The two ‘strongest pillars of the empiricist wing’: the Vienna Circle, German academia and emigration in the light of correspondence between Philipp Frank and Richard von Mises (1916–1939)

ABSTRACT This paper is divided into a surveying and argumentative part and a slightly longer documentary part, which is meant to verify or at least make more plausible claims made in the first part. The first part deals in broad outline with the relationship of Frank and von Mises to the Vienna Circle of Logical Empiricism on the one hand and to the physicists and mathematicians in the German-speaking world on the other. The varying special positions, partly the non-conformity of the two Austrian scientists are emphasized, in particular, their adherence to Ernst Mach’s epistemology and their shared interest in probability theory and applied mathematics. The impact of emigration and the after-effects in the U.S. are discussed. This leads to new insights into the fine structure of the Vienna Circle and the latter’s relationship to German academia within ‘Weimar Culture’. P. Forman’s interpretation (1971) of von Mises’ position is critically discussed. The second, documentary part, uses recently discovered correspondence between Frank and von Mises, and, to a lesser extent, von Mises’ personal diary. It aims at further substantiating some of the introductory theses and will at the same time provide material for a thorough biographical appreciation of the two scholars and friends.

Part I (general)

Frank and von Mises within German academia 1
The term 'the strongest pillars of the empiricist wing' 2 used for Philipp Frank  (1884-1966) and Richard von Mises (1883-1953) dates from 1946 and was young discipline. 6Both Frank and von Mises reached out for allies of the exact sciences among philosophers and engineers and practiced collaboration between physics and mathematics as most visibly expressed by their famous handbook Frank-Mises (1925/27). 7hus, Frank and von Mises were both insiders and outsiders of the German community of physicists and mathematicians.Their names could not  Von Mises is better known today in engineering (yielding condition of 1913 in the theory or plasticity) than in mathematics.His notion of 'applied mathematics', in particular his program of 1920/21, is discussed in Siegmund-Schultze, 'The joy', note 1.For von Mises' view of the relation between applied mathematics and probability theory, see Reinhard Siegmund-Schultze, 'Sets Versus Trial Sequences, Hausdorff Versus von Mises: "Pure" Mathematics Prevails in the Foundations of Probability Around 1920', Historia Mathematica, 37 (2010), 204-41.Not surprisingly von Mises' name is lesser known than the name of his brother, the conservative economist Ludwig von Mises (1881-1973) who was an academic latecomer compared to his younger brother.This reflects the broader and more public appeal of economics compared to mathematics.
immediately be associated by their peers with generally recognized excellence in either mathematics or physics.Von Mises' theory of probability, the foundations of which he published in two articles in the Mathematische Zeitschrift in 1919, was originally seen, especially by physicists, 8 as a promising connecting point for their own work.This was precisely the case because of its reference to the empirical notion of relative frequency of occurrence of events and by its promise to combine rigor and (mathematical) simplicity.One can even say that von Mises' theory was considered by physicists and by many mathematicians as a new paradigm for probability theory in its first decade.However, during the 1920s and later, von Mises' mathematical peers increasingly expressed logical concerns about his foundations for probability.A 1933 book by the young Russian Andrei N. Kolmogorov (1903-1987) made the measure-theoretic foundation of probability theory gradually the new paradigm of the theory. 9he relative outsider position of Frank and von Mises was even more visible in their political and philosophical opinions.Most associates of the Vienna Circle held leftist-liberal and internationalist political positions.Politically, Frank and von Mises deviated from the average of the Vienna Circle somewhat to the left (Frank) and to the right (von Mises). 10Philosophically, Frank and von Mises were mostly in accordance with each other but quite often outside the German mainstream. 11he relationship and future friendship between von Mises and Frank can be documented to have begun at the latest in 1916 (see below part II).Their philosophically based interest in probability theory and statistics, was closely connected to broad discussions of the role of causality in physics in the 1920s and 8 Including Einstein and von Mises' lifelong friend, the Belarusian Leonid Mandelstam (1879-1944).See Alexander Pechenkin, Leonid Isaakovich Mandelstam.Research, Teaching, Life (Cham: Springer, 2014).For Einstein's encouragement of von Mises see Reinhard Siegmund-Schultze, 'Indeterminismus vor der Quantenmechanik: Richard von Mises' wahrscheinlichkeitstheoretischer Purismus in der Theorie physikalischer Prozesse', in Mathematics Meets Physics: A Contribution to Their Interaction in the 19th and the First Half of the 20th Century, ed. by Karl-Heinz Schlote and Martina Schneider (Frankfurt a.M: Harri Deutsch, 2011), pp.241-70.9 The author is preparing a book, tentatively entitled Between Two Paradigms: The Correspondence between Richard von Mises and Andrei Kolmogorov 1932. 10 For von Mises, individualism and political nonconformism were typical.However, during World War I von Mises volunteered twice for military service.First for the Airforce in Vienna 1914, then for direct service as a pilot at the front when the war was almost over in 1918.He apparently kept emotional bonds to Austria and partly the Austrian monarchy (manifest in his title obtained by the family around 1880) even after the defeat in 1918.Even Frank, known for his firmly internationalist stance and for his socialist convictions in later years, could not fully free himself from the nationalistic mood of the time.In an obituary for a young promising Austrian (not German) physicist who had been killed in the war he described him as an example for the 'desire of the German people for education inspite of all slander from the enemy' (Philipp Frank, 'Max Behacker', Physikalische Zeitschrift, 17 (1916), 41-43, p. 42.)In his biography of Einstein, Frank stressed Einstein's pacifism which he himself was apparently not able to fully support at the time of WWI (Frank, Einstein, note 5, 119ff). 11In addition to Mach, it was the physical and philosophical heritage of Ludwig Boltzmann and Franz Exner which had influenced the Austrians.1930s where both men stressedin a general sensethe emancipatory role of Mach's unprejudiced thinking.Problems in the theory of measurement (particularly error theory) and in the mathematical foundations for statistical mechanics (often discussed in connection to the problem of causality) were increasingly recognized as fundamental in the physical community.They were bearing promise of fame in the context of recent discoveries in atomic theory. 12t is undisputed that von Mises' statistical conception of the principle of causality even in the case of macro-physical phenomena, which was closely related to his work on the foundations of the probability calculus (1919), led to a substantial enrichment of Frank's views, as Frank emphasized in his 1932 book: Perhaps Richard von Mises was the first to point out, in his lecture 'On the present crisis of mechanics' that in the field of mechanics in the narrower sense, there are observable processes in liquid and solid bodies that also cannot easily be presented with the help of causal laws. 13yond the problems of causality and probability, Frank considered von Mises' field of applied mathematics to be of crucial importance in securing the connection between facts and theories.In his obituary on von Mises Frank saw the main philosophical problem which von Mises wanted to address in the following way, which again characterizes the latter's role as a 'strong pillar of the empiricist wing': The problem of connection between sense observations and abstract principles has always been the critical point in the philosophy of science.As we see the problem, it is tackled most precisely by the methods of applied mathematics, and it is in this sense that v. Mises dealt with the tasks of 'Applied Mathematics and Mechanics,' building upon the ideas of the great Austrian scientist and philosopher Ernst Mach, who regarded both science and its philosophy as theories of sensations.(Schulphilosophie) 15 they attacked, included various philosophies represented mainly by humanities scholars but also supported by some natural scientists, especially in the biological and life sciences.These either propagated epistemological pessimism in the sense of the famous 'ignorabimus' of the Berlin physiologist Emil du Bois-Reymond (1818-1896) or represented 'metaphysical' positions that could not be verified experimentally or logically.There was an even clearer demarcation of the Vienna Circle from explicitly 'irrational' and anti-scientific so-called 'philosophies of life' (Lebensphilosophien), 16 which were propagated primarily by humanists.
