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

“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.”

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

“One must be sane to think clearly, but one can think deeply and be quite insane.”

“Merely having an open mind is nothing. The object of opening the mind as of opening the mouth is to shut it again on s...”

“It Begins with skepticism. The history of human folly, and our own susceptibility to illusions and fallacies, tell us th...”

“The conventional view serves to protect us from the painful job of thinking.”

“If you can talk brilliantly about a problem it can create the consoling illusion that it has been mastered.”

“Skeptical scrutiny is the means, in both science and religion, by which deep thoughts can be winnowed from deep nonsense...”

“I was never aware of any other option but to question everything.”