utilitarianism, in normative ethics, a tradition stemming from the late 18th- and 19th-century English philosophers and economists Jeremy Bentham and John Stuart Mill according to which an action (or type of action) is right if it tends to promote happiness or pleasure and wrong if it tends to produce unhappiness or pain—not just for the performer of the action but also for everyone else affected by it.

Mill defines “utilitarianism” as the creed that considers a particular “theory of life” as the “foundation of morals” (CW 10, 210). His view of theory of life was monistic: There is one thing, and one thing only, that is intrinsically desirable, namely pleasure.

Mill explains that utilitarianism seeks to increase pleasure in people’s lives, not avoid or prevent it. Mill also clarifies the definition of pleasure; he does not mean pleasure in the form of satisfying animalistic desires, but the higher forms of pleasure that only humans are able to appreciate.

In his brief essay Utilitarianism, John Stuart Mill provides a very succinct account of the Utility Principle. Actions are right in proportion as they tend to promote happiness, wrong as they tend to produce the reverse of happiness. By happiness is intended pleasure, and the absence of pain; by unhappiness, pain, and the privation of pleasure.

The doctrine that the basis of morals is utility or the greatest happiness principle, holds that actions are right in proportion as they tend to promote happiness, wrong in proportion as they tend to produce the reverse of happiness. By 'happiness' is meant pleasure and the absence of pain; by 'unhappiness' is meant pain and the lack of pleasure.