D O C U M E N T 7 3 J U L Y 1 9 2 0 3 3 3
Mit herzlichen Grüßen Ihr sehr ergebener
J. Petzoldt.
ALS. [19 057]. Typed next to address: “Tel. Spandau 2039 (Nebenanschluß).”
[1]Petzoldt (1862–1929) was Privatdozent in epistemology in the natural sciences at the Technical
University of Berlin-Charlottenburg.
[2]Hans Vaihinger’s “Als-Ob” conference had taken place in Halle on 29 May 1920, a day before
the annual meeting of the Kant Society (see Doc. 41, note 2). Vaihinger had also invited Albert Ein-
stein and Moritz Schlick, but both decided not to attend after initially accepting the invitation (see
Doc. 41 and Moritz Schlick to Einstein, 5 June 1920, in Calendar, resp. Doc. 47, note 2). Oskar Kraus.
[3]Petzoldt’s contributions to the debates caused controversy among the participants: “A rather
lively, at times heated debate followed; a number of scholars agreed with Kraus, whereas others,
above all Professor Petzoldt–Berlin, contended that Einstein’s theories would not represent mathe-
matical fictions but realities. At the end, it seemed as if the majority of the scholars would side with
Petzoldt rather than with Kraus.” (“Es entspann sich eine ungemein lebhafte, zum Teil hitzige
Debatte; eine Reihe von Gelehrten pflichtete Kraus bei, während andere, an der Spitze Professor
Petzoldt–Berlin, behaupten, daß die Einsteinschen Lehren nicht mathematische Fiktionen, sondern
Wirklichkeiten darstellen. Es hatte zum Schluß den Anschein, als ob der größte Teil der Gelehrten
nicht Kraus, sondern Petzoldt beipflichtete”; Berliner Tageblatt, 1 June 1920, Morning Edition). On
Petzoldt’s role at the Halle conference, see also the report in Schmidt, R. 1921 and the discussion in
Hentschel 1990, sec. 3.4.2.
[4]Josef Winternitz (1896–1952).
[5]Karl Scheel (1866–1936) was Director of the Physical-Technical Section of the Physikalisch-
Technische Reichsanstalt and editor of the Zeitschrift für Physik.
[6]Helge Holst (1871–1944), trained as a physicist, was a librarian at the Technical University of
Copenhagen. In Holst 1919, he had discussed, partly in response to Petzoldt 1918, the issue of a phys-
ical cause for special relativistic length contraction, arguing for what he called an absolute “Neutral-
feld” (“neutral field”) generated by the fixed stars that would be responsible for inertial effects and
would also provide a causal explanation of the Lorentz contraction. Holst had reiterated his position
against Petzoldt in Holst 1920a. Both papers had drawn criticism from Petzoldt in Petzoldt 1920 and
1921a (written earlier than Petzoldt 1920 but published later). A final response to Petzoldt’s criticism
by Holst, dated August 1920, appeared again in the Zeitschrift für Physik (Holst 1920b).
[7]Petzoldt 1921a.
[8]With reference to Einstein 1917a (Vol. 7, Doc. 42), where Einstein contends that the theory of
general relativity would allow us to give an answer to the question as to whether our world is finite or
infinite “almost with certainty” (“mit ziemlicher Sicherheit”; p. 500), and that it would be finite
(p. 501). Petzoldt rejects the question as “logically inadmissible” (“logisch unzulässig”; Petzoldt
1920, p. 473), since it would principally not be amenable to empirical test (Petzoldt 1921a, pp. 454–
455).
[9]Petzoldt 1921b.
[10]Max von Laue.
73. From German League for the League of Nations
Berlin, Unter den Linden 78 den 8. Juli 1920
Sehr verehrter Herr Professor!
Nach langem Zögern haben wir uns entschlossen, Ihre kostbare Zeit mit folgen-
der Bitte zu belastigen in Anspruch nehmen: In eingehender Rücksprache mit Dr.
Elisabeth
Rotten[1]
sind wir zu der Überzeugung gekommen, dass es eine dringen-
de Notwendigkeit ist, der deutschen Öffentlichkeit die Notlage der deutschen
Wissenschaft, das was zur Hilfe bisher geschehen ist und was noch geschehen