"In our opinion, truths of this kind should be drawn
from notions rather than notation."

Carl Friedrich Gauss
Disquisitiones Arithmeticae, Article 76

"In mathematics, the art of proposing a question
must be held of higher value than solving it."

George Cantor
Doctoral Thesis
"As far as the laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality."
Albert Einstein
Geometry and Experience

"There is no point in using exact methods where there is no clarity in the concepts and issues to which they are to be applied."
John von Neumann and Oskar Morgenstern
Theory of Games and Economic Behavior