"It's a great thing to be able to say, 'I don't know.'"

"By the way, Professor, you know that paper in which you say those quantities are analogous... Did you know they're proportional?"

"I have a lot of fun. I've always had a lot of fun. I don't know why I should stop."

"I'm not interested in science for the sake of science. I'm interested in science for the sake of understanding the world."

"I don't believe in miracles, because I believe in science."