Utilitarianism Explained: Bentham, Mill and the Problem of Predicting the Future

Last updated: October 21, 2026

Utilitarianism is the ethical theory that the right action is the one that produces the greatest overall happiness, counting everyone affected equally. Jeremy Bentham gave classical utilitarianism its first systematic statement in An Introduction to the Principles of Morals and Legislation (1789), which opens with the claim that nature has put humankind under “two sovereign masters, pain and pleasure”. John Stuart Mill refined it in Utilitarianism, serialised in Fraser’s Magazine in 1861 and published as a book in 1863, where actions are right “in proportion as they tend to promote happiness”, wrong as they tend to produce the reverse. The phrase “the greatest happiness for the greatest numbers” is older than both: Francis Hutcheson used it in 1725, as the SEP history of utilitarianism notes.

Our meme goes straight for the hardest part. Under the caption “Utilitarians correctly predicting the future to find what action causes the most good”, a cartoon hero clutches his temples while red psychic rings radiate from his head. A theory that judges actions by their consequences needs someone who can see them coming, and that someone is usually a tired person with incomplete information.

Bentham Built a Happiness Calculator

Bentham treated pleasure and pain as quantities that can, in principle, be measured and added up, and in chapter IV of the Introduction he listed what you would need to measure.

He starts with four circumstances for a single pleasure or pain taken by itself: its intensity, duration, certainty and propinquity, meaning how near or remote it is. He then adds fecundity (whether it tends to be followed by more of the same) and purity (whether it tends to be followed by the opposite), which he notes are strictly properties of the act that produces the pleasure. When more than one person is affected, a seventh enters: extent, the number of people the pleasure or pain reaches. Bentham describes this as a process for weighing an act, and he never calls it a calculus in that chapter; the labels “felicific calculus” and “hedonic calculus” came later. He trained as a lawyer and wrote the Introduction as groundwork for legal reform, so the method was meant for legislators deciding which punishments and policies would reduce misery, as the SEP entry on Bentham explains.

The same method made him openly indifferent to where a pleasure comes from. In The Rationale of Reward (1825) he wrote that, prejudice apart, push-pin, a children’s pin game, is of “equal value with the arts and sciences of music and poetry”. Critics heard philistinism. Defenders read it as a refusal to let educated elites rank other people’s enjoyments. Either way, a pleasure was a pleasure, and that gave his opponents a target they would use for the next two centuries.

Bentham Is Still at University College London

Bentham took his own theory further into the afterlife than most philosophers: he wanted his body to remain useful after his death.

At his request, his skeleton was dressed in his own clothes and seated in a wooden cabinet as what he called an “auto-icon”; a wax head replaced the real one, which had preserved badly. It has been on public display at University College London for well over a century and, since 2020, has sat in the UCL Student Centre; the Bentham Project’s page on the auto-icon tells the story, including the fate of the real head, which is kept separately. Bentham also designed the Panopticon, a prison built around unobserved inspection, in which inmates could be watched without knowing when, a design that later critics, Michel Foucault among them, read as a model of surveillance. The logic was the same: if something can produce a little more utility, including a dead philosopher, someone should arrange for it to do so.

The Pig Objection, and Mill’s Answer

Mill accepted Bentham’s principle but rejected the idea that all pleasures are equal. Some, he argued, are higher in quality, and quality counts as well as quantity.

Mill was raised by his father, James Mill, as a Benthamite heir, so the revision came from inside the family. He reports in chapter II of Utilitarianism that critics called the pleasure principle a “doctrine worthy only of swine”, and adds that the comparison had been made against the Epicureans at a very early period; our post on Epicurus on death shows how modest the original pleasure doctrine actually was. Mill’s reply contains the line people now search for, and often attribute to Bentham by mistake: “It is better to be a human being dissatisfied than a pig satisfied”; better to be Socrates dissatisfied than a fool satisfied. If the fool or the pig disagree, he adds, it is because they only know their own side of the question. His test, usually called the competent-judge test, asks people “competently acquainted with both” pleasures which one they prefer, even when it comes with more discontent, as the SEP entry on Mill’s moral and political philosophy sets out.

The move rescued utilitarianism from the pig and cost it the arithmetic. If pleasures differ in kind, there is no exchange rate between an hour of poetry and an hour of push-pin, and Bentham’s process of adding up stops working. Critics have also long suspected that Mill’s competent judges look a lot like educated Victorian gentlemen who already preferred poetry.

