Few people know how to take a walk. The qualifications are endurance, plain clothes, old shoes, an eye for nature, good humor, vast curiosity, good speech, good silence and nothing too much.
Ralph Waldo Emerson
It is not the slumber of reason that engenders monsters, but vigilant and insomniac rationality.
Gilles Deleuze, Anti-Oedipus: Capitalism and Schizophrenia
Pain and suffering are always inevitable for a large intelligence and a deep heart. The really great men must, I think, have great sadness on earth.
Fyodor Dostoyevsky, Crime and Punishment