An Introduction to the Principles of Morals and Legislation

Bentham's Introduction (1789) is the foundational text of utilitarian ethics, introducing the principle of utility and the felicific calculus.

Bentham argues that nature has placed mankind under the governance of pleasure and pain, that the principle of utility approves or disapproves actions based on their tendency to augment or diminish happiness, and that the felicific calculus provides a method for measuring and comparing pleasures and pains.