"A utilitarian theory which assumes that the rightness of an action depends entirely on the amount of pleasure it tends to produce and the amount of pain it tends to prevent. Bentham's utilitarianism is hedonistic. Although he describes the good not only as pleasure, but also as happiness, benefit, advantage, etc., he treats these concepts as more or less synonymous, and seems to think of them as reducible to pleasure. John Stuart Mill's utilitarianism, also described as hedonistic, differs importantly from Bentham's in taking some pleasures to be higher than other ones, so that when considering the values of the consequences of an action, not only the quantity but also the quality of pleasure has to be considered. This complicates the summing up, or may even make it impossible."
The Penguin Dictionary of Philosophy
ed. Thomas Mautner
The Abolitionist Project
Critique of Brave New World