Bohr’s inspirations

Bernadette Bensaude‐Vincent

SUMMARY. — This paper emphasizes the evolution of complementarity, in Niels Bohr's successive formulations of this idea, from 1927 to 1939, despite little, if any change in the definition of the concept with time. In the Como lecture, in 1927, Bohr introduced the idea of « complementary descriptions » in a problematic, polemical way. Against Schrödinger' s interpretation, he stressed the « irrationality » inherent in the quantum postulate. In 1935, Bohr again used complementarity polemically, in his reply to Einstein-Podolsky-Rosen. But far from intending it to convey irrationality this time, he meant to use it instead to prove that quantum mechanics is a complete theory. Finally, I will take up Bohr's attempts to apply complementarity to fundamental problems in biology, psychology, sociology, and so forth. I will argue that the introduction of complementarity outside physics was not motivated by an imperialist ambition of the Copenhagen School, but rather inspired by Bohr's own personal philosophy.

Wolfgang W. Osterhage

Helge Kastrup, Jeffry V. Mallow A

Niels Bohr made numerous contributions to physics. But his most important was to break the rules. Bohr propounded several postulates. First, that electrons revolved in their orbits around the nucleus of an atom without emitting energy. Second, that spectral lines came from electrons emitting energy by jumping from one orbit to a lower one. Third, that only certain orbital radii were allowed. All three of these unsubstantiated claims violated classical physics, according to which accelerating charges emit energy. Thus, electrons should lose their energy and spiral into the nucleus. But this theory could not account for spectra; Bohr's postulates could. Bohr was the leader of a brilliant group of physicists who developed most of the fundamentals of quantum mechanics and showed that its laws proved the validity of his inspired guesses. A non-member of the group was Einstein, who disagreed with his friend Bohr over the actual meaning of quantum mechanics.

François-Igor Pris

According to one possible diagnosis of the quantum measurement problem, it is a consequence of quantum fundamentalism claiming that ontology and epistemology of the world are exclusively quantum, and classical physics is only an approximation. For N. Bohr, the measurement problem is a pseudo-problem because any quantum phenomenon presupposes the classical context of an experimental setup and the use of classical concepts to describe it. We consider Bohr's position from the point of view of our contextual quantum realism (CQR), inspired by the later Wittgenstein philosophy. Our approach is consistent with H. Zinkernagel's interpretation, according to which Bohr's position is not only epistemological anti-fundamentalism, but also ontological anti-fundamentalism.