Utilitarianism began as a movement in ethics of the late eighteenth-century primarily associated with the English philosopher Jeremy Bentham. The basic principle of Utilitarianism involves a calculus of happiness, in which actions are deemed to be good if they tend to produce happiness in the form of pleasure and evil if they tend to promote pain. As such, the philosophy is said to derive from the classical concept of hedonism, which values the pursuit of pleasure and avoidance of pain. The sophisticated system proposed by Bentham and later expanded by John Stuart Mill and others regards not only the end product of happiness, or utility, in actions, but also considers the motives of actions and the extent to which happiness can be created not only for the individual, but also for the members of society as a whole.
Both Bentham and Mill forwarded a belief in the intrinsic nature of value; thus good or the lack thereof could be regarded as inherent in an act or thing—a concept that allowed for the mathematical calculation of utility. Beginning from this view, the Utilitarians created systems of moral behavior as standards for how an individual ought to act in society. Bentham's principle of utility is frequently regarded as the “greatest happiness principle,” the simple idea behind which is that individuals should endeavor to maximize happiness for the greatest number of people. While Bentham modified this concept over time, critics acknowledge that its essence remains intact throughout his work. Bentham developed this principle throughout a number of writings, including his most significant work of moral philosophy, An Introduction to the Principles of Morals and Legislation (1789). Ostensibly a plan for a penal code, An Introduction contains Bentham's view that individuals in society should act for the benefit of the community as a whole, and analyzes the means by which legislation should enumerate the penalties for those who refuse to contribute to the overall benefit of society. In this work, Bentham also sought to specifically record the sources of pleasure and pain, as well as to create a scale upon which the relative effects of individual acts in producing happiness or misery could be examined.
Notable among the Utilitarians to follow Bentham, the philosopher and economist John Stuart Mill made considerable contributions to Utilitarian philosophy, beginning with his succinct apologia for the doctrine in Utilitarianism (1861). The essay displays Mill's emphasis on rational calculation as the means by which human beings strive toward personal happiness. Mill's remaining philosophical writings elucidate his Utilitarianism, especially in regard to a number of related practical issues, including women's suffrage, and legislative and educational reform. Following his death, Mill's system was later expanded by his disciple Henry Sidgwick, who in his Methods of Ethics (1874) discussed the means by which individuals may endeavor to achieve moral action through reasoned behavior.
Numerous other individuals contributed to the Utilitarian movement in the nineteenth century, including the British philosophers John Austin and James Mill (J. S. Mill's father). In theory and in practice, Utilitarianism has continued to be influential, with the work of Bentham and Mill proving to be of the greatest importance and interest. Commentators on the writings of both men have continued the process of analyzing and codifying their work in order to more clearly define the doctrine. Among the principal interpretations have been a bifurcation of the philosophy into so-called “rule” and “act” Utilitarianism, the former emphasizing the importance of unbending codes of moral behavior that may not be violated, and the latter allowing for a freer interpretation that permits the breaking of certain Utilitarian rules under individual circumstances. Further criticism of Bentham's and Mill's Utilitarianism has focused on the important concept of justice as it applies to the principles of liberty and utility advocated by both. Additionally, critics have suggested the significant limitations of an ethical system that attempts to reduce human behavior and action to simple rational calculations of pleasure versus pain, but at the same time they acknowledge its considerable impact on nineteenth- and twentieth-century normative ethics.