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

by Steven Pinker

A famous 1994 cover story in The Atlantic by the journalist Robert Kaplan predicted “The Coming Anarchy.”

While Odysseus had himself tied to the mast and rationally relinquished his option to act, his sailors plugged their ears with wax and rationally relinquished their option to know. At first this seems puzzling. One might think that knowledge is power, and you can never know too much. Just as it’s better to be rich than poor, because if you’re rich you can always give away your money and be poor, you might think it’s always better to know something, because you can always choose not to act on it. But in one of the paradoxes of rationality, that turns out not to be true. Sometimes it really is rational to plug your ears with wax.27 Ignorance can be bliss, and sometimes what you don’t know can’t hurt you.

Rational ignorance is an example of the mind-bending paradoxes of reason explained by the political scientist Thomas Schelling in his 1960 classic The Strategy of Conflict.28 In some circumstances it can be rational to be not just ignorant but powerless, and, most perversely of all, irrational. In the game of Chicken, made famous in the James Dean classic Rebel Without a Cause, two teenage drivers approach each other at high speed on a narrow road and whoever swerves first loses face (he is the “chicken”).29 Since each one knows that the other does not want to die in a head-on crash, each may stay the course, knowing the other has to swerve first. Of course when both are “rational” in this way, it’s a recipe for disaster (a paradox of game theory we will return to in chapter 8). So is there a strategy that wins at Chicken? Yes—relinquish your ability to swerve by conspicuously locking the steering wheel, or by putting a brick on the gas pedal and climbing into the back seat, leaving the other guy no choice but to swerve. The player who lacks control wins. More precisely, the first player to lack control wins: if both lock their wheels simultaneously

In their article “The Nobel Disease: When Intelligence Fails to Protect against Irrationality,” Scott Lilienfeld and his colleagues list the flaky beliefs of a dozen science laureates, including eugenics, megavitamins, telepathy, homeopathy, astrology, herbalism, synchronicity, race pseudoscience, cold fusion, crank autism treatments, and denying that AIDS is caused by HIV.

Used

The cat that sits down on a hot stove-lid … will never sit down on a hot stove-lid again, and that is well; but also she will never sit down on a cold one any more. —MARK TWAIN1

The obvious reason that people avoid getting onto a train of reasoning is that they don’t like where it takes them. It may terminate in a conclusion that is not in their interest, such as an allocation of money, power, or prestige that is objectively fair but benefits someone else. As Upton Sinclair pointed out, “It is difficult to get a man to understand something, when his salary depends upon his not understanding it.”