The increasing struggle between the 'two cultures' with growing scientific specialization 17 played into this, and the Vienna Circle and the parallel Berlin group under Hans Reichenbach (1891-1953) could in some respects be considered as 'intellectual allies' of the physicists and mathematicians in the closely related German and Austrian communities.However, as Forman has convincingly shown in his influential article of 1971, 18 this does not take into account the political, often strongly nationalist emotions stirred by the defeat of Germany and Austria in the World War and the different philosophical traditions in both countries.In the 'Weimar culture' of Germany, politically conservative natural scientists and mathematicians such as Planck, Sommerfeld, Bieberbach and E. Schmidt (in contrast to Einstein, Hilbert and Born) often shared nationalist ideologies with the professors in philosophy and the humanities with whom they had to cooperate in the context of university politics; in some respects, they tried to come closer to them even philosophically.
Moreover, many of these expert scientists, as far as they reflected philosophically at all, were of the opinion that Mach's empiricism or at least its interpretation by the Viennese Circle did not sufficiently reflect the creative-subjective nor the truth-assuring objective in the process of cognition, nor their striving for a 'complete world view'.mechanics, consideredsomewhat ironically -Richard von Mises' concept of probability from 1919, which was philosophically linked to Mach's empiricism via the concept of relative frequency, as 'metaphysical speculation'. 20ith the following words Forman hints at the outsider role of Machian epistemology within the German 'Weimar Culture'.Forman referred to a lecture given by von Mises at Berlin University in 1930: I know of only one instance during the entire Weimar period of a German physicist venturing, in a general academic address, to mention Mach's name with clear approbation and to associate himself with Mach's epistemological doctrines.Nor was it mere coincidence that in taking this courageous stand at the end of the Weimar period Richard von Mises refused to associate himself with the demand for synthesis, 'counting it'as did Mach -'the highest philosophy to tolerate an incomplete world view.' 21 cannot be denied that von Mises felt pressured at the time to defend the rational method of mathematics and the natural sciences against claims for 'synthesis' from the side of traditional philosophers and humanists.In an unpublished manuscript he stood up against epistemological reflections by the president of the German Kaiser-Wilhelm Society, Adolf von Harnack (1930), which von Mises found too close to the 'school philosophies.'Harnack was a theologian but tried to find philosophical agreement with the scientists in his Society. 22In his semi-popular book Probability, Statistics, and Truth23 originally published in1928, and in various articles von Mises propagandized incessantly his theory of probability of 1919 and its philosophical connotations.
What is crucial to the present article is that, somewhat at odds with the admission of his courage, as in the above quotation, elsewhere in the same article Forman takes von Mises as a prime example of yielding to cultural pressure, replacing strict causality in physics with indeterminacy. 24 sympathize with Forman's theses in general, 25 in as much as they claim that philosophical and political conditions are bound to influence not just the choice of subjects but scientific content on the individual level.I even agree that von Mises is a prime example for such influence because his theory of probability and his physical statistics were clearly chosen and shaped by his philosophical, positivistic opinions coming from Mach, including the 'economy of thought' defended by Mach, and by von Mises' insistence on theorizing close to practice. 26Also in a political respect, von Mises is a good example for the Forman thesis, given the fact that his occasional German-Austrian nationalism restricted his contacts abroad, e.g. with Belgian and French mathematicians and thus impeded his influence.I even agree with a possible allegation of 'opportunism' against von Mises who joined in the widespread talk about 'crisis in science' after WWI in order to promote his probabilistic view of physics. 27hat I object to, however, is the absence in Forman's argument of von Mises' concrete professional position and philosophical interests when using him for philosophical and historical interpretation.In fact, the influences on von Mises, in particular his philosophical interests which long predated WWI and the Weimar milieu, and his mathematical interests were exactly not the ones Forman cites, culminating in the following claim: The cases of von Mises and Doetsch demonstrate most clearly that there were mathematical physicists who went so far in assimilating the values and mood of their intellectual milieu as to effectively repudiate their own discipline. 28n Mises was no 'mathematical physicist' or 'physicist' (as in the first quote) but an applied mathematician and probabilist.At times he even criticized the predominant focus of physical research on the proverbially 'modern', mindboggling physical theories (relativity and quantum mechanics) and the neglect of classical mechanics and of the numerical aspects in the latter as well as in pure mathematics. 29He also stressed the importance of his foundations of probability theory and physical statistics for those new theories.Ludford, 'Mechanics', note 1.

The peculiar position of 'the empiricist wing' within the Vienna circle
Von Mises' 1928 book, which is today still in print in English translation, appeared as volume III of 'Schriften zur wissenschaftlichen Weltauffassung' (Treatises on The Scientific Conception of the World), a series edited by Philipp Frank and Moritz Schlick.In the preface to his book von Mises expressed his own distance to work that 'searched for metaphysical meaning beyond the framework of sober cognition … frequently represented by philosophers.'30Understandably, people in the Vienna Circle such as Carnap, Schlick and Neurath considered von Mises an ally.
