The next question is how they move. If individual assumptions are predictors of extremism, as the author argues, then new information is the variable that can make the difference between, broadly, good forms of extremism (the civil rights movement, the American Revolution) and bad. As the behavioral psychologist Philip Zimbardo concluded about his own infamous prison experiment, “The line between Good and Evil, once thought to be impermeable, proved instead to be quite permeable.”

Its title notwithstanding, Going to Extremes is a study in moderation. While the book’s overarching subject is zealotry, and its narrative tension comes courtesy of polarization, Sunstein’s broad destination is the middle ground. Thus his ultimate breakaway moment, in which he ventures from description to prescription: what journalism now needs, he says, is an “architecture of serendipity.” Sunstein calls for a journalistic infrastructure that consciously re-imagines the front page of the dead-tree newspaper, ensuring that citizens will be exposed to the new information that they might not otherwise encounter.

If news organizations and journalistic innovators can overcome paradox to systematize serendipity, they will have a moderating influence, writes Sunstein. “Indeed, the architecture of serendipity is part of a well-functioning system of checks and balances; it helps to check the effects of echo chambers and ensure that those with blinders, or those who prefer information cocoons, occasionally see elsewhere. What they see may change their minds, even their lives.”

The regulator has spoken. The question that remains—and it is one that even the Kevin Bacon of Legal Academia might have trouble answering—is whether the moderate, middle-ground brands of journalism can shout loudly enough to stifle the bellowing of the echo chamber.

Megan Garber is an assistant editor at the Nieman Journalism Lab at Harvard University. She was formerly a CJR staff writer.