You may have no need for more, but I find Bertrand Russell to be very quotable:
1) A stupid man's report of what a clever man says can never be accurate, because he unconsciously translates what he hears into something he can understand.
2) If a man is offered a fact which goes against his instincts, he will scrutinize it closely, and unless the evidence is overwhelming, he will refuse to believe it. If, on the other hand, he is offered something which affords a reason for acting in accordance to his instincts, he will accept it even on the slightest evidence. The origin of myths is explained in this way.
3) Science may set limits to knowledge, but should not set limits to imagination.
4) The whole problem with the world is that fools and fanatics are always so certain of themselves, but wiser people so full of doubts.