Werner Heisenberg

“An expert is someone who knows some of the worst mistakes that can be made in his subject, and how to avoid them.”

“There are things that are so serious that you can only joke about them.”

“The reality we can put into words is never reality itself.”

“Not only is the Universe stranger than we think, it is stranger than we can think.”

“I think that modern physics has definitely decided in favor of Plato. In fact the smallest units of matter are not physical objects in the ordinary sense; they are forms, ideas which can be expressed unambiguously only in mathematical language.”

“The positivists have a simple solution: the world must be divided into that which we can say clearly and the rest, which we had better pass over in silence. But can anyone conceive of a more pointless philosophy, seeing that what we can say clearly amounts to next to nothing? If we omitted all that is unclear, we would probably be left completely uninteresting and trivial tautologies.”

“I remember discussions with Bohr which went through many hours till very late at night and ended almost in despair; and when at the end of the discussion I went alone for a walk in the neighbouring park I repeated to myself again and again the question: Can nature possibly be so absurd as it seemed to us in these atomic experiments?”

“In the history of science, ever since the famous trial of Galileo, it has repeatedly been claimed that scientific truth cannot be reconciled with the religious interpretation of the world. Although I an now convinced that scientific truth is unassailable in its own field, I have never found it possible to dismiss the content of religious thinking as simply part of an outmoded phase in the consciousness of mankind, a part we shall have to give up from now on, Thus in the course of my life I have repeatedly been compelled to ponder on the relationship of these two regions of though, for I have never been able to doubt the reality of that to which they point.”

“We have to remember that what we observe is not nature in itself butnature exposed to our method of questioning.”

“If we wanted to construct a basic philosophical attitude from these scientific utterances of Pauli's, at first we would be inclined to infer from them an extreme rationalism and a fundamentally skeptical point of view. In reality however, behind this outward display of criticism and skepticism lay concealed a deep philosophical interest even in those dark areas of reality of the human mind which elude the grasp of reason. And while the power of fascination emanating from Pauli's analyses of physical problems was admittedly due in some measure to the detailed and penetrating clarity of his formulations, the rest was derived from a constant contact with the field of creative processes, for which no rational formulation as yet exists.”

“If nature leads us to mathematical forms of great simplicity and beauty—by forms, I am referring to coherent systems of hypotheses, axioms, etc.—to forms that no one has previously encountered, we cannot help thinking that they are “true,” that they reveal a genuine feature of nature…. You must have felt this too: the almost frightening simplicity and wholeness of the relationships which nature suddenly spreads out before us and for which none of us was in the least prepared.”

“Quantum theory provides us with a striking illustration of the fact that we can fully understand a connection though we can only speak of it in images and parables.”

“Revere those things beyond science which really matter and about which it is so difficult to speak.”

“What we observe is not nature itself, but nature exposed to our method of questioning.”