It is not surprising that our language should be incapable of describing the processes occurring within the atoms, for, as has been remarked, it was invented to describe the experiences of daily life, and these consists only of processes involving exceedingly large numbers of atoms. Furthermore, it is very difficult to modify our language so that it will be able to describe these atomic processes, for words can only describe things of which we can form mental pictures, and this ability, too, is a result of daily experience. Fortunately, mathematics is not subject to this limitation, and it has been possible to invent a mathematical scheme—the quantum theory—which seems entirely adequate for the treatment of atomic processes; for visualization, however, we must content ourselves with two incomplete analogies—the wave picture and the corpuscular picture.

—     Werner Heisenberg

The Physical Principles of the Quantum Theory, trans. Carl Eckart and Frank C. Hoyt (1949), 11.

See also:  |  Atom (92)  |  Particle (13)  |  Quantum Physics (14)  |  Wave (16)

It seems sensible to discard all hope of observing hitherto unobservable quantities, such as the position and period of the electron… Instead it seems more reasonable to try to establish a theoretical quantum mechanics, analogous to classical mechanics, but in which only relations between observable quantities occur.

—     Werner Heisenberg

In Helge Kragh, Quantum Generations: A History of Physics in the Twentieth Century (1999), 161.

See also:  |  Electron (30)  |  Observation (147)  |  Quantum Physics (14)  |  Theory (192)

Our scientific work in physics consists in asking questions about nature in the language that we possess and trying to get an answer from experiment by the means at our disposal. In this way quantum theory reminds us, as Bohr has put it, of the old wisdom that when searching for harmony in life one must never forget that in the drama of existence we are ourselves both players and spectators. It is understandable that in our scientific relation to nature our own activity becomes very important when we have to deal with parts of nature into which we can penetrate only by using the most elaborate tools.

—     Werner Heisenberg


The Copenhagen Interpretation of Quantum Theory (1958). In Steve Adams, Frontiers (2000), 13.

See also:  |  Experiment (218)  |  Quantum Theory (19)  |  Question (52)  |  Research (221)

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.

—     Werner Heisenberg

The Representation of Nature in Contemporary Physics’, Symbolism in Religion and Literature (1960), 231. Cited in John J. Stuhr, Philosophy and the Reconstruction of Culture (1993), 139.

See also:  |  Change (44)  |  Man (115)  |  Nature (255)  |  Object (14)  |  Procedure (6)  |  Recognize (4)  |  Science (463)  |  Scientific Method (62)