Logical empiricism in Turkish exile: Hans Reichenbach’s research and teaching activities at Istanbul University (1933–1938)

Abstract

In this article, I seek to shed new light on a lesser-known stage of the development of Hans Reichenbach’s thought, namely his research, output and teaching activities at Istanbul University (1933–1938). I argue that the experience of Turkish exile was decisive in the elaboration of Reichenbach’s probability theory of meaning and knowledge. His work Experience and Prediction, produced while in Istanbul, should therefore be put in its Turkish context of elaboration and reception. To this end, I will take into consideration not only Reichenbach’s efforts to popularize and extend the Berlin Group’s program of scientific philosophy in Turkey and throughout Europe in the 1930s, but also the forgotten work of Reichenbach’s students—most of them women—at Istanbul University.

1 Introduction

The crucial role of exile in the establishment and self-description of logical empiricism as a philosophical paradigm, and furthermore in the development of the philosophy of science (Dahms, 1988a), has mostly focused on migration to the United States, neglecting resettlement and network development elsewhere in the 1930s. This may partially explain why the history of the Berlin Group, led by Hans Reichenbach (1891–1953), long formed a research gap in the history of logical empiricism, especially in comparison with the Vienna Circle. Unlike other core members of the Berlin Group,¹ Reichenbach was able to continue his academic career, emigrating first to Turkey in 1933 and then to the United States in 1938. Reichenbach’s research and teaching activities at Istanbul University, where other scholars and scientists close to the Berlin Group or in contact with Reichenbach were also appointed after the 1933 Turkish university reform, has not received much attention.² Reichenbach’s stay in Istanbul has sometimes even been dismissed as a failure and a time of intellectual isolation.

The aim of this paper is to show that Reichenbach’s Turkish exile was not an insignificant step on his journey to North America. During his five-year exile in Istanbul, Reichenbach succeeded to some extent in recreating the working atmosphere he had encountered in Berlin by organizing an interdisciplinary colloquium, several seminars, and public conferences. Moreover, his time in Istanbul was not one of solitude as during this time Reichenbach developed academic relations with institutions and scholars from other countries, especially in France. It was indeed during these years that Reichenbach earned his truly international reputation by contributing to international congresses and academic journals. Reichenbach was able not only to diffuse and popularize logical empiricism in a very active manner but also to develop his own probability theory of meaning and knowledge based on the rejection of the verifiability conception of meaning. This theory, associated with a vivid critique of positivism, is revealed in Experience and Prediction (Reichenbach, 1938a), a book he wrote in Istanbul, which reflects his collective experience working and teaching there.³ My main claim is that it was precisely during this stay in Istanbul that Reichenbach sought to continue the realization of the Berlin Group’s program of scientific philosophy or analysis of science and adopted his unique conception of “logistic empiricism” that he emphatically opposed to the “logical positivism” of the Vienna Circle (Reichenbach, 1936a).⁴

I start by giving some details about Reichenbach’s background and activities in Berlin (1) and by presenting the specificity of his philosophical views as well as the interdisciplinary program of the Berlin Group (2). Then, I present the circumstances of Reichenbach’s arrival in Istanbul, including major transformations underway at the Istanbul University Department of Philosophy (hereafter IUDP) following the 1933 Turkish university reform (3). I then provide an overview of Reichenbach’s efforts to popularize the sciences and disseminate ideas about logical empiricism during his stay there, continuing the activities of the Berlin Group. This includes the organization of interdisciplinary meetings (4) but also publishing and active participation in international congresses (5). Finally, I consider another kind of reception linked to Reichenbach’s sojourn in Istanbul, which is his teaching activities and the work of his, mainly female, students at Istanbul University (6) and its impact in Turkey after Reichenbach’s departure (7).

2 Reichenbach and the Berlin Group

A fact seldom emphasized is that Reichenbach’s departure for Istanbul was not only the result of an initially envisaged temporary exile, but also a strategic choice that allowed him to secure his academic career in the field of philosophy. His stay in Istanbul marks a decisive moment in the institutionalization of logical empiricism, a paradigm that was then still encountering a great deal of resistance in the academic philosophy field in Germany. Reichenbach found in Istanbul a milieu through which the difficulties he encountered, in Berlin, in obtaining recognition for his work disappeared. Not only was he received as an eminent philosopher from Berlin with an international reputation when he arrived in Istanbul in 1933, he was also appointed as a full professor with a five-year contract⁵ and was given the task of reorganizing and heading the IUDP.

Reichenbach studied physics, mathematics and philosophy in Munich, Göttingen, and Berlin, where he met Albert Einstein and attended his lectures on the theory of relativity. During his philosophy studies, he was particularly impressed by Ernst von Aster in Munich and Ernst Cassirer in Berlin, because of their “understanding of the problems of natural philosophy” (Cohen & Reichenbach, 1978, 1f.). His original approach, combining physics and philosophy, was not developed without difficulties, to the point that Reichenbach wrote his doctoral dissertation Der Begriff der Wahrscheinlichkeit für die mathematische Darstellung der Wirklichkeit [The Concept of Probability in the Mathematical Representation of Reality] largely without academic supervision (Salmon, 1977, p. 9, Eberhardt, 2009, p. 125).⁶ He obtained his habilitation and authorization to teach physics (venia legendi) at the Technische Hochschule in Stuttgart in 1922, where he worked as a physics and philosophy lecturer.

After researching causality and probability with a fellowship of the Emergency Association of German Science (Notgemeinschaft der deutschen Wissenschaft), Reichenbach applied for a re-habilitation in the University of Berlin Faculty of Arts (philosophische Fakultät) in 1926. With the support of Max Planck and Max von Laue, Reichenbach was finally appointed as a non-permanent Associate Professor at the Faculty of Sciences with a “teaching assignment on [the] Epistemological Foundations of Physics” (Hoffmann, 1994, p. 28), without, however, obtaining authorization to teach in the Department of Philosophy.⁷ He expressed the difficulties he encountered in a letter addressed to his former teacher in Munich, Ernst von Aster:

My re-habilitation to Berlin, which I told you about at the time, has unfortunately still not been completed; there are terrible obstacles to overcome, and the matter, which is very much supported by Planck and Laue, is still pending. It is not even a chair, but only a teaching assignment.⁸

In the 1920s, Berlin was one of the most important centres of modern physics, marked by the work of Albert Einstein, Max Planck and Max von Laue, and could therefore be seen as the ideal place to develop a new philosophy taking into account the latest developments in modern physics. Reichenbach was in this context the main popularizer of the theory of relativity and its central defender against attacks by both scholars and popular press. However, Reichenbach was aware that his commitment to the theory of relativity represented an obstacle to his career in the field of philosophy, where he was mistrusted for his popularization activities and in particular his axiomatic work on the theory of relativity (Tilitzki, 2002, p. 234). In a letter (27.01.1929), Reichenbach complained to Einstein about the latter’s lack of support in his struggles with his career, even though Einstein had published a very favorable review of his 1928 book Philosophie der Raum-Zeit-Lehre (Röseberg, 1998, p. 30).

Despite the difficulties Reichenbach encountered in obtaining the recognition of academic philosophers at Friedrich Wilhelm University, he experienced in Berlin a particularly productive period with the formation of what he called the “Berlin Group.” Initially formed as a continuation of his seminars, the Berlin Group included Kurt Grelling,⁹ Walter Dubislav,¹⁰ Alexander Herzberg,¹¹ and occasional representatives of the Berlin School of Gestalt Psychology such as Wolfgang Köhler (1887–1967) and Kurt Lewin (1890–1947). Reichenbach’s doctorate students Carl Gustav Hempel (1905–1997) and Olaf Helmer (1910–2011) also participated in discussions.

This informal working group found an institutional anchor in moving closer to the Berlin Society for Empirical Philosophy (Gesellschaft für empirische Philosophie)¹² of which Reichenbach became a member in 1928. After Joseph Petzoldt’s death in 1929,¹³ Reichenbach, along with Herzberg and Dubislav,¹⁴ took over the direction of the society (Hoffmann, 2008, 48f.). Its reorientation was reflected by the change of its name to the Society for Scientific Philosophy (Gesellschaft für wissenschaftliche Philosophie) in 1931 (Nehls, 1932, Milkov, 2013b, p. 12). The activities of the Berlin Society consisted essentially in the organization of public lectures on philosophically significant problems in the empirical sciences, including physics, biology, medicine and psychology. Public lectures took place at the auditorium of the Charité medical clinic. They were intended for broader public and were discussed in newspapers such as the Vossische Zeitung and the Berliner Tageblatt (Danneberg & Schernus, 1994, 405ff.). Another important activity of the Gesellschaft consisted in the publication of articles related to its activities, first in the Annalen der Philosophie edited by Hans Vaihinger and Raymund Schmidt, then in the journal Erkenntnis co-founded in 1930 by Hans Reichenbach and Rudolf Carnap (Hegselmann & Siegwart, 1991), which Reichenbach directed from Istanbul after 1933. Another activity was the organization of colloquia and congresses, allowing for exchange with other representatives of logical empiricism, with the explicit intent of internationalizing the movement.

