Hedonism is a school of philosophy which argues that pleasure has an ultimate importance and is the most important pursuit of humanity. The name derives from the Greek word for "delight" (ἡδονισμός hēdonismos from ἡδονή hēdonē "pleasure", a cognate of English sweet + suffix -ισμός -ismos "ism"). The basic idea behind hedonistic thought is that pleasure is the only thing that is good for a person.
This is often used as a justification for evaluating actions in terms of how much pleasure and how little pain (i.e. suffering) they produce. In very simple terms, a hedonist strives to maximize this net pleasure (pleasure minus pain). The nineteenth-century British philosophers John Stuart Mill and Jeremy Bentham defended the ethical theory of utilitarianism, according to which we should perform whichever action maximizes the aggregate good.
Conjoining hedonism, as a view as to what is good for people, to utilitarianism has the result that all action should be directed toward achieving the greatest total amount of happiness. Though consistent in their pursuit of happiness, Bentham and Mill’s versions of hedonism differ. There are two somewhat basic schools of thought on hedonism: