120 Quotes by Werner Heisenberg

Both matter and radiation possess a remarkable duality of character, as they sometimes exhibit the properties of waves, at other times those of particles. Now it is obvious that a thing cannot be a form of wave motion and composed of particles at the same time - the two concepts are too different

Every experiment destroys some of the knowledge of the system which was obtained by previous experiments.

Whether we electrons, light quanta, benzol molecules, or stones, we shall always come up against these two characteristics, the corpuscular and the undular.

The more precise the measurement of position, the more imprecise the measurement of momentum, and vice versa.

The ontology of materialism rested upon the illusion that the kind of existence, the direct "actuality" of the world around us, can be extrapolated into the atomic range. This extrapolation is impossible, however.

Science no longer is in the position of observer of nature, but rather recognizes itself as part of the interplay between man and nature. The scientific method ... changes and transforms its object: the procedure can no longer keep its distance from the object.

The physicist may be satisfied when he has the mathematical scheme and knows how to use for the interpretation of the experiments. But he has to speak about his results also to non-physicists who will not be satisfied unless some explanation is given in plain language. Even for the physicist the description in plain language will be the criterion of the degree of understanding that has been reached. Physics and Philosophy

By getting to smaller and smaller units, we do not come to fundamental or indivisible units. But we do come to a point where further division has no meaning.

Nonsense. Space is blue and birds fly through it.