Tolerance: Can We Live Among Beliefs We Do Not Share?

Key Takeaways

• The Two Faces of Tolerance: Tolerance has always oscillated between a negative posture—enduring what one dislikes—and a positive ideal of respecting diversity. Locke grounded it in religious liberty, Mill in individual autonomy; each offered a different foundation for the same word.
• The Paradox of Tolerance: Karl Popper’s warning that unlimited tolerance necessarily leads to the disappearance of tolerance poses a dilemma no democratic society can sidestep. The insight that an open society may be destroyed from within has only grown more urgent in the age of digital discourse.
• The Limits and Possibilities of Tolerance: In a pluralist society, is tolerance merely the minimum condition for coexistence, or an active virtue in its own right? From Rawls’s political liberalism to Wendy Brown’s critical analysis, the scope and boundaries of tolerance continue to be redrawn.

Why Has This Question Been Asked?

Walk down any busy street and you will hear, if you listen closely, the faint hum of competing convictions. Different prayers, different dietary rules, different ideas about what makes a good life. This has been true since the earliest human settlements. In ancient Rome’s cosmopolitan quarters, in the mixed neighborhoods of medieval Iberia, in the apartment blocks of modern London or Tokyo—wherever people gather, differences of belief are inevitable. A community without disagreement has never existed.

The question is what to do with those differences. History offers one stark answer: punish the wrong belief. There was a time when burning a heretic was considered an act of mercy, a way of saving the soul that had gone astray. In 1553, in Geneva, the Protestant leader Jean Calvin presided over the execution of Michael Servetus, who had denied the doctrine of the Trinity. Servetus was burned alive. Persecution was not a Catholic monopoly. The conviction that one possesses the truth can become, with terrifying ease, a warrant for taking another person’s life. Tolerance emerged as a subject of philosophical inquiry precisely when that conviction began to crack.

“The mere certainty that I am right does not, by itself, entitle me to coerce another.” This realization was not born in the quiet of a scholar’s study. It was born in blood. In the St. Bartholomew’s Day Massacre of 1572, thousands of French Protestants were slaughtered in a single night. During the Thirty Years’ War (1618–1648), the population of the Holy Roman Empire fell by roughly a third. The seed of tolerance was sown in ground soaked red.

It is worth remembering that tolerance did not first appear as a moral ideal. It appeared as exhaustion. The Edict of Nantes (1598) and the Peace of Westphalia (1648) did not resolve the question of religious truth. They merely established frameworks for living together without resolving it—agreements to disagree. Like travellers in a bitter winter who share a fire not out of friendship but because the cold will kill them otherwise, the warring parties of early modern Europe chose coexistence over mutual annihilation. Only later would this grudging compromise begin its slow transformation into something more principled. How that transformation unfolded is the story we are about to follow.

Origins and Development

The history of tolerance is not a straight line. From the practical coexistence of antiquity through the theological intolerance of the Middle Ages to the theoretical foundations of modernity, the path bends back on itself, retreats, leaps forward. Let us walk a short stretch of it.

Ancient Rome was generous enough to welcome the gods of conquered peoples into its own Pantheon—but only so long as those gods did not threaten the imperial order. Christianity was persecuted not for the content of its faith but for its political refusal to honour the emperor as divine. When Christianity itself became the state religion, the tables turned. Augustine, in his letters to the Donatists (Epistulae, 93 and 185), invoked Luke 14:23—compelle intrare, “compel them to come in”—to justify what he called “righteous persecution,” the use of force to rescue souls from error. Under this theological cover, the Inquisition was built and maintained for centuries as an instrument of justice.

The turning point was the Reformation and the wars it unleashed. When Martin Luther nailed his Ninety-Five Theses to the church door in 1517, he was not preaching tolerance. Protestant sects and Catholics alike condemned each other as heretics. But it was precisely the carnage that followed—generation after generation of it—that forced tolerance onto the political agenda as a matter of sheer survival.

