An expert is a person who has few new ideas; a beginner is a person with many.

I do not believe in a personal God and I have never denied this but have expressed it clearly.

Lasting harmony with a woman (was) an undertaking in which I twice failed rather disgracefully.

The formulation of the problem is often more essential than its solution, which may be merely a matter of mathematical or experimental skill.

I have not eaten enough of the tree of knowledge, though in my profession I am obligated to feed on it regularly.

The more a country makes military weapons, the more insecure it becomes: if you have weapons, you become a target for attack.

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