"The man who seeks to influence the course of history must not be afraid of unpopularity."

"Religion and natural science are fighting a joint battle in an incessant, never-ending crusade against skepticism and against dogmatism, against unbelief and against superstition, and as the motto for…"

"When you change your opinion, you are not a weakling. You are a scientist."

"New scientific ideas never spring from a communal body, however organized, but rather from the head of an individually inspired researcher who struggles with his problems in lonely thought and unites …"

"The human mind is capable of understanding the universe."