3 Turkish exile as a matrix of an anti-positivist theory of meaning and knowledge

Having anchored itself to the Society for Scientific Philosophy, the Berlin Group positioned itself in opposition to the Vienna Circle, particularly after the publication of its 1929 manifesto “The Scientific Conception of the World. The Vienna Circle” (Wissenschaftliche Weltauffassung. Der Wiener Kreis), published by the Ernst Mach Society and co-authored by Rudolf Carnap, Hans Hahn, and Otto Neurath (Stadler & Uebel, 2012). The Berlin Group promoted a descriptive approach to problems specific to individual disciplines (Einzelwissenschaften) such as physics (theory of relativity and quantum mechanics) and psychology (Gestalt theory, psychoanalysis); the Viennese in contrast, were more oriented towards mathematical logic and had a more programmatic, even prescriptive, conception of philosophy (Dahms, 1988a, p. 162).

At the same time, relations between Reichenbach and the leading figure of the Vienna Circle, Moritz Schlick (1882–1936), deteriorated¹⁵ to the point that in 1931 Schlick wrote a negative recommendation when Reichenbach sought a professorship in Germany (Milkov, 2015a, p. xx). Schlick openly rejected the realism advocated by Reichenbach and was concerned about the tendencies of the Berlin Group and Reichenbach’s “far-fetched ideas on probability” (verdrehte Wahrscheinlichkeitsideen), as he wrote in a letter to Carnap dated September 19, 1931 (Stadler, 2011, p. 143). Because of his disagreements with Reichenbach, Schlick refused to join the editorial board of Erkenntnis. This was for Reichenbach additional evidence that the journal was the press organ of the Berlin Group and not of the Vienna Circle, as seen in his letter to Max Black (18.04.1938), with whom he shared the same critical attitude towards positivism:

I was much interested to read your hard criticism of positivism. You know that my attitude toward positivism is as critical as yours. […] the movement of scientific philosophy should not be identified with positivism, and not with the Vienna circle. Unfortunately, our German branch of this movement, as it was centered around Erkenntnis, has been identified in the English literature with the Vienna circle […] I may add here the remark that Erkenntnis was not a foundation of the Vienna group, but of the Berlin group, and that when I invited the Vienna group to collaborate in the edition of this journal, Schlick refused to accept because of the differences in his view and mine. (cited from Schernus, 1994, p. 35).

After leaving Germany in 1933, Reichenbach’s criticism of the Vienna Circle became increasingly open and virulent: he found the group too dogmatic and under the influence of Ludwig Wittgenstein, “the most radical mind among modern positivists” (Reichenbach, 1938a, p. 74); something for which he held Moritz Schlick particularly responsible.¹⁶ It was especially during his stay in Istanbul, a time when he obtained relative institutional security compared to the precariousness of his situation in Germany, that Reichenbach developed his probability theory of meaning and knowledge, recurrently and polemically presented as a critique of positivism. Criticism of the Vienna Circle’s neopositivist program is indeed a leitmotiv of Reichenbach’s work from that time.¹⁷ Such a critical approach reached its climax in Experience and Prediction, written in Istanbul and published in 1938 by University of Chicago Press. In this key epistemological work, Reichenbach speaks of positivism as a “dangerous fanatic doctrine” and compares it to a “religious sect”¹⁸ with “its dogmas and its preachers:”

These are the fundamental ideas of positivism as they are generally developed by their adherents. There is something very suggestive in these conceptions, something comparable to the convincing clarity of a religious conversion; and the ardor with which this interpretation of the existence problem has been emphasized by the preachers of positivism reminds one indeed of the fanaticism of a religious sect. […] it is the danger of fanatic doctrines that they forget the necessary criticism of their basic conceptions; we must take care that admiration of the lucidity of the theory¹⁹ does not restrain us from a sober examination of its logical bases [sic]. (Reichenbach, 1938a, p. 103).

Reichenbach’s attempt to position himself and the Berlin Group within logical empiricism in the 1930s was accompanied by the development of distinct terminology to prevent the group being labelled as positivist.²⁰ He indeed never associated himself with “logical positivism”, a term that emerged in the early 1930s (Blumberg & Feigl, 1931). In his essay “Logistic Empiricism in Germany and the Present State of its Problems” (Reichenbach, 1936a), which can be read as a counterpoint to the Vienna Circle’s manifesto (Sinaceur, 2018, p. 48)²¹ or even better as a “Berlin manifesto in exile” (Stadler, 2011, p. 146), Reichenbach uses the expression “logistic empiricism” to describe the Berlin Group in order to distinguish it from the “logical positivism” of the “Viennese Circle” and in particular the position of Carnap and Schlick. Even though Reichenbach considers in this essay that the two movements were linked and originated from the same “epistemological turn” due to the development of natural sciences in the nineteenth century (Reichenbach, 1936a, p. 141), he clearly affirms his rejection of “positivism” and particularly of Wittgenstein’s philosophy, in a very similar way to that in Experience and Prediction (Reichenbach, 1938a, p. 49, 74f.)—the name of Schlick, however, does not appear in this book.

According to Reichenbach, Schlick “had held a realistic conception of physics, but impressed by the ideas of Wittgenstein, was converted to positivism” (Reichenbach, 1936a, p. 143). He further adds that the members of the Berlin Group—specifically mentioning Dubislav, Herzberg and Grelling—share the same method of scientific analysis (wissenschaftsanalytische Methode), i.e., “the method of examining details” (Reichenbach, 1936a, p. 150), without any adhesion to a doctrinal system. The members of the Vienna Circle, conversely, are presented in this essay as adherents of a “refurbished logistic materialism.” In this perhaps caricatural presentation of the Vienna Circle,²² Reichenbach opposes his own conception of empiricism in relation to his probabilistic solution to the problem of induction, which he elaborated precisely in the years spent in Istanbul (see Padovani, 2011, p. 41). The reason why the Berlin Group could not accept positivism, according to him, is its lack of a theory of propositions about the future “in which the two truth-values, true and false, are replaced by a continuous scale of probability” (Reichenbach, 1936a, p. 154).

Upstream of the concept of positivism used by Reichenbach in the 1930s is an ambivalent reference to Ernst Mach, the emblematic figure of both the Berlin Society of Petzoldt’s time and the Verein Ernst Mach (Association Ernst Mach) led by Schlick. Reichenbach explains Mach’s epistemological ideas and more generally the “systems of positivism, created by Mach and others,” together with “the pragmatism of Peirce, James and Dewey,” as both a constitutive step in the formation of scientific philosophy and a rather dogmatic²³ moment of this “new phase of philosophical analysis” (Reichenbach, 1936a, p. 141). This offensive against positivism as a dogmatic materialism—which can be read both as a criticism of the initially positivistic or empirio-criticist orientation of Society for Empirical Philosophy led by Petzoldt and as a willingness to distance himself from certain features he attributed to the Vienna Circle—²⁴ finds its most complete expression in the first two chapters of Experience and Prediction (1938). This critique of positivism is in line with those developed at the same time by other thinkers close to the logical empiricism of the Berlin Group, notably Gestalt theoreticians.²⁵

Reichenbach’s determination to distance himself from positivism and to have the Berlin Group recognized is also clearly found in his correspondence during this period, notably in his letters to his former philosophy professors²⁶ Ernst Cassirer²⁷ and Ernst von Aster.²⁸ Deprived of his chair at the University of Giessen in 1933, Ernst von Aster went into exile in Sweden, where he published a monograph devoted to contemporary philosophy in 1935, including a chapter “Logistical Neopositivism,” where he mentions Reichenbach but fails to reference the Berlin Group (v. Aster, 1935, pp. 177–211). Reichenbach wrote to Ernst von Aster that he was very disappointed by this omission, which leads one to believe that this philosophical orientation arose exclusively in Vienna and Prague, though the Berlin Group was just as active as the Circle of Vienna:

First of all, I must say that I very much regret that you almost always write only about the Vienna Circle, so that it seems as if this whole philosophical direction originated in Vienna and Prague alone. Our Berlin group was just as active a center as the Vienna Circle, and there has never been any doubt about this within our movement.²⁹

Reichenbach mentions in this letter the extensive organizational work carried out in Berlin within the framework of “our Society for Scientific Philosophy,” with the organization of conferences and discussions “every two or three weeks,” bringing together between 100 and 300 people. In the letter, he also mentions his own seminars and colloquia for further discussion, and the fact that it was in Berlin that the journal Erkenntnis was founded.

