Little distinguishes democracy in America more sharply from Europe than the primacy—and permissiveness—of our commitment to free speech. Yet ongoing controversies at American universities suggest that free speech is becoming a partisan issue. While conservative students defend the importance of inviting controversial speakers to campus and giving offense, many self-identified liberals are engaged in increasingly disruptive, even violent, efforts to shut them down. Free speech for some, they argue, serves only to silence and exclude others. Denying hateful or historically “privileged” voices a platform is thus necessary to make equality effective, so that the marginalized and vulnerable can finally speak up—and be heard.

The reason that appeals to the First Amendment cannot decide these campus controversies is because there is a more fundamental conflict between two, very different concepts of free speech at stake. The conflict between what the ancient Greeks called isegoria, on the one hand, and parrhesia, on the other, is as old as democracy itself. Today, both terms are often translated as “freedom of speech,” but their meanings were and are importantly distinct. In ancient Athens, isegoria described the equal right of citizens to participate in public debate in the democratic assembly; parrhesia, the license to say what one pleased, how and when one pleased, and to whom.

When it comes to private universities, businesses, or social media, the would-be censors are our fellow-citizens, not the state. Private entities like Facebook or Twitter, not to mention Yale or Middlebury, have broad rights to regulate and exclude the speech of their members. Likewise, online mobs are made up of outraged individuals exercising their own right to speak freely. To invoke the First Amendment in such cases is not a knock-down argument, it’s a non sequitur.

John Stuart Mill argued that the chief threat to free speech in democracies was not the state, but the “social tyranny” of one’s fellow citizens. And yet today, the civil libertarians who style themselves as Mill’s inheritors have for the most part failed to refute, or even address, the arguments about free speech and equality that their opponents are making.

The two ancient concepts of free speech came to shape our modern liberal democratic notions in fascinating and forgotten ways. But more importantly, understanding that there is not one, but two concepts of freedom of speech, and that these are often in tension if not outright conflict, helps explain the frustrating shape of contemporary debates, both in the U.S. and in Europe—and why it so often feels as though we are talking past each other when it comes to the things that matter most.

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Of the two ancient concepts of free speech, isegoria is the older. The term dates back to the fifth century BCE, although historians disagree as to when the democratic practice of permitting any citizen who wanted to address the assembly actually began. Despite the common translation “freedom of speech,” the Greek literally means something more like “equal speech in public.” The verb agoreuein, from which it derives, shares a root with the word agora or marketplace—that is, a public place where people, including philosophers like Socrates, would gather together and talk.

In the democracy of Athens, this idea of addressing an informal gathering in the agora carried over into the more formal setting of the ekklesia or political assembly. The herald would ask, “Who will address the assemblymen?” and then the volunteer would ascend the bema, or speaker’s platform. In theory, isegoria meant that any Athenian citizen in good standing had the right to participate in debate and try to persuade his fellow citizens. In practice, the number of participants was fairly small, limited to the practiced rhetoricians and elder statesmen seated near the front. (Disqualifying offenses included prostitution and taking bribes.)

Although Athens was not the only democracy in the ancient world, from the beginning the Athenian principle of isegoria was seen as something special. The historian Herodotus even described the form of government at Athens not as demokratia, but as isegoria itself. According to the fourth-century orator and patriot Demosthenes, the Athenian constitution was based on speeches (politeia en logois) and its citizens had chosen isegoria as a way of life. But for its critics, this was a bug, as well as a feature. One critic, the so-called ‘Old Oligarch,’ complained that even slaves and foreigners enjoyed isegoria at Athens, hence one could not beat them as one might elsewhere.

Critics like the Old Oligarch may have been exaggerating for comic effect, but they also had a point: as its etymology suggests, isegoria was fundamentally about equality, not freedom. As such, it would become the hallmark of Athenian democracy, which distinguished itself from the other Greek city-states not because it excluded slaves and women from citizenship (as did every society in the history of humankind until quite recently), but rather because it included the poor. Athens even took positive steps to render this equality of public speech effective by introducing pay for the poorest citizens to attend the assembly and to serve as jurors in the courts.

