John Stuart Mill on Free Expression

British 19th-century philosopher John Stuart Mill crafted a concise, razor-sharp, and lasting essay on the necessity of free speech and open debate. 

An engraving of John Stuart Mill from "John Stuart Mill: His Life and Life's Work" by Samuel Saenger, 1901. Public Domain

In his influential 1859 essay “On Liberty,” philosopher John Stuart Mill articulated one of the most compelling defenses of freedom of speech ever written. The book became so popular after its publication that British undergraduates in the 1860s were thought to know it by heart. Historian Peter Marshall described Mill’s work as “one of the great classics of libertarian thought” for its emphasis on individual freedoms.

Today, it’s the symbol of office for the president of England’s Liberal Democrat Party and serves as an emblem of democratic societies around the world. As the American electorate prepares for the 2024 presidential election, Mill’s comments can illuminate the value of the democratic process and the importance of open debate.

"On Liberty" by John Stuart Mill.

John Stuart Mill

Born in 1806, Mill received a rigorous education under his father’s demanding tutelage. After learning Latin and ancient Greek before age 10, Mill kept studying a wide range of disciplines, from poetry to zoology, though history remained his primary passion.

A few decades before Mill’s birth, the Western world witnessed two bloody revolutions. Across the Atlantic, the American Revolution secured independence from Britain’s tyrannical rule, effectively affirming freedom of religion and “freedom of speech, ... of the press; ... [and] the right of the people peaceably to assemble” as inalienable rights. In the Old World, the French Revolution of 1789 began with and partially accomplished the same objectives. Its despotic turn, however, made the precarious nature of freedom even more salient.

"John Stuart Mill," 1873, by an anonymous artist in the style of G.F. Watts. Oil on canvas; 26 1/5 inches by 21 3/4 inches. National Portrait Gallery, London. Public Domain

Writing in the mid-1850s as an accomplished political official and philosopher, Mill felt that freedom, and freedom of speech in particular, was still too flimsy a notion. It needed a more staunch defense. “On Liberty,” which offers three arguments in favor of free expression, attempts that defense.

The Potential Truth of Silenced Opinions

Mill’s first argument for protecting citizens’ expression holds that even unpopular or controversial opinions might be true. Throughout history, most truths that eventually became self-evident were once contentious. For example, the earth’s rotation around the sun prompted bloody diatribes between proponents of that opinion and opponents who wanted to silence it. It was highly unpopular for a time, but it was true.

As Mill recognized, silencing dissenting opinions assumes “our own infallibility.” Yet no one is infallible. No one can know whether an opinion is false unless it undergoes open discussion and critical scrutiny. Suppressing ideas stifles our collective search for truth and impairs every individual involved in that search: “The peculiar evil of silencing the expression of an opinion is, that it is robbing the human race; posterity as well as the existing generation; those who dissent from the opinion, still more than those who hold it,” Mill wrote.

Debate as an Essential Vehicle to Truth

If open expression is the engine that enables truth to surface, debate is the engine that brings it about. When an idea is challenged in a debate, all parties involved are forced to reexamine their beliefs, or at least justify them compellingly. In an ideal scenario, a debate would deepen everyone’s grasp of the reasons behind their claims, which should stand as close to the truth as possible.

Chamber of the House of Commons in the Houses of Parliament in the UK, where Mill’s “On Liberty” is symbolically gifted to each new president of the Liberal Democrat Party. Firebrace/Open Government License v3.0

Truth, Mill tells us, becomes clearer and stronger through the continual confrontations of conflicting views. A society that allows for free and open debate is one that fosters intellectual growth. As the Greek philosopher Plato put it almost 2,000 years ago through the figure of Socrates: “I am one of those who are very willing to be refuted if I say anything which is not true, and very willing to refute any one else who says what is not true, and quite as ready to be refuted as to refute; for I hold that this is the greater gain of the two, just as the gain is greater of being cured of a very great evil than of curing another.” Public and private conversations help us see important alternatives that we might otherwise miss and thus bring us closer to the truth.

Partial Truths as Part of Truth

Mill’s third argument maintains that incorrect ideas often contain slivers of truth. He reframed incorrect opinions as “partial” truths. Most of the issues that animate fervent political debate are complex. They can rarely be solved by single solutions. Although not every stance equally approximates truth, it’s very unlikely for one “side” of whatever argument to have a complete grasp of the right answer.

This attitude toward conflicting views begets humility and encourages the steadfast pursuit of truth, which is ultimately meant to reject falsehood. He wrote: “Every opinion which embodies somewhat of the portion of truth which the common opinion omits, ought to be considered precious, with whatever amount of error and confusion that truth may be blended.”

When a government protects the free and safe expression of ideas in public and private life, it ensures that its populace isn’t deprived of a path to greater understanding and, in Mill’s account, to a better life.

The Tyranny of the Majority and the Harm Principle

Behind these three arguments is Mill’s concern with what he called the “tyranny of the majority.” Government censorship is the most decisive obstacle for free expression, but public opinion can hinder it, too. The desire for social acceptance and the fear of ostracization can silence people just as effectively as legislation. Today, we call it “mob rule.” In Mill’s view, this tyranny of the majority is more pernicious that blatant legal tyranny because it’s harder to recognize.

Former President Donald Trump and Vice President Kamala Harris shake hands prior to the presidential debate at the National Constitution Center in Philadelphia on Sept. 10, 2024. Saul Loeb/AFP via Getty Images

To guard against mob rule, Mill introduced the “harm principle,” which would apply in all domains, including speech: “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.” Based on this principle, being offensive or disagreeable does not justify suppressing speech. Only a direct detrimental consequence on a person’s well-being could warrant the suspension of the perpetrator’s freedom of expression.

Of course, the harm principle is a theoretical standard. Its applications are less straightforward than its abstract formulation. For one, who is to decide when speech directly causes harm? Does that decision belong to the parties involved or to some legal third-party? Critics later worried that Mill’s vague principle could be used to justify invasive government interventions in the name of people’s well-being.

Another criticism concerns the assumption that the continuous clash of competing ideas eventually leads to truth. An increase in the quantity of available opinions and their respective contestations doesn’t guarantee a clearer grasp of the “better” ones, especially in complicated matters like morally charged issues. Moreover, the rise of independent media in recent years has given more people channels for expressing their opinions freely. However, is it really the case, as Mill would have us believe, that such a busy blend of competing thoughts makes truth clearer and stronger? Could it have the opposite effect?

Despite his scheme’s imperfections, Mill was among the first philosophers to emphasize that intellectual and moral progress can occur only in a society where open discourse is the norm. His defense of free expression remains a cornerstone of liberal thought, helping us to distinguish between free and tyrannical societies and bolster our commitment to democracy and liberty.

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