But it was also for political reasons that Reichenbach sought recognition for the Berlin Group, as the rest of the letter suggests:

This Berlin circle has now been driven apart by the Hitler government, but it still lives on as a virtual unity; and especially since our work has been so severely affected by political developments, it is important to me that this work at least be called our movement in history. How important I myself considered this Berlin center of our movement, you can also see from the fact that at that time I refused the appointment to the chair in Prague, which Carnap received later. Of course, at that time I had no idea that one day I would be forced to leave Berlin for political reasons.³⁰

As can be seen here, fighting for the widespread acceptance of logical empiricism in Germany and its implementation in university curriculums was not the only important point for Reichenbach. Bringing to life the memory of the activities and work of the Berlin Group, taking into account its very “virtual” unity, was for him an act of resistance in the face of Nazi attempts to annihilate it.

4 Reichenbach in the context of the Turkish university reform

On April 7th, 1933, the Nazi regime passed the “Law for the Restoration of the Professional Civil Service” (Gesetz zur Wiederherstellung des Berufsbeamtentums or Berufsbeamtengesetz, shortened hereafter to BBG), which led to several waves of dismissals at German universities between 1933 and 1935. Reichenbach’s right to teach at the University of Berlin was revoked on 5 September 1933 on the basis of the “Aryan clause,”³¹ (§ 3 BBG; Tilitzki, 2002, p. 602). He had started to organize his departure from Germany on the very day of the proclamation of the law however.³² Reichenbach went first to Switzerland before moving to Istanbul with the help of the Emergency Association of German Scientists Abroad (Notgemeinschaft deutscher Wissenschaftler im Ausland).

This Emergency Association was established in 1933 in Zurich by the physician Philipp Schwartz (1894–1977) to assist scholars being persecuted in Nazi Germany find new positions abroad. Having himself been deprived of his position at the University of Frankfurt from 1927 to 1933, Schwartz, with the Swiss pedagogue Albert Malche (1876–1956), organized the academic emigration of scholars to Istanbul University,³³ negotiating directly with his colleague doctor Reşit Galip, who was at that time the Turkish Minister of National Education and the main architect of the 1933 Turkish university reform (Widmann, 1973, pp. 49, 53–59). The protocol initially signed by Galip on the 06.07.1933 (see the procès verbal reproduced in Widmann, 1973, pp. 236–239) nominated two professors to the Department of Philosophy, Hans Reichenbach and Fritz Heinemann,³⁴ and expresses the wish to welcome among others Ernst Cassirer.

Reichenbach was given the title Professor Ordinarius at the Faculty of Letters (Edebiyat Fakültesi) at Istanbul University and was made the head of the Department of Philosophy, which was completely reorganized after the Turkish university reform. Reichenbach’s Chair of Systematic Philosophy and Logic (Umumî Felsefe ve Mantık) can be seen as the merger of the Chair of Logic held by Halil Nimetullah (1880–1957)³⁵ and the Chair of Metaphysics held by Ahmet Naim Babanzâde (1872–1934), positions which were closed in 1933 (Kafadar, 2000a, p. 52). The university reform that year and the dismissal of much of the teaching staff took place before Reichenbach’s arrival; however, the latter played an important role in the reorganization of the Department of Philosophy in the years that followed.

The initial working conditions he received were apparently good enough for him to refuse a proposal from Oxford University (Irzik, 2011, 160f.) and the University of Uppsala.³⁶ Reichenbach was very enthusiastic about his position in the first years, including the task of reorganizing the teaching of philosophy but also by the warm welcome in Istanbul and the interest of the students. He expressed this in a letter to Ernst von Aster, where he mentioned students’ interest and goodwill, which eased the linguistic difficulties he faced having, for example, to teach through the use of an interpreter.³⁷ In spite of administrative difficulties,³⁸ Reichenbach managed to provide two additional chairs for exiled professors: Ernst von Aster was appointed to a Chair of History of Philosophy in 1936, Wilhelm Peters to the new Chair of Experimental Psychology created in 1937.

However, both the situation and Reichenbach’s appreciation of it changed over the years and the new difficulties. Due to the arrival of a large number of scholars who had been dismissed in Germany and the sudden renewal of the teaching staff, including several dismissals that was felt as arbitrary, the Turkish university reform gave rise to tensions and sometimes hostile reactions among some Turkish colleagues, tainted with xenophobia and anti-Semitism. In Reichenbach’s correspondence, there are several allusions to this general atmosphere³⁹ and resentment (Irzik, 2011, p. 173). A particular point of contention was the fact that the working conditions and remuneration of foreign professors were particularly attractive, whereas most Turkish professors working in the department before the reform were suddenly dismissed. Only two assistant professors were allowed to continue: Mustafa Şekip Tunç (1886–1958) became Professor of Psychology and Education at the new Department of Philosophy⁴⁰; Orhan Sâdeddin (1899–1964), previously a doctoral student of Ernst von Aster’s at the University of Giessen in Germany in the 1920s,⁴¹ was kept on in 1933 as professor of the History of Philosophy but he was not able to assume his position for medical reasons (Gültekin & Kaya, 2016, p. 15). Sâdeddin’s career interruption contributed to Reichenbach’s obligation to teach this subject⁴² before Ernst von Aster’s appointment in 1936.

One of the main changes related to philosophical disciplines that occurred after Reichenbach’s arrival is the separation of psychology and sociology from the Department of Philosophy in order to become institutionalized as autonomous scientific disciplines. The Chair of Sociology, originally assigned in 1933 to another German émigré professor, Gerhard Kessler (1883–1963), was transferred to the Faculty of Economics (İktisat Fakültesi) in 1937. That same year, the institutional split between philosophical and experimental psychology was initiated, as a result of the appointment of the psychologist Wilhelm Peters (1880–1963) to the new Chair of Experimental Psychology. This creation of a new chair to meet the needs of training in experimental psychology was largely due to Reichenbach’s efforts,⁴³ reflecting his then-strong interest in scientific psychology, especially Gestalt theory, which had a central place in the work of the Berlin Group (Ash, 1994), but which had also enjoyed some popularity at Istanbul University (İstanbul Dârülfünûnu) starting in the late 1920s.⁴⁴ Reichenbach first tried to hire Wolfgang Köhler⁴⁵ and then Adhémar Gelb,⁴⁶ both well-known Gestalt psychology researchers, before supporting Wilhelm Peters’ candidacy.⁴⁷

5 The Berlin Group in Istanbul

Reichenbach was not the only German scholar linked with the Berlin Group to have taken refuge in Istanbul starting in 1933. Another academic, mathematician Richard von Mises (1883–1953), professor and director of the Institute of Applied Mathematics at the University of Berlin (Stadler, 2015, pp. 1, 6), came to Istanbul in 1933 and stayed there for as long as Reichenbach.⁴⁸ Richard von Mises was in contact with both Viennese and Berlin representatives of logical empiricism and participated before the First World War in a discussion group at a Viennese café considered to be the first iteration of what was to become the Vienna Circle. Although von Mises kept his distance (Bernhardt, 1994) or at least seems not to have been an official member of the Berlin Society (Danneberg & Schernus, 1994, p. 396), he was part of Reichenbach’s intellectual environment in Berlin and after 1933 in Istanbul. Reichenbach and von Mises seemed to have several theoretical disagreements during their stay in Istanbul, particularly on the theory of probability. Reichenbach had an expanded conception of probability that Mises rejected as “metaphysical” (Irzik, 2011, pp. 174f.).⁴⁹ Reichenbach’s correspondence also reveals more personal conflicts with von Mises regarding the recruitment policy at the Istanbul University. A subject of dissension was, for example, the attitude towards a colleague close to the Berlin group who also migrated to Istanbul, the astrophysicist Erwin Finlay-Freundlich (1885–1964).

