"The quantum hypothesis will never be overthrown."

"Mathematics, rightly viewed, possesses not only truth, but supreme beauty — a beauty cold and austere, like that of sculpture, without appeal to any part of our weaker nature, without the gorgeous tra…"

"The total number of particles in the universe is so large that it is impossible to count them."

"The quantum of action, as I called it, was a purely formal assumption and I really did not think much about it."

"My original decision to devote myself to science was a direct result of the discovery, which has never ceased to fill me with enthusiasm, that the laws of nature are accessible to human thought."