On Liberty is not merely a political text explaining the intricacies of how the state ought to act. It is a love letter to the individual virtues of intellectual curiosity, tolerance, and open‐​mindedness.

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Paul Meany
Intellectual History Editor

Paul Meany is the Editor for Intellectual History at Lib​er​tar​i​an​ism​.org, a project of the Cato Institute. Most of his work focuses on examining thinkers who predate classical liberalism but still articulate broadly liberal attitudes and principles. He is the host of Portraits of Liberty, a podcast about uncovering and exploring underrated figures throughout history who have argued for a freer world. His writing covers a broad range of topics, including proto‐​feminist writers, Classical Greece and Rome’s influence on the American Founding, ancient Chinese Philosophy, tyrannicide, and the first argument for basic income.

Published in 1859, John Stuart Mill’s On Liberty is one of the most celebrated defences of free speech ever written. In this elongated essay, Mill aims to defend what he refers to as “one very simple principle,” what modern commentators would later call the harm principle. This is the idea that people should only be stopped or restrained from acting when their conduct may harm another individual. Mill states 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.” However, Mill’s simple principle is not the only focus of On Liberty. He also discusses the struggle between liberty and authority, the importance of individuality, the limits of state authority, and the practical application of the harm principle. It is a small yet dense essay with many questions about how a free society ought to treat its citizens. Mill’s answers provide the bedrock of what we today call liberalism.

Who is John Stuart Mill

John Stuart Mill was born on May 20th, 1806, in London. John’s father, James Mill, was an ardent reformer and personal friend of Jeremy Bentham, the famous utilitarian philosopher. James Mill was determined to mould John into a well‐​educated leader and an advocate of his reforming ideals. To this end, John was given an extremely rigorous education from a young age. He learned Greek at the age of three, Latin at eight, and read Plato’s dialogues in the original language before his tenth birthday. He was also tutored by some of the brightest minds of his day, including Jeremy Bentham, economist David Ricardo, and classicist, George Grote. Not only did John have to study a wide array of topics, but he was also charged with teaching his younger siblings what he had learned. Given the heavy workload that James Mill imposed on his young son John, James Mill might come across to a modern reader as overly demanding. Regardless of how this might be perceived today, John would later praise his father’s methods, writing, “If I have accomplished anything, I owe it, among other fortunate circumstances, to the fact that through the early training bestowed on me by my father, I started, I may fairly say, with an advantage of a quarter of a century over my contemporaries.” After his intense education, Mill began working in the East India Company, in which he would serve for 35 years.

The Other Author of On Liberty

One can scarcely mention On Liberty without discussing Harriet Taylor. Mill met Harriet in 1831 at a dinner party. The pair quickly became good friends. Mill thought Harriet his intellectual equal and treated her as such. However, Harriet’s husband, John Taylor, disapproved of their friendship and demanded that Harriet break off their friendship. Harriet’s husband eventually softened his approach and allowed Mill to see Harriet occasionally. While Mill and Harriet’s relationship was solely platonic at this time, they married in 1851, two years after the death of John Taylor.

On Liberty was intended to be a short essay, which Mill began writing in 1854 with Harriet’s help. However, when On Liberty was nearing completion in 1858, Harriet suddenly died, from which point onwards Mill made no further edits to the text, defining the work as a tribute to her memory. Today any copy of On Liberty will bear the name of John Stuart Mill, but Mill himself described On Liberty as “more directly and literally our joint production than anything else which bears my name.” Harriet’s influence can also be felt in Mill’s work On the Subjection of Women, a foundational text for liberal feminism inspired by Harriet’s passionate advocacy of female equality. It is challenging to quantify Harriet’s influence on Mill, but if we take Mill’s word, Harriet’s discussions and scrutiny were formative in shaping Mill’s philosophy.

Introduction of On Liberty

Mill opens On Liberty by explaining the nature of liberty versus authority. Traditionally, liberty was defined as “the protection against the tyranny of political rulers.” To achieve liberty, limits on state authority ought to be imposed, which would eventually lead to those in power becoming more akin to tenants than perpetual rulers. By Mill’s time, the old orders of monarchy and aristocracy were waning, and democratic republics began to predominate the European political landscape.

