STEVEN PINKER: Three Reasons To Affirm Free Speech.
There’s a systematic reason why dictators brook no dissent. The immiserated subjects of a tyrannical regime are not deluded that they are happy. And if tens of millions of disaffected citizens act together, no regime has the brute force to resist them. The reason that citizens don’t resist their overlords en masse is that they lack what logicians call common knowledge—the knowledge that everyone else shares their knowledge. Common knowledge is a prerequisite to coordinating behavior for mutual benefit: two friends will show up at the same café at a given time only if each knows that the other knows that both know about the appointment. In the case of civil resistance, people will expose themselves to the risk of reprisal by a despotic regime only if they know that others are exposing themselves to that risk at the same time.
Common knowledge is created by public information, such as a broadcasted statement. The story of the Emperor’s New Clothes illustrates the logic. When the little boy shouted that the emperor was naked, he was not telling them anything they didn’t already know, anything they could not see with their own eyes. But he was changing the state of their knowledge nonetheless, because now everyone knew that everyone else knew that the emperor was naked. And that common knowledge emboldened them to challenge the emperor’s authority with their laughter.
In his computer simulations of artificial societies, the sociologist Michael Macy has shown that open channels of communication are essential in preventing unpopular beliefs—those that no one believes but no one dares deny—from becoming entrenched. If true believers can punish skeptics, then a minority view can take over. But if skeptics can sample the beliefs of their compatriots, the collective delusions can unravel.
It may seem outlandish to link American campus freedom—which by historical and global standards is still admirably high—to the world’s brutal regimes. But I’m here to tell you that the connection is not that far-fetched.
To some, that’s not a bug, but a feature.