Everybody has some false beliefs rattling around in their head. Let’s say you’ve got a thousand beliefs, and ten of them are mistaken. If we knew which of our beliefs were false, we could just go in and remove them. The problem is that we don’t know which ones they are. If you think you have absolutely no false beliefs lurking in your mind, guess what: That’s one of them! On the other hand, if you let your fallibility undermine your confidence in the truth, you’ve let a few stray notes ruin the whole song.