There is hardly another principle in physics with wider scope of applicability and more far-reaching consequences than Pauli's exclusion principle. This book explores the principle's origin in the atomic spectroscopy of the early 1920s, its subsequent embedding into quantum mechanics, and later experimental validation with the development of quantum chromodynamics. The reconstruction of this crucial historic episode provides an excellent foil to reconsider Kuhn's view on incommensurability. The author defends the prospective rationality of the revolutionary transition from the old to (...) the new quantum theory around 1925 by focusing on the way Pauli's principle emerged as a phenomenological rule 'deduced' from some anomalous phenomena and theoretical assumptions of the old quantum theory. The subsequent process of validation is historically reconstructed and analysed within the framework of 'dynamic Kantianism'. (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 book gives an painstaking analysis of Niels Bohr's understanding of quantum mechanics based on a claim that Bohr was influenced by Harald Høffding's approach to philosophical problems.

Introductory survey -- Atomic theory and mechanics -- The quantum postulate and the recent development of atomic theory -- The quantum of action and the description of nature -- The atomic theory and the fundamental principles underlying the description of nature.