Logic itself almost demands this lack of self-insight: For poor performers to recognize their ineptitude would require them to possess the very expertise they lack. To know how skilled or unskilled you are at using the rules of grammar, for instance, you must have a good working knowledge of those rules, an impossibility among the incompetent. Poor performers—and we are all poor performers at some things—fail to see the flaws in their thinking or the answers they lack.

In the classroom, some of best techniques for disarming misconceptions are essentially variations on the Socratic method.

For individuals, the trick is to be your own devil’s advocate: to think through how your favored conclusions might be misguided; to ask yourself how you might be wrong, or how things might turn out differently from what you expect. It helps to try practicing what the psychologist Charles Lord calls “considering the opposite.” To do this, I often imagine myself in a future in which I have turned out to be wrong in a decision, and then consider what the likeliest path was that led to my failure. And lastly: Seek advice. Other people may have their own misbeliefs, but a discussion can often be sufficient to rid a serious person of his or her most egregious misconceptions.