“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.
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 unwise. 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. 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.”
From Chapter 7 of Karl Popper’s notes to The Open Society and Its Enemies.
Several years after the publication of The Open Society, John Rawls took up the so-called “Paradox of Tolerance” but prescribed a different sort of state response to intolerant factions. For Rawls, the paradox certainly exists, yet it does not dictate we should practice intolerance towards those who are themselves intolerant.
While Popper looked to preempt intolerant groups from acting criminally — by advocating a sort of prior restraint approach — Rawls believed that action against intolerant sects is justified only when they pose a direct threat to the security of other members of a society. This approach aligns with the principle of stability of a tolerant society, which states that the members of an intolerant faction will gradually acquire the tolerance of society at large, and soon find themselves integrated within it.