"(Gr.hedone pleasure) a method of working out the sum total of pleasure and pain produced by an act, and thus the total value of its consequences; also called the felicific calculus; sketched by Bentham in chapter 4 of his Introduction to the Principles of Morals and Legislation 1789. When determining what action is right in a given situation, we should consider the pleasures and pains resulting from it, in respect of their intensity, duration, certainty, propinquity, fecundity (the chance that a pleasure is followed by other ones, a pain by further pains), purity (the chance that pleasure is followed by pains and vice versa), and extent (the number of persons affected). We should next consider the alternative courses of action: ideally, this method will determine which act has the best tendency, and therefore is right. Bentham envisaged the calculus could be used for criminal law reform: given a crime of a certain kind it would be possible to work out the minimum penalty necessary for its prevention."
The Penguin Dictionary of Philosophy
ed. Thomas Mautner
The Abolitionist Project
Critique of Brave New World