Clear Quote by David Hilbert

An old French mathematician said: "A mathematical theory is not to be considered complete until you have made it so clear that you can…

— David Hilbert

This common and unfortunate fact of the lack of adequate presentation of basic ideas and motivations of almost any mathematical theory is probably due…

— Mikhail Leonidovich Gromov

To understand theory is not enough. Much practice is necessary...

— Kimon Nicolaides

Whenever a theory appears to you as the only possible one, take this as a sign that you have neither understood the theory nor…

— Karl Popper

[The infinitely small] neither have nor can have theory; it is a dangerous instrument in the hands of beginners [ ... ] anticipating, for…

— Francois-Joseph Servois

Experience has shown repeatedly that a mathematical theory with a rich internal structure generally turns out to have significant implications for the understanding of…

— William Thurston

Theory, from whatever source, is not perfect until it is reduced to practice.

— Hosea Ballou

“Somewhere out there is a theory that would explain my empirical observations, and this theory has yet to be discovered. Mathematics thrives on such…

— Henri Darmon

“It is my conviction that pure mathematical construction enables us to discover the concepts and the laws connecting them, which give us the key…

— Albert Einstein

“In other words, general set theory is pretty trivial stuff really, but, if you want to be a mathematician, you need some and here…

— Paul Halmos

Theories are not so much wrong as incomplete

— Isaac Asimov

Never abandon a theory that explains something until you have a theory that explains more.

— John McCarthy