There are two ways to live: you can live as if nothing is a miracle; you can live as if everything is a miracle. The most beautiful thing we can experience is the mysterious. It is the source of all true art and all science. He to whom this emotion is a stranger, who can no longer pause to wonder and stand rapt is awe, is as good as dead: his eyes are closed.

A man's moral worth is not measured by what his religious beliefs are but rather by what emotional impulses he has received from Nature during his lifetime.

As soon as science has emerged from its initial stages, theoretical advances are no longer achieved merely by a process of arrangement. Guided by empirical data, the investigator rather develops a system of thought which, in general, is built up logically from a small number of fundamental assumptions, the so-called axioms. We call such a system of thought a theory. The theory finds the justification for its existence in the fact that it correlates a large number of single observations, and it is just here that the 'truth' of the theory lies.

I was just more stubborn and more passionate than most about physics.

The only sure way to avoid making mistakes is to have no new ideas.

I'd rather be an optimist and a fool than a pessimist and right.

Not all things worth counting are countable and not all things that count are worth counting.