Finlay-Freundlich was in contact with Reichenbach from the early 1920s and linked to the Berlin Society, where he once gave a lecture. He was one of the first astronomers willing to test Einstein’s theory of relativity (Hentschel, 1994). From 1933 to 1937, Finlay-Freundlich headed the new Astronomical Institute of Istanbul University, where he had a solar observatory constructed (Dölen, 2010/4, p. 238). He ended his contract in Istanbul in 1937 having accepted a chair at the German University in Prague. He remained in contact with Reichenbach, who continued to express his support while von Mises judged Finlay-Freundlich’s departure before the end of his contract with the Istanbul University more harshly.⁵⁰

Other individuals close to Reichenbach were also invited to Istanbul University but did not come: Ernst Cassirer, who, together with Richard von Mises and Max Born, was a member of the board of the Notgemeinschaft (Widmann, 1973, p. 54), as well as Albert Einstein, who negotiated unsuccessfully with Hikmet Bayur, the then Turkish Minister of National Education, to allow a group of professors, doctors and pharmacists at risk in Germany to work in Turkey (Dölen, 2010/3, pp. 455–465 and 581–604).

During his stay in Istanbul, Reichenbach’s efforts to develop the program of scientific philosophy were not limited to statements about the existence of the Berlin Group and its autonomy from the Vienna Circle. In Istanbul, Reichenbach continued the interdisciplinary activities characteristic of the Berlin Group and of the Berlin Society for Scientific Philosophy, with however a greater concern for internationalization due to the perilous situation many scholars faced in Germany.⁵¹ In addition to seminars held at Istanbul University and a colloquium under the aegis of the Turkish Philosophical Society, Reichenbach organized events for the general public in order to reach a wider audience. This interest in popularization is also manifest in his publishing activities, both in scientific journals and in mainstream cultural media. Some of his lectures were published in Turkish literary and cultural periodicals, such as Varlık (Being)⁵² and Edebiyat (Literature) (Reichenbach, 1934a, b). Another example of these efforts to popularize scientific culture is the 1938 publication of one of his public lectures, “Tabiat Kanunu Meselesi” [The Problem of Natural Law], by CHP Press (Reichenbach, 1938b).

Reichenbach’s engagement with Istanbul’s philosophical circles through his lectures and publication activities is reminiscent of the activities of the Berlin Group, which had initially formed around Reichenbach’s seminars given at Friedrich Wilhelm University, and from 1928 onwards through a colloquium organized with Walter Dubislav (Milkov, 2015a, p. ix). According to Matilt Kamber, a graduate of the IUDP, in addition to seminars given in German with the help of an interpreter⁵³ and warmly received lectures in French, Reichenbach organized an interdisciplinary colloquium at Istanbul University that brought together professors from different departments, particularly from the Faculty of Science: “There were physicists, biologists, mathematicians, physicians, and dentists, and each philosophical problem was discussed from different points of view” (Kamber, 1978, p. 38).

In one of his letters, Carl Hempel mentions that Reichenbach told him about a colloquium held in Istanbul “by a small circle of scholars speaking German,” which he described as “a weak substitute for the circle in Berlin” (Hempel, 1991, p. 10). However, the few extant testimonies of those who attended Reichenbach’s colloquia in Istanbul all emphasize the high level of the discussions and the participants’ great pedagogical and scientific interest in the meetings, which were open to the public. In an interview, Reichenbach’s student and assistant Neyire Adil Arda noted that the colloquia, which brought together teachers from various disciplines and faculties, were the place for important discussions on philosophical and scientific subjects. She added that the practice of holding colloquia was entirely new at that time in Turkey and even still rare in the United States (Kaynardağ, 1999, pp. 22f.).

An important witness of Reichenbach’s activity is the Turkish historian of philosophy and thought Hilmi Ziya Ülken (1901–1974).⁵⁴ Ülken mentions in his Türkiye’de Çağdaş Düşünce Tarihi [History of Contemporary Thought in Turkey] that Reichenbach, together with professors from the Faculty of Letters and the Faculty of Science, founded an Association of Natural Sciences (Tabiat İlimleri Derneği), where he presented his theory of knowledge entitled “empirisme logistique” (logistical empiricism) as well as the principles of probabilistic logic at courses, seminars and lectures given between 1933 and 1936 (Ülken, 1966, p. 692).

In a report on the activities of the Turkish Philosophical Society, “Yeni Felsefe Cemiyeti ve Türkiye’de Felsefe Cemiyetinin Tarihçesi” [The New Philosophical Society and the History of the Turkish Philosophical Society] published in 1943 in the sociology journal of Istanbul University, Ülken devotes several pages to a colloquium regularly organized by Reichenbach (Ülken, 1943, pp. 395–400). In it he gives a description of several sessions and emphasizes the importance of the discussions that took place, bringing together professors, advanced students or simply those curious and interested. Held over three years, with one session every two weeks, this colloquium brought together a relatively small but highly qualified and specialized audience, allowing for in-depth discussions spread over several sessions, depending on the subject (Ülken, 1943, 395f.). According to Ülken, Reichenbach initially wanted every faculty member to give a lecture within the framework of the colloquium, which was however impossible to put into practice. The first lecture, given by Ülken himself, was a presentation of “Cassirer’s book on the concept of substance and the concept of function” (see Cassirer, 1910), which gave rise to discussions on the links “between the school of neo-Kantism and the new school of logistic realism” (“yeni Kantcılık ile yeni realist logistik mektepler arasında”) (Ülken, 1943, p. 396).⁵⁵ The second lecture was a presentation by Reichenbach on his study of the question of space and time, with a discussion of the principles of Einstein’s physics and the consequences for “the new scientist philosophy” (yeni ilimci felsefe). This discussion was prolonged in following sessions with a conference on “the principles of the philosophy of logistical empiricism” (empirisme logistique felsefesinin esasları), in which philosophers and also scientists in the disciplines of natural sciences participated⁵⁶ (Ülken, 1943, p. 396). Ülken mentions another lecture by Reichenbach on probability logic (ihtimaliyet mantığı) and on the application of the probabilistic conception to the natural sciences, followed by a lively discussion in which the physiologist Hans Winterstein⁵⁷ and the physicist Harry Dember⁵⁸ took part by raising critical objections. Other sessions mentioned by Ülken include a lecture on “American philosophy” by the Robert College philosophy teacher Eleanor Bisbee⁵⁹ (Ülken, 1943, p. 397); another lecture, given by Ülken on determinism in the social sciences, based in part on Neurath’s “positive sociology,” gave rise to a debate between Kessler and Reichenbach, the latter advocating a probabilistic approach and the use of statistics in the social sciences (Ülken, 1943, pp. 397f.).

The report given by Ülken bears witness to the fact that the colloquium organized by Reichenbach had a reach far beyond the Department of Philosophy, and that Reichenbach transposed the interdisciplinary practices of the Berlin Group to Istanbul. These activities were also accompanied by an important development in publications related to logical empiricism. In addition to his active participation in the colloquium organized by Reichenbach, Ülken contributed greatly to this reception of logical empiricism in the 1930s, as will be shown in the following section.

6 The reception of Logical Empiricism in Turkey in the 1930s.

Two vectors of internationalization and science communication, academic journals and international congresses,⁶⁰ show Reichenbach’s production and networking practices during his stay in Istanbul. These activities made important discussions within the field of logical empiricism possible. They also contributed to the international diffusion of this paradigm, especially in Turkey and France. Reichenbach’s publishing activities highlight his fruitful collaboration with his colleague Hilmi Ziya Ülken, who was one of the first to disseminate logical empiricism in Turkey. On the other hand, in international congresses, one sees dissension with contemporaries such as Ziyaeddin Fahri Fındıkoğlu, who worked to discredit Reichenbach and “neo-positivism” more generally. Thus, in Istanbul, the reception of Reichenbach’s philosophical views was polarized from the outset through these two sociologists, who were initially his colleagues at the Department of Philosophy.⁶¹

6.1 Hilmi Ziya Ülken’s contribution to the introduction of Logical Empiricism in Turkey

Reichenbach helped arrange for the publication of texts related to logical empiricism in Turkish, based mostly on then-contemporary French publications. Ülken translated a short book of Moritz Schlick under the title İlim ve Felsefe [Science and Philosophy] that rejects the opposition between logical positivism and realism—an opposition that would become central in Reichenbach’s theory of knowledge. In his short preface, Ülken presents Schlick as a major figure of the “new logical and scientific philosophy represented in Vienna and Berlin and distinct from the English school” (Schlick, 1934b, 3f.). Published in the same book collection of the newspaper “Vakit” [Time] as Schlick’s, a short book of Reichenbach was translated by Ziya Somar⁶² under the title İlmî Felsefe [Scientific Philosophy] (Reichenbach, 1935c; see also Reichenbach, 1932).

