Karel Reach was the last to leave Prague. He had lived there his entire life. He defended his dissertation (“On General Semantics”) at the city's German University in 1933.Footnote 1 By the end of the decade, his entire committee had left the country. The logician Rudolf Carnap, Reach's advisor, had been a new arrival in the Czechoslovak capital. He was also the first to go. While meeting with Reach as often as twice a week, Carnap interspersed poorly attended seminars on set theory with teaching himself English and applying for Rockefeller Foundation grants.Footnote 2 Colleagues at the University of Chicago helped him get a position there; he moved to the United States at the end of 1935. Philipp Frank, the second member of Reach's dissertation committee, had moved to Prague in 1912 to take the chair in theoretical physics previously held by Albert Einstein. Like Carnap, Frank spent the mid-1930s learning English.Footnote 3 In the summer of 1938, he traveled from Prague to Girton College, Cambridge to attend the fourth International Congress for the Unity of Science. The plan was to use England as a departure point for a lecture tour in the United States. He and his wife Hania were on a transatlantic steamer when Germany annexed the Sudetenland.Footnote 4 Frank had told a colleague that he would be back in Prague by Christmas; the trip turned into a permanent move.Footnote 5 Leo Wenzel Pollak, the third and final member of Reach's dissertation committee, fled to Dublin in March 1939, as Germany was annexing Bohemia and Moravia.Footnote 6 Pollak had a marginally less perilous experience than Oskar Kraus, Reach's habilitation advisor, whom the Germans arrested after they took possession of Prague. Released after six weeks, the elderly Kraus escaped to England.Footnote 7 Reach hoped to follow him.
Intellectual historians and historians of science have given the group of highly educated individuals who fled fascism a variety of designations (refugee academics, émigré intellectuals, scientists-in-exile). For most academics, getting out meant getting hired. This article is about the interpersonal and academic infrastructures that scholars used to coordinate their escapes from Central Europe. It is also about the ways in which those infrastructures failed.
Rank-and-file academics, the focus of this article, fell somewhere in between “the little people” of social history and the big names of intellectual history (émigrés who made it out).Footnote 8 I illuminate this mid-level group by focusing on the Unity of Science movement during the rise of fascism. For our purposes, the movement was an interpersonal network built and maintained by Otto Neurath, a Viennese economist, philosopher, and visual education expert.Footnote 9 I call members of the network “unifiers” (not a term that they used) to provide a collective noun that does not rely on their disciplinary affiliations, geographical locations, or other social positions.
As explained below, some—but not all—of the people I discuss belonged to the Vienna Circle, and some—but not all—were logical empiricists. This article is not a history of logical empiricism, the Vienna Circle, or even the Unity of Science movement, but it does complement existing narrative syntheses on those topics, some of which take a more sympathetic approach than others.Footnote 10 What an author thinks about logical empiricism tends to color what they have to say about its practitioners.Footnote 11 I concentrate on unpublished sources, like personal letters, that figure less prominently in other accounts.Footnote 12 Such sources allow me to reconstruct how members of the movement interacted with each other, a behind-the-scenes approach that moves beyond what now-famous scholars wrote in their programmatic texts.
By focusing on the actions of the unifiers from roughly 1930 until the end of the Second World War, this article provides a fuller, more accurate picture of academic production in the midst of widespread emigration.Footnote 13 As a label, “émigré scholar” can only be employed after the fact, and it is not clear that those to whom it was granted had more in common than those who missed its touch. Initial waves of emigrants settled in France, Belgium, the Netherlands, Czechoslovakia, and the Baltic states, only to find themselves facing the prospect of a second emigration, this time with less money, stricter border controls, and stiffer competition for fewer academic positions. Lingering in Central Europe, and not jumping immediately to successful resettlement in the United States or United Kingdom, illuminates the changing material conditions that shaped interwar scholarship.
Historiography has separated “the exodus of scientific reason” from the researchers and academics who were murdered in the Holocaust.Footnote 14 The “exodus” narrative is easier to tell. Its protagonists have recognizable names, and their work changed nearly every aspect of postwar intellectual life.Footnote 15 Certain aspects of that narrative make it attractive: the savior role of the United States and the United Kingdom; the irrationality of fascist states driving away their best and brightest; and émigrés’ depth and variety of talent as a satisfying rejoinder to antisemitism.Footnote 16 The narrative is also easy to access and reproduce. Successful émigrés were more likely to have intact archives. Many lived long enough to see their experiences become a historical phenomenon, and more than a few provided blueprints for others to interpret their past.Footnote 17
Those attractive aspects have shadows. Émigré scholars were exceptional cases: the number of successful escapes was a fraction of a fraction of the total number of people murdered in the Holocaust.Footnote 18 The deaths of the “unexceptional” were not less of a tragedy. Allowing the highly educated to remain in the Reich would not have made persecution and extermination rational. The desire to tell and re-tell the émigré story has filtered successful escapees away from Holocaust historiography, occluding that emigration and death were two sides of the same coin.
