There Are None So Blind...

A fool knows what he knows.
A wise man knows what he doesn't know.
And a complete idiot knows things that just are not true, and refuses to accept otherwise.

Concerning these matters it has also been said:

"Never argue with a fool. He'll drag you down to his level, and then beat you with years of experience." -Mark Twain

Pictures Courtesy of Pixabay. Public Domain.