Every mathematical discipline goes through three periods of development: the naive, the formal, and the critical. — David Hilbert Critical Copy Share Image
An old French mathematician said: "A mathematical theory is not to be considered complete until you have made it so clear that… — David Hilbert Clear Copy Share Image
Sometimes it happens that a man's circle of horizon becomes smaller and smaller, and as the radius approaches zero it concentrates on… — David Hilbert Approach Copy Share Image
