Quotes by Augustus De Morgan

"I am perfectly convinced that I have both seen, and heard in a manner which should make unbelief impossible, things called spiritual which cannot be taken by a rational being to be capable of explanation by imposture, coincidence, or mistake."

"Lagrange , in one of the later years of his life, imagined that he had overcome the difficulty ( of the parallel axiom ). He went so far as to write a paper, which he took with him to the Institute, and began to read it. But in the first paragraph something struck him that he had not observed: he muttered: ' Il faut que j'y songe encore ', and put the paper in his pocket.' [ I must think about it again ]."

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