White supremacists are really, really hoping that you don’t keep reading this article. They don’t want you to learn about the Paradox of Tolerance, because then they’d lose a powerful weapon in their fight to make society more racist. Ready to make a white supremacist mad?

Fortunately for us, the Paradox of Tolerance, a concept coined by philosopher Karl Popper, is easy to understand and remember. The “paradox” part makes it sounds complicated and hard, but it’s really just a rule with one exception. It goes like this:

A tolerant society should be tolerant by default, With one exception: it should not tolerate intolerance itself.

To give a specific example, a tolerant society should tolerate protest marches in general, but it shouldn’t tolerate a white supremacist march advocating for the oppression and killing of people of color – like the march in Charlottesville, Virginia, in August 2017 that ended with white supremacists beating and killing people who were opposed to their message of intolerance.

So that’s one form of tolerance: tolerance of everything except intolerance itself. But the version of tolerance that white supremacists really want you to believe is this one: you should not only tolerate their march to advocate removing human rights from people of color, but you, as a tolerant person, should even fight to protect their right to march – in the name of tolerance! The specific idea here is that a tolerant society should tolerate all intolerant speech – including protests, marches, and assemblies – as long as it falls short of the established legal limits of free speech in the United States (which are many and include incitement to violence, yelling “Fire!” in a crowded theater, defamation, child pornography, etc.).

The American Civil Liberties Union (ACLU) believes in protecting intolerant speech right up to the U.S. legal limit. That’s why the local branch of the ACLU went to court to force the Charlottesville government to grant a permit for the march to take place in a location the white supremacists chose for its potential for intimidation and violence. The ACLU’s reasoning? People marching to increase tolerance (e.g., civil rights marches) could be blocked by intolerant local governments if intolerant people planned to attack them – which was a real problem during the civil rights era in the U.S.

What the ACLU discounted is that a white supremacist march differs from a civil rights march because allowing it to go forward would reduce free speech overall by intimidating and silencing people of color and their advocates. Our worst fears came true during this march: when a white supremacist protester killed Heather Heyer, he took away her right to speech (and life) forever. The Paradox of Tolerance acknowledges that some speech should not be protected precisely because allowing it to go forward promotes the destruction of the basis of free speech – in this case, it normalizes the idea that people of color should have fewer rights than white people.

To many people, the Paradox of Tolerance may seem like heresy! Especially if you’re a U.S. progressive, you’ve probably been taught your whole life that tolerance is paramount, free speech must be protected regardless of its content, and the ACLU is always on the right side of history. Yet your heart is crying out that the Charlottesville march was wrong, that it should have been prevented, and that it left our society less free and fair.

Your heart is right. It’s the people teaching you that you must always tolerate intolerance who are wrong.

Here’s another way to think about the Paradox of Tolerance: a tolerant society must protect its own existence if tolerance is to exist in the world. If tolerating intolerance results in the destruction and disappearance of tolerant society, then that tolerant society has a right to self-protection – in the form of refusing to tolerate intolerance. The Paradox of Tolerance suggests that we should view advocacy of intolerance and persecution as a criminal behavior in and of itself. Many European countries do have specific laws making advocacy of white supremacy illegal, in contrast to the United States.

Consider World War II: The more intolerant fascist Axis powers wanted to destroy more tolerant societies completely, and the Allied powers had to fight back – be intolerant – in order for more tolerant societies to exist today. In fact, the Paradox of Tolerance was formulated and named in 1945, as World War II was winding down. The effects of fascism, including World War II, were much more devastating in many European countries, which may be one reason free speech laws in European countries tend to specifically outlaw marches by neo-Nazis and similar forms of pro-fascist speech, in line with the Paradox of Tolerance.

To be clear, the Paradox of Tolerance doesn’t imply that we should completely suppress or silence every single intolerant opinion. If expressing an intolerant opinion is unlikely to endanger the existence of a tolerant society, the more everyday forms of defense such as criticism, disgust, and natural consequences are a better way of protecting tolerance. It’s when society is favorable to bigoted and intolerant ideas – such as when an openly white supremacist president who was elected with 46% of the vote is using presidential power to enforce racist government policies in a country with a long record of white supremacy – that we should stop speech that threatens to tip our entire society into a vast increase in intolerance.

One more thing: we’re in no danger of impoverishing the “marketplace of ideas” – the majority of bigoted and intolerant opinions already get plenty of exposure. They are the opinions we have heard over and over again from people in power throughout history. We don’t need to fight to amplify the voices of the already powerful.

Your heart knows when unlimited tolerance is the wrong answer. Listen to your heart. And then memorize the Paradox of Tolerance, so your head and your heart can act in concert.

Thank you to several anonymous activists who contributed to this article.

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