Thoughts. What I notice when I watch.
There is an image that shows up in every big argument online. A comic, a few panels, and at the end a line with Popper's name under it: tolerate the intolerant and you lose tolerance. It gets shared to shut someone out. And it gets shared to mock the people shutting someone out. Both sides quote the same man, and both sides stop reading at the same place.
I did the same for years. Then I looked up where the line actually comes from.
It sits in a footnote
Karl Popper wrote The Open Society and Its Enemies during the Second World War, in exile in New Zealand. He had left Vienna in 1937. The book came out in London in 1945, two volumes, a reckoning with Plato, Hegel and Marx, and with the idea that someone holds the right answer to the question "who should rule?"
The paradox of tolerance is not the subject of the book. It sits in the notes to chapter seven, in a footnote, and Popper does not put it there on its own. He names three paradoxes side by side: the paradox of freedom, where freedom without any restraint leaves the bully free to enslave the meek. The paradox of democracy, where a majority may decide that a tyrant should rule. And, in his own words, the "less well known" paradox of tolerance.
The part everyone knows reads:
"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."
That is where the meme ends.
The sentence after
Popper keeps writing. And the next thought is not a footnote to the footnote. It is the condition without which the first part would be a manual for censorship:
"In this formulation, 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."
Most unwise. Not "possibly problematic". Popper thinks it is a mistake to suppress views you can still argue against.
Only then comes the right to suppress, and with a reason that says exactly when it applies:
"But we should claim the right to suppress them if necessary even by force; for it may easily turn out that they are not prepared to meet us on the level of rational argument, but begin by denouncing all argument; they may forbid their followers to listen to rational argument, because it is deceptive, and teach them to answer arguments by the use of their fists or pistols."
That is the threshold. Not: a view I find repulsive. But: a movement that abolishes the conversation itself and puts violence in its place.
The threshold is a test
Read the whole footnote and the meme line changes. It is no longer a permission. It is a question you have to ask before you use it:
Can I still answer this with an argument?
If yes, suppression is a mistake by Popper's own account, and one that damages the open society itself. Its whole advantage is that errors become visible in public and can be corrected. Ban a view you could still refute and you give up exactly that mechanism. You also hand the view something it did not have before: the status of the forbidden.
If no, if nobody on the other side listens anymore because listening was forbidden, and threats and violence arrive instead of arguments, then the open society has the right to defend itself. If necessary by force.
Both halves are in the same footnote. Quote only one of them and you are not quoting Popper. You are quoting yourself with Popper's name underneath.
Who decides
That leaves the question every debate about the paradox eventually gets stuck on: who establishes that the threshold has been crossed?
For Popper the answer is not a person, and certainly not an audience. He ends the footnote like this:
"We should therefore claim, in the name of tolerance, the right not to tolerate the intolerant. We should claim that any movement preaching intolerance places itself outside the law, and we should consider incitement to intolerance and persecution as criminal, in the same way as we should consider incitement to murder, or to kidnapping, or to the revival of the slave trade, as criminal."
This is the part both camps like to skip. Popper moves the decision out of the mood of the moment and into the law. A law has to be known in advance, it applies to everyone equally, and it is applied by courts you can appeal to. That fits what chapter seven actually defends: the important question is not who should rule, but how to build institutions so that bad rulers can be removed without bloodshed.
So the paradox of tolerance is not a free pass for the feeling that someone has gone too far. It is an argument for turning limits into procedures before you need them.
Two ways to misquote Popper
The first: anyone who disagrees with me is intolerant. The paradox becomes a license to declare people you are arguing with enemies of the open society. That is the opposite of what Popper wrote. A view you can refute is a view you should refute.
The second: Popper stood for unlimited tolerance, so nothing may ever be banned. That is not in there either. Popper explicitly claims the right not to tolerate the intolerant, if necessary by force, once they swap arguments for fists.
The two mistakes look like opposites. They have the same origin: you read up to the point that supports your position, and you stop there.
What I take from it
I no longer use the quote as a closing line. I use it as the start of two questions.
The first: do I still have an argument? If yes, then that is my job, not a moderation decision. Tolerance in Popper's sense is not niceness. It is the tiring willingness to keep disagreeing when muting would be easier.
The second: who decides, and by what procedure? If the answer is "me, now, because it feels wrong", I am not with Popper. I am with the very question he wrote his whole book against.
The paradox is a good sentence. It is worth reading to the end.
As of 11 October 2026. This is an opinion piece. Sources:
- Karl R. Popper, The Open Society and Its Enemies, Vol. 1, Routledge, London 1945, notes to chapter 7, note 4. The three paradoxes (freedom, tolerance, democracy) appear there side by side. All quotes in this piece are from that note.
- The idea that democracy is measured by whether a government can be removed without bloodshed is in chapter 7 of the same volume.