“Certainty is the most vivid condition of ignorance and the most necessarycondition for knowledge.”

“Scientific knowledge is a body of statements of varying degrees of certainty -- some most unsure, some nearly sure, none absolutely certain.”

“To admit ignorance is the highest knowledge. It is the necessary condition for all learning.”

“All political theories assume, of course, that most individuals are very ignorant. Those who plead for liberty differ from the rest in that they include among the ignorant themselves as well as the wisest. Compared with the totality of knowledge which is continually utilized in the evolution of a dynamic civilization, the difference between the knowledge that the wisest and that the most ignorant individual can deliberately employ is comparatively insignificant.”

“Most people ignore most poetry because poetry ignores most people.”

“Probability is not a mere computation of odds on the dice or more complicated variants; it is the acceptance of the lack of certainty in our knowledge and the development of methods for dealing with our ignorance.”