1 8 0 D O C U M E N T S 1 8 0 , 1 8 1 A P R I L – M A Y 1 9 2 8 180. To F. A. Staedtler [Berlin,] 28 April 1928 Dear Sir, The talk that I gave in Davos[1] has not been published. The aspect of my point of view[2] that is of interest to you is the following: The facts of radioactivity and those that are dealt with by the quantum theory have led to a theoretical develop- ment that in a certain sense denies the strictly causal course of elementary physical processes. In place of the causal theory, a new theory has emerged, whose axiom- atic basis is formed by statistical laws. A well-known example: Rutherford’s decay law for radioactive atoms.— Although it must be admitted that this development is based upon the weighty force of facts, I have nevertheless expressed my opinion that a more complete level of physical understanding will lead us back to the postulate of causality.— Respectfully yours, 181. From Rudolf Goldschmidt[1] Charlottenburg 9, Lindenallee 45, 2 May 1928 Dear Professor Einstein, I would be very grateful if you could quite briefly let me know your opinion of the following two points: 1.) Is it not so that the increased damping is perhaps the reason why in the case of my membrane, a tinny sound (proper tone) doesn’t occur? Electrical equivalent: An ohmic resistance in series with an inductance L and a capacitance C. [2] Thus, with increasing C, the damping also increases. Probably, the equivalent also increases for lower eigenoscillations. 2.) Is the following claim, which I have written for the English patent applica- tion, in order? “A membrane under magnetic or electrostatic tension, in which sufficient stresses are artificially produced that its elasticity characteristic curve becomes adapted to the curvature of the magnetic or electrostatic characteristic curve (as- similated), so that the membrane is put into a state of pseudoastatic equilibrium.”[3] With kind regards, also to your wife, yours sincerely, Rud. Goldschmidt Logarithmic decrement = C L ---- 