No problem is ever solved in the same consciousness thas was used to create it.

When I think of the most able students I have encountered in my teaching - I mean those who have distinguished themselves not only by skill but by independence of thought - then I must confess that all have had a lively interest in epistemology.

Insofar as mathematics is true, it does not describe the real world. Insofar as it describes the real world, it is not true.

A man must learn to understand the motives of human beings, their illusions, and their sufferings.

Anybody who really wants to abolish war must resolutely declare himself in favor of his own country's resigning a portion of sovereignty in place of international institutions.

One who scorns the power of intuition will never rise above the ranks of journeyman calculator.

A hundred times every day I remind myself that my inner and outer life are based on the labors of others.