We should take care not to make intellect our god; it has, of course, powerful muscles, but no personality."

"I think and think for months and years. Ninety-nine times, the conclusion is false. The hundredth time I am right."

A theory can be proved by experiment; but no path leads from experiment to the birth of a theory.

"Everything should be made as simple as possible, but not simpler."

Try not to become a man of success but rather try to become a man of value.