The first section of this article shows how academics under pressure paid careful attention to routine scholarly activities like editing journals and planning conferences. They knew that communication and self-presentation mattered, and we cannot fully understand their publications without that context in mind. To circulate their ideas, they typed on sheets of paper and mailed those sheets: everything from intergovernmental agreements, stationery shops, and access to a letterbox underpinned their scholarship.Footnote 19 The second section of the article shows how the unifiers tried to cope with escalating political oppression and violence. During the 1930s and throughout the war, countries censored mail, closed borders, and confined thousands of people.Footnote 20 How individuals experienced those years depended on their place of birth, job, political affiliation, and whether someone in power thought they were Aryan. Those who most needed to get their names in front of senior colleagues were least able to do so. Mass firings only worsened the position of already-disadvantaged researchers.
Over the course of the 1930s, the rise of fascism forced academics to transition from promoting themselves to preserving their lives. The two activities overlapped: in a world of closed borders, would-be emigrants had to make themselves attractive to potential host countries. In practice, that meant showing you had a job waiting for you. Senior academics tended to have international connections (friends in high places) who could help.Footnote 21 The unifiers had built networks to establish their movement, and the article concludes by showing how they leveraged those networks to secure their safety. For any given person, that leverage went both ways: “up” toward contacts in target countries and “down” toward people left behind, many of whom were also trying to emigrate. Relative positions changed over time. People relocated. The geopolitical landscape also shifted around them.
Like academic work, emigration was a social and material process. It required exchanging information and coordinating action across distances. Professional inequalities predated the need to emigrate; new political pressures worsened existing hierarchies. Retrospectively, emigration helps us see a dynamic present both in the unifiers’ project and the interwar academic landscape writ large. Professional advancement relied on a collective, but its fruits went to individuals. The labor of many facilitated the success of the few, and linked chains of interpersonal judgment determined who counted as successful. At every point, would-be émigrés needed to balance the individual process of emigration—selling oneself as unique, the best possible candidate—with the reality of their reliance on each other.
A Very Powerful Movement
According to Otto Neurath, unified science needed a movement.Footnote 22 “Movement” was his term for the group he was perpetually attempting to build. In the 1930s, the Unity of Science movement teetered on the edge of the established sciences, never codified membership criteria, and had no way to measure its success. Its affiliates—however defined—disagreed on methodological and epistemic questions, although they generally stressed the importance of empirical observations and the rigor of modern symbolic logic. They earned doctorates in a range of subjects, lived in several countries, practiced various occupations, and belonged to different generations. They shared no single university, lab, or object of study. They did not exchange specimens or equipment.Footnote 23 Their insecure sociopolitical position made them especially reliant upon each other, and their geographical spread has left a rich archive of correspondence documenting their attempts to establish their movement and, later, to emigrate.
Unified science did not mandate one philosophical position.Footnote 24 Instead, Neurath claimed that a shared storehouse of terms would facilitate work within and between disciplines. He told social scientists that they needed “to join meteorological, ethnological, biological, and chemical arguments.”Footnote 25 The goal was “a language which enables them to speak of animals, plants, and crystals in the same way, as far as possible, without anticipatively creating distinctions”; in short, “a lingua franca of unified science.”Footnote 26 This was the power of rejecting metaphysics (things beyond language) and embracing language-as-convention: people who accepted the right definitions became nodes in an intersubjective network of knowledge verification.
The prolific writers among the unifiers, including Neurath and Carnap, had no shortage of things to say about what science was and was not. Philosophers and intellectual historians have produced a rich body of scholarship on the nuances of their work.Footnote 27 In this section, I do not explicate the unifiers’ philosophical positions on various topics, choosing instead to focus on the nuts-and-bolts practices of scholarship. Highlighting what people did, and not just what they said, shows commonalities among the experiences of interwar academics: both those who faced persecution and those who did not.
Once Neurath decided on the need for a movement, he enlisted people whom he knew personally in two connected projects. First, they wrote, solicited, and promoted a raft of publications, including the journal Erkenntnis and the never-completed International Encyclopedia of Unified Science.Footnote 28 Second, they held six international congresses in Europe and, later, the United States. They published the congress proceedings in the journals that they edited; the journals also carried advertisements and registration information for the congresses. Both served as recruitment tools. Even defined narrowly, the group of organizers and editors behind the projects fluctuated between eight and twelve people.
