Irving Kristol offers a sobering insight into the difficulty of changing minds. He writes:
Wrong ideas, once implanted in a young person’s mind, become so plausible, so self-evident as it were, that change is hard. . . . It is a “progressive” illusion to think that, in the marketplace of ideas, truth will always win out over error. It is truth that needs help, while error usually manages to make its own way very nicely.
His example is a political one but still useful for those who don’t share his politics.
I remember a course I once taught at New York University on urban problems, in which we took up the issue of rent control. After a few weeks, the students had grasped what is apparent to most people who study the problem: That, except under emergency conditions, rent control is a bad idea in both theory and practice. Nevertheless, by the time the students took their examinations at the end of the term, it became clear that at least half the class had simply forgotten what they had learned about rent control; and once again, it seemed to them to be a perfectly good idea.