Ethical Theory Spring 2021

Mill’s Moral Theory


Bentham’s moral theory is called act utilitarianism. It tells people (and institutions like the state) to choose the action (or policy) that produces a greater balance of happiness over unhappiness than all the available alternatives.

At one point, Mill suggests a different moral theory: rule utilitarianism.

Bentham also has an egoistic psychological theory and, accordingly, a theory of sanctions that would motivate egoistic people to behave as utilitarianism recommends.

Mill has a very different psychological theory and a different theory of sanctions.

Rule Utilitarianism

Here is how Mill answers the objection that utilitarianism requires people to take far too much into account.

Those alone the influence of whose actions extends to society in general, need concern themselves habitually about so large an object. In the case of abstinences indeed—of things which people forbear to do, from moral considerations, though the consequences in the particular case might be beneficial—it would be unworthy of an intelligent agent not to be consciously aware that the action is of a class which, if practised generally, would be generally injurious, and that this is the ground of the obligation to abstain from it. The amount of regard for the public interest implied in this recognition, is no greater than is demanded by every system of morals; for they all enjoin to abstain from whatever is manifestly pernicious to society. (2.19, italics added)

The italicized phrase is what I want to emphasize. Bentham told people to choose the action that would produce the greatest overall good. Mill appears to be saying something quite different: choose the action which “is of a class” that would produce the greatest overall good if people generally chose the actions in that class. This has been translated as “follow the rule that would produce the greatest overall good if it were generally followed.” (The rule would be used to identify the class of actions; that’s why this is thought to be a translation of what Mill is saying.)

Try to think of cases in which the difference would matter.

Psychological Egoism and Sanctions

Unlike Bentham, Mill believes that we are motivated by something he calls a conscience. This gives us “a pain … attendant on violation of duty” which leads those who have “properly cultivated moral natures” to shrink from violating their duty “as an impossibility” (3.4).

This causes a problem. Since most people think of their duty in non-utilitarian terms, won’t this lead them to shrink from acting as utilitarians do? For instance, they will think it is immoral to pass out information about birth control in poor neighborhoods when a good utilitarian, like John Stuart Mill, knows that the opposite is true.

Mill tries to do two things. First, he tries to show that the conscience is not an infallible guide to right and wrong. Second, he argues that it is possible to align people’s conscience with utilitarianism. If so, the internal sanction of conscience could motivate us to act like utilitarians. Bentham, by contrast, only discussed external sanctions, such as legal punishment.

Two proofs of utilitarianism

At the beginning of chapter four, Mill offers arguments for the two pillars of utilitarianism: (1) that happiness is the only good and (2) that what matters is the happiness of all people.

The first argument is meant to show that happiness is good. It goes like this.

  1. People desire happiness
  2. The best proof that something is desirable is that people desire it. By analogy, the best proof that something is visible is that people see it.
  3. So the best proof available shows that happiness is desirable.

This appears to commit the fallacy of equivocation. Equivocation involves using a term with two different meanings. In this case, “desirable” means “capable of being desired” in the second premise but in the conclusion (3) “desirable” means “good” or “worth being desired.” So the conclusion does not follow from the premises. The most that follows is that happiness can be desired, not that it is good or worth being desired.

The second argument is meant to show that everyone’s happiness matters. It goes like this.

No reason can be given why the general happiness is desirable, except that each person, so far as he believes it to be attainable, desires his own happiness. This, however, being a fact, we have not only all the proof which the case admits of, but all which it is possible to require, that happiness is a good: that each person’s happiness is a good to that person, and the general happiness, therefore, a good to the aggregate of all persons. (4.3)

This argument commits the fallacy of composition. From the fact that each person desires his or her own happiness, it doesn’t follow that anyone desires everyone’s happiness, much less that everyone (“the aggregate of all persons”) does. By analogy, the atoms in my desk are not visible to my unaided eye, but it doesn’t follow that the aggregate of atoms that makes up the desk is not visible to my unaided eye.

Key Points

These are the concepts from today’s class that you should know or have an opinion about.

  1. The difference between act and rule utilitarianism.
  2. Mill’s internal sanction.
  3. The two proofs of utilitarianism in chapter four.


Mill, John Stuart. (1861) 2000. Utilitarianism. Edited by Mark C. Rooks. British Philosophy: 1600-1900. Charlottesville, VA: InteLex Corporation.