Werner Heisenberg

"One should as a rule respect public opinion in so far as is necessary to avoid starvation and to prevent one's head being cut off."

"I would say that the attempt to objectify results of quantum mechanics has led to a great confusion in the minds of physicists."

"Change does not come from any new knowledge, but from a new feeling of what is true."

"The understanding of nature requires repeated interaction with it."

"There is something beautiful about a problem in physics, about the forms in which nature presents itself."

"What is real is that which can in principle be determined."

"Mathematics is the tool specially suited for dealing with abstract concepts of any kind."

"Reality is merely an illusion, albeit a very persistent one."

"The scientist only has the right to make statements which he can verify."

"We cannot observe absolute quantities at all; we can only observe differences."

"The hope that new experiments will be performed and will lead to new discoveries of truth."

"In quantum theory, no elementary phenomenon is a phenomenon until it is a registered phenomenon."

"God does not play dice with the universe."

"A new scientific truth does not triumph by convincing its opponents, but rather because its opponents eventually die."

"The most important tool of the theoretical physicist is his waste paper basket."

"To understand the world, one must not confuse the facts with the interpretation."

"The properties of an atom will only show up when there is an interaction with another system."

"What we cannot understand is perhaps not a mystery but something we have not yet learned how to ask."

"Anybody who has been seriously engaged in scientific work knows that over the entrance to the gates of science are written the words: You must have faith."

"The closed world of the atom became a window on the vast mysteries of existence."

"In every important case in which the past history of a particular field is examined, it is found that a revolutionary change in the point of view is the only way out."

"The decisive question about any piece of behavior is whether it aims at its right goal."

"Measurement does not create reality; it reveals only what existed before measurement."

"Nature speaks the language of mathematics."

"What is a photon? It is what makes the light."

"The idea of motion and the idea of rest are always meaningful relative to some frame of reference."

"Enthusiasm is a great asset in science; it allows one to overcome many obstacles."

"We are suspended in language in such a way that we cannot say what is up and what is down."

"The atoms or elementary particles are not real; they form a world of potentialities or possibilities."

"Every experiment destroys the state which had existed before."