Quote by David Hilbert
"A problem solved is a door opened; we never know what lies beyond."
More from David Hilbert
"Mathematics is the foundation of all exact knowledge of natural phenomena."
"One cannot escape the feeling that these mathematical formulas have an independent existence and an intelligence of their own."
"The art of doing mathematics consists in finding that special case which contains all the germs of generality."
"If I were to awaken after having slept for a thousand years, my first question would be: has the Riemann hypothesis been proven?"