These translations accompanied the preparation of the second and final issue of the journal Felsefe Yıllığı [Annals of Philosophy], the press organ of the Turkish Society for Philosophy, edited by Ülken in 1935. Years later, Ülken described how this issue was the most important publication on logical empiricism in Turkey (Ülken, 1966, pp. 692–694). This issue was indeed largely devoted to works on logical empiricism, but it also discussed developments in the field of scientific psychology with contributions on Gestalt theory, one of the main interests of the Berlin Group. In this issue, works by Gestalt psychologists such as Kurt Koffka, Wolfgang Köhler, David Katz and Max Wertheimer were reviewed by Mümtaz Turhan (Turhan, 1935), who had studied in Germany between 1928 and 1935, writing his doctorate thesis under the direction of Max Wertheimer (Turhan, 1937). In 1936, Turhan was appointed as Wilhelm Peters’ assistant, interpreter, and translator at the Istanbul University Faculty of Letters.

A defining aspect of the reception of logical empiricism in this issue of Felsefe Yıllığı is that it essentially relayed the French reception, which developed rapidly in parallel with the preparation of the Parisian congresses of 1935 and 1937, in which Reichenbach also actively participated. In addition to book reviews by Reichenbach, Philipp Frank and Moritz Schlick, published in French by the Hermann publishing house, this issue also contained Turkish translations of articles originally published in Erkenntnis (Carnap 1935, Reichenbach, 1935b). It is Reichenbach’s translated article on “the logical foundations of the concept of probability” in which he expounds upon his solution to the problem of induction, published in German in 1933 and in French in 1935 (Reichenbach, 1933, 1935a). Nusret Şükrü [Hızır], who had translated this article, also translated a report on the 8th International Philosophy Congress—published in the same issue—which took place in Prague in 1934 (Ülken, 1935, pp. 347–353).

Other contributions in this issue can be linked to the Berlin Group’s activities related to physics and psychology. For example, the translation of two articles by the French physicist and Nobel Laureate Louis de Broglie (1892–1987)⁶³ reflects Reichenbach’s willingness to strengthen ties with French academics in a common effort to promote the philosophy of science. Indeed, Louis de Broglie had previously agreed to head the French Society of the Philosophy of Science, which Louis Rougier hoped to establish as a French equivalent to the groups of Vienna and Berlin, although this project was never realized (Padovani, 2006, p. 230). Also noteworthy are the contributions of the philosopher and psychologist Richard Müller-Freienfels (1882–1949), originally published in the journal Recherches philosophiques and translated into Turkish by Mustafa Şekip Tunç. One of these articles was initially presented as a lecture: “Die Hauptrichtungen der gegenwärtigen Psychologie” [Major Trends in Contemporary Psychology] given in 1928 by the Gesellschaft für empirische Philosophie, where Müller-Freienfels gave a second lecture in 1934 (Danneberg & Schernus, 1994, pp. 457f.).

The only original and untranslated contribution in this issue was that of the Friedrich Wilhelm University philosophy professor David Baumgardt (1890–1963), who was dismissed from his position in 1935 due to anti-Semitism (Tilitzki, 2002, p. 603). For this issue, Baumgardt prepared a short essay, “Die Gesamtlage der Philosophie in Deutschland” [The Situation of Philosophy in Germany], where the scientific philosophy of modern empiricists such as Hans Reichenbach and Walter Dubislav is portrayed as a safeguard against the irrational tendencies of certain trends in German metaphysic, particularly those popular at the time in Nazi Germany, such as Ludwig Klages’ Lebensphilosophie, Othmar Spann’s political theory and above all Martin Heidegger’s ontology (Baumgardt, 1935, pp. 309f.; Roure, 2020a, pp. 343–345).

In Felsefe Yıllığı, Ülken presented the philosophy of the Vienna Circle and that of the Berlin Group in an indiscriminate manner, stressing that which unified these movements over on their internal disagreements, using expressions such as “Scientific Philosophy” (îlmi felsefe) and “New Positivism” (yeni pozitivizm) to speak of them (Ülken, 1935, p. 330). Moreover, in his book Yirminci Asır Filozofları [Philosophers of the 20th Century], published in 1936, Ülken devoted an entire chapter to the “Philosophy of Physics” (Fizik Felsefesi), divided into three sections: Ernst Mach, Albert Einstein and Logical Empiricism.⁶⁴ Logistic or logical empiricism (“ampirizm logistik” or “mantikî ampirizm”) is presented as a unified European movement, not only limited to Vienna and Berlin but also present in Poland, Finland, Turkey, Sweden, and which had been received sympathetically in France, especially by the physicist Marcel Boll, the logician Louis Rougier and the philosopher Gaston Bachelard (Ülken, 1936, p. 322). Ülken emphasizes the role of international congresses and of the journal Erkenntnis in this international diffusion of logical empiricism. After this general presentation of the movement, Ülken introduces its different representatives: Moritz Schlick, Philipp Frank, and Hans Reichenbach, who is the subject of a more detailed examination. The section ends with a long piece devoted to two Cambridge professors: Arthur Eddington (1882–1944), who introduced Einstein’s theory of relativity to the English-speaking scientific community, and James Jeans (1877–1946).

Despite Reichenbach’s impact on the Department of Philosophy and his importance there, the interest in logical empiricism in Turkey gradually faded after his departure for Los Angeles. This situation can partly be explained by the circumstantial character of this reception, linked to Reichenbach’s efforts to make logical empiricism known in Turkey. However, and above all, the strong criticism of Reichenbach’s position, which was assimilated to a new positivism, should be seen as a major reason for it. This criticism was to take hold during the Second World War and especially in the IUDP.

6.2 Ziyaeddin Fahri Fındıkoğlu and his critique of Logical Empiricism as Neopositivism

Regardless of the efforts undertaken by Ülken to make logical empiricism known and to develop the philosophy of science in Turkey, logical empiricism was attacked and condemned as a “neo-positivism.” This can be seen in the activities of a lesser-known figure in the dissemination of logical empiricism in the 1930s in Turkey, that of the sociologist Ziyaeddin Fahri Fındıkoğlu (1901–1974). The example of Fındıkoğlu is interesting insofar as it attests also to the changing attitude towards Reichenbach and a shift in the reception of logical empiricism in Turkish Academia. Fındıkoğlu adopted increasingly critical, even hostile positions towards Reichenbach and his “doctrine.” After a stay in Berlin in 1936, Fındıkoğlu published, in a Turkish journal, a study on the University of Berlin Department of Philosophy, where he publicly attacked Reichenbach, calling him an impostor and presenting him as a stranger to philosophy before his departure from Germany. He claimed that Reichenbach was not a real philosopher and that his appointment in Istanbul was fraudulent, and only made possible due to prevailing ignorance in Turkey and with the support of “foreign specialists” who organized the reform and who also had “no clue” (Fındıkoğlu, 1936, pp. 368f., 447).

From 1934 Fındıkoğlu worked as an assistant of the sociologist Gerhard Kessler who was hired as Ordinarius Professor in the Department of Philosophy at the same time as Reichenbach. Fındıkoğlu did not work directly with Reichenbach, but showed at first a certain interest for Reichenbach’s ideas, translating for example a text on “neopositivism” from the already mentioned monography by Ernst von Aster (v. Aster, 1937). Moreover, Reichenbach and Fındıkoğlu both participated in international philosophy congresses, in Prague (1934) and in a following one in Paris—the Descartes Congress (1937). Between these congresses, Fındıkoğlu published a brochure entitled Felsefe Kongrelerinde Türkiye [Turkey at the Philosophy Congresses] to promote the creation of an official national delegation to represent Turkey at such congresses. He also actively campaigned for this in his own monthly journal of ethics and sociology İş (Action), calling for a more genuine Turkish participation.

