When I was a boy taking piano lessons, one thing above all was guaranteed to frustrate my teacher. My fingers would land on the same wrong keys for the seventh or eighth time in a row and Mrs. Feigenbaum would snap in exasperation: “Jeff Jacoby, make a different mistake for a change!”

It isn’t only music students in grade school who often seem unable to stop playing the same jarring tune. Whole societies do, too. Again and again they revert to mistakes they were supposed to have jettisoned long ago — blunders and fallacies that they should know from painful experience are guaranteed to fail.

Do nations ever permanently put a bad idea to rest? How many times do protectionism, Luddism, or censorship have to be exposed as destructive delusions before a stake driven through their ideological hearts finally stays there? How often do the most intellectually incoherent nostrums have to be demolished by reality before they stop being resurrected and given another chance?

These ideological addictions are as old as society. In Mel Brooks and Carl Reiner’s classic comedy sketch “The 2000 Year Old Man” — in which a TV reporter interviews a man who has been around for millennia — the ancient caveman played by Brooks reminisces about his cave’s anthem: “Let them all go to hell, except Cave 76!” It’s a perfect parody of blind nativism — crude, funny, and depressingly recognizable. The satire works because, alas, the joke still lands.

Some of the undead fallacies barely bother to change their wardrobe. Politicians in the 21st century still promise to generate prosperity by restricting imports, despite three centuries of evidence that trade barriers punish more than they protect. Modern-day Luddites may not smash looms but they do torch 5G cell towers and strike to keep driverless trucks off the highway — even though technology has always created more jobs and wealth than it destroyed. And while the label “appeasement” is no longer fashionable, the practice of trying to placate tyrants into good behavior — for example, by flying pallets loaded with cash to Tehran — keeps making a comeback.

Why do these spurious ideas and so many others, from racial determinism to government price controls, refuse to stay interred?

The main reason, I think, is that they serve a useful purpose. Falsehoods can be emotionally reassuring even when they’re materially harmful. Anti-immigrant nativism, for instance, offers a convenient target and a simple remedy: “Foreigners are stealing our jobs and debasing our culture, so stop letting them in.” It’s terrible economics but potent politics. The age-old suspicion of new technology appeals to people’s hunger for stability, all the more so when unfamiliar machines threaten the livelihoods that give people their identity. Even policies that must fail in the end may nevertheless satisfy a yearning for control — or the illusion of control.

Bad ideas don’t always rise from the grave on their own. Often they get pulled back into daylight by leaders who find them handy. Populists rebrand tariffs as “economic patriotism.” Racial quotas in hiring and admissions are disguised as tools to ensure “diversity.” Better to flatter foreign despots, political leaders insist, than to risk war or the loss of business. And because so many of these nostrums expand the reach of government, politicians find them doubly irresistible: Policies that fail the public can still succeed in concentrating power, which is the one currency no officeholder ever has enough of.

Finally, bad ideas endure because human beings often are more attracted to stories and slogans than to facts. The 20th-century thinker Isaiah Berlin, in his famous essay on the hedgehog and the fox, described the “great chasm” separating those who relate everything to a single central vision from everyone else. It is these “hedgehogs” who become the demagogues and utopians, convinced they alone possess the master key. Their certainty — and the charisma it frequently breeds — is what keeps bad ideas alive long after facts should have killed them.

Society will never banish bad ideas once and for all. (What would happen to opinion columnists if it did?) Sometimes a bad idea appears to be comprehensively discredited, as when the defeat of the Soviet Union in the Cold War seemed to spell extinction for communism — until it returned after a cycle of dormancy, refurbished and rebranded, beckoning new believers. At best, the task of sober citizens is to shorten the half-life of bad ideas: to speak up, to puncture the slogans, to slow the damage until reason can reassert itself. Those are the times, as George Orwell said, when the restatement of the obvious becomes the first duty of honest men and women.

My piano teacher wanted her pupil to at least make different mistakes. Humanity may never manage even that. But it can, with vigilance, do a better job of resisting the old ones.