Political Philosophy Fall 2019

Mill’s Libertarianism


On Liberty falls into four broad parts:

  1. Introductory: Mill sets out his reasons for writing the book and the abstract propositions he will defend (ch. 1).
  2. Liberty of Thought and Expression: Mill argues for liberty in one particular set of cases, thought and expression (ch. 2).
  3. Liberty of Action: Mill defends liberty for actions in general (chs. 3-4).
  4. Specific policy implications (ch. 5).

Today we talked about the third and fourth parts: Mill’s defense of liberty in general, rather than liberty for the special case of thought and expression.

In these chapters, Mill makes a case for thinking that individuals should be free to do nearly any self-regarding action, that is, anything that effects only their own lives. His case for liberty of action is similar to his case for liberty of thought and expression. He argues that individuals need to discover things for themselves and that society benefits from the innovations made by people with unusual abilities and tastes.

One point that I tried to make is that Mill goes beyond the obvious points about why individual liberty makes people happy. He rests a lot on cases where individuals make bad choices for themselves. Even then, he says, the utilitarian goal of promoting happiness is best achieved by leaving them at liberty rather than interfering with their choices.

The Harm Principle

In the introductory chapter, Mill says that his project is to find a principle for deciding when society may and may not limit individual liberty. Then he announces what that principle is.

That principle is, that the sole end for which mankind are warranted, individually or collectively, in interfering with the liberty of action of any of their number, is self-protection. That the only purpose for which power can be rightfully exercised over any member of a civilized community, against his will, is to prevent harm to others. (ch. 1, par. 9)

This is known as the Harm Principle. It seems to be quite uncompromising: we are only allowed to limit an individual’s liberty to prevent that person from harming others, period. The most natural understanding of “harm” is an action that makes someone worse off than they would have been without the action. But there is reason to wonder if this is what Mill has in mind since he lists several cases in which society can force people to do things for the benefit of others as opposed to preventing them from harming others; these are listed on the handout.

The beginning of chapter 4 suggests something different. There, Mill defines “harm” as a violation of an individual’s rights. If that is what he means, it pushes the question back to what rights we have. I think Mill has to choose between two options:

  1. A list of rights drawn roughly from common sense, much like what you find in Locke.

  2. A list of rights derived from utilitarianism, as Mill suggests in chapter 5 of Utilitarianism.

Mill does not go into this. But I think he is rhetorically suggesting the first while actually relying on the second.


One thing that Mill seems pretty clear about is that there is a distinction between actions that harm others and actions that merely offend others. According to the harm principle, society may limit liberty to prevent harmful actions, but it may not do so in order to prevent merely offensive ones. Mill’s argument for this distinction is on the second page of the handout (ch. 4, par. 12).

Mill’s argument is that the public will get it wrong if they try to regulate offensive thoughts. Why? He draws a distinction between “questions of social morality” and “questions of self-regarding conduct.” He says that the public will generally be right when it comes to social morality because they are affected by their decisions.

However, the public will generally be wrong when it comes to regulating people’s opinions because they are not generally affected by their decisions. Consequently, he believes, we should pay no attention to the feelings of someone who is offended by another person’s opinions.

Individual Benefits of Liberty

Mill is a utilitarian, so he has to show that the extensive individual liberty that he advocates is the best way of promoting utility. He tries to do this by showing that individual liberty benefits individuals and also that it benefits society.

Mill’s first line of arguments for the individual benefits of liberty are pretty much what you would expect. He maintains that individuals will, generally speaking, make choices that make themselves happy. So leaving individuals at liberty to decide what to do is a good way of making them happy. This is probably true but not terribly interesting: anyone could have thought of this so we don’t need Mill’s big brain to make the point.

What I think is most interesting about Mill is that most of the arguments make a case for liberty even when individuals do not make good choices. After all, no one is perfect and we are all subject to well known flaws in our decision making. More importantly, the people Mill is arguing against will typically believe that individuals do not make the correct choices for themselves. Mill side-steps their arguments by maintaining that individual liberty is still superior to the alternatives even when individuals do not choose well.

Why? One kind of argument concerns individual self-development. Mill maintains that individuals learn from their mistakes and they only learn by trying things for themselves. So even if they are bad decision makers, the only way to make them better is to leave them at liberty. (I suppose he was assuming that improved individual decision making is far superior to constant social paternalism. It would be interesting to spell out exactly why that is so.)

On the other side, Mill has many arguments for the conclusion that the alternatives to individual decision making are all worse. Society knows less and cares less about an individual’s life than that individual does. So even if the individual chooses badly, society would be worse. Hence, he concludes, individuals should be left at liberty.

Key Concepts

  1. The distinction between harm and offense.
  2. Why individual liberty of action makes individuals better off.
  3. Why individual liberty makes society better off.

Religious Persecution and Marriage

There are two bits at the end that we did not talk about but that are worth noting.

One concerns the persecution of Mormons in the United States (see ch. 4, ¶22). Mill takes this to be a good example of how intolerant democratic societies can be. He’s right! It is also an episode of American history that is often swept under the rug. It should be acknowledged along with slavery, internment, the dispossession of Native Americans, and all the rest of the more familiar cases, in my opinion.

The other concerns Mill’s argument that individuals should not be allowed to sell themselves into slavery. (More precisely, the state should not enforce any such contracts.) That seems to run afoul of his idea that individuals should be free to do any merely self-regarding act that they choose. It’s my life, after all, why can’t I spend it as a slave if that’s what I want? I don’t mean to be flip. I could agree to an onerous labor agreement in order to support my family. Or maybe I think it is important to commit myself to a monastic life. These are both things that someone may rationally decide to do.

I think Mill’s idea was that liberty is important for self-development. People who sell themselves into slavery lose the chance at development. Since Mill’s case for liberty rests on its role in individual development, it does not extend to this case. Just to be clear: that is speculation on my part, it is not something that Mill explicitly says.

I also want to point out that Mill was really talking about marriage. He is not actually worried about the widespread use of voluntary slavery contracts. His real target is divorce laws that made it very difficult for women to get out of bad marriages. Here is what the law was like in his time, according to Colin Heydt, the author of the entry on Mill in the Internet Encyclopedia of Philosophy.

(1)  British women had fewer grounds for divorce than men until 1923; (2) Husbands controlled their wive’s personal property (with the occasional exception of land) until the Married Women’s Property Acts of 1870 and 1882; (3) Children were the husband’s; (4) Rape was impossible within a marriage; and (5) Wives lacked crucial features of legal personhood, since the husband was taken as the representative of the family (thereby eliminating the need for women’s suffrage).

Mill is saying that marriage in his time was similar to voluntary slavery. He is arguing that the fact that women enter marriage voluntarily doesn’t make this OK. This is a theme he expanded on in his On the Subjection of Women (1869).

You might agree with his conclusion that the marriage laws were bad but dispute his reasons for saying so. That is, you might think it’s unfair or unequal and not, as he says, that it is inconsistent with women’s liberty.


Mill, John Stuart. (1859) 2000. On Liberty. Edited by Mark C. Rooks. British Philosophy: 1600-1900. Charlottesville, VA: InteLex Corporation.


There was a handout for this class: 17.MillHarmPrinciple.handout.pdf