The Mind-Reading Problem

The meme’s objection is old, and Mill answered it directly: nobody has time to calculate the consequences of every act before acting.

Mill’s reply in chapter II is that we do not start from zero each time. There has been “ample time, namely, the whole past duration of the human species”, during which people have learned which kinds of action tend to promote happiness. Rules such as “don’t lie” and “keep promises” are the stored results of that experience, what Mill calls secondary principles, and we can rely on them without running the numbers. In the twentieth century the philosopher J. O. Urmson (1953) read Mill as a rule utilitarian, and the labels became standard: act utilitarianism judges each action by its own consequences, while rule utilitarianism judges actions by whether they follow rules whose general acceptance produces the best results. Whether Mill himself fits either label is still debated in the SEP entry cited above.

A classic case shows where the two part ways. You promise a dying friend to give her savings to a cause she loved, and you know the money would do more good elsewhere. Act utilitarianism says break the promise, since nobody will find out and more happiness results. Rule utilitarianism says keep it, because a practice of keeping promises to the dying produces more happiness than one in which such promises are quietly recalculated. Act utilitarians answer that following a rule when breaking it would clearly do more good is irrational; J. J. C. Smart called it “rule worship” in a 1956 paper, and others argued that a rule refined to cover every exception collapses back into act utilitarianism, as the SEP entry on rule consequentialism discusses. Mill himself drew a limit elsewhere: in On Liberty (1859) he argued that the only legitimate reason to coerce someone is to prevent harm to others, which works in practice as a protection that no ordinary calculation should override.

The Trolley and the Surgeon

Several well-known objections to utilitarianism come as thought experiments in which the sums come out right and the answer still feels wrong.

The philosopher Philippa Foot introduced the runaway tram in “The Problem of Abortion and the Doctrine of the Double Effect” (Oxford Review, 1967): the tram’s driver can steer onto a track where one person will die instead of five. Foot set it beside a case in which five patients could be saved by killing one man and making a serum from his body, which Foot treated as plainly impermissible.

Judith Jarvis Thomson coined the name “trolley problem” in a 1976 paper in The Monist, where she sharpened the medical case into a transplant surgeon who could save five dying patients with the organs of one healthy visitor, and in a 1985 paper she moved the choice from the driver to a bystander at a switch. Ordinary intuitions split along the same line. In a 2020 study of about 70,000 people in 42 countries, roughly 81 percent would switch the track, while only about half would push a man off a footbridge to stop the trolley, though the numbers are the same, five against one. Critics read this as evidence that people care about rights, intentions and the difference between doing and allowing, and that a theory counting only outcomes leaves something out.

Bernard Williams pressed a related point in Utilitarianism: For and Against (1973), a book he wrote with the utilitarian J. J. C. Smart. In his example, a visitor named Jim is told that if he shoots one of twenty captured villagers, the other nineteen will go free; if he refuses, all twenty die. Williams’ complaint is that utilitarianism finds the answer obvious: a theory that treats your own projects and integrity as one more input to the calculation turns a person into a channel for outcomes, as the SEP entry on Williams explains.

Utilitarianism Is Still Running Things

For all the objections, utilitarian reasoning still shapes practical ethics and public policy, often under other names.

Peter Singer’s essay “Famine, Affluence, and Morality” (Philosophy & Public Affairs, 1972), written in November 1971 as refugees from East Bengal (now Bangladesh) were dying, used a child drowning in a shallow pond to argue that if you can prevent something very bad without sacrificing anything morally significant, you ought to, whether the child is in front of you or on another continent. The argument helped inspire the effective altruism movement, which tries to direct donations to wherever they do the most measurable good, and which has its own critics. Health systems ration with the same logic: England’s NICE judges new treatments partly by cost per quality-adjusted life year, and governments weigh regulations with cost-benefit analysis. All of them inherit Bentham’s ambition to put ethics on a measurable footing along with the meme’s problem: someone has to predict the consequences before they happen. The honest version of utilitarianism admits that it often cannot, and asks for the best estimate anyway.

For a philosopher who thought ethics starts with duty rather than consequences, read Kant’s categorical imperative, categorically explained.