“Every sentence I utter must be understood not as an affirmation but as a question.[A caution he gives his students, to b...”

“We shall require a substantially new manner of thinking if mankind is to survive.”

“Most people would die sooner than think in fact they do.”

“In a republican nation, whose citizens are to be led by reason and persuasion and not by force, the art of reasoning bec...”

“Reason respects the differences and imagination the similitudes of things.”

“A point of view can be a dangerous luxury when substituted for insight andunderstanding.”

“All things must be examined, debated, investigated without exception and without regard for anyone's feelings.”

“It is the mark of a good action that it appears inevitable in retrospect.”

“You don't kill your way to peace.”

“Accuracy of observation is the equivalent of accuracy of thinking.”

“[T]he vast majority of human beings are not interested in reason or satisfied with what it teaches.”

“Scepticism does not abolish the world, it turns it into questions.”