Timeline

• 313: Emperor Constantine issues the Edict of Milan, granting legal recognition to Christianity
• 380: Emperor Theodosius makes Christianity the state religion and bans pagan worship
• 1517: Luther’s Reformation; the religious unity of Western Christendom shatters
• 1572: St. Bartholomew’s Day Massacre in France
• 1598: Henri IV issues the Edict of Nantes, guaranteeing Protestants freedom of worship
• 1648: Peace of Westphalia reaffirms the 1555 Peace of Augsburg principle cuius regio, eius religio and extends it to Calvinists
• 1685: Revocation of the Edict of Nantes; Pierre Bayle publishes his Philosophical Commentary in defense of tolerance
• 1689: John Locke publishes A Letter Concerning Toleration
• 1763: Voltaire publishes the Treatise on Tolerance
• 1859: John Stuart Mill publishes On Liberty, extending the principle of tolerance to all areas of individual freedom
• 1945: Karl Popper publishes The Open Society and Its Enemies, formulating the paradox of tolerance
• 1993: John Rawls publishes Political Liberalism, proposing the idea of an “overlapping consensus”

Major Positions and Arguments

Locke: Faith Cannot Be Coerced

In 1689, from his exile in the Netherlands, John Locke released a slim Latin treatise into the world: Epistola de Tolerantia—A Letter Concerning Toleration. Modern tolerance theory begins here.

Locke’s framing of the problem was disarmingly clear. What is the business of the state? To protect “civil interests”—life, liberty, and property—not to save souls. Faith, he argued, belongs to the inner life of the mind, and no external force can alter it. A magistrate may hold a sword to your throat and command you to believe, but the sword cannot reach the place where belief resides. You can order a man to walk to the well, but you cannot order him to find the water sweet.

State-imposed religion is doubly irrational, Locke maintained. The salvation of souls lies beyond the magistrate’s jurisdiction. And even if it did not, coercion is the wrong instrument: it can produce outward conformity, never genuine conviction. Churches, therefore, must be voluntary associations, independent of the state.

Locke’s tolerance, however, had firm boundaries. He excluded atheists from its protection, on the grounds that “those who deny the existence of God are not to be tolerated at all,” since promises, oaths, and contracts—the sinews of civil society—rest ultimately on the belief in a God who enforces them. He also excluded Catholics, not for their theology but for their political allegiance to a foreign sovereign, the Pope. Locke’s tolerance embraced the diversity of Protestant belief while assuming that civil society required, at minimum, a shared faith in God. That assumption would become the next frontier for the thinkers who followed him.

Bayle and Voltaire: The Rights of Conscience and the Weapon of Reason

While Locke was composing his letter, another defense of tolerance was quietly taking root across the Channel. In 1686, Pierre Bayle published his Commentaire philosophique—a “philosophical commentary” on the biblical phrase “compel them to come in”—demonstrating how that single verse from Luke had been weaponized to justify centuries of persecution. Bayle went further than Locke in one crucial respect: he affirmed the rights of the conscientia errans, the erring conscience. Even if a person’s beliefs are objectively false, to punish that person for holding them sincerely is an act of injustice.

Bayle’s intellectual heir appeared a century later. In 1763, Voltaire published his Traité sur la tolérance—the Treatise on Tolerance—prompted by the Calas affair, one of the great miscarriages of justice in French history. Jean Calas, a Protestant merchant in Toulouse, was accused of murdering his son Marc-Antoine to prevent the young man from converting to Catholicism. In 1762, Calas was broken on the wheel. The evidence was flimsy; the son had almost certainly taken his own life. The verdict reeked of sectarian fanaticism—fanatisme, the word Voltaire wielded like a blade. For three years he campaigned for Calas’s posthumous rehabilitation, and in 1765 the conviction was overturned. The Treatise was written in the heat of that fight: an indictment of fanaticism in the name of reason and humanity.

