3 4 D O C U M E N T S 8 , 9 J U N E 1 9 2 7 8. To Hendrik A. Lorentz [Berlin?,] 17 June [19]27 Dear Professor Lorentz, I recall that I promised you that I would deliver a report on quantum statistics at the Solvay Congress.[1] However, after much reflection one way and the other, I have come to the conviction that I am incapable of producing a report that really corresponds to the state of affairs. The reason for this is that I have not been able to follow the modern development of quantum theory as intensively as would be necessary for this task. That is partly because I am altogether not talented enough receptively to completely follow this stormy development, and partly also because, inwardly, I do not approve of the purely statistical way of thinking on which the new theories are based. I am still looking for a theory that is fully deterministic, and in doing so I have for the time being lost contact with the development. However, I have not advanced enough in my own efforts to be able to say whether they prom- ise any success. You will be justifiably annoyed with me for telling you this only now. But up to this point I still nourished the hope that I would be able to contribute something valuable in Brussels now I have given it up. I beg you from the bottom of my heart not to be angry because of this I didn’t undertake it lightly, but rather tried as hard as I could. I will gladly come to Brussels. But if the number of partic- ipants cannot be increased,[2] then I must be replaced by someone else (e.g., by Mr. Fermi in Bologna,[3] who could certainly do it well, or by Langevin,[4] who has, according to his own account, recently advanced the statistical theory of quanta very significantly.) I am glad that you returned from America in sound health and are happy to be back,[5] and that I will soon have the pleasure of seeing you again. In the meantime, kind regards from your A. Einstein 9. Recommendation for Emil Julius Gumbel[1] Berlin, 18 June 1927 I have known and admired Dr. Gumbel for years, both personally and as a math- ematician. He is an independent, smart fellow and has published a series of note- worthy works in the area of mathematical statistics. His statistical publications have also rendered significant service to public life. I am convinced that he would provide good service to the Chilean state as a university teacher.