ethical theory which holds that the right action is the one that maximizes aggregate well-being From Wikiquote, the free quote compendium
Utilitarianism is a theory in normative ethics holding that the moral action is the one that maximizes utility. Utility is defined in various ways, including as happiness or pleasure, well-being and the lack of suffering. Utilitarianism is a form of consequentialism, which implies that the consequences of one's conduct are the ultimate basis for any judgment about the rightness or wrongness of that conduct. This view can be contrasted or combined with seeing intentions, virtues or the compliance with rules as ethically important.
The most prominent and influential utilitarians were Jeremy Bentham, John Stuart Mill, Henry Sidgwick, and Peter Singer.
Seamless Wikipedia browsing. On steroids.