Pauli talks about questions concerning the "Dialectica" issue. He also writes about recent progress in theoretical work on electrodynamics and mesonic problems. He reminds Bohr to not forget Sommerfeld's 80th birthday on the 5th December 1948.

Pauli thanks Bohr for his letter of November 26. He is expecting now almost every day the appearance of the issue of "Dialectica". He is not sure whether it was really a good idea to send him some manuscripts by Born.

Pauli thanks Bohr for his last letter and for the enclosed page by Rosenfeld, which he is now returning. He agrees that there is an elementary error on this page, which he explains further.

Pauli writes about to their talk on the connection between the concepts of "God" and "knowing" or "knowledge". It is true that such a connection exists in the official "confession" of the Christian Churches, but besides it there was always a more hidden tradition of a God who is only dreaming (and also brings forth creation in a kind of dreaming state).

Pauli thanks Bohr for his letter of the 7th August and he is glad to inform him that they got a stipend of 3000 Swiss francs for Alder as a contribution to the costs for his stay in Copenhagen. Pauli hopes that Bohr can get an additional contribution which will enable him to be in Copenhagen for 6 months starting about October the first. Pauli has had interesting ongoing discussions with Møller-Kristensen and with Peierls on the formfactor theories. Like Bohr, Pauli thinks it unlikely that they will make real progress this way, but it seems to Pauli to be of interest to learn a little more about where formally the limitations of these models become obvious. Pauli received from Schrödinger the proofs of a paper (British Journal of Philosophy of Science) of which Pauli was unable to make any sense. It is in a way even more empty than Bohm's attempts to resume de Broglies old wave theory.

Pauli writes about his trip to Copenhagen and Leyden. He sends a manuscript of his lecture "Wahrscheinlichkeit und Physik" which he has given at a congress on probability and statistics in Zürich. He also mentions de Broglie's new paper.

Pauli gives his reactions to the articles by Waddington and R Goldschmidt and the latter's book on adaptation and mutation. He writes on Oppenheimer and Delbrück's views. He also comments on Bohr's article "Physical science and the study of religions".

Pauli sends a few informal lines in answer to Bohr's letter of the 3rd March. Meanwhile he has seen Delbrück and received from him a report about his meeting with Bohr in Copenhagen. He said that Bohr changed his mind on these biological questions soon after he had sent his letter to Pauli. This seems to Pauli quite satisfactory as he is now rather convinced that there is no causal connection between the happenings in a gene and the environment (milieu) of the organism. Now Pauli has spoken with Delbrück and also with other biologists he sees much better where the real problems are. Meanwhile another of their common friends, Otto Stern, passed through New York on his trip from California to Europe. Bohr will soon see him in Copenhagen.

Pauli was glad to get Bohr's message that he will make a short stop in Zürich. Pauli gives some organisational information.

Pauli comments on Bohr's lecture on "Unity of knowledge". He differs from Bohr in his view on the degree of detachment in science. He explains his opinion with reference in physics, psychology and biology. He speaks about a remark made by Bohr on psychoanalytical treatment on the role of the unconscious and Jung's school.