The point is that even a statement as intuitively obvious as 2+2=4 should still be allowed to be overthrown.
I think including the idea of changing beliefs in this post was a mistake, for it’s not the point, but most of the discussion is spent on it. A belief as obvious as “2+2=4” should still have a reason behind it, the way you come to believe even the simplest things should be set up so that you’d believe them correctly, whatever they turn out to be, instead of having them fixed by the magical “a priori”.
I think including the idea of changing beliefs in this post was a mistake, for it’s not the point, but most of the discussion is spent on it. A belief as obvious as “2+2=4” should still have a reason behind it, the way you come to believe even the simplest things should be set up so that you’d believe them correctly, whatever they turn out to be, instead of having them fixed by the magical “a priori”.