Utilitarianism is an ethical framework for effective moral action. Fundamentally, it is based quantifying good in terms of utility and attempting to maximize that quantity. Utility is often defined as happiness or pleasure, although there are other variants, such as the satisfaction of preferences, or preference utilitarianism. Utilitarianism is often defined as an effort to achieve the greatest good for the greatest number. There are also numerous sub-strands of utilitarianism with various caveats and footnotes on the basic theme. Utilitarianism is a form of consequentialism, where the ends justify the means: if an interim valley of negative utility must be traversed to reach a peak of greater utility, then utilitarianism advocates it.

Utilitarianism has been used as a framework to argue for the value of different actions or political philosophies since it was first formulated. People have probably had utilitarian thoughts for a very long time, but in written records it originates with the Greek philosopher Epicurus. The origins of modern utilitarianism can be traced to the 18th century British philosopher Jeremy Bentham. He called his formulation “the greatest happiness principle.” Following Bentham was John Stuart Mill, who greatly admired Bentham, and published the famous short work Utilitarianism. Today, John Stuart Mill is the name most often associated with utilitarianism.

In Utilitarianism, Mill argued that cultural, intellectual, or spiritual pleasures had a deeper meaning than mere physical pleasure, because someone who had experienced both would value the former more highly. In his other works, such as the essay On Liberty, Mill used utilitarianism to argue for his “liberty principle,” which states “the only purpose for which power can be rightfully exercised over any member of a civilized community, against his will, is to prevent harm to others.”

There have been multiple variations of utilitarianism developed since the days of Mill. The overarching framework of utilitarianism is compatible with a number of different philosophies. The first notable division is that between act utilitarianism and rule utilitarianism. Under act utilitarianism, each action is examined on a case-by-case basis and selected according to which is predicted to lead to the highest utility. Under rule utilitarianism, the moral agent looks to formulate and act under guidance of rules which maximize utility if they were to be consistently followed.

In negative utilitarianism, the goal is to minimize negative utility — pain and suffering — rather than maximize positive utility, as it is argued that the negativity of negative utility is greater than the positivity of positive utility. However, it has been pointed out that an implication of negative utilitarianism is that we should act to radically decrease the population or even eliminate it entirely, as a subgoal of eliminating negative utility. For this reason, negative utilitarianism is controversial.