Quotes by Werner Heisenberg

• What we observe is not nature itself, but nature exposed to our method of questioning.
• Every word or concept, clear as it may seem to be, has only a limited range of applicability.
• The violent reaction on the recent development of modern physics can only be understood when one realises that here the foundations of physics have started moving; and that this motion has caused the feeling that the ground would be cut from science.
• Natural science, does not simply describe and explain nature; it is part of the interplay between nature and ourselves.
• The problems of language here are really serious. We wish to speak in some way about the structure of the atoms. But we cannot speak about atoms in ordinary language.
• The solution of the difficulty is that the two mental pictures which experiment lead us to form - the one of the particles, the other of the waves - are both incomplete and have only the validity of analogies which are accurate only in limiting cases.