In 1945, philosopher Karl Popper described a problem every free society eventually runs into: the paradox of tolerance In The Open Society and Its Enemies, he wrote: "Unlimited tolerance must lead to the disappearance of tolerance" His reasoning was simple. If a society tolerates everything, including people who reject tolerance itself, those intolerant groups can use that freedom to gain power and eventually take away everyone else's freedom The tolerant end up defeated, and tolerance disappears with them Popper wasn't suggesting that every intolerant opinion should be simply silenced...he was careful here too Popper said that intolerance should first be met with rational debate, and only suppressed when groups abandon reason for violence ("fists or pistols") The danger comes when groups reject rational debate, forbid their followers from listening to opposing views, and respond to disagreement with their fists or pistols At that point, an open society has the right to protect itself His point was that tolerance is not weakness. But for tolerance to survive, an open society must be willing to defend the very freedoms that make it possible