This brochure brings together texts that show the evolution of his relationship with Reichenbach. At the beginning of this brochure, in a text written immediately after the Congress in Prague, Reichenbach was still praised as a brilliant representative of Istanbul University (Fındıkoğlu, 1937a, pp. 2, 6). But the Parisian Congress of Scientific Philosophy in 1935, where Reichenbach gave the opening speech on behalf of the Berlin Group, however, gave Fındıkoğlu the opportunity to express his disagreement with Reichenbach and his movement, through the translation of a pamphlet against logical positivism by the French metaphysician Louis Lavelle (Fındıkoğlu, 1937a, pp. 12–17). In this text, originally published in the newspaper Le Temps on 27 December 1936, Lavelle describes “the school of neo-positivism” as “nominalist scholasticism” and “intellectual asceticism.” He presents it as an attitude of distrust of thought and a limitation of the mind that, in his opinion, should renounce calling itself philosophy. On the basis of a similar caricatured understanding of the “neopositivism,” Fındıkoğlu continued to accuse Reichenbach, throughout the early 1940s, of having had a negative influence on the development of social sciences in Turkey (Fındıkoğlu, 1941, p. 156).

The 1937 Descartes Congress highlighted even deeper divergences between Reichenbach and Fındıkoğlu. In a proposal to the Descartes Congress, which was not accepted but published in the journal İş, Fındıkoğlu presents the Turkish reception of Descartes as proof that Turkey belongs in Europe, highlighting the prominent role of the “New Turkey” in the project of “Cartesianising the Muslim Oriental World” (Fındıkoğlu, 1937b, p. 86). In his journal, Fındıkoğlu also published a discourse by Mustafa Şekip Tunç as the representative of the IUDP, in which the later presents, in Bergsonian terms, the new Turkey as the inheritor of Descartes and his fight against the obscurantism of “centuries of mystical fatalism” (Şekip [Tunç], 1938, p. 7). In contrast to these nationalistic reappropriations of the figure of Descartes, Reichenbach’s contribution to the Descartes Congress with his paper “Scientific Philosophy” dealt with the fundamental difference between Cartesian epistemology and the empiricist views of the Berlin Group (Reichenbach, 1937a, p. 87), defending a probabilistic conception of knowledge. The model of scientific philosophy no longer implied the certainty of mathematical knowledge, as it was for Descartes, but rather the empirical knowledge of physics, which is necessarily uncertain because it is predictive.⁶⁵ It is on the same basis that in this paper Reichenbach opposed all apriorist philosophies—such as ontology, phenomenology and any philosophical system based on immediate intuition (Reichenbach, 1937a, p. 91).

Although it sheds light on the dissonance between Reichenbach and some of his colleagues at Istanbul University, his active participation in philosophy congresses introduces nuance to the idea of scientific isolation during his stay in Istanbul.⁶⁶ The reception of logical empiricism by Ülken and briefly by Fındıkoğlu may have had internal, institution-related causes resulting from Reichenbach’s position of authority at Istanbul University. In what follows, I show a more discrete but active reception of Reichenbach’s philosophy in the context of his teaching activities, which had an impact in the training of secondary school teachers and after the Second World War in the development of philosophy of science in Turkey.

7 Reichenbach’s teaching style and the work of his assistants and students at the IUDP

As an Ordinarius Professor of Logic and Systematic Philosophy between 1933 and 1938, Reichenbach played an important role in the reorganization of the Department of Philosophy. He lectured on the philosophy of science, symbolic logic and the history of philosophy, the latter at least for one year before Ernst von Aster’s appointment in 1936. Reichenbach also introduced a new method of teaching philosophy and undertook interdisciplinary research, seeking to build bridges between the Department of Philosophy and the various disciplines of the Faculty of Science. He not only sought to attract natural science students to philosophy (Irzik, 2011, p. 172), but in order for philosophy students to be provided with an overview of the natural sciences, he redesigned the philosophy curriculum. In a text recounting memories of her studies at the Department of Philosophy, Matilt Kamber wrote the following about the interdisciplinary teaching methods Reichenbach introduced at Istanbul University:

Philosophy belonged to the Faculty of Letters, yet Professor Reichenbach put philosophy into a unique position. Like regular science students, philosophy students had to attend classes in the Faculty of Science. To be more specific, they had to study two theoretical sciences and one experimental [science] each semester for four years. So they studied mathematics, biology, physics, medicine, chemistry, physiology, and genetics in addition to the different humanity courses such as literature, sociology, psychology, history, etc. (Kamber, 1978, pp. 37f.)

A quick overview of the graduation theses of Reichenbach’s students—most of whom were women—shows their ability to deal with philosophical issues of modern logic and empirical sciences. Among them, Feride Noyan⁶⁷ wrote her graduation thesis on The Problem of the Reality of Atoms (Atomların Şeniyeti Meselesi, 1937). In the text, she uses various course notes of the exiled professors—those of Reichenbach but also of von Aster and Alexander Rüstow⁶⁸—and refers to popular science books such as Reichenbach’s Atom and Cosmos (1930 for the first German edition), as well as to important works of physicists such as Niels Bohr, Charles Fabry and Jean Perrin.⁶⁹ Another student, Zehra Raif Akaç, based her graduation thesis “Logistic Objections against Logic” (Lojistiğin Lojiğe İtirazları, 1939) on the notes of Reichenbach’s logic courses and on Susan Stebbing’s book A Modern Introduction to Logic (Stebbing, 1930). Zehra Raif’s name appears in the list of assistants in the Department of Philosophy for the year 1937/1938 (Edebiyat Fakültesi 1937–1938 Ders Yılı Talebe Kılavuzu, p. 70), but her work was completed after Reichenbach’s departure and was therefore evaluated by Ernst von Aster and Mazhar Şevket İpşir[oğlu].

Following their graduation, two of Reichenbach’s students spent their careers split between the United States and the Robert College for Girls in Istanbul: Neyire Adil Arda (Baysal) and the aforementioned Matilt Kamber.

Neyire Adil Arda (1914–1999) received her education at the American College for Girls in 1931⁷⁰ and studied philosophy and psychology at Istanbul University. She began her studies before the reform, continuing afterwards with great interest in the courses delivered by Mustafa Şekip Tunç and İsmayıl Hakkı Baltacıoğlu (1886–1978); she also spoke of Orhan Sâdeddin as “a good professor” (Kaynardağ, 1999, p. 21). The reform of 1933 permitted her to study, in addition to one’s main discipline, two other disciplines in another faculty. Following the advice of Tunç,⁷¹ Neyire Adil Arda oriented her studies towards Reichenbach’s philosophical courses. As a secondary subject, she chose mathematics, as taught by Richard von Mises and Kerim Erim. She also attended psychiatry courses given by Mazhar Osman and Hans Winterstein (Kaynardağ, 1999, p. 22). She also mentioned that she was close to the chemist Fritz Arndt, who lived like her in Bebek and with whom she took the boat to go to the university (Kaynardağ, 1999, p. 26).

These choices reflect the interests of Reichenbach and his circle; the intellectual profile of Neyire Adil Arda, of all of Reichenbach’s students, best corresponded to the work undertaken in the program of scientific philosophy. Her graduation thesis was “The Problem of Induction” (İstikra Problemi, 1935), for which she received a result equivalent to an A (“pek iyi,” very good) from Reichenbach himself. This nearly 40-page study discusses the works of English scholars such as the Oxonian sinologist Homer H. Dubs, Rational Induction: An Analysis of the Method of Science and Philosophy (Oxford 1930) and the economist John Maynard Keynes, American philosophers of sciences such as Ernest Nagel and Charles Sanders Peirce, Alfred Whitehead’s book Process and Reality (1929) and the views of Hans Reichenbach on his probability theory as discussed in his paper “The logical foundations of the concept of probability” (Reichenbach, 1933). The latter paper, as mentioned, had been translated into Turkish by Nusret Hızır and published in Felsefe Yıllığı (Reichenbach, 1935b). Neyire Arda officially became Reichenbach’s assistant and worked as his interpreter during his classes. In the preface of his book Experience and Prediction, Reichenbach thanked her in person: “I welcome the opportunity to express my warmest thanks to friends and students here in Istanbul and […] especially to my assistant, Miss Neyire Adil-Arda, without whose constant support I should have found it very much harder to formulate my views.” (Reichenbach, 1938a, p. v). It is therefore highly plausible that some of her activities were related to the preparation of this book, although more research is needed to better clarify the nature and extent of Arda’s activity.