Neurath's movement spanned several existing networks. One cluster of participants originated in the Berlin Society for Empirical Philosophy.Footnote 29 Another came from the former Habsburg Empire, with representatives in and around the German University in Prague and the University of Vienna. The latter city's Ernst Mach Society paralleled the Berlin Society.Footnote 30 Society members and guests delivered public lectures that encouraged logical thinking and the testing of received truths. Neither society had a university affiliation, but professors of mathematics, physics, and philosophy populated their ranks. Other members, most of whom had doctoral degrees, worked in adjacent professions like secondary school teaching and librarianship.Footnote 31 Neurath, for example, was the founding director of the Social and Economic Museum in Vienna, where he and his coworkers invented Isotype, a method of visual education meant to reach the city's working underclasses.Footnote 32
Neurath and other leaders of the Ernst Mach Society also participated in an invitation-only discussion group that addressed epistemological questions. In 1929, Neurath, the logician Rudolf Carnap, and the mathematician Hans Hahn published a manifesto declaring their group the Vienna Circle (there were in fact many circles active in the city).Footnote 33 Neurath, Carnap, and Hahn presented the document at the Prague Conference for the Epistemology of the Exact Sciences, a meeting which was co-sponsored by the Ernst Mach Society and the Berlin Society for Empirical Philosophy.Footnote 34 They scheduled the conference to coincide with the Congress of German Physicists and Mathematicians to allow spillover from the latter to the former. The authors subsequently reprinted part of the manifesto as a handbill and distributed it to audiences at the Ernst Mach Society's lectures.Footnote 35 The claim of being the Vienna Circle, the manifesto, and the conference debut were exercises in branding, and lasting ones at that.Footnote 36 Ten years later, Neurath still reveled in the name's staying power. As he saw it, “the Vienna Circle” had been so effective because it was underspecified: anyone could read into it what they wanted.Footnote 37
The unifiers wanted something more sustained than a one-off manifesto. Luckily, they got an opportunity to pick up a preexisting journal—complete with its list of subscribers. Founded after the Great War, the Annalen der Philosophie had barely weathered the tumultuous 1920s.Footnote 38 Felix Meiner, its publisher, specialized in philosophy and traveled from Leipzig to philosophical conferences as part of his work. In 1929, he attended the Prague conference at which the self-named Vienna Circle presented their manifesto. Meiner, Carnap, and the Berlin-based philosopher Hans Reichenbach began to negotiate a takeover of the Annalen, which they renamed Erkenntnis. For the first four years of the new journal's life, the Ernst Mach Society (represented by Carnap) and the Berlin Society (represented by Reichenbach) sponsored the journal, with due credit awarded on the masthead. Neurath frequently weighed in. Despite holding no official position, he pitched editorial cooperation as a form of teamwork.Footnote 39 Helped by a price affordable to individuals, Erkenntnis got 400 subscribers and financial viability.Footnote 40
Running a journal meant control over what appeared in its pages. Max Horkheimer led the Frankfurt-founded, Marxism-inflected Institute for Social Research, and he had moved both himself and his Institute to New York after the Nazis began to fire and persecute its members.Footnote 41 Finding fascist tendencies in logical empiricism, Horkheimer published a strident attack against the movement and its pretensions to unified science.Footnote 42 He edited the Institute's journal, and he placed his attack in its pages. Neurath, who thought the Institute and the Unity of Science movement could cooperate, drafted a conciliatory response and sent his manuscript to Horkheimer. Neurath could have published in Erkenntnis, but his letters to Horkheimer indicate that he did not want to preach to the choir.Footnote 43 Readers unfamiliar with anything but the attack needed to see the defense. In the academic equivalent of a pocket veto, Horkheimer sat on the manuscript for long enough that Neurath asked for it back.Footnote 44
Neurath used the unifiers’ publications to tap into other interpersonal networks. In the summer of 1934, he began to plan the first International Congress for the Unity of Science. Given the symbolic power of international conferences in both science and politics (not to mention their role in the overlap between the two), staging a congress instantiated the movement's legitimacy.Footnote 45 Neurath's first step was to ask people he already knew to pass along recommendations. He then wrote to dozens of possible candidates, referencing their mutual acquaintance(s) as a bulwark to his credibility and enclosing copies of Erkenntnis articles he thought they would find interesting.