Von Mises, however, always emphasized the independence of his political and professional judgment.This holds also for his position vis-à-vis the Vienna Circle, with which he was in any case only relatively loosely connected because of the increasing geographical distance of his places of activity (Straßburg until 1914, Berlin (1920-1933), Istanbul until 1939).In the anonymously published 1929 'Manifesto' 'Wissenschaftliche Weltauffassung.Der Wiener Kreis' (The Scientific Conception of the World.The Vienna Circle),31 von Mises was not even named among the authors classified there as 'close to the circle'.Philipp Frank, on the other hand, was listed in the Manifesto as one of the 14 'members' of the circle. 32The failure to name von Mises had a specific reason.In preparation for the Manifesto, Rudolf Carnap (1891-1970) had asked von Mises for bibliographical information.In a letter of 5 July 1929, von Mises responded: Although I appreciate Mr. Schlick personally and support his philosophical standpoint, insofar as it coincides substantially with Mach's opinions, I nevertheless do not feel entitled to appear as a member of the Schlick Circle [nicht für berechtigt (halte), als Mitglied des Schlickschen Kreises aufzutreten].I believe, that my position vis-à-vis today's school philosophy [heutigen Schulphilosophie], in particular with respect to what is called the 'autonomy of the humanities' [was man als 'Autonomie der Geisteswissenschaften' bezeichnet] is much stronger and more radical than Mr. Schlick and other leading representatives of the Vienna school would like it to be. 33 addition, responding to a flyer 34 which had been enclosed in Carnap's letter and which called for joining the 'Verein Ernst Mach', von Mises declared, somewhat aristocratically, that he was not willing to join the Verein which was 'missing stature' ['jedes Format vermissen'].In his letter to Carnap von Mises found it objectionable to 'fight astrological and similar pseudoscientific tendencies only to give space to an apocryphal 'Lebensmechanik' and to consider a 'soziologische Graphik' important for a scientific world view.'As a result, no work by von Mises is mentioned in the Manifesto, except for the 1928 book which von Mises obviously could not and would not disassociate from the Vienna Circle in whose series it had appeared.Frank, however, together with Carnap, did join the Verein Ernst Mach, which had certain connections with the working-class movement and social democracy in Austria, although his personal contribution to the Verein was apparently limited due to his location in Prague.
Von Mises' letter to Carnap is partly directed against Otto Neurath (who was named on the flyer in connection with 'soziologische Graphik'), and in his letter he appealed to Carnap explicitly as an assumed ally on the scientific side of the two cultures.Quite obviously, von Mises considered himself, rather than the Vienna circle, as the real heir of Mach.In particular, he held views of his own about the notion of 'Positivism' as opposed to 'Empiricism'. 35His positions towards sociology and the humanities seem to have further changed later when he introduced the philosophical notion of 'connectibility'36 and no longer found 'metaphysical sentences' totally meaningless. 37ooking at the examples of his 1928 book on probability theory and his 1929 letter to Carnap, it cannot be denied that von Mises tone was at times rather aggressive which sometimes worked against him.Von Mises could sometimes be rather abrupt in his behaviour which Frank occasionally tried to mitigate by his more conciliatory manner. 38lthough von Mises took part in the Prague Conference of 1929 and in the Paris congress in 1937,39 he did not participate in the three Unity of Science Congresses which took place in Paris (1935), Copenhagen (1936) and Cambridge (England 1938). 40As explained above von Mises did not want to appear as a spokesman for the Vienna Circle, although many took him for one given that two books written by him in 1928 and 1938 appeared in series published by the Circle.
There was, of course, an additional reason for von Mises' absence from most Unity of Science Congresses: his emigration to Istanbul in late 1933.Finally, von Mises did take part officially in the Fifth International Congress for the Unity of Science at Cambridge, Massachusetts in September 1939.Von Mises had just arrived there at his final stop on his flight from the Nazis.

The impact of Emigration 41
One particular kind of outsider position that all three Mach followers (Neurath, Frank and von Mises) had in common with many other German and Austrian scientists was their Jewish origin.At least in von Mises' case disadvantages connected to this can be traced even in his early career.The main consequence, of course, was the emigration of the three men, fleeing the Nazis.
The specificity of Austrian and Czechoslovakian emigration consisted in the late date of 1938/39 for most of the refugees, when other emigrants from Europe were already occupying positions in the USA. 42In the case of von Mises and Frank, it is documented that they struggled to obtain permanent positions at Harvard University. 43Frankalthough a professor in Europe since 1912never attained a full professorship in the United States. 44Being 54 years old at the time of emigration in 1938, the effect of his age and of his transition to philosophy was even stronger than in the case of von Mises, who continued to work in his core subject of applied mathematics. 45hus, even during emigration and in exile, the scientific and philosophical impact of the two 'strongest pillars of the empiricist wing' remained ambivalent. 46Gerald Holton has described the 'fortunes' of Positivism in America and particularly the leading role of Philipp Frank in it. 47He mentions Frank's and von Mises' closeness to some American philosophers (Morris, Quine, Bridgman) who had always been critical of traditional German idealist 41 For the emigration of German-speaking mathematicians in general see Reinhard Siegmund-Schultze, Mathematicians fleeing from Nazi Germany: Individual Fates and Global Impact (Princeton, NJ, and Oxford: Princeton University Press, 2009). 42See below in part II the remark by Frank on Menger, who had arrived earlier, although also from Austria. 43Gerald Holton, 'Ernst Mach and the Fortunes of Positivism in America', ISIS, 83(1992)  44 'Philipp being both a philosopher and a physicist, there was not one obvious department ready to receive him in both capacities' (Holton, 'Philipp Frank at Harvard University', note 43, p. 300) The expropriation of their royalties for the 'Frank-Mises' which along many other German books had been licenced for American republication by the Alien Property Custodian during the war was of great concern to Frank and von Mises.It seems to have confirmed their feeling of being social outsiders.It is discussed in Frank's interview (Kuhn, 'Oral History', note 11) and in Siegmund-Schultze, 'Frank-Mises', note 1. 45 The latter did not receive a full professorship in applied mathematics at Harvard until 1945, when he was 62 years old, contrary to what some biographers claim. 46Some more details below in the second, documentary part. 47Holton, 'Ernst Mach and the Fortunes', note 43.
philosophy.But this protection apparently was not strong enough for Frank to get an appropriate position in the United States.Dissenting views within the American community of philosophers of science about the philosophical tendencies coming from Europe, in particular reservations about some sociological and political connotations, could not fail to influence developments.Political factors such as McCarthyism and the Cold War added to this, as did a generally observed 'depoliticization' of emigrants, who had to strive to adapt to the moral and political conditions in their host country, the United States.Frank assumed the presidency of the newly established 'Institute for the Unity of Science' in Boston (1947-1958).The Institute was meant to be the official successor of Neurath's earlier European institute until it was closed for various, as Frank would have called them, 'extra-scientific reasons'. 48

Summary for the more general first part
The discussion until this point has aimed at showing that the personal positions and accomplishments of Frank and von Mises can serve to draw a more nuanced picture of the interplay of German and Austrian scientific, philosophical and political traditions than is hitherto to be found in the literature, including, above all, applied mathematics and probability theory as factors.This will be further corroborated in the discussion of their correspondence in part II.
