It is true that my parents were worried because I began to speak fairly late, so that they even consulted a doctor. I can't say how old I was - but surely not less than three.

Playfullness is the essential feature of productive thought.

Most of the fundamental ideas of science are essentially simple, and may, as a rule, be expressed in a language comprehensible to everyone.

Concepts that have proven useful in ordering things easily achieve such authority over us that we forget their earthly origins and accept them as unalterable givens.

This is a question too difficult for a mathematician. It should be asked of a philosopher"(when asked about completing his income tax form)

Be a loner. That gives you time to wonder, to search for the truth. Have holy curiosity. Make your life worth living.

The Universe is difficult to comprehend because it is obvious.