After her graduation, Neyire Adil Arda attended Harvard University with the aim of writing a doctoral thesis on the notion of “problem”⁷² under the supervision of Clarence Irving Lewis (Kaynardağ, 1999, pp. 24f.). She spent two years at Radcliffe College (1936–1937) and one year at the University of California, Los Angeles (UCLA), preparing her doctoral thesis.⁷³ According to Paul Wienpahl’s notes on Reichenbach, the arrival of Neyire Adil Arda at the Department of Philosophy at UCLA coincided with that of Reichenbach.⁷⁴ After spending one year in Los Angeles, Neyire Adil Arda was called back to Istanbul University (ACG Alumni Bulletin, 1960, p. 55) in 1939. University records indicate that upon her return to Turkey, she taught sociology and statistics applied to the social sciences as Ülken’s assistant. In her own words, she decided to return to Turkey because of the war and left her books, notes and photos related to Reichenbach in the United States (Kaynardağ, 1999, p. 25). She continued to work as an assistant in the Department of Philosophy and Ernst von Aster accepted supervising her doctoral thesis, which she had begun in the United States, and which remained unfinished. Unhappy that Adil Arda spent much more time on her doctoral research than her teaching duties, Ülken reported her to the administration, calling her work irregular (devamsız). This greatly upset her and led to her to resign after von Aster’s death in 1948 (Kaynardağ, 1999, p. 25). After serving as an assistant of philosophy from 1939 to 1949 at Istanbul University, she married the architect Halûk Baysal (1918–2002) and in 1960 it was reported that “since 1949 she has done social work and been a housewife” (ACG Alumni Bulletin, p. 58). That same year, she was appointed as the Turkish Vice-President of the Robert College for Girls in Istanbul, Arnavutköy, where she also worked as an instructor of logic until 1972.⁷⁵

Matilt Kamber completed her graduation thesis on “The Mathematical Concepts in Locke and Hume” (Hume ve Locke’ta Riyazî Mefhumlar) in 1936. Her work was approved by Reichenbach as well as by Tunç and Halil Vehbi Eralp (1907–1994), who was the assistant at the Chair of History of Philosophy from 1933. In addition to the use of Reichenbach’s courses notes in her study, all the literature cited was related to an American school of psychology initiated by William James (1842–1910).⁷⁶ Kamber worked as a philosophy teacher at the American College for Girls in Istanbul (The Record, 1966) and went to California where she had relatives.⁷⁷ In the 1970s, she worked as a philosophy and logic instructor at Columbia College (Lopeman & Ogle, 1982).

Only two of Reichenbach’s students were able to continue their academic career in Turkey, although outside IUDP. Nusret Şükrü Hızıroğlu, better known as Nusret Hızır (1899–1980), began work as Reichenbach’s assistant and translator due to his knowledge of German. He had previously studied physics in Germany and afterwards wrote a graduation thesis approved in 1939 by Ernst von Aster on The Classification of Sciences (İlimleri Tasnifi Hakkında) that contained a section about Reichenbach’s views on this topic. Among his sources, Hızır used the Systematische Wörterbuch der Philosophie [Systematic Dictionary of Philosophy] by Karl Wilhelm Clauberg and Walter Dubislav (Clauberg & Dubislav, 1923), as well as Paul Oppenheim’s works on the classification of sciences and on the formation of scientific concepts (Oppenheim, 1926, 1928). It was only after the Second World War that Hızır was able to become a philosophy professor at Ankara University.

The other student, Nezahat Nazmi Tanç, better known by her married name, Nezahat Arkun, was able to pursue an academic career at Istanbul University, but in the Department of Psychology. Her graduation thesis “Logical Behaviorism according to Carnap and Reichenbach” (Mantıkî Behaviorism’in Carnap ve Reichenbach’a Göre Tefsiri) was published in the only issued volume of the journal of the Istanbul philosophy seminar (Arkun [Tanç], 1939). The issue had been prepared by Reichenbach but was published only after his departure and edited by Eralp (Roure, 2020a, pp. 350f.). In 1948, Arkun completed her doctoral thesis, “Statistical Study on Suicide in Istanbul” (İstanbul’daki İntiharlar Üzerine İstatistiki bir Araştırma), under the supervision of Wilhelm Peters (Toğrol, 1972, pp. 61f.). In 1968, she became a professor of psychology at Istanbul University, where she mainly pursued studies in social psychology, using statistical methods (Arkun, 1963, 1965).

8 The IUDP after Reichenbach’s departure and the development of philosophy of science in Turkey

Despite the importance of Reichenbach’s influence on his students, we can only note that none of his students, not even the most outstanding among them, pursued an academic carrier within the IUDP. The difficulties faced by Reichenbach’s students may partially be explained by the fact that they did not hold a PhD, a qualification that did not yet exist in the Faculty of Letters during Reichenbach’s stay. The requirement that those pursuing an academic career at the Department of Philosophy held a PhD was introduced at the Faculty of Letters in 1937. This administrative change favored the recruitment of Turkish students trained in Germany, where it was possible for them to obtain a PhD (Roure, 2018, p. 44, Roure 2022b, pp. 152, 163f.), to the detriment of the students trained by Reichenbach, who were only holders of a bachelor’s degree. Moreover, students who had studied abroad in the 1930s were again favored over those who had only studied in Turkey by the condition that doctoral students needed to have mastered a foreign language (French, German or English).

This might however not be the only explanation. Reichenbach’s departure for the United States had many consequences, one of which being that he was no longer in a position to support his own students. More importantly, the situation in the IUDP changed profoundly despite von Aster’s expressed willingness to continue the interdisciplinary work undertaken by Reichenbach (v. Aster, 1939, p. 6). This change was obvious for his contemporaries, as shown by Kamber’s complaint about the end of a “Golden Age of the university”: “Unfortunately, this ideal situation did not last for long, for as soon as Professor Reichenbach moved to the United States, the Department of Philosophy reverted to the old system without any interdisciplinary activity” (Kamber, 1978, pp. 38f.).

Reichenbach’s departure was indeed followed by a wider change of perspective within IUDP. His role there was strongly downplayed, especially among a new generation of PhD graduates trained in Nazi Germany, appointed as professors in the Department of Philosophy from 1939 onwards. After Reichenbach’s departure in 1938 and exacerbated after Ernst von Aster’s death in 1948, the Department of Philosophy, under the leadership of Takiyettin Mengüşoğlu (1905–1984), saw the development of philosophical currents that were openly hostile to logical empiricism and in particular to Hans Reichenbach. Reichenbach had been the target of personal attacks, for example in the doctoral thesis of Mengüşoğlu (Roure, 2021, p. 167). This work, supervised by Nicolai Hartmann⁷⁸ and published in Berlin in 1937, begins with a personal attack against Reichenbach caricatured as “the positivist” (Temuralp [Mengüşoğlu], 1937, pp. 2, 4f.).

Mengüşoğlu was only successfully accepted into the Department of Philosophy after Reichenbach’s departure. There, he worked actively to widely disseminate contemporary strains of German ontology and philosophical anthropology. His efforts to have his former professor Nicolai Hartmann appointed to the chair left vacant by Reichenbach are documented in his correspondence. In the end, Mengüşoğlu was able to arrange for the appointment of Heinz Heimsoeth (1886–1975)—a philosopher and metaphysician close to Hartmann—who occupied this chair from 1950.⁷⁹ In the 1950s, ontology and philosophical anthropology became dominant in this department and almost hegemonic in defining its particular conception of philosophy and modernity.

The hostility towards logical empiricism contributed to the development of a historiographical legend, according to which Reichenbach’s philosophy was largely inaccessible to his audience because of its highly technical nature. Such remarks are actually linked to a willingness to discredit Reichenbach in the field of philosophy, by assimilating him to a physicist or a mathematician. Statements expressing such difficulty or over-technicality of Reichenbach’s thinking essentially came from philosophers who were openly hostile to logical empiricism and who didn’t work with Reichenbach, with the exception of Reichenbach’s assistant Macit Gökberk (1908–1993).

Gökberk, who worked as an assistant at the Philosophical Seminar at the time of the Turkish university reform, disliked being assigned as Reichenbach’s assistant from the very beginning (Berkes, 2014, p. 103). He expressed the difficulties he faced in understanding Reichenbach’s philosophy,⁸⁰ which he was supposed to translate. In 1935 Gökberk decided to continue his studies abroad and went to Berlin, which he later explained was based on a desire to improve his German and to prepare a doctoral thesis while taking advantage of lectures by Nicolai Hartmann and Eduard Spranger there (Kaynardağ, 1986a, pp. 24f.).⁸¹ But Gökberk’s is an isolated case however, and the significant collaborative work between Reichenbach and his students, assistants and translators suggest we should contextualize statements on the difficulty and inadequacy of Reichenbach’s teaching.

