Enlightenment Now: The Case for Reason, Science, Humanism, and Progress

The principal reason people disagree about climate change science is not that it has been communicated to them in forms they cannot understand. Rather, it is that positions on climate change convey values—communal concern versus individual self-reliance; prudent self-abnegation versus the heroic pursuit of reward; humility versus ingenuity; harmony with nature versus mastery over it—that divide them along cultural lines.¹⁶

The values that divide people are also defined by which demons are blamed for society’s misfortunes: greedy corporations, out-of-touch elites, meddling bureaucrats, lying politicians, ignorant rednecks, or, all too often, ethnic minorities.

Kahan notes that people’s tendency to treat their beliefs as oaths of allegiance rather than disinterested appraisals is, in one sense, rational. With the exception of a tiny number of movers, shakers, and deciders, a person’s opinions on climate change or evolution are astronomically unlikely to make a difference to the world at large. But they make an enormous difference to the respect the person commands in his or her social circle. To express the wrong opinion on a politicized issue can make one an oddball at best—someone who “doesn’t get it”—and a traitor at worst. The pressure to conform becomes all the greater as people live and work with others who are like them and as academic, business, or religious cliques brand themselves with left-wing or right-wing causes. For pundits and politicians with a reputation for championing their faction, coming out on the wrong side of an issue would be career suicide.

Given these payoffs, endorsing a belief that hasn’t passed muster with science and fact-checking isn’t so irrational after all—at least, not by the criterion of the immediate effects on the believer. The effects on the society and planet are another matter. The atmosphere doesn’t care what people think about it, and if it in fact warms by 4° Celsius, billions of people will suffer, no matter how many of them had been esteemed in their peer groups for holding the locally fashionable opinion on climate change along the way. Kahan concludes that we are all actors in a Tragedy of the Belief Commons: what’s rational for every individual to believe (based on esteem) can be irrational for the society as a whole to act upon (based on reality).¹⁷

The perverse incentives behind “expressive rationality” or “identity-protective cognition” help explain the paradox of 21st-century irrationality. During the 2016 presidential campaign, many political observers were incredulous at opinions expressed by Trump supporters (and in many cases by Trump himself), such as that Hillary Clinton had multiple sclerosis and was concealing it with a body double, or that Barack Obama must have had a role in 9/11 because he was never in the Oval Office around that time (Obama, of course, was not the president in 2001). As Amanda Marcotte put it, “These folks clearly are competent enough to dress themselves, read the address of the rally and show up on time, and somehow they continue to believe stuff that’s so crazy and so false that it’s impossible to believe anyone that isn’t barking mad could believe it. What’s going on?”¹⁸ What’s going on is that these people are sharing blue lies. A white lie is told for the benefit of the hearer; a blue lie is told for the benefit of an in-group (originally, fellow police officers).¹⁹ While some of the conspiracy theorists may be genuinely misinformed, most express these beliefs for the purpose of performance rather than truth: they are trying to antagonize liberals and display solidarity with their blood brothers. The anthropologist John Tooby adds that preposterous beliefs are more effective signals of coalitional loyalty than reasonable ones.²⁰ Anyone can say that rocks fall down rather than up, but only a person who is truly committed to the brethren has a reason to say that God is three persons but also one person, or that the Democratic Party ran a child sex ring out of a Washington pizzeria.

The conspiracy theories of fervid hordes at a political rally represent an extreme case of self-expression trumping truth, but the Tragedy of the Belief Commons runs even deeper. Another paradox of rationality is that expertise, brainpower, and conscious reasoning do not, by themselves, guarantee that thinkers will approach the truth. On the contrary, they can be weapons for ever-more-ingenious rationalization. As Benjamin Franklin observed, “So convenient a thing is it to be a rational creature, since it enables us to find or make a reason for everything one has a mind to.”