ZusammenfassungNach einer historischen Übersicht über die Entwicklung der naturwissenschaftlichen Disziplinen in den vergangenen Jahrhunderten wird auseinandergesetzt, dass wir seit der Quantentheorie einige frühere Theorien, wie etwa die Newton'sche Mechanik, als abge‐schlossene Theorien bezeichnen. Der Sinn dieser Begriffsbildung wird besprochen, ebenso die Bedingungen, unter denen eine Theorie als abgeschlossen bezeichnet werden kann.

Heisenberg, in constructing quantum mechanics, explicitly followed certain principles exemplified, as he believed, in Einstein's construction of the special theory of relativity which for him was the paradigm for radical theoretic change in physics. These were the principles of scientific realism, stability of background knowledge, E-observability, contextual re-interpretation, pragmatic continuity, model continuity, simplicity. Fifty years later, in retrospect, Heisenberg added the following two: a principle of non-proliferation of competing theories - scientific revolutions are not a legitimate goal of physics - (...) and a principle of tenacity - existing theories are to be conserved as far as possible. The conservative as well as the revolutionary potential of these principles is then discussed. A more penetrating philosophical criticism of these principles is postponed. (shrink)

SummaryA short exposition is given of the foundation of the causal description in classical physics and the failure of the principle of causality in coping with atomic phenomena. It is emphasized that the individuality of the quantum processes excludes a separation between a behaviour of the atomic objects and their interaction with the measuring instruments denning the conditions under which the phenomena appear. This circumstance forces us to recognize a novel relationship, conveniently termed complementarity, between empirical evidence obtained under different (...) experimental conditions. An appropriate tool for a complementary mode of description is provided by the quantum‐mechanical formalism which allows us to account for regularities of definite or statistical character beyond the grasp of classical physical explanation. – N. B. (shrink)

On several occasions I have pointed out that the lesson taught us by recent developments in physics regarding the necessity of a constant extension of the frame of concepts appropriate for the classification of new experiences leads us to a general epistemological attitude which might help us to avoid apparent conceptual difficulties in other fields of science as well. Since, however, the opinion has been expressed from various sides that this attitude would appear to involve a mysticism incompatible with the (...) true spirit of science, I am very glad to use the present opportunity of addressing this assembly of scientists working in quite different fields but united in their striving to find a common ground for our knowledge, to come back to this question, and above all to try to clear up the misunderstandings which have arisen. (shrink)

The aim of this paper is to examine in detail the similarities and dissimilarities between Werner Heisenberg’s account of closed theories and Thomas Kuhn’s model of scientific revolutions. My analysis draws on a little‐known discussion that took place between Heisenberg and Kuhn in 1963, in which Heisenberg, having just read Kuhn’s Structure of Scientific Revolutions, compares Kuhn’s views to his own account of closed theories. I conclude that while Heisenberg and Kuhn share a holist conception of theories, a revolutionary model (...) of theory change, and even a notion of incommensurability, their views diverge fundamentally when it comes to the issue of scientific realism. I show that, contrary to popular opinion, Heisenberg is not an instrumentalist, but rather a pluralistic realist. (shrink)

The contributions of few contemporary scientists have been as far reaching in their effects as those of Nobel Laureate Werner Heisenberg.

An attempt is made to give a coherent account of the logical essence of the Copenhagen interpretation of quantum theory. The central point is that quantum theory is fundamentally pragmatic, but nonetheless complete. The principal difficulty in understanding quantum theory lies in the fact that its completeness is incompatible with external existence of the space—time continuum of classical physics.