The world was moving towards greater equality, a trend Mill appreciated, although not without reservation. With the rise of democratic government came a new threat, what Alexis De Tocqueville described as “tyranny of the majority.” Mill believed that a new form of social tyranny was emerging, one that was in some ways worse than actual tyranny as it has “fewer means of escape, penetrating much more deeply into the details of life, and enslaving the soul itself.”

At best, this new tyranny could lead to conformity; at worst it stifled the originality and intellectual vigor needed for progress. Mill believes that all eras are either organic or critical. In organic periods people accept some form of positive creed. In critical ones, positive creeds lose their sway without other beliefs emerging to take their place. During critical periods we yearn for new ideas, according to Mill, so we allow people to pursue their lives in “in innumerable and conflicting directions.” This freedom to experiment with different ideas and ways of life allows for progress, both material and moral.

Self‐​Regarding Sphere

At this point in the text, Mill has already outlined the principle which he wishes to defend, the harm principle. In the chapter entitled “Of The Liberty of Thought and Discussion,” Mill argues in favour of freedom of speech in the vast majority of situations, barring a few key exceptions such as when an individual incites immediate violence. Mill deals with three cases of free speech: one in which the suppressed opinion is true, one in which it is partly true, and, lastly, one in which it is wholly false.

Mill explains that “mankind can hardly be too often reminded, that there was once a man named Socrates.” The ancient philosopher Socrates, famous for his Socratic method argument, was put to death by an Athenian jury on charges of impiety and corrupting the youth. Similar to Socrates, Jesus Christ was also persecuted for his beliefs, which in Mill’s day were considered the moral backbone of English society. No person no matter how intelligent is wholly infallible and, for Mill, “All silencing of discussion is an assumption of infallibility.” Therefore, no person has the right to silence others. We should all be keenly aware of our fallibility. Even if the vast majority of people in any given society agree on some issues, it does not justify silencing dissenters. Mill passionately explains that even if “all mankind minus one, were of one opinion, and only one person were of the contrary opinion, mankind would be no more justified in silencing that one person, than he, if he had the power, would be justified in silencing mankind.” Mill laments that so many people have fallen into what he calls the “pleasant falsehood” of believing that “truth triumphs over persecution.” Truth does not inherently triumph over falsehood. The annals of history repeat this lesson constantly, which is why we should always be hesitant to suppress dissenting or differing views, even on the most fundamental questions of life.

What about an opinion which is neither wholly true nor wholly false? Mill was a keen advocate of progress. He rightly believed that the era in which he lived was marked by unprecedented material and moral progress. But Mill did not believe that progress consists of false beliefs being replaced with true beliefs. Instead, he viewed improvement as a cyclical process in which different elements of truth rise and fall. In time, the rigorous challenging of mixed doctrines would allow future thinkers to separate the true parts from the false parts of any given ideology.

But what about wholly false opinions? In modern terms, why should flat earthers, holocaust deniers, and climate change deniers be allowed to express their opinions? For Mill, “however true [the received opinion] may be, if it is not fully, frequently, and fearlessly discussed, it will be held as a dead dogma,not a living truth.” Mill makes a distinction between what he calls true belief and knowledge. True belief is holding correct beliefs; however, knowledge is holding beliefs because they are justified through rational argumentation. If we simply hold onto our beliefs without passionately defending them, they will hold progressively less sway in our mind as they decay into a dead dogma. False beliefs provide us with the opportunity to defend our most cherished beliefs, making sure that they remain a living truth rather than dead dogma. By continually challenging our beliefs, we strengthen them further. Our beliefs are like muscles. If we do not make use of them they will weaken; by consistently defending our opinions, we bolster them against falsities that would usurp their position in our minds.

Note that Mill does not base his arguments for free speech on universal or natural rights. Like both his father and Jeremy Benthem, Mill was a utilitarian, which is the doctrine that actions are right or ethical when they promote the maximum happiness for the majority of people. Simply put, the greatest happiness for the greatest number. Utilitarianism can, at times, have a shaky relationship with the concept of natural or innate rights. The father of Utilitarianism, Jeremy Bentham famously described natural rights as “nonsense on stilts.” It is essential to understand that Mill believes that humans are “progressive beings.” He explains that “the source of everything respectable in man either as an intellectual or as a moral being” is that we are “capable of rectifying…mistakes, by discussion and experience.” Thus those who censor opinions commit “a peculiar evil” by “robbing the human race” of the path to truth. While Mill’s case for free speech is not built upon a foundation of natural rights, it is based upon the proposition that free and unhindered discussion corrects our errors and does so to the long term benefit of humanity. This allows us not only to improve our own lives but those of our future descendants who will also benefit from our discoveries.