Frank's opinion of von Mises' role as one of the 'strongest pillars of the empiricist wing' of the Vienna Circle is perhaps best summarized in the final sentence of his review in ISIS of the German original of von Mises' book on Positivism (1939).With these remarks Frank probably also characterizedto a certain degreehis own position within the Unity of Science movement: A 'professional' mathematician who has also been a 'professional' engineer has a good start in appreciating the real bearing of formal thinking on empirical science, especially if he has, in addition, a 'philosophical mind.'He has an advantage in training which can hardly be made up by a profound knowledge of mathematical logic.And these are precisely the qualifications which make v. Mises so able to present the subject matter of his book. 49ile Frank fell gradually into oblivion after his death in 1966 because of the new tendencies in analytical, logic-based philosophy in the style of Carnap, Tarski, Quine and their followers, von Mises' posthumous fame suffered from an at least temporary failure of his foundations in probability theory.His name in the latter was partly restored by the renaissance of his notion of 48  randomness in algorithmic complexity theory in the 1960s in the works of the same Kolmogorov who had once destroyed von Mises paradigm in the 1930s.Moreover, von Mises is still quoted for some of his innovative results in statistics, among them the circular distribution (to be mentioned in the second part below), and even more so in mathematical engineering.
As to the long-term influence of Frank, von Mises and Neurath on the Unity of Science Movement I want to finish the more general part of this paper with a sobering quote by the noted eyewitness Gerald Holton from the standpoint of the twenty-first century: Throughout academe, not only in science, but also in social studies and in the humanities, a new password to success is now 'integration' and 'interdisciplinarity.' The same applies to many segments of industry.
All this is not precisely what Philipp, Otto Neurath, and their friends were fighting for … , not least because it is rather less engaging philosophically. 50rt II (documentary and biographical)

Early correspondence between Frank and von Mises during WWI and discussions on aerodynamics and statistical error theory
The first document I could find which proves a contact between the two men is a short note in von Mises' personal diaries, 51 written in the German shorthand Gabelsberger, on February 14, 1915, mentioning a meeting with Frank in a café in Vienna.I have no evidence that von Mises ever took part in the meetings of the so-called 'First Vienna Circle' between 1907 and 1912. 52We know from Frank's own 1949 account 53 that the discussions in this group about the philosophical implications of modern science were strongly influenced by the philosophical works of Abel Rey (1873-1940), Mach and Poincaré.Frank mentions the mathematician Hans Hahn (1879-1934) and the sociologist Otto Neurath as participants but not von Mises.However, von Mises came regularly to Vienna from Brno/Brünn and Straßburg during the semester vacations and he would do so until the death of his mother Adele in 1937.Thus, it is highly probable that the two men who were almost the same age, and so prone to the Vienna coffeehouse atmosphere, knew each other before the First World War at least superficially.Moreover, from early on, von Mises was highly interested in philosophical topics; his diary for 1903/4 mentions 50  Mach, Nietzsche, Sombart several times.Unfortunately, there is a gap in von Mises' diaries from 1906 to 1912, the year when Frank left Vienna for Prague.
Therefore, we cannot say much about the early period.There does not exist a proper Nachlass (literary estate) of Frank, and the discussion has to be limited mainly to the scattered correspondence between von Mises and Frank which is kept in the Richard von Mises-Papers at the Harvard University Archives. 54It consists of 17 letters (including one postcard) from Frank to von Mises plus two typewritten letter-copies from von Mises to Frank, all written in German and dated between 27 August 1916-17 June 1939.There is a general problem of dates because Frank's letters usually do not give the year.Frank's seven handwritten letters and one typewritten letter from 9 July 1918 are, in addition, difficult to decipher.His seven typewritten letters from 1939 are clearly legible.In addition, I will draw on some other related correspondence.
From the correspondence in the Richard von Mises Papers it seems very likely that geophysicist Heinrich Löwy (born in 1884), who later on was also connected to the Vienna Circle, 55 was instrumental in bringing Frank and von Mises into closer contact.The first piece of correspondence, Frank's postcard to von Mises of 27 August 1916 (see Figure 2), contains greetings to Löwy.The latter, his sister Margit Ornstein, and Frank were close friends with the engineer and philosopher Josef Popper-Lynkeus (1838-1921), 56 who in turn was a friend of Ernst Mach.On March 24, 1918, von Mises wrote in his diary: 'Afternoon with Frank … at the café.Then with Fr. at Popper's, who is in very good spirits, very fresh and stimulating.' 57t was in connection with soliciting articles by von Mises and Frank on the occasion of Popper-Lynkeus' eightieth birthday in 1918 that Löwy's letters to von Mises mention Frank as well.Löwy was on 'Du'terms with von Mises, 58 and the latter supported him occasionally with scientific advice and with money. 59As a matter of contrast, Frank and von Mises in their early correspondence, addressed each other as 'Lieber Herr' or 'Lieber Kollege', and only 54 All letters except two are in the main correspondence of von Mises for the respective years, which is HUG 4574.5. in the late 1920s did they go over to 'Lieber Freund' without ever dropping the 'Sie'. 60eedless to say, the war had its influence on the emotions of the two men and on the topics in their correspondence.Frank was at that time professor in Prague, and von Mises was an officer in the flying corps of the Austrian army in and around Vienna.In the postcard of 27 August, 1916, Frank commented on von Mises' aerodynamic wing theory. 61t is well known that at that time von Mises constructed the first 'Großflugzeug' (huge airplane) in Vienna, a 600 horsepower bomber plane (which never went into service due to motor problems), and that he used his theory for the design of the wings.It is interesting and revealing particularly with respect to Frank's mathematical abilities to read in the postcard: Dear Herr von Mises!I have carefully checked your formula for the distance h of the centre of pressure from the [aerodynamic] centre.It is absolutely correct.However, the calculation has in my opinion a mistake.… after integration that discrepancy [Unterschied] disappears … 62 Thus, the physicist Frank had discovered a self-correcting mathematical error in the work of the applied mathematician von Mises.Frank's excellent  Then in the afternoon with Frank … at Einstein's.A quite astonishing impression.A man who radiates light, who rests in himself and speaks cheerfully with clarity and delicacy. 65week later, Frank asked von Mises (24 May 1918) to send him offprints from Vienna which Einstein had intended for him, and which he himself had not managed to get over the (then still German-Austrian) border to Prague due to military censorship (the prints lacked the necessary official certification).
Von Mises and Frank used Die Naturwissenschaften and Physikalische Zeitschrift to present their views on probability theory and statistics in physics around the end of the War, but surprisingly without referring to each other in their publications. 66Their correspondence shows, however, that their collaboration was already then much closer than it would appear from their publications.
