“Dogmatism is the greatest of mental obstacles to human happiness.”

“To like many people spontaneously and without effort is perhaps the greatest of all sources of personal happiness.”

“It is not what the man of science believes that distinguishes him, but how and why he believes it. His beliefs are tentative, not dogmatic; they are based on evidence, not on authority or intuition.”

“Dogmatism and skepticism are both, in a sense, absolute philosophies; one is certain of knowing, the other of not knowing. What philosophy should dissipate is certainty, whether of knowledge or ignorance.”

“Freedom in general may be defined as the absence of obstacles to the realization of desires.”

“I think we ought always to entertain our opinions with some measure of doubt. I shouldn't wish people dogmatically to believe any philosophy, not even mine. ”

“Machines deprive us of two things which are certainly important ingredients of human happiness, namely, spontaneity and variety.”