Maybe it came in the form of racism or sexism, such as in the cases of Roseanne Barr, Quinn Norton, or Sarah Jeong. Maybe it was someone whose jokes were too foul, such as former Guardians of the Galaxy director, James Gunn. Maybe it was even the President of the United States and his alleged description of the country of Haiti. No matter what your political or ideological beliefs, chances are that some figure or topic in the recent news will have confirmed it for you: there are certain things that we simply cannot say.

But should we not be allowed to use this kind of language? Should hate speech—a category already exempt from free speech laws in several European nations—or any other language or topic that could be considered too grotesque or dangerous—be banned from public forums, social media, press organizations, etc.? Let us consider the implications of doing so.

In order to ban hate speech, we would first have to agree upon what is and is not ok to say. The obvious problem is that this hypothetical list of taboo topics will be radically different, depending on who is making that decision. As Christopher Hitchens pointedly asks,

To whom do you award the right to decide which speech is harmful, or who is the harmful speaker? Or to determine in advance what are the harmful consequences going to be, that we know enough about in advance to prevent? To whom would you give this job? To whom are you going to award the job of being the censor?

Consider the would-be censors in the case of Fallon Fox, a transwoman, who fights in the women’s featherweight division of the Ultimate Fighting Championship (UFC). Some have argued that Fox, who spent the first thirty years of her life as a male, has inherent physical advantages—such as greater bone density and muscle strength—over female fighters, due to her genetics. However, others have been quick to quell these conversations, labeling those who’ve suggested this as transphobic. Their remarks, they argue, constitute hate speech and warrant censorship of the topic. Regardless of your leanings on this issue, do you feel that the answer is so obvious that the very discussion should be prevented?

Consider what would happen if the right to censorship were given to those who are vehemently against homosexuality. Currently, there are laws in several US states making it a criminal offense for schools to talk about homosexuality in health classes. What if the advocates of these laws were given the right to censor such discussions at a national level? Do you think the prevention of this kind of discussion would be beneficial?

What if the censor were the government of a religious nation which had criminalized atheism? Remember, this censor has not only the right to decide which speech is unacceptable, but can also choose a punishment. The punishment it has chosen is death. Do you think this is a fair penalty for the crime of atheist speech?

There is no agreed-upon answer as to which topics should be considered offensive and which should not. You probably feel that your own instincts on each topic represent the most moral options. But what if the appointed censor—whether it be the government, a business, etc.—were to disagree? What if it were to deem taboo the discussions that you felt to be necessary and allow those you felt should be prevented? When you give away the right to choose for yourself, this is an inevitability.

And, even if we could agree upon the speech that should be disallowed, what should the punishment be? Should the offender be fired? Fined? Jailed? The New York Times has shown that inconsistencies about this can exist even within an organization. While they have been quick to reaffirm their confidence in the newly hired Sarah Jeong, despite her history of racist tweets, they were equally quick to fire Quinn Norton for the same offense earlier this year. She was terminated within seven hours of her hiring. To cite Christopher Hitchens again: “To whom would you delegate the task of deciding for you what you could read? To whom would you give the job of deciding for you, relieve you of the responsibility of hearing what you might have to hear?”

If each of the examples above could be considered hate speech, or words that “by their very utterance inflict injury,” then maybe this ambiguous category is not so useful at determining what should or should not be protected by a country’s free speech laws. However, there is another category of speech which may be considered more obviously dangerous.

A 1969 US Supreme Court decision stated that speech can be prohibited by law if it is “directed at inciting or producing imminent lawless action” and is “likely to incite or produce such action.” While hate speech is often open to interpretation, words that promote civil unrest and lawlessness must be easier to determine. Surely this category, at least, should fall outside the bounds of free speech?

This is the very argument that the Athenians used to sentence Socrates to death. While the official crimes against him were “introducing new deities” and “corrupting youth,” it is commonly believed that the government feared that his anti-democratic teachings could lead to another period of instability in the region. Do you think the government was right to kill this man in the interests of preventing a breach of the peace?

Consider a more recent political figure: Martin Luther King, Jr. One of the foundations of King’s civil rights movement was the practice of civil disobedience—the refusal to obey government demands or commands and nonresistance to consequent arrest and punishment. Isn’t this inciting lawlessness by definition?