Voltaire’s method was not systematic argument but corrosive wit. He preferred irony and satire to the architecture of philosophical systems. The famous declaration—“I disapprove of what you say, but I will defend to the death your right to say it”—was not actually written by Voltaire; it was coined by his later biographer Evelyn Beatrice Hall. Yet it captures his spirit with uncanny precision. When Voltaire spoke of tolerance, he kept returning to a single, stubborn fact: an innocent old man was tortured to death because he prayed in the wrong way. Illuminate the darkness of fanaticism with the light of reason. That was the work of his life.

Mill: Individual Autonomy and the Harm Principle

Where Locke and Voltaire argued chiefly about religion, John Stuart Mill, in his 1859 On Liberty, flung the doors wide open. Thought, speech, ways of living—anything that belongs to the domain of the individual deserves protection. The scope of tolerance expanded, in a single book, from the chapel to the whole of human life.

Why must liberty be preserved? Mill offered two interlocking reasons. The first was utilitarian: the free circulation of ideas helps us discover truth. In the second chapter of On Liberty he marshalled four arguments against the suppression of any opinion. The silenced opinion may be true. It may contain a portion of truth. Even if entirely false, its collision with the prevailing view forces us to sharpen the grounds of that view. And without such collision, received wisdom degenerates into “dead dogma.” The American jurist Oliver Wendell Holmes Jr., in his celebrated dissent in Abrams v. United States (1919), spoke of a “free trade in ideas”—a phrase whose intellectual parentage leads straight back to Mill.

The second, and for Mill the deeper, reason was the value of individuality. In the third chapter of On Liberty, drawing on Wilhelm von Humboldt, Mill argued that the purpose of human life is “the highest and most harmonious development of [one’s] powers to a complete and consistent whole.” To choose one’s own way of living, even if others think the choice foolish, is essential to that development. A field planted with a single crop may be efficient, but a field sown with many different seeds is more likely to yield unexpected harvests. What Mill feared above all was the “tyranny of the majority”—not the tyranny of law but the invisible pressure of social opinion, which can crush individuality more effectively than any statute. It was the weight of “what will people think?” that kept Mill awake at night, not the policeman’s baton.

Where, then, does freedom end? Mill drew one clean line: the harm principle. “The only purpose for which power can be rightfully exercised over any member of a civilised community, against his will, is to prevent harm to others.” Paternalism—interfering with someone for their own good—is in principle illegitimate. Yet this seemingly crisp rule turns blurry the moment you try to apply it. Are words that wound a person’s deepest sense of self a form of harm? Is the erosion of a community’s traditions? Mill’s line may have been drawn not with a thick marker but with a faint pencil, and where exactly to place things on either side of it remains the subject of fierce debate.

Popper: The Paradox of Tolerance

Locke, Voltaire, Mill: three thinkers who built, brick by brick, the case for tolerance. But in 1945, with the smoke of the Second World War still hanging in the air, Karl Popper shook the whole edifice with a single, devastating observation. In a footnote to The Open Society and Its Enemies, he formulated what has come to be known as the paradox of tolerance.

“Unlimited tolerance must lead to the disappearance of tolerance. If we extend unlimited tolerance even to those who are intolerant, if we are not prepared to defend a tolerant society against the onslaught of the intolerant, then the tolerant will be destroyed, and tolerance with them.”

Karl Popper, The Open Society and Its Enemies, vol. 1, ch. 7, note 4 (1945)

This argument is frequently misunderstood. Popper was not calling for the routine suppression of intolerant movements. In the same note he continued: “I do not imply, for instance, that we should always suppress the utterance of intolerant philosophies; as long as we can counter them by rational argument and keep them in check by public opinion, suppression would certainly be most unwise.” Force is the last resort, reserved for movements that “answer arguments by the use of their fists or pistols” and teach their followers to do the same.

