Mathematics has the completely false reputation of yielding infallible conclusions. Its infallibility is nothing but identity. Two times two is not four, but it is just two times two, and that is what we call four for short. But four is nothing new at all. And thus it goes on and on in its conclusions, except that in the higher formulas the identity fades out of sight.
Johann Wolfgang von GoetheWith the growth of knowledge our ideas must from time to time be organized afresh. The change takes place usually in accordance with new maxims as they arise, but it always remains provisional.
Johann Wolfgang von GoetheJust as, out of habit, one consults a run-down clock as though it were still going, so too one may look at the face of a beautiful woman as though he still loved her.
Johann Wolfgang von Goethe