In contrast, several students and assistants who attended Reichenbach’s lessons praised the innovative character of his teaching style compared to the memorization-based and top-down, frontal and passive teaching traditions common at the time. Kamber described students’ enthusiasm for Reichenbach’s classes: “I cannot find [the] words to describe how much we enjoyed these classes and how much of his philosophy was imparted to us in a very simple and lucid manner.” Halil Vebhi Eralp, who was from 1933 onwards an assistant at the Chair of History of Philosophy and translated several writings of Reichenbach,⁸² also mentions the vivacity of the seminars and lectures given by Reichenbach and the originality of his concepts. Many students from Istanbul, as well as from Berlin and later the United States, spoke to the fact that Reichenbach was a “virtuoso pedagogue” (in Nusret Hızır’s words), respectful of his students and accessible, always seeking to develop dialogue on an equal footing (see Hempel, 1991, pp. 5f.). Neyire Adil Arda noted that

Prof. Reichenbach was a teacher like we had never seen before. His classes were both lively and simple. I sometimes translated his logic lessons. His English was very good and he also had a fairly good knowledge of French. He held the students in high esteem, never put them down, he always wanted to engage in dialogue. He considered the students as colleagues and addressed them saying: “Kollege, what do you think about this?” […] Reichenbach wanted the students to always be “active,” he asked them questions and expected them to do the same. However, I remember that many students were taking notes. I couldn’t do that because I was translating most of the time. I only managed to take a few small notes. (Kaynardağ, 1999, pp. 22f.)

Encouraging interdisciplinary and scientific work,⁸³ he also developed multilingual and participatory teaching methods in which translation had a central role (Roure, 2022b, pp. 153f.). Reichenbach took the work of his assistants very seriously and made himself available as needed to prepare the interpretation with them in advance⁸⁴ to facilitate better communication with the students, even more so as he used to speak freely without notes. Based on his knowledge of Turkish and because of the attention he paid to his audience, he was also able to check the accuracy of the translations.⁸⁵ Kamber gives some indications on Reichenbach’s pragmatic approach to the different languages known to his students and on his own method of learning foreign languages.⁸⁶

What can be seen as a defeat for Reichenbach’s work within the Department of Philosophy was counterbalanced by the activity of his students, mainly in connection with the development of the social sciences but also modern logic and philosophy of sciences. The teaching activities of Reichenbach’s students in high schools as well as in universities should be considered not as a doctrinal allegiance to Reichenbach but much rather as different contributions to develop his conception of scientific philosophy.

In the field of experimental psychology, the work of Nezahat Arkun and of Mümtaz Turhan, who had contributed to Felsefe Yıllığı II, participated in the dissemination of behaviorism, psychoanalysis and Gestalt psychology in Turkey. They were able to pursue an academic career at the Department of Psychology at Istanbul University, which was established in the continuation of the efforts of Reichenbach and Peters. Also, the flourishing development of modern logic and philosophy of sciences in Ankara from the 1960s relates to Reichenbach’s legacy. His student and assistant Nusret Hızır, who is considered to be Reichenbach’s principal disciple in Turkey (Örs, 2006, pp. 198–201), was able to continue his academic career in philosophy after the Second World War at Ankara University and become an active member of the Philosophy Society of Turkey. Hilmi Ziya Ülken, who had been the main mediator of logical empiricism in the 1930s Turkey and published in 1942 his book Mantık Tarihi [History of logic], also left the IUDP after 1960 to join the University of Ankara, where he wrote a book on philosophy of science entitled İlim Felsefesi I (Ülken, 1968) in which the ideas of Reichenbach and logical empiricism in general were given an important place in a history of ideas perspective. In a chapter devoted to the pluri-valent logic (birçok değeri mantık) of his Felsefeye Giriş [Introduction to Philosophy], also published in Ankara, Ülken mentions the work of Reichenbach, Carnap and the Polish School in developing probability logic (Ülken, 1963, pp. 122f.). It is also in Ankara, at the Middle East Technical University (Ortadoğu Teknik Üniversitesi), that a specific program of philosophy of science and symbolic logic was set up in the 1960s by Teo Grünberg (born in 1927) and Hüseyin Batuhan (1921–2003) (Irzık & Güzeldere 2006, p. 3). The latter had been a student and an assistant of Ernst von Aster and expressed his disappointment with the philosophical orientation of the IUDP after von Aster’s death (Roure, 2022b, pp. 167f.). His wife Turan Pamuk, whom he met in the 1940s, had studied philosophy with Reichenbach (Batuhan, 2002, p. 24).

After 1960 and in connection with the influence of the American academic model in Turkey, the philosophy of science and analytic philosophy, in accordance with Reichenbach’s program of a “scientific philosophy,” found in Ankara a favorable institutional framework for its development (Kafadar, 2000b, p. 429).⁸⁷ On the contrary, after the death of Ernst von Aster in 1948 and until the 1960s, the IUDP remained dominated by philosophical currents such as ontology and philosophical anthropology.⁸⁸

9 Conclusion

The interaction of Reichenbach with his assistants and students as well as the work the latter produced are particularly significant in order to understand the fruitful nature of his stay in Istanbul.⁸⁹ Contrary to the general perception, this stay was not a somewhat sterile period of solitude but a particularly active and productive one. It prolonged the Berlin Group’s activities, enriched through the experience of multilingualism and the challenge of translation. It was during this stay that Reichenbach developed and matured, in constant interaction with his assistants and students, his theories of meaning and knowledge which are found in Experience and Prediction. Considering the context of the elaboration and dissemination of Reichenbach’s epistemological reflections in the 1930s is therefore necessary for a new and more complete reading of his work. Reichenbach’s interest in the Turkish grammar he was studying at the time, as evidenced by several passages of Experience and Prediction and later works,⁹⁰ as well as his determination to distance himself from the label of positivism in the context of the French and Turkish reception of logical empiricism in the 1930s, are indeed elements that have been neglected until now but deserve further research. Reichenbach’s critique of positivism disappeared completely from the later work and is not reflected in the American reception.

The relatively limited impact of Reichenbach’s output in Turkey, where he stayed much less time than in the United States, can be partly explained by the administrative difficulties,⁹¹ and the hostility he encountered among some of his colleagues. Furthermore, the United States prior to the second War not only offered more favorable working conditions, but above all a greater security regarding the political situation compared to Turkey and other countries in Europe. The precarious status of emigrants in Turkey grew over the years and under the effect of the national socialist propaganda in Istanbul; it therefore led to the necessity of finding an alternative. Reichenbach’s correspondence shows that he had been preparing his departure since 1936, and was hoping to emigrate to the United States, where he had many supports.⁹² Charles W. Morris (1901–1979), who helped Reichenbach obtain a position in the United States, asserted at the Prague Congress in 1934 that American pragmatism and “logical positivism” are complementary and pleaded for a closer cooperation between these two aspects of “modern empiricism” (Morris, 1936, p. 130). The international congresses Reichenbach participated in during his stay in Istanbul allowed him to build a network and to organize the transatlantic emigration of himself and some of his colleagues and students. In a letter dated 27.03.1938 addressed to Freundlich (see above, n. 50), Reichenbach expressed his happiness at the prospect not only of leaving Turkey, but “the European soil.”

The war was the main reason for which Reichenbach was not able to help further his students left in Turkey. His stay in Istanbul was not long enough for him to supervise doctoral theses. It is only in 1937 that this degree was effectively introduced at the Faculty of Letters of Istanbul University and the students trained prior to this date were destined to become teachers in high schools, according to the French educational model that was still largely dominant in Turkey, even after 1933 (Roure, 2022b, p. 141). Reichenbach, who deplored in several letters the insufficient character of the school education in Turkey, actively promoted the training of high school teachers at that time, which he saw as a prerequisite for the development of a quality academic and scientific culture. From the point of view of scientific policy and institutional forms of philosophy, Reichenbach contributed also to the transformation of educational practices. He involved the students in his own research activities, inaugurating therefore a teacher-student relation which had never happened before in Turkey in the field of philosophy. He also encouraged some of his students—especially two women, Neyire Adil-Arda and Nezahat Arkun [Tanç]—to continue their studies toward a doctorate degree. From an administrative and pedagogical point of view, Reichenbach had also the opportunity, by influencing the recruitment policy, to reorganize the IUDP and orient it towards more interdisciplinary and multilingual teachings. At the same time, he contributed to the development of quantitative methods in the social sciences and to the institutionalization of experimental psychology there, and more generally to the development of the philosophy of science and modern logic in Turkey—although for mostly political reasons evoked above, this development could not be realized in a university setting until after the war and especially from the 1960s. The influence of the American university, which was developing at that time in the field of university philosophy, can thus be read as a reactivation and transformation of a forgotten heritage.