Mill on liberty of thought and expression

I gave some background to Mill’s On Liberty, said that I did not think Mill was wholly committed to the famous Harm Principle (see the handout), and then we discussed Mill’s case for liberty of thought and expression.


There are two things about Mill’s life that it helps to know about when reading On Liberty. The first is that his father, James Mill, and Jeremy Bentham were staunch advocates for enabling more people to vote. John Stuart Mill was not opposed to that. But he was rather worried about the dangers of an intolerant, closed-minded public taking charge.

The second fact is that Mill had an unusual and long-standing relationship with Harriet Taylor. Harriet Taylor was inconveniently married to John Taylor at the time. Mill was a public figure and I have no doubt that he was highly self-conscious about this. Make of it what you will.

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.

This is known as the Harm Principle. It seems to be quite uncompromising: we are only allowed to limit an individual’s liberty for the sake of preventing that person from harming others, period.

However, Mill himself endorsed several apparent exceptions to this principle. He allowed for limits to individual liberty for the sake of helping others. So I am not sure what to make of the Harm Principle. I proposed that it would be more fruitful to look at his case for liberty in particular areas.

Utilitarianism and liberty

Mill’s utilitarian case for liberty rests on two propositions:

  1. Liberty is beneficial to the individual.
  2. Liberty is beneficial to society.

While Mill’s case is complex, there are some common themes.

In making the case for the benefits of individual liberty, Mill repeatedly asserts that individuals have to make opinions and ways of living their own and that they can do that only if they are at liberty to make up their own minds or choose their own way of life.

In addition, many of his arguments apply even to cases in which individuals do not make good decisions. In these cases, Mill tries to show that the alternatives to individual liberty would generally be worse.

When making the case for the social benefits of liberty, Mill tends to emphasize how unusual individuals can make discoveries that benefit the rest of society.

Liberty of thought and expression

The official topic of chapter two is liberty of thought and expression. Mill seeks to show that society should never suppress opinions. To reach this conclusion, he tries to show that suppression would be worse than tolerance in three cases:

  1. The opinion to be suppressed is incorrectly believed to be false.
  2. The opinion to be suppressed is correctly believed to be false.
  3. The opinion to be suppressed is partly true and partly false.

Mill assumes that suppression will always be favored on the grounds that the opinion being suppressed is false. That is what those doing the suppressing will believe.

So he begins by arguing that no one can have good enough reason for believing that an opinion should be suppressed because it is false. He begins with an assertion that those who wish to suppress an opinion must be certain that it is false.

This is a very high standard, of course. We don’t hold that those making other momentous decisions, like decisions to execute a criminal or start a war, have to be completely certain.

Mill recognizes this and moves to a different claim: we are justified in thinking that an opinion is false only if those who hold it have “every opportunity” of supporting their views and “complete liberty of contradicting and disproving” our contrary opinions. But, of course, the only way to meet that condition is never to suppress opinions.

Max pointed out the flaw in the argument. As long as we permit thorough debate before the decision to suppress has been taken, we can meet the condition and then we can suppress the opinion, contrary to the conclusion Mill wanted to establish.

So Mill probably needs to rely on the argument he gives for the second possibility: that the opinion to be suppressed is correctly believed to be false. There, Mill argues that false opinions should be tolerated on the grounds that doing so is a necessary condition of ensuring that those who hold true opinions understand the reasons for their beliefs. Otherwise, Mill claims, even true beliefs will be held as dead dogmas that are not genuinely understood.

Let us now pass to the second division of the argument, and dismissing the supposition that any of the received opinions may be false, let us assume them to be true, and examine into the worth of the manner in which they are likely to be held, when their truth is not freely and openly canvassed. However unwillingly a person who has a strong opinion may admit the possibility that his opinion may be false, he ought to be moved by the consideration that however true it may be, if it is not fully, frequently, and fearlessly discussed, it will be held as a dead dogma, not a living truth. (chapter 2, par. 21)

If Mill can make this argument stick, he will have a case against the suppression even of false opinions. Namely that even true beliefs will be lost if they are not confronted with false ones. The idea is that those who hold the true beliefs will not understand them if they are insulated from the expression of contrary opinions, even if they are false.

One other thing is worth noting. Mill assumes that true opinions lead to greater overall utility. Otherwise, his arguments in this chapter do not amount to a utilitarian case for liberty.

Key concepts

  1. How Mill argues that individual liberty benefits the individual.
  2. How Mill argues that individual liberty benefits society.
  3. How Mill argues against the suppression of opinions in particular.


(This is something extra; it is not essential for our class.)

Semassa asked about whether utilitarians count the members of future generations or not. I said that they do but that they are divided over whether to maximize average utility or total utility. Here is why that matters. If you maximize total utility, you will have a very large population of people living lives of merely acceptable quality. If you maximize average utility, by contrast, you will have a smaller population of people living much higher quality lives.

The point was first noted by Henry Sidgwick in 1907.

“Assuming, then, that the average happiness of human beings is a positive quantity, it seems clear that, supposing the average happiness enjoyed remains undiminished, Utilitarianism directs us to make the number enjoying it as great as possible. But if we foresee as possible that an increase in numbers will be accompanied by a decrease in average happiness or vice versa, a point arises which has not only never been formally noticed, but which seems to have been substantially overlooked by many Utilitarians. For if we take Utilitarianism to prescribe, as the ultimate end of action, happiness on the whole, and not any individual’s happiness, unless considered as an element of the whole, it would follow that, if the additional population enjoy on the whole positive happiness, we ought to weigh the amount of happiness gained by the extra number against the amount lost by the remainder. So that, strictly conceived, the point up to which, on Utilitarian principles, population ought to be encouraged to increase, is not that at which average happiness is the greatest possible,—as appears to be often assumed by political economists of the school of Malthus—but that at which the product formed by multiplying the number of persons living into the amount of average happiness reaches its maximum.” (Sidgwick, The Methods of Ethics, Bk. 4 Ch. 1 Sec. 2 Para. 4.)

The topic was picked up again by one of our contemporaries, Derek Parfit. As luck would have it, Parfit will be speaking at Scripps at 4:15 on April 16.

His talk will be titled “Can we avoid the repugnant conclusion? A problem in the ethics of population.” If you’re curious, you can read a short article laying out what the repugnant conclusion is; I put it on the sakai site. Or you could come by Pearsons 203 on Thursday, April 8 at 4:15; I will explain it in about half an hour. Or do both!


There was a handout for this class: 16.Mill.handout.pdf