"The most ignorant are the most conceited. Unless a man knows that there is something more to be known, his inference is, of course, that he knows every thing. Such a man always usurps the throne of universal knowledge, and assumes the right of deciding all possible questions. We all know that a conceited dunce will decide questions extemporaneous which would puzzle a college of philosophers, or a bench of judges. Ignorant and shallow-minded men do not see far enough to see the difficulty."
January 1, 1970
https://en.wikiquote.org/wiki/Dunce