D O C . 3 3 M A Y 1 9 1 9 2 9 your presence in Zurich. Maxwell’s results could certainly be derived more ele- gantly by Hilbert’s method using integral equations and, in the worst case, this alone could justify a dissertation. I am quite satisfied with physics life in Zurich, not only regarding the profes- sional aspect but also the spirit of camaraderie at the institute. Only the faculty works a bit slowly I have not been able to hold my trial lecture up to now, as it is only today that the faculty is convening to pass a resolution about the date. Whether I am still going to be able to give a lecture is, hence, questionable. With respectful greetings, I remain very devotedly yours, Paul Epstein. 33. To Hans Vaihinger [Berlin,] 3 May 1919 Highly esteemed Colleague, You have had to suffer much hardship, as I sadly gather from your amicable and long letter. And yet, those of our kind are still better off than most others, for we are accustomed to placing the focus of our attention beyond personal experience. This kind of liberation is actually the most valuable thing that true culture can give a person. I am sorry that you devoted so much attention to my marginal notes in Study’s book they were jotted down hastily and with little care. I do see that Study does not do you justice. I gave you the book only because it is written with such wit and is amusing, not because I wanted to plead for that view. I find that his “realism” is philosophically quite foggy, only substantiated in the little book so that the reader gets a Molière-like slap. I find the book General Theory of Knowledge [Allgemeine Erkenntnislehre] by M. Schlick, which takes a somewhat similar point of view, much more penetrating. If I find any fault with certain propositions posed by you with regard to the “fic- tions,” it is primarily that fictions are inherently contradictory. The concept “point,” for ex. is, in my view, not inconsistent if one realizes that what is involved here is merely a concept, not an object of perception. I absolutely do not see how this concept, within its own system, leads to mutually contradictory conclusions. The assumption that I held out the prospect of a paper for the Kant-Studien is based on error. I am too little versed in philosophy to take an active part in it my- self if I can be passively receptive to the work of the men in this field, I am content enough. I just promised to pass on information, verbally as well as in writing, about matters regarding my specialty in particular that are of interest to philosophers.