As a form of free speech then, isegoria was essentially political. Its competitor, parrhesia, was more expansive. Here again, the common English translation “freedom of speech” can be deceptive. The Greek means something like “all saying” and comes closer to the idea of speaking freely or “frankly.” Parrhesia thus implied openness, honesty, and the courage to tell the truth, even when it meant causing offense. The practitioner of parrhesia (or parrhesiastes) was, quite literally, a “say-it-all.”

Parrhesia could have a political aspect. Demosthenes and other orators stressed the duty of those exercising isegoria in the assembly to speak their minds. But the concept applied more often outside of the ekklesia in more and less informal settings. In the theater, parrhesiastic playwrights like Aristophanes offended all and sundry by skewering their fellow citizens, including Socrates, by name. But the paradigmatic parrhesiastes in the ancient world were the Philosophers, self-styled “lovers of wisdom” like Socrates himself who would confront their fellow citizens in the agora and tell them whatever hard truths they least liked to hear. Among these was Diogenes the Cynic, who famously lived in a barrel, masturbated in public, and told Alexander the Great to get out of his light—all, so he said, to reveal the truth to his fellow Greeks about the arbitrariness of their customs.

The danger intrinsic in parrhesia’s offensiveness to the powers-that-be—be they monarchs like Alexander or the democratic majority—fascinated Michel Foucault, who made it the subject of a series of lectures at Berkeley (home of the original campus Free Speech Movement) in the 1980s. Foucault noticed that the practice of parrhesia necessarily entailed an asymmetry of power, hence a “contract” between the audience (whether one or many), who pledged to tolerate any offense, and the speaker, who agreed to tell them the truth and risk the consequences.

If isegoria was fundamentally about equality, then, parrhesia was about liberty in the sense of license—not a right, but rather an unstable privilege enjoyed at the pleasure of the powerful. In Athenian democracy, that usually meant the majority of one’s fellow citizens, who were known to shout down or even drag speakers they disliked (including Plato’s brother, Glaucon) off the bema. This ancient version of “no-platforming” speakers who offended popular sensibilities could have deadly consequences—as the trial and death of Socrates, Plato’s friend and teacher, attests.

Noting the lack of success that Plato’s loved ones enjoyed with both isegoria and parrhesia during his lifetime may help explain why the father of Western philosophy didn’t set great store by either concept in his works. Plato no doubt would have noticed that, despite their differences, neither concept relied upon the most famous and distinctively Greek understanding of speech as logos—that is, reason or logical argument. Plato’s student, Aristotle, would identify logos as the capacity that made human beings essentially political animals in the first place. And yet neither isegoria nor parrhesia identified the reasoned speech and arguments of logos as uniquely deserving of equal liberty or license. Which seems to have been Plato’s point—how was it that a democratic city that prided itself on free speech, in all of its forms, put to death the one Athenian ruled by logos for speaking it?

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Unsurprisingly perhaps, parrhesia survived the demise of Athenian democracy more easily than isegoria. As Greek democratic institutions were crushed by the Macedonian empire, then the Roman, parrhesia persisted as a rhetorical trope. A thousand years after the fall of Rome, Renaissance humanists would revive parrhesia as the distinctive virtue of the counselor speaking to a powerful prince in need of frank advice. While often couched in apologetics, this parrhesia retained its capacity to shock. The hard truths presented by Machiavelli and Hobbes to their would-be sovereigns would inspire generations of “libertine” thinkers to come.

Still, there was another adaptation of the parrhesiastic tradition of speaking truth to power available to early modern Europeans. The early Christians took a page from Diogenes’s book in spreading the “good news” of the Gospel throughout the Greco-Roman world—news that may not have sounded all that great to the Roman authorities. Many of the Christians who styled themselves as “Protestants” after the Reformation thought that a return to an authentically parrhesiastic and deliberately offensive form of evangelism was necessary to restore the Church to the purity of “primitive” Christianity. The early Quakers, for example, were known to interrupt Anglican services by shouting down the minister and to go naked in public “for a sign.”

