Pauli comments about a talk with Fröhlich on Schafroth's results.

Pauli writes about E. A. Burtt's "The Metaphysical Foundations on Modern Science". He criticizes the ascription of "ultimate reality and causal efficacy" to the world of mathematics, and comments on the distinctions science-theology, man-universe, and metaphysics-positivism.

Schafroth replies to Pauli's critics on his supraconductivity paper. He writes a postscriptum as regards to Fröhlich's arguments quoted by Pauli.

Bohr is sorry not to have written for so long, but his time has been very occupied since his return from America. He says that it was nice to be at the Princeton Institute again, and it was a special pleasure to see in how quiet and dignified a manner Oppenheimer took the decision of the Atomic Energy Commission. Both he and his wife were more glad than they have been for a long time, and it has been a great encouragement to them to feel what good friends they have not only amongst the physicists but also in wide circles of the American community, for whom this unreasonable matter has been a great shock. Now he hopes that Robert will have more time for his scientific work, and he is - like the whole circle in Princeton - deeply interested in the many problems which the experiments with the elementary particles always make more contemporary. When Bohr was in Princeton they had also many discussions about the general biological and psychological questions in which also Delbrück took part. Bohr hopes that Pauli will soon come to Copenhagen and speak to the CERN group, and that his wife will come too.

Pauli writes about his lecture in Mainz, and asks for information about the following participants: Bense, Hall, Hartner and Kuypers.

Thirring makes remarks about a statement by Heisenberg on renormalization.

Thirring writes about the necessity for a clearer definition of Heisenberg's formalism in the light of Lee's model.

Pauli comments on Heisenberg's article "The development of the interpretation of quantum theory", characterised as a complete discussion of the literature against the "Copenhagen interpretation". Pauli agrees with Heisenberg that the "Copenhagen interpretation" is not positivist.