James Martin/CNET

This is a guest column. See below for Greg Lukianoff's bio.

Last month was a bittersweet seventh birthday for Twitter. The Union of Jewish French Students sued the social-media giant for $50 million in a French court in light of anti-Semitic tweets that carried the hashtag #unbonjuif ("a good Jew"). In January, Twitter agreed to delete the tweets, but the student group now wants the identities of the users who sent the anti-Semitic messages so that they can be prosecuted under French law against hate speech. Twitter is resisting. It claims that as an American company protected by the First Amendment, it does not have to aid government efforts to control offensive speech.

Internationally, America is considered radical for protecting speech that is highly offensive. But even in the U.S., Twitter should not be surprised to discover ambivalence and even outright hostility toward its principled aversion to censorship, especially in that once great institution for the open exchange of ideas: American higher education.

"Hate speech" is constitutionally protected in the United States. But the push against "hurtful" and "blasphemous" speech (primarily speech offensive to Islam) is gaining ground throughout the world. Last fall, for example, when many thought a YouTube video that satirized Mohammed caused a spontaneous attack on our consulate in Benghazi, academics across the country rushed to chide America for its expansive protections of speech. And as someone who has spent more than a decade fighting censorship on American college campuses, I run into antagonism toward free speech on a regular basis, most recently last month, when I spoke at Columbia Law School. After my speech, law professor Frederick Schauer criticized his American colleagues for not being more skeptical about the principle of free speech itself.

Forcing hate speech underground by banning it is like taking Xanax for syphilis. You may briefly feel better about your horrible disease, but your sickness will only get worse.

This has become a fairly standard refrain, in my experience, as academics who want to limit free speech often paint themselves as a beleaguered, enlightened minority struggling against the unquestioned dogma of free speech. Free speech is certainly alive in U.S. courts. For example, since 1989 more than a dozen courts have declared different politically correct college speech codes unconstitutional. Nevertheless, the idea that hurtful or offensive speech should be banned prevails on American campuses: approximately 63 percent of over 400 top colleges maintain codes (PDF) that violate First Amendment principles. Meanwhile, prominent professors, such as Jeremy Waldron and Richard Delgado, attempt to seize the moral high ground for "enlightened censorship," and some students even paint themselves as heroes for tearing down campus "free speech walls."

What strikes me about the arguments academics make against free speech is how shallow they tend to be. The critics somehow miss that First Amendment jurisprudence is an extraordinarily thoughtful exposition on what limits are appropriate in a free and diverse society -- and, contrary to the meme of America's mindless approach to speech, there are limits (including, for example, libel, as well as threats or incitement to imminent illegal action).

The authors of the Constitution also realized that people -- flawed, imperfect humans, with biases, blind spots, shortcomings, and agendas -- will decide what speech is and is not acceptable. Part of the wisdom of First Amendment law is that it recognizes that we flawed humans will be tempted to ban speech for no better reason than that officials (or voters) simply dislike or disapprove of an idea or a particular speaker. That's why First Amendment doctrine forbids the use of highly subjective standards, which would invite arbitrary punishment of dissenters, oddballs, satirists, or the misunderstood. Too many scholars seem to think a robot could simply apply such standards to produce a perfect outcome every time.

A common academic argument against free speech relies on the idea that the primary, if not sole, justification for freedom of speech is that it is necessary in order for society to discover "objective truth" -- what I will call "Big T" Truth. But now, so the fashionable argument goes, the academy has found that objective truth does not exist, so we are free to regulate harmful, hurtful, or hateful speech because the benefit of unfettered speech -- revelation of Truth -- is illusory. (A revealing preview of today's anti-free speech arguments can be found in the oft-overlooked dissent to Yale's famous 1975 pro-free speech, pro-academic freedom "Woodward Report" [PDF].)

The idea that society achieves something positive by mandating that people with bad opinions must hide them, or discuss them only in forums of the like-minded, is not only extraordinarily naive, it can be dangerous. Bigots driven into echo chambers may only become more extreme.

No doubt the open, anarchical, epistemological system that was celebrated in the Enlightenment -- which Jonathan Rauch dubbed "liberal science" in his classic work on the value of freedom of speech, "Kindly Inquisitors" -- has resulted in a flowering of creative and scientific thought. It has helped reveal what we consider to be objective facts (e.g., the Earth is an oblate spheroid; gravity is a fundamental force). But the free exchange of ideas benefits society not only by unearthing "Big T" truths; more importantly, it continually exposes mundane yet important pieces of information about the world. I will call this "Little t" truth. "Little t" truths include: who disagrees about what and why, what people feel about a particular issue, what events the newspapers think are important to report. The fact that "Argo" is a movie is truth, whether or not it represents an accurate view of history, as is the fact that some topics of discussion interest no one, while others are radioactive.

Twitter provides a powerful way to view the world. Never before have human beings been able to check the global zeitgeist with such immediacy and on such a massive scale. Its primary service is not to dispense the Platonic ideal of Truth ("the form of beauty = x"), but rather to provide unparalleled access to the peculiar thoughts, ideas, misconceptions, genuine wisdom, fetishes, fads, jokes, obsessions, and problems of a vast sea of people from different cultures, classes, countries, and backgrounds.

In order to be an effective mirror to global society, Twitter thinks of itself primarily as a platform and does its best to get out of the way. Therefore, we know things we simply would not know otherwise -- from the trivial to the serious. The people who want to scour mass media and cleanse it of all hateful or hurtful opinions miss that their purge would deny us important knowledge. Simply put, it is far better to know that there are bigots among us than to pretend all is well. As Harvey Silverglate, co-founder of FIRE (the Foundation for Individual Rights in Education, where I serve as president), likes to say, he supports free speech because he thinks it's important that he know if there's an anti-Semite in the room so he can make sure not to turn his back to that person.

The idea that society achieves something positive by mandating that people with bad opinions must hide them, or discuss them only in forums of the like-minded, is not only extraordinarily naive, it can be dangerous. Bigots driven into echo chambers may only become more extreme, as discussed in Cass Sunstein's book, "Going to Extremes." Meanwhile, what does society gain from such quarantining? A coerced but false silence that, if anything at all, plays into the hands of the paranoid and dangerous who already believe that there is a global conspiracy to shut them up. Forcing hate speech underground by banning it is like taking Xanax for syphilis. You may briefly feel better about your horrible disease, but your sickness will only get worse.

Simply making bigoted speech illegal results in two distortions of reality. First, it can create an overly rosy picture of public sentiment, thus preventing real and festering social problems from being addressed. Or second, paradoxically, it may lead people to believe that they live in a far less tolerant society than they actually do. John L. Jackson, an anthropology professor at the University of Pennsylvania, teased out this idea in his 2008 book "Racial Paranoia: The Unintended Consequences of Political Correctness." Jackson argues that if a minority group believes that only the threats of formal or informal punishments are preventing people from constantly shouting racial slurs at the top of their lungs, the minority may conclude that those other people are far more hateful and bigoted than they may, in fact, be. In this way, attempts to police hateful or hurtful speech may be making people more paranoid than they need to be about the feelings most people actually hold in their hearts.

The only lasting fix to the real problem of racism or anti-Semitism is cultural. A necessarily incomplete attempt to suppress bigotry may well have far worse unintended consequences, as legal regimes that try to ban hate speech drive social resentments underground, thus preventing the right allocation of resources to address social problems openly.

Twitter lets us see people as they are -- a mixed lot on any given day, to be sure. But it is especially important for a free society to learn not just the good news but the bad news as well.