Behind the paradox lay the bitter memory of the Weimar Republic. Germany’s democratic constitution had permitted the Nazi Party to come to power through legal elections, and the Nazis then destroyed democracy from within. Popper wrote The Open Society in wartime exile in New Zealand, watching from afar as totalitarianism consumed Europe. The note carries the weight of that helpless witnessing.

The paradox remains urgent because the pattern keeps recurring. Democratic procedures can be exploited to undermine the very foundations of democracy—free speech, minority rights, the separation of powers. What Popper forces us to confront is not an abstract moral puzzle. It is a practical question: at what point must a free society draw the line and refuse to tolerate those who seek to abolish freedom itself? That is not a question you can answer in an armchair. It is more like steering a ship through a storm, where the decision to turn the wheel must be made in the teeth of the wind.

Rawls: Overlapping Consensus

Half a century after Popper’s warning, John Rawls approached the problem of tolerance from a different direction. In Political Liberalism (1993), Rawls began from what he called “the fact of reasonable pluralism.” In a free society, reasonable people will inevitably arrive at different comprehensive doctrines—different religious, philosophical, and moral worldviews. This is not a failure of reason. It is the natural consequence of liberty.

Can citizens who hold incompatible comprehensive doctrines nevertheless agree on principles of justice? Rawls believed they can, through what he termed an “overlapping consensus.” A Catholic may support certain political principles for Catholic reasons; a Kantian for Kantian reasons; a utilitarian for utilitarian reasons. Each arrives at the same destination by a different path. The consensus does not require anyone to abandon their deep convictions. Like branches growing from different roots that nonetheless meet and interweave at a certain height, diverse worldviews can converge in the political domain.

With Rawls, the meaning of tolerance shifted at its foundations. We do not tolerate others because they are wrong and we are charitably overlooking their error. We accept that, under conditions of freedom, sincere and rational people will reach different conclusions about the deepest questions—and that this divergence is itself something to be respected. Two people gazing at the same night sky may connect the stars into different constellations. Neither is wrong. Rawls’s vision of tolerance rests on that quiet kind of respect.

Wendy Brown: A Critical View of Tolerance

Rawls reimagined tolerance as respectful coexistence. But what if the very word “tolerance” conceals something troubling? The political theorist Wendy Brown, in her 2006 book Regulating Aversion: Tolerance in the Age of Identity and Empire, turned a sharp light on the concept’s underside.

Look closely at the verb “to tolerate,” Brown urged, and you will find a power asymmetry built into its grammar. The one who tolerates occupies the position of the norm; the one who is tolerated is the deviation. Is tolerance actually dissolving discrimination, or is it merely managing discrimination’s persistence in a gentler key—a technique of governance rather than a path to justice?

Consider the phrase “tolerating homosexuality.” Embedded in those two words is the assumption that heterosexuality is the standard from which homosexuality departs. If genuine equality is the goal, then what is needed may not be “tolerance” but recognition—or, more fundamentally, justice. Brown exposed the way the rhetoric of tolerance can function as a veil, softening the appearance of structural inequality without addressing its substance.

Brown was not rejecting tolerance outright. Her question was sharper than that: is the word being used as a convenient piece of cloth to wrap up problems and set them aside? If we do not look at what lies inside the wrapping—the imbalance of power, the structural discrimination, the silence of those who cannot speak—then tolerance becomes nothing more than a lid on a pot that is still boiling.

Key Controversies

The Grounds of Tolerance

The justifications offered for tolerance differ strikingly from one thinker to the next. Locke grounded tolerance in an epistemological fact (faith cannot be coerced) and a political boundary (the salvation of souls is not the state’s business). Mill stood on different terrain: the moral value of individual autonomy and the utilitarian benefits of intellectual diversity. Rawls, for his part, sought to ground tolerance not in any particular comprehensive doctrine but in the conditions necessary for political stability under reasonable pluralism.

