“Morality is of the highest importance -- but for us, not for God.”

“The most important human endeavor is the striving for morality in our actions. Our inner balance and even our very existence depend on it. Only morality in our actions can give beauty and dignity to life.”

“Play is the highest form of research.”

“Imagination is the highest form of research.”

“You are right in speaking of the moral foundations of science, but you cannot turn around and speak of the scientific foundations of morality.”

“Force always attracts men of low morality.”

“There is nothing divine about morality, it is a purely human affair.”