Already in January 1918 von Mises had published in Physikalische Zeitschrift a 'Simple and exact derivation of Maxwell's velocity-distribution theorem', 67 based on some of his new ideas for a rigorous mathematical theory of probability.On May 24th of the same year, von Mises received a letter from Frank which said the following: I should be pleased if you would publish rather soon your method which you applied in the problem of integer-valued atomic weights.The calculations which I have had made here on the question of electrical elemental quanta are approaching the end and I want to refer to your method in my publication.Obviously, Frank was referring to previous discussions with von Mises of an unpublished manuscript of the latter, and he was soliciting an article from him for the Physikalische Zeitschrift to which Frank had better access.Von Mises' publication appeared in that journal later that year under the title 'On the integer-valuedness of atomic weights and related questions.' 69 The question was whether experimental determinations of atomic weights can be taken as coming from, and confirming, integer-valued weights with measurements having normally distributed error terms.The method presented in this paper was in fact mathematically more sophisticated than the one that Frank had applied on his experimental data.By the use of trigonometric functions (cos x, sin x) the 'linear' result of a measurement was mapped ('wrapped') by von Mises into a point on the circumference of an appropriately chosen circle with the consequence that only the deviations from an integer value are preserved.Thus, the data for atomic weights was not 'directed by nature' but by mathematical intervention. 70on Mises' work on directional statistics was, in the long run, successful, less so for the concrete problem at hand but for other statistical situations: The circular normal distribution which von Mises derived in his article under the name 'cyclical error function' [zyklische Fehlerfunktion], is today counted as a major and early example of 'directional distributions.' Modern researchers in this field write: From the point of view of statistical inference, perhaps the most useful distributions on the circle are the von Mises distributions. 71though the surviving correspondence between Frank and von Mises is generally not very philosophic in content, it contains one interesting passage, which sheds light on some nuances in the respective relations of the two men to their common hero Ernst Mach.
In an undated letter by Frank to von Mises of late 1919 or early 1920 one reads the following commentary on an obituary, which von Mises had written on his friend, the physicist Arthur Szarvassi (1873-1919): I found your remark that his adherence to Mach's way of thinking led him to mistrust Einstein's theory is perhaps subject to a misunderstanding.After all Mach was from the beginning one of the most active followers of Einstein's. 72he respective passage in von Mises' obituary on Szarvassi reads as: When around 1908, in the context of Minkowski's work, Einstein's new electrodynamics developed into the ruling doctrine, for Szarvassi this became a dead-serious matter.To distance oneself so clearly from all classical approaches and concepts seemed to the convinced follower of Mach's not sufficiently justified by the economy of thought [denkökonomisch].… (58) … Nevertheless, the knowledgeable will not find the result worthless and the intellectual accomplishment inferior; anyhow the hesitating reservation with respect to the new is a much more dignified [vornehmer] trait than the attitude of the all too many73 who cannot rapidly enough tune their weak voices in accordance with the new key. 74is passage may sound conservative to modern ears, but one should be aware that 'informed scepticism' vis-à-vis the revolutionary scientific notions of relativity and quanta on the part of mathematicians and physicists was accepted as worthy of discussion even by strong adherents of the new theories such as von Laue and Born. 75Questions as to the extent to which Mach was a supporter of Einstein and the extent to which the latter was influenced by Mach, whether Mach's scepticism against atomism was justified etc., were discussed then 76 and remain disputed even today. 77The one interpretation of von Mises' quote which is least credible is that he himself doubted the revolutionary contribution by Einstein.On 11 September 1920 he wrote to his mother in Vienna: You want an expert opinion about Einstein?There is no doubt at all that he is an incomparably brilliant natural scientist.What he has achieved in different fields will be countedas long as people live and thinkto the very greatest.Even today there is no serious expert who doubts it.I emphasize this all the more, because I myself (in a point, which has nothing to do with his theory of relativity) represent an opinion deviating from his and hold it up with all energy against him.In the physical society in Berlin we have recently sharply argued in front of a 'assembly of kings' [Parkett von Königen]. 78at is indicated in this letter is, however, that von Mises wanted to carve a niche for himself with respect to the role of his new probability theory in physics, among other things discussing physical and philosophical causality in the framework of quantum theory.
7. The Frank-Mises handbook as reflected in the correspondence between the two men 79 Much of the correspondence between Frank and von Mises relates to their influential two-volume Die Differential-und Integralgleichungen der Mechanik und Physik, [Differential and Integral Equations of Mechanics and Physics] first published in 1925 and 1927.This is understandable, because the project required much consultation between them as well as with the numerous authors of the handbook.The book would soon become an important tool for theoretical physicists.
The first piece of correspondence between Frank and von Mises, which alludes to the project as 'Weber-Riemann' 80 apparently proposed by von Mises, is Frank's letter to Mises dated 24 May 1918, mentioned above.Frank writes: I am beginning to think a little bit about the Weber-Riemann, which is stimulated by a special course which I am now giving on spherical and Bessel-functions. 81e first volume 'Mathematical Part' (Mathematischer Teil) of the Frank-Mises finally appeared in 1925, seven years after Frank's letter (Frank/Mises 1925/27).Von Mises was the main editor and author of several entries; additional authors were prominent mathematicians such as Gabor Szegö, Karl Löwner, Constantin Carathéodory, Ludwig Bieberbach, Hans Rademacher and Richard Courant.The second 'Physical Part' (1927) had in addition to Frank as editor and author prominent applied mathematicians and physicists such as Reinhold Fürth, Fritz Noether, Theodor von Kármán, Arnold Sommerfeld, Erich Trefftz and Carl W. Oseen as authors of independent contributions.
One obvious and pardonable shortcoming of Frank-Mises in both the mathematical and physical parts became visible soon after the publication of the first edition: it did not and could not fully account for the new wave mechanics and the hyperbolic partial differential equations like the Schrödinger-equation, which constituted one of the two alternative methods in quantum mechanics developed between 1925 and 1927 (the other being the matrix-or operator approach). 82One could therefore argue that the collaboration of Frank and von Mises for the Frank-Misesalthough using modern mathematical methods such as Hilbert's theory of integral equationswas focussed more on the classical parts of physics, unlike their philosophical discussion of causality.
Frank-Mises was gradually becoming a classic under its new short name, replacing 'Weber-Riemann'.It received enthusiastic reactions from many quarters, for instance in the Soviet Union (where a pirate translation of the volume on physics of the second edition appeared in 1937) and from the US.

