Augustus De Morgan

“Wrong hypotheses, rightly worked from, have produced more useful results than unguided observation.”

“A paradox is something which is apart from general opinion, either in subject matter, method, or conclusion.”

“Detach a dog from a supposition of which he is fond—and you have a philosopher.”

“The moving power of mathematical invention is not reasoning but imagination.”

“A mathematician's reputation rests on the number of bad proofs he has given.”

“All the mathematical sciences are founded on relations between physical laws and laws of numbers, so that the aim of exact science is to reduce the problems of nature to the determination of quantities by operations with numbers.”

“Common sense is that which judges the things given to it by other senses.”

“I did not hear what you said, but I will contradict you.”

“It is easier to square the circle than to get round a mathematician.”

“I have not the smallest molecule of faith in aerial navigation other than ballooning, or of the expectation of good results from any of the trials we hear of.”

“The first man who noticed the analogy between a group of seven fishes and a group of seven days made a notable advance in the history of thought.”

“To prove a thing is to make it so.”

“The science of logic is the science of the necessary laws of thought.”

“Great fleas have little fleas upon their backs to bite 'em, And little fleas have lesser fleas, and so ad infinitum.”