"The quantum theory is an 'unpleasant' theory, which I should have liked to assume to be true only if I were forced to do so by the facts."

"I am born into an environment — I know not whence I came nor whither I go nor who I am."

"Even if I should be right in this, I do not know whether my way of approach is really the best and simplest. But, in short, it was mine."

"The world is a dream, and we are the dreamers."

"The problem of the 'thing in itself' is not a problem that can be solved by science. It is a philosophical problem."