Utilitarianism. By John Stuart Mill

Utilitarianism is an ethical theory which states that the best action is the one that maximizes utility. "Utility" is defined in various ways, usually in terms of the well-being of sentient entities. Jeremy Bentham, the founder of utilitarianism, described utility as the sum of all pleasure that results from an action, minus the suffering of anyone involved in the action. Utilitarianism is a version of consequentialism, which states that the consequences of any action are the only standard of right and wrong. Unlike other forms of consequentialism, such as egoism, utilitarianism considers all interests equally. Proponents of utilitarianism have disagreed on a number of points, such as whether actions should be chosen based on their likely results (act utilitarianism) or whether agents should conform to rules that maximize utility (rule utilitarianism). There is also disagreement as to whether total (total utilitarianism) or average (average utilitarianism) utility should be maximized.