The glory of the Internet is that it allows like-minded people to find one another. And the horror of the Internet is that it allows like-minded people to find one another. Coin collectors, baseball-card enthusiasts, and used-book readers have all benefited from the opportunities offered by online connection. So have neo-Nazis, child-pornographers, and Communist agitators. Where they were once connected only by the sickly sweet smell of the ink from the mimeograph machine clumping away on the kitchen table, the forces of anger now have instantaneous links.
And that instantaneity allows a radicalizing more rapid than the world has ever seen. Back in a 1999 study called “The Law of Group Polarization,” legal scholar Cass R. Sunstein suggested that discussion among people with similar views causes a hardening of opinion. “In a striking empirical regularity,” he wrote, “deliberation tends to move groups, and the individuals who compose them, toward a more extreme point in the direction indicated by their own predeliberation judgments.” It hardly matters whether the groups are pro-gun, pro-abortion, or pro-anarchy. With sufficient group discussion on one side of an issue, everyone involved takes a step toward the extreme: The mildly supportive become strongly supportive, the strongly supportive become wildly supportive, and the wildly supportive become fanatical psychopaths.