It is odd to think that there is a word for something which, strictly speaking, does not exist, namely, "rest." We distinguish between living and dead matter; between moving bodies and bodies at rest. This is a primitive point of view. What seems dead, a stone or the proverbial "door-nail," say, is actually forever in motion. We have merely become accustomed to judge by outward appearances; by the deceptive impressions we get through our senses.

No language which lends itself to visualizability can describe quantum jumps.

His [Erwin Schrödinger's] private life seemed strange to bourgeois people like ourselves. But all this does not matter. He was a most lovable person, independent, amusing, temperamental, kind and generous, and he had a most perfect and efficient brain.

Intellect distinguishes between the possible and the impossible; reason distinguishes between the sensible and the senseless. Even the possible can be senseless.

If God has made the world a perfect mechanism, He has at least conceded so much to our imperfect intellect that in order to predict little parts of it, we need not solve innumerable differential equations, but can use dice with fair success.

It is true that many scientists are not philosophically minded and have hitherto shown much skill and ingenuity but little wisdom.

I believe there is no philosophical high-road in science, with epistemological signposts. No, we are in a jungle and find our way by trial and error, building our road behind us as we proceed.