Hutcheson followed this passage with various mathematical algorithms “to compute the Morality of any Actions”. In this he pre-figured the hedonic calculus of Bentham. It is claimed that the first systematic theory of...