Utilitarianism is a normative ethical theory that posits the best action is the one that maximizes overall happiness or utility. Its roots can be traced back to ancient philosophies, notably Epicureanism, which emphasized the pursuit of pleasure and avoidance of pain. However, utilitarianism as a formalized doctrine emerged in the late 18th and early 19th centuries.

Jeremy Bentham is often considered the founder of modern utilitarianism. In works like An Introduction to the Principles of Morals and Legislation (1789), Bentham proposed that the value of an action should be judged by its utility, defined as the net pleasure or happiness it produces. He introduced the “hedonic calculus,” a method for quantifying happiness to guide moral decision-making. Bentham’s approach was act-utilitarian, focusing on the consequences of individual actions.

John Stuart Mill, a philosopher and economist, expanded on Bentham’s ideas in the mid-19th century. In his book Utilitarianism (1863), Mill introduced qualitative distinctions between pleasures, arguing that intellectual and moral pleasures are superior to physical ones. He also addressed common criticisms of utilitarianism, such as its implications for justice and individual rights, attempting to reconcile utilitarian principles with a respect for individual liberties.

The 20th century saw further developments in utilitarian thought. Philosophers like G.E. Moore introduced ideal utilitarianism, which considers a range of values beyond mere pleasure and pain. R.M. Hare developed preference utilitarianism, emphasizing the satisfaction of individual preferences. Peter Singer applied utilitarian ethics to practical issues like animal rights and global poverty, advocating for effective altruism.

Utilitarianism has faced various criticisms over the years, including challenges related to justice, rights, and the feasibility of calculating overall happiness. Critics argue that strict adherence to utilitarian principles can justify actions that violate individual rights or moral intuitions. Despite these debates, utilitarianism remains a significant and influential theory in ethical philosophy, impacting fields like economics, public policy, and bioethics.