Jeremy Bentham’s aim in writing An Introduction to the Principles of Morals and Legislation was to discover the foundations for a scientific approach to penal legislation. Because he found these in human nature, rather than in statutes and precedents, his work is also a book on morals.
Two distinct elements appear in Bentham’s theory. The first is a psychology of motivation according to which all the actions of people are directed toward pleasures or away from pains. The second is a principle of social ethics according to which each person’s actions ought to promote the greatest happiness of the greatest number of persons. That the two principles are independent in their origin and application is not altered by the fact that happiness, according to Bentham, consists in nothing other than pleasure and the avoidance of pain.