Fierz writes about the problem of space in connection with field theory and geometry. He makes some remarks on Pauli's two opposites: (+ -) and (p,q), and the speculations about similar opposites in psychology (individual and society). He also writes about Newton's concept of space and on Henry More's influence on him.

Fierz writes on the elaboration of the concepts of polar opposites and complementary opposites. He refers to Kant and Leibniz.

Fierz makes some remarks on Aristotle's realism and its contrast to Plato's idealism.

Fierz agrees to participate on the symposium on "Phenomenon and physical reality". He describes his interpretation of the concepts of "phenomenon" and "reality", and relates this to the present situation of physics.

Fierz argues against Jordan's theory of gravitation, makes remarks on an anticipation of Mach's principle by Euler, and comments on Pauli's lecture in mainz.

Fierz makes some remarks on some recent papers about weak interactions.

Fierz sends some corrections to a first letter he had written on the same day (see letter fierz_0016-283r).

Fierz replies to a letter by Pauli and makes some remarks on the $\beta$-decay. Fierz sent another letter on the same day including some corrections to this one (see letter fierz_0016-282r).

Fierz makes further remarks concerning a paper by Stückelberg.

Fierz sends some calculations with reference to Chandra's work on the infinitesimal Lorentz group.