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. But let a man know that there are things to be known, of which he is ignorant, and it is so much carved out of his domain of universal knowledge. And for all purposes of individual character, as well as of social usefulness, it is quite as important for a man to know the extent of his own ignorance as it is to know any thing else. To know how much there is that we do not know, is one of the most valuable parts of our attainments; for such knowledge becomes both a lesson of humility and a stimulus to exertion.

The most deluded people are those who choose to ignore what they already know.

Most fools think they are only ignorant.

The most hopelessly stupid man is he who is not aware he is wise.

The most hopelessly stupid man is he who is not aware that he is wise.

School teachers, taking them by and large, are probably the most ignorant and stupid class of men in the whole group of mental workers.

It is the stupid and the ugly who have the best of it in this world

There are so many different kinds of stupidity, and cleverness is one of the worst.

It is the stupidest children who are most childish and the stupidest grown-ups who are most grown-up.

Imagine the people who believe such things and who are not ashamed to ignore, totally, all the patient findings of thinking minds through all the centuries since the Bible was written. And it is these ignorant people, the most uneducated, the most unimaginative, the most unthinking among us, who would make themselves the guides and leaders of us all; who would force their feeble and childish beliefs on us; who would invade our schools and libraries and homes. I personally resent it bitterly.

Sophistry is only fit to make men more conceited in their ignorance.

The ignorant are not blissful; they are the butt of a joke they're not even aware of.

The highest form of ignorance is when you reject something you don’t know anything about. — Wayne Dyer

An ignorant person is one who doesn't know what you have just found out.