Or judging by the URL, the alternate title would have been: Why do people persist in believing things that just arent true?
Key snippets:
One thing he learned early on is that not all errors are created equal. Not all false information goes on to become a false belief—that is, a more lasting state of incorrect knowledge—and not all false beliefs are difficult to correct. Take astronomy. If someone asked you to explain the relationship between the Earth and the sun, you might say something wrong: perhaps that the sun rotates around the Earth, rising in the east and setting in the west. A friend who understands astronomy may correct you. It’s no big deal; you simply change your belief.
But imagine living in the time of Galileo, when understandings of the Earth-sun relationship were completely different, and when that view was tied closely to ideas of the nature of the world, the self, and religion. What would happen if Galileo tried to correct your belief? The process isn’t nearly as simple. The crucial difference between then and now, of course, is the importance of the misperception. When there’s no immediate threat to our understanding of the world, we change our beliefs. It’s when that change contradicts something we’ve long held as important that problems occur.
The campaign against smoking is one of the most successful public-interest fact-checking operations in history. But, if smoking were just for Republicans or Democrats, change would have been far more unlikely. It’s only after ideology is put to the side that a message itself can change, so that it becomes decoupled from notions of self-perception.