The Copenhagen interpretation of quantum mechanics has established the language that is generally used when quantum mechanics is applied. In Parts I and II and in the first chapter of Part III, the author describes the main features in the philosophy behind the Copenhagen interpretation. What then follows are his personal views on the basis of this "Copenhagen philosophy". The author hopes to convince the reader of the incompatibility of quantum mechanics with realism if the latter neglects the role of consciousness in the conceptions of reality. He also tries to pave the road for a timely discussion of the science-religion debate in view of a correct interpretation of the message of nature spelled out in the language of quantum physics.

When I meet a difficult problem, I begin to go around it, approaching it again and again from different directions. If I persistently continue these approaches, it can happen that no problem remains. (RolfNevanlinna, in a private discussion.) In 1976, after a mainly administrative period of some 15 years, I spent a couple of months at CERN, working in the Pauli Collection. When I found the Pauli-Fierz correspondence, I had the intuitive feeling that there was the key: that "it was an objective description, and that it was the only possible objective description" for the mysteries of quantum mechanics. Here I have cited Bohr in his 'last interview' (see Chap. 7), which I became acquainted with only later, but I was immediately convinced that Pauli's view was more profound than anything else I had read about in quantum mechanics. However, nowadays the investigation of the foundations of quantum theory is dominated by 'realism', which means that the influence of the psyche on our conception of reality is ignored. This book is an attempt to show that this is not possible in quantum mechanics.