“If you thought that science was certain - well, that is just an error on your part.”

“A philosopher once said, "It is necessary for the very existence of science that the same conditions always produce the same results." Well, they don't!”

“If you thought you were trying to find out more about it because you're gonna get an answer to some deep philosophical question...you may be wrong! It may be that you can't get an answer to that particular question by finding out more about the character of nature. But my interest in science is to simply find out about the world.”

“It is surprising that people do not believe that there is imagination in science. It is a very interesting kind of imagination, unlike that of the artist. The great difficulty is in trying to imagine something that you have never seen, that is consistent in every detail with what has already been seen, and that is different from what has been thought of; furthermore, it must be definite and not a vague proposition. That is indeed difficult.”

“Religion is a culture of faith; science is a culture of doubt.”

“Science is like sex: sometimes something useful comes out, but that is not the reason we are doing it. ”

“So I have just one wish for you – the good luck to be somewhere where you are free to maintain the kind of integrity I have described, and where you do not feel forced by a need to maintain your position in the organization, or financial support, or so on, to lose your integrity. May you have that freedom.”