The personal relation of von Mises and Frank in the 1920s and 1930s, particularly during emigration
During the work on the Frank-Mises book in the 1920s and 1930s the two men got closer to each other.While von Mises was at that time undoubtedlyas can be seen from his impressive list of publicationsmuch more productive as a scientist than Frank, the latter became much more involved in philosophical matters.Von Mises was obviously very impressed by Frank's erudition 83 and continued to take him seriously also for his mathematical and physical knowledge.The two men visited each other in Berlin and Prague.They repeatedly acted on each other's behalf, for instance by reviewing each other's books. 84on Mises recommended Frank as the author for the article 'Waves' (Volny) in the first edition of the Great [Large] 85 Soviet Encyclopedia which led to a publication in Russian. 86In August 1928 both von Mises and Frank were among 21 foreigners (Max Born, Paul Dirac, Peter Debye and others) in the huge VI.Russian Congress of Physicists which took place between 4 and 15 August 1928 in Moscow and several cities at the Volga River, finishing in Saratov.Both gave talks, von Mises in Kazan, Frank in Saratov, the latter in Russian. 87When a month later Frank was unable for personal reasons to participate in the Hamburg meeting of the Deutsche Physikalische Gesellschaft he asked von Mises, still addressing him as 'Lieber Kollege' (Prague September 15, [1928]), to extend an invitation to the Physikertag in Prague in 1929 to the applied mathematicians.It was on the latter occasion that the famous first public meeting of the Vienna Circle would take place, which was organized by Frank, about which there are also a few notes in von Mises diaries. 88 letter by Frank, dated Prague December 6 [probably 1930], for the first time used 'Lieber Freund' when addressing von Mises, though keeping the 'Sie' in the text.The letter is interesting because it contains some background information on the eventual appointment of Rudolf Carnap to a professorship at Prague, which finally went into effect in 1931, but not before it had been turned down by Hans Reichenbach.I give the following short excerpts: 89 As to the matter R. [Reichenbach] the situation is the following: three years ago, when he still was in Stuttgart, we made in our faculty of natural sciences a proposal for the creation of a philosophical professorship, namely 1. place R., 2. place Carnap.The order was decided by the responsible committee, which was influenced by enthusiastic letters from Berlin, although some were against it.The decisive role was played by a letter from v. L. [undoubtedly von Laue; R.S.] which convinced not me but other physicists. 90ank then reported on Reichenbach's negotiations with the ministry in Prague which were about to fail at that time, because of the rather meagre offers by the ministerial authorities.Frank then said: As I evaluate it, the negotiations will barely succeed.I have the impression that R. wants to reach some advancements in Berlin and wishes to stay, because he has all kinds of fringe activities and benefits there.Hopefully he has luck in Berlin, we would then be satisfied by the one who is proposed in second place.Here R.v.T. [Rausch v. Traubenberg] is dean who is very much under the influence of v. L. and will do all he can for R. I believe, however, it is of general interest to keep R. in Berlin where he has a larger realm of action, where he can influence broader masses, while for our smaller circumstances perhaps a more quiet man [Kraft?, difficult to read; R.S.] such as C. is sufficient. 91ank's rather lukewarm commentary on Hans Reichenbach, the leader of the allied Berlin Circle of Empirical Philosophy, ended with the request to handle his letter confidentially.So, Frank seems to have trusted von Mises who was not on the very best terms with Reichenbach.
During his two emigrations von Mises stayed in close contact with Frank.Hilda Geiringer (1893-1973), his future wife, reported to his mother in August 1933 on the situation in Berlin: Outstanding, helpful, active is Philipp Frank, who was twice in Berlin and has done much for us now in England.… One learns little new about people.Most of them are as one would have suspected. 92llingness to help was not one-sided either.When the situation was getting dangerous for Frank in Prague, von Mises received a letter from Otto Neurath, then in New York, asking von Mises to write something on Frank's achievements in physics and mathematics. 93W. Kaempffert, the Science Editor of the New York Timeswho happened to be related to Neurath through his mother's family 94wanted to introduce Frank to the American public and needed information about him.Neurath wrote to von Mises on November 15, 1936: Frank is still too little known here.One is familiar with some of his physical work.But he should be much more known, because he wants to visit America at some point. 95urath asked von Mises to send him an evaluation of Frank's scientific work as a physicist and mathematician.Von Mises responded with a two-page letter dated 3 December 1936, which stressed Frank's long chapter 'Classical Mechanics and Ray Optics' in the second edition of the physical part of the Frank-Mises book (1935) and Frank's work in complex function theory, which von Mises had used in 1917 in his aerodynamic wing theory (see above).The article on Frank appeared anonymously (but was certainly written by Kaempffert) in the New York Times of January 10, 1937, under the title 'Unifying the Sciences', without, however, using any of the information gathered from von Mises. 96 Finally in October 1938, Frank was on a lecture tour in the United States; the news about the Munich treaty (29 September 1938) and the impending collapse of Czechoslovakia had reached him already on the ship.Gerald Holton has described 97 96 The argument in the article remained extremely popular in its content by comparing for example empiricism to the common sense approach of a potatoe farmer. 97Holton, 'Ernst Mach and the Fortunes', note 43, pp.57-59.
find a secure position, possibly in Istanbul where his friend von Mises was at the time.
On October 14, 1938, he wrote to von Mises from New York, alluding to the impending adoption of anti-Semitic measures in Prague after the Munich Agreement of September that year, prior to the German occupation of the entire country in March 1939: Dear Friend, the situation in Prague seems to be extremely bad.The Czech government itself seems to become a pure Nazi government and I am convinced that we all will be treated very badly if the University is liquidated.Whether I will get something here is very uncertain and I ask you [Sie] to say in Istanbul expressly that I would like to take the position as I have also written to the rector. 98lf a year later, the situation had changed considerably for the two men.Now it was no longer Frank who was looking for a position in Istanbul, but von Mises, who wanted to leave Turkey where he no longer felt safe.After the Germans had occupied the rest of Czechoslovakia in March, von Mises wrote to Frank on April 5, 1939: You did not write the letter to the rector which you announced in your letter from 7 February.So I assume you have found something in the U.S. and have changed your mind.… Meanwhile Neurath will have told you about my own hesitations.This attitude is, however, totally overtaken by events.The political events, which are getting more and more catastrophic, force me to look for another place.So I would like you to help me.… I am able to live several years without regular income.The problem is I need at least a one-year-contract for a paid university position in order to get the immigration visa.I am also satisfied with a pro-forma-contract, if it is viable for the consulate. 99 his answer from April 16, 1939, Frank reported that he had got a monthly advance payment on a biography of Einstein from the Alfred Knopf publishers, the owner of which was a relative of Kaempffert.Then Frank advised his friend about possible positions for him in the U.S.: As for the possibility of getting a contract, from my experience I would think it would be best to contact Catholic universities.They are the least antagonistic to strangers, and in cases like yours100 are likely to be helpful.They also do not ask in any way about ancestry and are anxious to help any Catholic, sometimes even non-Catholics.
I would not advise the University at Notre Dame because there are already some Viennese there who always do you more harm than good.Menger101 in particular fights any hiring of foreigners.Using information from Frank, Ms. Lieber had sent to her brother the following information on von Mises and Frank: He is about fifty-five years old, an aristocrate by birth (somewhere he has a drop of Jewish bloodbut he was not asked to leave Berlin 107on the contrary they were very annoyed at his leaving).He is a man of extraordinary culture and charm and a devout Catholic.Also, he is wealthy and does not need money!And he is a bachelor!… All this was told to us by Professor Frank and his wife.Frank is to be in the Department of Philosophy in Harvard next year, he was formerly at the University of Prague, having been chosen as Einstein's successor by Einstein himself, he is now in close touch with Einstein here and a man of the highest integrity.When we heard all this, we naturally thought you might be interested in getting von Mises for Duquesne for next year.The Franks say that no small University could hold him for over one year, for he will doubtless be much sought after by the big places, but for some reason they think it would be easier to negotiate his coming here with a small place. 108ank in his letter to von Mises commented on the religious issues, alluding to still existing anti-Semitic policies in some American universities:   I have the feeling that the Viennese Circle people become formalists and less and less interested in empiricism as a living thing.
