What a distressing contrast there is between the radiant intelligence of the child and the feeble mentality of the average adult.
-Sigmund Freud

In view of the fact that God limited the intelligence of man, it seems unfair that he did not also limit his stupidity.
-Dean Acheson

The only good is knowledge and the only evil is ignorance.
-Socrates

I know nothing except the fact of my ignorance.
-Socrates

If you gave her a penny for her thoughts, you'd have change coming.
-Buster Bunny, "Tiny Toon Adventures"