Mill argues that in the vast majority of cases we are afforded absolute liberty of thought and expression. But thought and expression do not compose the entirety of life. We also need to make choices and interact with others. In the chapter entitled Of Individuality, as one of the elements of well‐​being, Mill makes a case for the positive value of individuality.

Mill believes that every person has their own personal preferences and tastes in all aspects of life. Mill explains that “human nature is not a machine to be built after a model, and set to do exactly the work prescribed for it, but a tree, which requires to grow and develop itself on all sides, according to the tendency of the inward forces which make it a living thing.” Since there is no one masterplan or method that guarantees a fully flourishing life, Mill believes that there must be “experiments of living.”

Mill despised and feared conformity. He deeply feared a future in which people lived their life based upon nothing but custom and habit. He explains,“The despotism of custom is everywhere the standing hindrance to human advancement.” Mill’s opposition to custom is nuanced. He is not a libertine who supports eccentricity for its own sake. Instead, he argues that when people act upon custom alone, they do not make a decision, they simply follow what has already been done without thought. Our perception and judgement must be fine‐​tuned, and this can only be achieved by exercising our choice. Therefore, Mill explains that “he who does anything because it is the custom makes no choice. He gains no practice either in discerning or desiring what is best.”

But as before with freedom of speech, Mill does not base his arguments in the inherent value of choice or individuality. He believes allowing for individuality and choice creates an industrious and creative environment in which progress is unimpeded. As he explains, “Genius can only breathe freely in an atmosphere of freedom.” Mill’s arguments for individuality also have a personal tinge to them. He had felt firsthand the judgmentalism of Victorian England. At the age of 17, he had been arrested for distributing information on birth control. In his adult life, he was looked at with scorn for his relationship with Harriet Taylor. And throughout his life he had to hide his atheist beliefs fearing ridicule from society at large.

Limits of Authority

In the penultimate chapter, “Of The Limits to the authority of society over the individual,” Mill discusses when state‐​sanctioned coercion is legitimate. The state provides a degree of security and stability. Therefore Mill concludes we have reciprocal obligations to the state and society at large such as respecting others rights and paying our fair share in taxes to uphold justice. But the relationship between the individual and the state is not a one‐​way street; in return for their cooperation and services, the state ought to acknowledge certain limits which it ought not cross as a general rule.

According to Mill, legal coercion is society’s most profound disapproval of specifically egregious actions. It is not to be used lightly; it must only be used to prevent the most egregious and apparent harms. Mill explains that not all harmful or immoral activity ought to be punished by legal coercion.

He also distinguishes between natural and artificial punishments. Artificial punishments are acts of legal coercion while natural punishments consist of the unfavorable social opprobrium of certain conduct. For example, if a person is drunk during the day at home, we ought not to bring the weight of the state upon him but we can voice our disapproval and even disassociate with this person.

There are two spheres of action for Mill: self‐​regarding and other‐​regarding. One affects only the agent while the other affects the agent and other people. In the realm of self‐​regarding acts, Mill believes that “there should be perfect freedom” from coercion. We may be able to attempt to convince others that their self‐​regarding conduct is harmful or unwise by offering “considerations to aid his judgment [and] exhortations to strengthen his will.” But ultimately, the individual is the final judge. To this end Mill is wholly opposed to paternalism.

However, any other‐​regarding action may be subject to the laws and regulations of society. For example, drinking alcohol and selling alcohol are wholly different endeavours. For Mill, society has a legitimate interest in regulating trade to assure there is no foul play or dishonesty in marketing. But these regulations may never result in an outright ban. If he were alive today, Mill would likely approve of health warnings being placed on cigarette packs, but would never advocate for an outright prohibition on cigarettes.

