Mathematics knows no races or geographic boundaries; for mathematics, the cultural world is one country.
David HilbertAs long as a branch of science offers an abundance of problems, so long it is alive; a lack of problems foreshadows extinction or the cessation of independent development.
David HilbertIf I were to awaken after having slept for a thousand years, my first question would be: Has the Riemann hypothesis been proven?
David HilbertA mathematical problem should be difficult in order to entice us, yet not completely inaccessible, lest it mock at our efforts. It should be to us a guide post on the mazy paths to hidden truths, and ultimately a reminder of our pleasure in the successful solution.
David Hilbert