The German philosopher Rainer Forst, in Toleration in Conflict (2003; English translation 2013), organized these competing justifications into four ideal types. (1) The permission conception: the powerful grant tolerance as a favour. (2) The coexistence conception: rival groups accept tolerance as a pragmatic means of keeping the peace. (3) The respect conception: citizens recognize one another as moral and political equals, even when they disagree. (4) The esteem conception: the beliefs of others are regarded as positively valuable. Forst argued that only the respect conception avoids collapsing into a relationship of domination. The same word, “tolerance,” can shelter radically different realities depending on which root it grows from.

Tolerance versus Recognition

In his 1994 essay “The Politics of Recognition,” the Canadian philosopher Charles Taylor drew a distinction that has shaped debate ever since. Tolerance can mean merely putting up with someone’s existence. Recognition means affirming their culture and identity as genuinely valuable. For minorities, mere tolerance can feel like a backhanded compliment: “We will endure you” is not the same as “You belong here as an equal.”

Taylor traced the tension between two modern ideals: a politics of equal dignity, which demands identical treatment for all, and a politics of difference, which demands that distinct cultural identities be acknowledged and valued. Yet the call to recognize all cultural practices equally carries its own dangers. It risks turning a blind eye to oppression within a culture—the denial of women’s rights, for instance, or the refusal to let members leave. Susan Moller Okin posed the question most pointedly in her 1999 essay: “Is Multiculturalism Bad for Women?” The line between cultural respect and complicity in harm is not easy to draw.

Hate Speech and Free Expression

No contemporary debate tests the boundaries of tolerance more fiercely than the question of hate speech. If we follow Mill’s liberty principle faithfully, even the most offensive expression should remain unregulated so long as it does not directly cause harm. The United States Supreme Court has largely adopted this position, holding that hateful speech is protected under the First Amendment unless it constitutes incitement to “imminent lawless action” (Brandenburg v. Ohio, 1969).

Against this, Jeremy Waldron argued in The Harm in Hate Speech (2012) that hate speech damages the “dignity” of minorities and erodes the basic “assurance of inclusion” that allows them to live safely within society. The injury is not merely a bruised feeling. It strikes at the very premise that a group is accepted as a legitimate part of the community. Where we draw the boundary of “harm” determines how wide or narrow the space of tolerance will be. And the hand that draws that boundary may always, inevitably, tremble a little.

Influence and Legacy

The words of philosophers eventually hardened into law and institutions. Article 10 of the French Declaration of the Rights of Man and of the Citizen (1789) declares that no one shall be disturbed on account of their opinions, including religious opinions, provided their expression does not disturb the public order established by law. Across the Atlantic, the Virginia Statute for Religious Freedom, drafted by Thomas Jefferson and enacted in 1786, bears the unmistakable imprint of Locke. The First Amendment to the United States Constitution—its Establishment Clause and Free Exercise Clause—can be read as Lockean tolerance translated into the language of constitutional law.

In Europe, the Basic Law of the Federal Republic of Germany (1949), forged in the aftermath of Nazism, adopted the principle of streitbare Demokratie—“militant democracy.” This is, in effect, Popper’s paradox rendered as a legal doctrine. Political parties that seek to abolish the free democratic basic order may be declared unconstitutional and banned. Intolerance, under certain conditions, will not be tolerated. The scars of Weimar remain visible in the architecture of German law.

In literature, Gotthold Ephraim Lessing’s play Nathan der Weise (Nathan the Wise, 1779) offered the parable of the three rings. A father bequeaths to his three sons three rings, indistinguishable from one another, only one of which is the “true” ring. Which is genuine? No one can tell. Therefore, the wise Nathan counsels, let each son prove the virtue of his ring by living well. The play is a monument of the German Enlightenment and a literary touchstone for interfaith dialogue that continues to be performed on stages around the world.