Applying Mill’s System

In the final chapter, Mill discusses the practical applications of his two major principles, which are “that the individual is not accountable to society for his [self‐​regarding] actions” and “that [for] such actions as are prejudicial to the interests of others, the individual is accountable, and may be subjected to social or legal punishment.” Of all the chapters of On Liberty this one covers the broadest range of ideas, ranging from voluntary slavery, the selling of narcotics, suicide, divorce, and birth control. Since it is impossible to cover all of Mill’s conclusions effectively, I will focus upon the area most pertinent for classical liberals, the role of the state.

A General Acceptance of Laissez‐​Faire

As previously mentioned, Mill believes that “trade is a social act,” which means that society has a legitimate interest in regulating certain aspects of selling. Despite society being justified in regulating trade, Mill believes that the doctrine of laissez‐​faire is preferable. He explains that “it is now recognised, though not till after a long struggle, that both the cheapness and the good quality of commodities are most effectually provided for by leaving the producers and sellers perfectly free.” However, Mill does not ground the doctrine of laissez‐​faire in natural rights but its practical benefits. Protectionism or constant regulating “are wrong solely because they do not really produce the results which it is desired to produce by them.” While members of a society are justified in interfering with trade, Mill argued that such control was often inexpedient and could be harmful. He concluded that the majority of the time in economic affairs laissez‐​faire was a preferable system.

The Looming Fear of Increased State Power

Mill feared “the great evil of adding unnecessarily to [government] power.” People are self‐​interested, and this does not magically change when they are in positions of power, as they will use their positions to benefit themselves. Even if politicians were benevolent and only wanted the best for their citizens, Mill was still sceptical about state intervention. Mill believed that “when the thing to be done is likely to be better done by individuals than by the government,” non‐​intervention is the best policy. As a general rule, individuals understand their own situation and preferences better than a third party. Even benevolent governments interventions could end up being flawed and misguided.

Mill feared the growth of a state in which “everything is done through the bureaucracy.” He feared bureaucracy because in a bureaucracy “nothing to which the bureaucracy is really adverse can be done at all.” Mill cites China and Russia as examples of extreme bureaucratic states which curtailed liberty. Mill believed that bureaucracy would naturally lead to stagnation and eventual decline due to the power of vested interests which cripple creativity.

Mill further believes that individuality and spontaneity created progress. Thus, the governing body of society must mirror this by cultivating independent associations and cooperatives which provide alternative solutions. Charities, cooperatives, and voluntary organizations develop individual’s sense of duty and empathy for others. Non‐​intervention allows people to solve their problems and can be a “means to their own mental education.” Mill explains that the state’s “business is to enable each experimentalist to benefit by the experiments of others; instead of tolerating no experiments but its own.”

On Liberty Today

Mill rightly predicted that of all his writings On Liberty would be the most discussed. Surely enough, he was proven correct. On Liberty became massively popular following its publication in 1858. To this day, it is still hailed as one of the best defenses of free speech. But while this is true, this praise does not capture the colossal scope of this small but potent essay. Mill not only called for legal defenses of free speech but also for the promotion of individuality and widespread tolerance on a societal level. Despite his utilitarian roots, Mill’s thoughts in On Liberty represent a love letter to spontaneity, individuality, and the robust importance of choosing one’s own path in life.

This vision of the good life is threatened by two main villains, political and social tyranny. Political tyranny ought to be limited by a general acceptance of laissez‐​faire policies and careful application of the harm principle. Social tyranny is a harder problem to tackle because correcting it requires not only legal corrections but societal change. To curb social tyranny, we ought to celebrate the value of choice and the innumerable ways we can peacefully live our lives not only by experimenting but through critiquing and advising each other on how best to live. Mill never wanted people to invoke the harm principle in order to tell people to stop criticizing their choices. Instead, he wanted us all to engage with each other on how we ought to maximize our happiness through lively and critical discussion over how best to live our lives.

There are many new challenges to Mill’s vision of a free world in the 21st century. The surveillance state intruding upon people’s privacy, the rising popularity of regulating speech, and the unstoppable growth of the regulatory state all threaten the legacy that Mill bequeathed liberal‐​minded people. But On Liberty is not merely a political text explaining the intricacies of how the state ought to act. It is a love letter to the individual virtues of intellectual curiosity, tolerance, and open‐​mindedness.