“Anytime somebody is absolutely certain about something, they are almost always absolutely wrong”

“What can you do with a person who says that he is absolutely uncertain about everything, and that he is absolutely certain about that?”

“I'm fine. Well, I'm not fine - I'm here.""Is there something wrong with that?""Absolutely.”

“There are things we know for certain.""Oh? Name one.""The sun's going to come up tomorrow morning.""Why?""It always has.""Does that really mean that it always will?"A faint look of consternation crossed her face. "It will, won't it?""Probably, but we can't be absolutely certain. Once you've decided that something's absolutely true, you've closed your mind on it, and a closed mind doesn't go anywhere. Question everything, Pol. That's what education's all about.”

“We can be absolutely certain only about things we do not understand.”

“Philosophers say a great deal about what is absolutely necessary for science, and it is always, so far as one can see, rather naive, and probably wrong.”