Jeremy Bentham was a philosopher and legal reformer who gave utilitarianism its first systematic statement and spent his life applying it to law, punishment and institutions.

The principle of utility

An Introduction to the Principles of Morals and Legislation (1789) opens by placing humanity under two masters, pain and pleasure, and defines the principle of utility as approving an action in proportion as it tends to increase happiness.

Two features made it radical. Pleasure is treated as measurable, by intensity, duration, certainty, nearness, and how much further pleasure it produces — the felicific calculus. And every person's pleasure counts equally, which in 1789 was a levelling claim with immediate political consequences.

Reform

The theory was built to be used. Bentham argued for prison reform, the decriminalisation of homosexuality, animal welfare — asking of animals not whether they can reason or talk but whether they can suffer — and against legal fictions and the common law's accumulated obscurity. He dismissed natural rights as nonsense upon stilts, holding that rights come from law rather than from nature.

The panopticon

His prison design placed cells in a ring around a central tower, so an inmate could be watched at any moment without knowing when. It was never built to his plan in his lifetime, and Foucault later used it as the image for how modern institutions produce subjects who monitor themselves.

Afterwards

John Stuart Mill, whose father was Bentham's associate, revised the theory by distinguishing higher from lower pleasures — a correction aimed squarely at the claim that quantity is all that matters.

Bentham left instructions that his body be preserved and kept at University College London, where it remains.