The open secret of real success is to throw your whole personality into your problem.

To write and speak correctly is certainly necessary; but it is not sufficient. A derivation correctly presented in the book or on the blackboard may be inaccessible and uninstructive, if the purpose of the successive steps is incomprehensible, if the reader or listener cannot understand how it was humanly possible to find such an argument....

John von Neumann was the only student I was ever afraid of.

What is the difference between method and device? A method is a device which you use twice.

Look around when you have got your first mushroom or made your first discovery: they grow in clusters.

The best of ideas is hurt by uncritical acceptance and thrives on critical examination.

You should not put too much trust in any unproved conjecture, even if it has been propounded by a great authority, even if it has been propounded by yourself. You should try to prove it or disprove it.