How so many people can believe demonstrably false things, and persist in their beliefs for years despite mountains of contrary evidence, is a great problem. There are of course liars and grifters, some of them in positions of great authority; and there are many others who are simply deceived or misinformed. A far worse problem, though, are all those who espouse obviously wrong things, while being well-informed and perfectly sincere. A great part of the maskers, the lockdowners and even the vaccinators, are like this. There are some cynical and evil voices, and there are some stupid people, but then there are all the others, who simply believe ridiculous things despite it all. There are social, psychological and emotional explanations, but being wrong is above all an intellectual problem, and it is so pervasive, because of our intellectual limitations.