These two examples alone should make the dangerous ambiguity of this category apparent. In fact, in a case just twenty years prior to the above-mentioned decision, a majority of the Supreme Court argued that

[The] function of free speech under our system of government is to invite dispute. It may indeed best serve its high purpose when it induces a condition of unrest, creates dissatisfaction with conditions as they are, or even stirs people to anger. Speech is often provocative and challenging. It may strike at prejudices and preconceptions and have profound unsettling effects as it presses for acceptance of an idea. That is why freedom of speech, though not absolute, is nevertheless protected against censorship or punishment.

This touches on the most important facet of free speech: that the most uncomfortable, challenging and even inflammatory subjects—those that promote unrest—should not be avoided. In fact, they are the most important topics to discuss, in the interests of the progression of society. As George Bernard Shaw once pointed out, “All great truths begin as blasphemies.”

When Charles Darwin’s theory of evolution was first introduced to the mainstream, many in the church considered—as some still do—the topic too dangerous and heretical to discuss. The same was said of Galileo’s assertion that the Earth was not the center of the universe. By giving up the right to talk about uncomfortable topics and to consider unpopular opinions, we risk silencing revolutionary ideas such as these. Given the tumultuous history of free speech throughout the world, it’s difficult not to wonder how many ideas have already been lost to time for this reason.

More recent examples of discussions being silenced are, unfortunately, quite easy to come by. In January of this year, James Damore was fired for discussing possible explanations for gender gaps and differences in the tech world.

Is it possible that Damore was motivated by some kind of gender bias? Yes. However, there is an alternative explanation: that he wrote in the interest of allowing people to live as they are, instead of trying to fit an expected narrative. The inclusion in his memo of this quotation from a 2008 study published in the Journal of Personality and Social Psychology suggests he did:

Note that contrary to what a social constructionist would argue, research suggests that “greater nation-level gender equality leads to psychological dissimilarity in men’s and women’s personality traits.” Because as “society becomes more prosperous and more egalitarian, innate dispositional differences between men and women have more space to develop and the gap that exists between men and women in their personality becomes wider.”

And, even if any doubt remains as to the purpose of someone’s speech, the speech itself cannot be automatically condemned. There is a reasonable conversation to be had on the subject. This is why we can’t accept the censorship of even those things that are obviously hateful or dangerous, as what is obvious is too dependent on personal opinion, and the line between vitriol and harsh truths is often too blurry.

In any case, a speaker’s motivations should only affect our moral judgments of that speaker. They have no implications for the merit of the words themselves. Recent revelations that Albert Einstein might have been a racist, for example, might change how we view the person, but they do not make his theories of special and general relativity any less valid.

When Google fired James Damore, they were well within their rights. In fact, this is true of many such cases. While the US Constitution’s First Amendment may prevent the government from restricting speech, private companies such as the New York Times are bound to no such code. They may hire (or fire) anyone they choose, just as social media companies may ban anyone they choose—they may even do so in concert, as when Facebook, Apple, YouTube and Spotify simultaneously banned InfoWars’ Alex Jones.

But, in doing so, these companies may be endangering the very principles which led to the enactment of free speech laws in most of the free world. The selective censoring of television and film, of social media, of electronic encyclopedias and of Web search engines is equally dangerous whether left up to the government or to company CEOs. Would you trust the heads of major corporations with the role of censors?

We should never have to fear the mere discussion ­of any topic, ever. That is the surest way to prevent any progress on it.

To encourage progress, we must actively invite those unpopular ideas to the table of discussion. No matter how harsh a truth may be, reality remains unaffected by your wish that it be proved untrue. Considering opinions that run counter to your own—even those that may seem outrageous or appalling—will inevitably lead you closer to the truth.

Most often, it will do so by reasserting beliefs you already hold. In such cases, you can then say that you hold your beliefs honestly, having put them to the test. However, every once in a while, you may find that the ideas you were initially so quick to reject go on to become your most firmly held convictions. At that point, you will have grown as a person. This is true progress, and it is the only necessary argument for speech that is wholly and truly free.