Werner Heisenberg

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

"The first gulp from the glass of natural sciences will turn you into an atheist, but God is waiting for you at the bottom of the glass."

"An expert is a person who has made all the mistakes that can be made in his field."

"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 atoms or elementary particles themselves are not real; they form a world of potentialities or possibilities rather than one of things or facts."

"What we observe is not nature in itself, but nature exposed to our line of questioning."

"The same organizing principles that work in nature work in the human soul."

"Quantum mechanics makes absolutely no sense."

"A scientist only has the right to make a statement when he is absolutely sure of his facts."

"The first principle is that you must not fool yourself, and you are the easiest person to fool."

"Anybody who is not shocked by quantum theory has not understood it."

"I can only say that my own experiences have impressed me with the conviction that there are many things in the mind of man that are beyond the material world."

"The task is not so much to see what no one has yet seen, but to think what nobody has yet thought about that which everybody sees."

"If we cannot think in a certain way, we cannot speak in a certain way, and so we cannot think in that way."

"Nature isn't classical, dammit, if you want to make a simulation of nature, you'd better make it quantum mechanical."

"Every tool carries with it the spirit by which it has been created."

"The more success the quantum theory has, the sillier it looks."

"I think that the structure of the physical world is rational."

"You can't do better than that. You can't say that."

"The first step toward improvement in any field is the clear recognition of the current situation and its shortcomings."

"God runs electromagnetics by wave theory on Mondays, Wednesdays, and Fridays; by quantum theory on Tuesdays, Thursdays, and Saturdays; and He is still deciding about Sunday."

"The transition from the past to the future is brought about by a free will."

"What can be said at all can be said clearly; and whereof one cannot speak, thereof one must be silent."

"There is no reason to assume that the beginning of the world has to be understandable to us even if all seemingly separate scientific questions can be answered."

"The alternative to Cartesian dualism is not materialism, but rather a different understanding of matter and mind."

"In an expanding universe, time is on the side of the dungeon master."

"The revolution in physics that began with Planck and Einstein was not finished in 1930; we still don't know the ultimate truth."

"I believe that the present phase of industrial civilization is leading inevitably to disaster."

"Evil is when evil is justified by those responsible for it."

"Physics is really nothing more than a system of concepts by which we can describe the facts of nature and the interrelations of these facts."