On another occasion he called 'Carnap much Tarskicized.' 112Frank on his part wrote in a letter on December 15, 1945, that did not reach Neurath before his death on December 22, also in English: I think that the prospect for Unified Science in the English Speaking Countries is not bad.But it has to be stimulated by a broader approach.The overemphasis of formal logic discourages scientific people to participate actively or passively.
Instead Frank recommended the philosophical position of his friend von Mises.In the preface of his book Modern Science and its Philosophy (1949) 113 (see Figure 4) Frank said: I hope that the Harvard Press [where Frank's book appeared] will soon publish a volume which is written along similar lines, the lucid and straightforward book 'Positivism' by R. v. Mises. 114 But Frank went on, in his 1949 book, without mentioning Richard von Mises at all, and had, instead, the following to say on A. J. Ayer's Language, Truth, and Logic (1936). 115He 'published the most readable book on logical empiricism that has been written in English, and perhaps the most readable book altogether' (57). 116What shall one make of this remark?Had Frank succumbed to the dominance of English as a scientific language by then?But in that case, why did he add 'the most readable book altogether' which seems to discriminate against von Mises' German book on Positivism of 1939, which Frank had just praised?The explanation seems to be that von Mises' book, which was not mentioned by Ayer at all even in the second edition of his own book 1946, was in fact not 'written along similar lines' but was the product of a working scientist who did not play to the traditional canon of academic philosophy.Maybe Frank felt an increasing need to define his position as a professional philosopher of science after basically having left physics.The same feeling on Frank's parttogether with him sometimes appearing as an 'unworldly dreamer' (see below)may also have contributed to a long delay in Frank's review of von Mises' book, which prompted the editor of ISIS, George Sarton, into an emotional and probably unjust outburst. 117he last trace of a collaboration between von Mises and Frank in the von Mises Papers at Harvard is a letter from the editor of the journal Scientific American (13 April 1953) thanking von Mises for his willingness to write the  Frank (1884-1966).In this issue, a glowing review of Frank's 1949 book appeared. 117Sarton chided Frank for this delay in a letter from 25 April 1941: 'You may think that a book left unreviewed is a very small matter at a time when the author might have been imprisoned or killed.That is not my way of looking at it.I realize that my possibilities of good are very small but if a sufficient number of people do good deeds, the mass of those deeds, however small each of them may be, will move the scales in the right direction.Why do you try to push them in the other direction?' (Houghton Library, Harvard University bMS AM 1803.1 (226)).Thanks go to Friedrich Stadler (Vienna) for alerting me to this letter to which he also refers without quoting in Friedrich Stadler, 'George Sarton, Ernst Mach, and the Unity of Science Movement.A Case Study in History and Philosophy of Science', Sartonia, 31 (2018), 63-121.Curiously there are only few documents extant about the relation between Frank and his colleague at Harvard, Sarton, although their concerns for 'Scientific Humanism' seem to be closely related.
article 'Fundamental Questions of the Sciences' for the September 1953 issue.A previous letter from the editor of the journal (February 19, 1953) indicates that Frank had originally been asked to write that article but had declined and recommended von Mises.118Von Mises' death in July 1953 did not allow this publication to materialize. 119In his 1957 book Philosophy of Science Frank supported, in chapter 14 on 'Validation of Theories', von Mises' notion of probabilityat least its philosophical implications120 against the discussion of a 'probability of a theory' as advocated by the philosophers Reichenbach and Carnap. 121artly due to his advanced age Frank was not very active, after his friend's death, in the struggles for the royalties of the American edition of the Frank-Mises book or in the publication of von Mises' Selected Papers, and he left this more or less entirely to von Mises' widow, Hilda Geiringer.In a letter to her friend from the days in Berlin, the mathematician Gabor Szegö (1895-1985), Geiringer wrote on 6 April 1959, sceptical about a possible involvement of Frank's in the latter project: Ph.F. is 75 years old, is a lovely and enormously clever man but an 'unworldly dreamer' when it comes to doing something in the interest of others.Not unlike Karman.If F. is chairman nothing will happen.By the way, he travels around wherever he can still find a position that tempts him. 122ank would finally figure as one of the editors of the von Mises Selecta, which appeared in 1963/64, although he apparently did not contribute anything.As a matter of contrast, Geiringer, who did the bulk of the work, was not listed among the exclusively male editors, although this may have been her own decision because she felt too close to her late husband.
In 1965 von Mises' widow Hilda Geiringer summarized the relations between Frank and von Mises at the end of her address dedicated to the eightieth birthday of then mentally ailing Philipp Frank in 1964: I myself have known Philipp Frank for almost 50 years and I would like to finish with a happy recollection.Mises and I often visited the Franks, Philipp and the gentle and beautiful Hania.Mises knew the great men of his time: the poets, the great physicists, mathematicians, and philosophers.When after such a visit with the Franks, after talks on many things and many people, we left, Mises would say to me: 'Der Gescheiteste von allen ist doch der Philipp Frank.' [The most clever of all remains Frank.] 123
by a foundation) had to be made for Hilda Geiringer.A leading applied mathematician in her own right, she found only a temporary position at the women's college Bryn Mawr in Philadelphia, which was located far away from Harvard.After marrying von Mises in 1943, Geiringer was appointed at the small Wheaton College, 38 miles from Boston, where she retired in 1959 (Figure3).It was not until 1945 that von Mises himself finally got a full professorship at Harvard.9.Epilogue: relations between Frank and von Mises during the postwar years at HarvardNo correspondence between Frank and von Mises after 1939, when they both lived in Cambridge, Massachusetts, has come to light.Shortly after the war von Mises got the letter from Neurath's widow Marie with the remark about the 'strongest pillars of the empiricist wing' of the Vienna Circle which was quoted above.In fact, Neurath, in the last years of his life in Oxford, had frequently expressed reservations in his correspondence with Frank against the growing formalism in the work of Reichenbach and Carnap.Frank had similar experiences from his work with Carnap in Prague in the early 1930s.111On June 16, 1944, Neurath wrote to Frank in English:

Figure 4 .
Figure 4.The title page of the Saturday Review 32 (1949) with a portrait of PhilippFrank (1884- 1966).In this issue, a glowing review of Frank's 1949 book appeared. 14 The Law of Causality and Its Limits, ed. by Robert S. Cohen (Dordrecht, Boston, MA: Springer, 1998) [Translation of the German original of 1932, which was also published in French, Paris: Flammarion 1937], p. 72.