Isegoria, too, had its early modern inheritors. But in the absence of democratic institutions like the Athenian ekklesia, it necessarily took a different form. The 1689 English Bill of Rights secured “the freedom of speech and debates in Parliament,” and so applied to members of Parliament only, and only when they were present in the chamber. For the many who lacked access to formal political participation, the idea of isegoria as an equal right of public speech belonging to all citizens would eventually migrate from the concrete public forum to the virtual public sphere.

For philosophers like Spinoza and Immanuel Kant, “free speech” meant primarily the intellectual freedom to participate in the public exchange of arguments. In 1784, five years before the French Revolution, Kant would insist that “the freedom to make public use of one’s reason” was the fundamental and equal right of any human being or citizen. Similarly, when Mill wrote On Liberty less than a century later, he did not defend the freedom of speech as such, but rather the individual “freedom of thought and discussion” in the collective pursuit of truth. While the equal liberty of isegoria remained essential for these thinkers, they shifted focus from actual speech—that is, the physical act of addressing others and participating in debate—to the mental exercise of reason and the exchange of ideas and arguments, very often in print. And so, over the course of two millennia, the Enlightenment finally united isegoria and logos in an idealized concept of free speech as freedom only for reasoned speech and rational deliberation that would have made Plato proud.

This logo-centric Enlightenment ideal remains central to the European understanding of free speech today. Efforts in Europe to criminalize hate speech owe an obvious debt to Kant, who described the freedom of (reasoned) speech in public as “the most harmless” of all. The same could never be said of ancient or early modern parrhesia, which was always threatening to speakers and listeners alike. Indeed, it was the obvious harm caused by their parrhesiastic evangelism to their neighbors’ religious sensibilities that led so many evangelical Protestants to flee prosecution (or persecution, as they saw it) in Europe for the greater liberty—or license—of the New World. American exceptionalism can thus be traced all the way back to the seventeenth and eighteenth centuries: while America got the evangelicals and libertines, Europe kept the philosophers.

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Debates about free speech on American campuses today suggest that the rival concepts of isegoria and parrhesia are alive and well. When student protesters claim that they are silencing certain voices—via no-platforming, social pressure, or outright censorship—in the name of free speech itself, it may be tempting to dismiss them as insincere, or at best confused. As I witnessed at an event at Kenyon College in September, when confronted with such arguments the response from gray-bearded free-speech fundamentalists like myself is to continue to preach to the converted about the First Amendment, but with an undercurrent of solidaristic despair about “kids these days” and their failure to understand the fundamentals of liberal democracy.

No wonder the “kids” are unpersuaded. While trigger warnings, safe spaces, and no-platforming grab headlines, poll after poll suggests that a more subtle, shift in mores is afoot. To a generation convinced that hateful speech is itself a form of violence or “silencing,” pleading the First Amendment is to miss the point. Most of these students do not see themselves as standing against free speech at all. What they care about is the equal right to speech, and equal access to a public forum in which the historically marginalized and excluded can be heard and count equally with the privileged. This is a claim to isegoria, and once one recognizes it as such, much else becomes clear—including the contrasting appeal to parrhesia by their opponents, who sometimes seem determined to reduce “free speech” to a license to offend.

Recognizing the ancient ideas at work in these modern arguments puts those of us committed to America’s parrhesiastic tradition of speaking truth to power in a better position to defend it. It suggests that to defeat the modern proponents of isegoria—and remind the modern parrhesiastes what they are fighting for—one must go beyond the First Amendment to the other, orienting principle of American democracy behind it, namely equality. After all, the genius of the First Amendment lies in bringing isegoria and parrhesia together, by securing the equal right and liberty of citizens not simply to “exercise their reason” but to speak their minds. It does so because the alternative is to allow the powers-that-happen-to-be to grant that liberty as a license to some individuals while denying it to others.

In contexts where the Constitution does not apply, like a private university, this opposition to arbitrariness is a matter of culture, not law, but it is no less pressing and important for that. As the evangelicals, protesters, and provocateurs who founded America’s parrhesiastic tradition knew well: When the rights of all become the privilege of a few, neither liberty nor equality can last.