Rationality: What It Is, Why It Seems Scarce, Why It Matters

by Steven Pinker

Three quarters of Americans believe in at least one phenomenon that defies the laws of science, including psychic healing (55 percent), extrasensory perception (41 percent), haunted houses (37 percent), and ghosts (32 percent)—which also means that some people believe in houses haunted by ghosts without believing in ghosts.12 In social media, fake news (such as Joe Biden Calls Trump Supporters “Dregs of Society” and Florida Man Arrested for Tranquilizing and Raping Alligators in the Everglades) is diffused farther and faster than the truth, and humans are more likely to spread it than bots.13 It

The technique is called Odyssean self-control, and it is more effective than the strenuous exertion of willpower, which is easily overmatched in the moment by temptation.

They can claim that no Scotsman puts sugar on his porridge, and when confronted with Angus, who puts sugar on his porridge, say this shows that Angus is not a true Scotsman. The no true Scotsman fallacy also explains why no true Christian ever kills, no true communist state is repressive, and no true Trump supporter endorses violence. These tactics shade into begging the question, a phrase that philosophers beg people not to use as a malaprop for “raising the question” but to reserve for the informal fallacy of assuming what you’re trying to prove.

Sometimes both sides pursue the fallacy, leading to the style of debate called burden tennis. (“The burden of proof is on you.” “No, the burden of proof is on you.”) In reality, since we start out ignorant about everything, the burden of proof is on anyone who wants to show anything. (As we will see in chapter 5, Bayesian reasoning offers a principled way to reason about who should carry the burden as knowledge accumulates.)

Another diversionary tactic is called tu quoque, Latin for “you too,” also known as what-aboutery. It was a favorite of the apologists for the Soviet Union in the twentieth century, who presented the following defense of its totalitarian repression: “What about the way the United States treats its Negroes?” In another joke, a woman comes home from work early to find her husband in bed with her best friend. The startled man says, “What are you doing home so early?” She replies, “What are you doing in bed with my best friend!?” He snaps, “Don’t change the subject!”

The ignorance is measurable. Pollsters repeatedly find that while people tend to be too optimistic about their own lives, they are too pessimistic about their societies.

Though editors have told me that readers hate math and will never put up with numbers spoiling their stories and pictures, their own media belie this condescension. People avidly consume data in the weather, business, and sports pages, so why not the news?

Holding a warm mug makes you friendlier. (“Warm”—get it?) Seeing fast-food logos makes you impatient. Holding a pen between your teeth makes cartoons seem funnier, because it forces your lips into a little smile. People who are asked to lie in writing have positive feelings about hand soap; people who are asked to lie aloud have positive feelings about mouthwash.16 Any reader of popular science knows of other cute findings which turned out to be suitable for the satirical Journal of Irreproducible Results.

(This is the moral argument for redistribution: transferring money from the rich to the poor increases the amount of happiness in the world, all things being equal.)

A pious old man beseeches the Almighty. “O Lord, all my life I have obeyed your laws. I have kept the Sabbath. I have recited the prayers. I have been a good father and husband. I make only one request of you. I want to win the lottery.” The skies darken, a shaft of light penetrates the clouds, and a deep voice bellows, “I’ll see what I can do.” The man is heartened. A month passes, six months, a year, but fortune does not find him. In his despair he cries out again, “Lord Almighty, you know I am a pious man. I have beseeched you. Why have you forsaken me?” The skies darken, a shaft of light bursts forth, and a voice booms out, “Meet me halfway. Buy a ticket.”

Are we mortals perpetually doomed to choose between the awful cost of mistaken inaction (a city bombed, a cancer left to spread) and the dreadful cost of mistaken action (a ruinous provocation, disfiguring surgery)? Signal Detection Theory says we are, but it also shows us how to mitigate the tragedy. We can bend the tradeoff by increasing the sensitivity of our observations.

The philosophers Liam Clegg and Daniel Dennett have argued that human behavior is inherently unpredictable not just because of random neural noise in the brain but as an adaptation that makes it harder for our rivals to outguess us.4 A Non-Zero-Sum Game: The Volunteer’s Dilemma Rational actors can end up in outguessing standoffs not just in games that pit them in zero-sum competition but in ones that partly align them with common interests.

Economists took advantage of the happenstance during the half decade and found that towns with Fox News in their cable lineups voted 0.4 to 0.7 points more Republican than towns that had to watch something else.28 That’s a big enough difference to swing a close election, and the effect could have accumulated in the subsequent decades when Fox News’ universal penetration into TV markets made the effect harder to prove but no less potent.

Tell people there’s an invisible man in the sky who created the universe, and the vast majority will believe you. Tell them the paint is wet, and they have to touch it to be sure. —George Carlin

In signal detection terms, the cost of missing a real conspiracy is higher than that of false-alarming to a suspected one. This calls for setting our bias toward the trigger-happy rather than the gun-shy end of the scale, adapting us to try to get wind of possible conspiracies even on tenuous evidence.

We should not lose sight of how much rationality is out there. Few people in developed countries today believe in werewolves, animal sacrifice, bloodletting, miasmas, the divine right of leaders, or omens in eclipses and comets, though all were mainstream in centuries past.

the editor of Forbes magazine announced, “Let it be known to the business world: Hire any of Trump’s fellow fabulists, and Forbes will assume that everything your company or firm talks about is a lie.”

What’s the harm in conspiracy theories? FBI identifies “conspiracy-driven domestic extremists” as a new domestic terror threat. What’s the harm in getting health advice from an #herbalist? A 13-year-old died after being told not to take insulin. Now the herbalist is headed to jail. What’s the harm in a #faithhealing church? Ginnifer fought for her life for 4 hours. Travis Mitchell, her father, “laid on hands” and the family took turns praying as she struggled to breathe and changed colors. “I knew she was dead when she didn’t cry out anymore,” Mitchell said. What’s the harm in believing in supernatural beings? Sumatran villagers killed an endangered tiger because they thought it was a shape-shifting “siluman.” What’s the harm in seeing a #psychic? Maryland “psychic” convicted of scamming clients out of $340K.

“perpetual peace” in 1795. One of them is democracy, which, as we saw in the chapter on correlation and causation, really does reduce the chance of war, presumably because a country’s cannon fodder is less keen on the pastime than its kings and generals. Another is international trade and investment, which make it cheaper to buy things than to steal them, and make it unwise for countries to kill their customers and debtors. (The European Union, awarded the Nobel Peace Prize in 2012, grew out of a trade organization, the European Coal and Steel Community.)

Many cruel and unjust practices have declined over the course of history. They include human sacrifice, slavery, despotism, blood sports, eunuchism, harems, foot-binding, sadistic corporal and capital punishments, the persecution of heretics and dissidents, and the oppression of women and of religious, racial, ethnic, and sexual minorities.

the nature of the arc and its power to pull the levers of human behavior are mysterious. One can imagine more prosaic pathways: changing fashions; shaming campaigns; appeals to the heart; popular protest movements; religious and moralistic crusades. A popular view is that moral progress is advanced through struggle: the powerful never hand over their privileges, which must be wrested from them by the might of people acting in solidarity.