In the twentieth century, the reach of tolerance extended far beyond religion. Race, sex, sexual orientation, disability, cultural background—wherever human difference exists, the question of tolerance follows. The Universal Declaration of Human Rights (1948) affirmed freedom of thought, conscience, and religion in Article 18. The International Covenants on Human Rights (1966) gave these principles binding legal force. And in 1995, UNESCO’s Declaration of Principles on Tolerance defined tolerance as “respect, acceptance and appreciation of the rich diversity of our world’s cultures, our forms of expression and ways of being human.” From “enduring what you dislike” to “respecting what is different”—the centre of gravity of the word has shifted, over the centuries, a considerable distance.

Connecting to the Present

The questions raised by tolerance thread through our daily lives more deeply than we might suppose.

There was a time when encountering a different opinion meant a conversation at the neighbourhood fence, a debate in a pub, at most a letter to the editor. Those encounters had faces, tones of voice, the pause in which you read the other person’s expression. Today, the opinions of strangers from every corner of the world arrive instantly, anonymously, stripped of context. We collide with disagreement far more often, yet we have fewer means of handling the collision gracefully. The reflex to block or mute is, in one light, a surrender of tolerance; in another, it is the only way to preserve one’s sanity. The art of living with difference has not kept pace with the technology that multiplies our exposure to it.

Tolerance is tested in concrete, everyday decisions, not only in the digital sphere. Should school cafeterias offer halal meals? Should the wearing of religious veils be permitted in public spaces? In 2004, France passed a law banning conspicuous religious symbols in state schools, igniting fierce debate. Behind each of these specific questions, the same fundamental problem that Locke identified over three centuries ago—how to reconcile private conviction with public order—is still breathing.

There is one more dimension that deserves attention: the phenomenon of social exclusion based on past statements or actions. A remark made a decade ago is unearthed and, overnight, a person loses their standing in their community. Is this legitimate accountability, or a new form of intolerance? Mill’s fear of the “tyranny of the majority”—operating not through law but through the invisible weight of public opinion—seems to have found a fresh incarnation. At the same time, people who were silenced for years are finally finding a voice. Simple judgments about who is right are not available here. The stubbornness of the question is itself the point.

Questions for the Reader

• What is the belief or practice you find most difficult to tolerate? Where does the line lie, and what grounds your decision to draw it there?
• Does the posture of “tolerating” someone treat them as an equal—or does the very word imply a hierarchy?
• If an intolerant movement sought power through democratic means, at what point would you argue that the limits of tolerance have been reached?

References

• Primary Texts
  • John Locke, A Letter Concerning Toleration (1689)
  • Pierre Bayle, Commentaire philosophique sur ces paroles de Jésus-Christ: Contrains-les d’entrer (1686)
  • Voltaire, Traité sur la tolérance (1763)
  • John Stuart Mill, On Liberty (1859)
• Studies
  • Karl Popper, The Open Society and Its Enemies, vol. 1 (1945)
  • John Rawls, Political Liberalism (Columbia University Press, 1993)
  • John Rawls, A Theory of Justice, §35 “Toleration of the Intolerant” (Harvard University Press, 1971)
  • Wendy Brown, Regulating Aversion: Tolerance in the Age of Identity and Empire (Princeton University Press, 2006)
  • Rainer Forst, Toleranz im Konflikt (Suhrkamp, 2003); English translation: Toleration in Conflict: Past and Present (Cambridge University Press, 2013)
  • Jeremy Waldron, The Harm in Hate Speech (Harvard University Press, 2012)
  • Charles Taylor, “The Politics of Recognition,” in Multiculturalism, ed. Amy Gutmann (Princeton University Press, 1994)
  • Susan Moller Okin, “Is Multiculturalism Bad for Women?” in Is Multiculturalism Bad for Women?, ed. Joshua Cohen et al. (Princeton University Press, 1999)
• Overviews
  • Susan Mendus, Toleration and the Limits of Liberalism (Macmillan, 1989)
  • John Horton & Susan Mendus, eds., Toleration: An Elusive Virtue (Princeton University Press, 1996)