Real knowledge is to know the extent of one's ignorance.
“By three methods we may learn wisdom: First, by reflection, which is noblest; Second, by imitation, which is easiest; and third by experience, which is the bitterest.”
“To live is the rarest thing in the world. Most people exist, that is all.”
“Uneasy lies the head that wears a crown.”
“If you would be a real seeker after truth, it is necessary that at least once in your life you doubt, as far as possible, all things.”
“Our life is frittered away by detail… simplify, simplify.”
“People demand freedom of speech as a compensation for the freedom of thought which they seldom use.”