"It has been said that man is a rational animal. All my life I have been searching for evidence to support this."

"The desire for safety stands against every great and noble enterprise."

"The fact that an opinion has been widely held is no evidence whatever that it is not utterly absurd; indeed in view of the silliness of the majority of mankind, a widely spread belief is more likely t…"

"I am not interested in the universe as a whole, but in certain parts of it."

"We are faced with the paradoxical fact that education has become one of the chief obstacles to intelligence and freedom of thought."