The theoretical idea ... does not arise apart from and independent of experience; nor can it be derived from experience by a purely logical procedure. It is produced by a creative act. Once a theoretical idea has been acquired, one does well to hold fast to it until it leads to an untenable conclusion.

God does not play dice.

Chess holds its master in its own bonds, shackling the mind and brain so that the inner freedom of the very strongest must suffer.

What I seek to accomplish is simply to serve with my feeble capacity truth and justice, at the risk of pleasing no one.

You cannot simultaneously prevent and prepare for war.

Success comes from curiosity, concentration, perseverance and self criticism.

Insofar as we may at all claim that slavery has been abolished today, we owe its abolition to the practical consequences of science