Max Planck of Berlin and Arnold Sommerfeld of Munich repeatedly distanced themselves from Mach.This is shown in particular by the discussion of Arnold Sommerfeld in September 1929 in Prague at the First International Meeting of the Vienna Circle, organized by Frank. 19Max Born, Göttingen, who himself worked on the statistical foundations in quantum 15 Meaning the traditional idealistic philosophy taught at universities.The term was used extensively, although somewhat vaguely, by Frank in 1929 in his Prague lecture, translated as Philipp Frank, 'Physical Theories of the Twentieth Century and School Philosophy', in Modern Science and its Philosophy, ed. by Philipp Frank (Cambridge: Harvard University Press, 1949), pp.90-121.Frank himself later self-critically called this term 'perfunctory' (Frank, 'The Humanistic Background', note 1, 347).See also below von Mises' letter to Carnap of July 1929. 16Typically represented by Oswald Spengler in Germany and Othmar Spann in Austria. 17It was the time when the traditional philosophical faculties at the universities split into natural science faculties and philosophical faculties, the latter becoming philosophical or humanistic in the narrower sense. 18Paul Forman, 'Weimar Culture, Causality, and Quantum Theory, 1918-1927: Adaptation by German Physicists and Mathematicians to a Hostile Intellectual Environment', Historical Studies in the Physical Sciences, 3 (1971), 1-115. 19See Stöltzner, 'Scientific World Conception on Stage', note 11, In Stöltzner Max Born's critical position against Frank's lecture in Prague is also discussed (pp.75/76).At the Prague conference, Sommerfeld largely denied Mach's influence on Einstein's theory of relativity, which had been claimed by Frank.
For the most part, they do not contain long reflections but merely dates, persons and very short descriptions of events.Frank is mentioned over 400 times in the diaries (sometimes abbreviated as 'Fr.'), very often relating to discussions in cafés.52RudolfHaller, 'Der erste Wiener Kreis', Erkenntnis, 22 (1985), 341-58.Von Mises' participation in this circle is assumed in Stadler, 'The Vienna Circle', note 31, p. 457. 53Philipp Frank, 'Historical Background', in Frank, Modern Science, note 15, pp.1-61.
There are two letters which are in other boxes: an undated letter by Frank to von Mises from late 1919 or early 1920 which is HUG 4574.5.3, folder: undated, and one by Frank to von Mises from early 1920 in HUG 4574.5.8. 55Unlike von Mises, Löwy is mentioned in the Manifesto of 1929 among the 'nahestehende Autoren' (authors close to the Circle), see above part I. 56 Ingrid Belke, Die sozialreformerischen Ideen von Josef Popper-Lynkeus (1838-1921) (Tübingen: Mohr, 1978). 57'Nachmittags mit Frank … im Café.Dann mit Fr. bei Popper, der sehr guter Dinge, sehr frisch und anregend ist.' Von Mises' diaries, note 51. 58This was apparently from shared military service, while Frank was not serving during the war for unknown reasons. 59Not much seems to be known about Löwy's biography.He published several articles on Mach and Popper and on epistemological problems.On 30 March 1930, Sigmund Freud responded with an interesting letter to Löwy and to von Mises who had planned a collection on scientific creativity, which however did not materialize.See Reinhard Siegmund-Schultze, 'A married couple of mathematicians from Vienna remembers Sigmund Freud (1953)', online Science in Context, (2023), 1-47, https://doi.org/10.1017/S0269889722000229,p. 5. From the 1920s Löwy worked on oil detection methods, visiting various African countries but apparently without ever having a permanent position.He is on no list of émigrés although he clearly had to leave Vienna as well.He went to Cairo around 1938, but I could not find out the year of his death.
104On April 30, Frank wrote to von Mises about a sudden turn in his personal situation after he had been appointed to a one-year-position at Harvard.Four weeks later, on 30 May, he wrote to his friend about his efforts to get something for him at the famous Institute for Advanced Study in Princeton, where emigrant-mathematicians such as Hermann Weyl and John von Neumann had leading positions.I am now for some time in Princeton, to discuss with Einstein my planned book.On this occasion I have talked to v. Neumann and Veblen about your situation.I have not raised the matter with Weyl because I believe he won't be particularly inclined..103.. Theople there say that your case is not that complicated because you could get a contract from a university.They want to reserve their help for more complicated cases.But it was indicated to me, particularly by von Neumann, that in a situation of emergency you could possibly get a contract from them anyway.104Because Frahalf of von Mises with the big institutions as the IAS and the New School for Social Research were to no avail, he now triedas he had announced beforewith a small catholic university in Pittsburgh (Duquesne).On 15 June 1939 he wrote to von Mises with tongue in cheek, alluding to Lillian R. Lieber(1886-1986)105the sister of the dean of the graduate school of that university:For the university there is only one thing what matters, according to Mrs. Lieber.This is that you are a 'gentleman'.She said they had had German refugees there last year, who were no gentlemen.106 But you need not take these things too seriously at all, for Mr. Rosanoff the Dean of the Graduate School is himself a Russian Jew.There is apparently no importance attached to racial issues at the university there.109Atthatpoint of time in June 1939, von Mises had already got a pro-forma contract from Harvard and did not consider the offer from Duquesne.110Hehad to pay his own salary at Harvard, although, as it turned out, only for the first year.A similar arrangement (although with partial contribution 105 Lieber was a chemist, mathematician, and popular science writer, then at Long Island University in Brooklyn, New York, whom Frank's Polish wife Hania happened to know.See David L. Roberts, Republic of Numbers: Unexpected Stories of Mathematical Americans Through History (Baltimore: Johns Hopkins University Press, 2019), pp.142-52. 106ür die Universität ist nach den Mitteilungen der Mrs. Lieber nur eines wichtig, dass Sie nämlich ein "gentleman" sind.Sie sagte, dass sie voriges Jahr German refugees dort hatten, die das nicht waren' (Frank to von Mises, 15 June 1939, typewritten, Harvard University Archives, HUG 4574.5, box 3, folder 1939, Mises Correspondence).107This is of course a misunderstanding.Von Mises would have been dismissed anyway in 1935 at the latest.See Siegmund-Schultze, Mathematicians Fleeing, note 41. 108 Lillian Lieber to M. Rosanoff (12 June 1939), attached as a copy to Frank's letter.109'Siemüssen aber diese Dinge nicht gar zu ernst nehmen, denn Mr. Rosanoff der Dean of the Graduate School ist selbst ein russischer Jude.Es wird offenbar an der dortigen Universität den Rassenfragen keine Bedeutung zugemessen'.110Thisled to some irritation on the part of Rosanoff, who complained about it in a letter to von Mises.However, his sister had informed him before about the quality of the candidate and warned him about von Mises' chances with other employers.