Through this method, Neurath struck up a correspondence with L. Susan Stebbing, a professor of philosophy at Bedford College in London.Footnote 46 In his first letter to her, Neurath claimed that her name had come up alongside those of Rudolf Carnap and Philipp Frank as possible congress participants.Footnote 47 Frank was a professor of physics in Prague; like Carnap, he had been friends with Neurath for years, and all three had discussed Neurath's conference plans extensively. Neurath's invitation suggested a more professional relationship between the men, lending legitimacy to their plans by implying that the conference had already garnered the international interest of prestigious professors—like Stebbing.
Neurath invited Stebbing to both the congress and to a special pre-congress planning meeting. The Erkenntnis articles came later; she parried by apologizing for being too busy to read them.Footnote 48 She did, however, attend the Paris conference, and she became something like the British forward base for the movement. A few years later, she invested considerable time and effort in co-organizing the 1938 Cambridge congress, including making all the arrangements with Girton College, its host institution.
In planning for the first Paris congress, Neurath also contacted the Polish logician Alfred Tarski, who had attended a few Vienna Circle meetings. Neurath hoped he could build a bridge from the movement to Tarski's Warsaw-based academic network. Tarski complied, proffering the logician Janina Hosiasson as one possible congress invitee “from our Circle.”Footnote 49 Hosiasson accepted invitations to participate in Unity of Science activities, but she later frustrated Neurath by submitting contributions late and publishing in journals other than Erkenntnis, a behavior he appealed to Tarski to correct (or, at least, to ensure that she submitted a substitute article to Erkenntnis as recompense).Footnote 50
The Paris congress “fulfilled its purpose to show logical empiricism as a powerful movement.”Footnote 51 Or at least, Neurath reported as much in 1936, when talking up the next International Congress for the Unity of Science. Niels Bohr, the Nobel Prize-winning physicist, hosted the congress in Copenhagen.Footnote 52 Bohr's cooperation was the equivalent of a celebrity endorsement, and Neurath milked the connection by enlisting Bohr to contribute to the first issue of the encyclopedia.Footnote 53 Neurath also sent him some Erkenntnis articles. Bohr felt he did not have enough time to write a proper entry, but when pressed, he submitted a little less than a page of text.Footnote 54 Compared to the chapter-length submissions from less famous contributors, his stood out. Bertrand Russell provided a similarly skimpy three pages.Footnote 55 Stebbing wryly commented that the two entries must have been included “to indicate the goodwill of these distinguished thinkers” because they served “no other purpose.”Footnote 56
Neurath repeatedly stressed the need for propaganda. He knew that his allies did not always appreciate his efforts. Even though the word meant something similar to “advertising,” but with political rather than commercial undertones, that did not necessarily make it more palatable to academics unaccustomed to stumping for power.Footnote 57 Some participants in the movement complained about Neurath's (self) promotion. In 1937, Neurath tried to coax a reluctant Reichenbach to that year's meeting with the promise that, unlike the previous two congresses, it was not for “propaganda”; the editorial committee would use the smaller conference to settle practical questions about the encyclopedia.Footnote 58
Neurath had a point: propaganda generated interest. Publicity-minded, he subscribed to several news clipping services, and the 1937 International Philosophy Conference was a large enough event (800 people) that a few attendees wrote accounts for mainstream papers. Although the movement's presence was modest—one panel with five speakers—several of the reports commented on it. Some praised Carnap, but Neurath, whom unnamed sources called “the propaganda boss of the Vienna Circle,” got the most lines of text.Footnote 59
Similarly, the science section of the popular American weekly magazine Time covered the encyclopedia's 1938 debut (with praise for its “editor-in-chief … the hulking, booming Otto Neurath, who gives the impression of oozing vitality from every pore”).Footnote 60 The following fall, the 1939 congress hosted at Harvard also garnered a few lines. The article remarked on Dr. Neurath's plan to “overstep a Tower of Babel” by “developing a common grammar of science—a unified manner of scientific exposition—so that one savant can understand another if he looks up unfamiliar words.”Footnote 61
That said, interest did not always yield support. Most of the clippings from the Paris philosophy conference panned the Unity of Science movement. The “Varieté Neurath” might have been entertaining, but the “reduction of philosophy” to the Unity of Science through “the sum of trivialities” was “by no means the mood of the majority” at the congress.Footnote 62 Similarly, the unnamed Time correspondent reported that if the speakers at the Harvard congress “were using a unified language, it was so technical that news hawks tore their hair trying to get plain-talk stories.”Footnote 63 Another reporter “observed that the only semblance of unity he saw was a gathering of the delegates around a radio to hear war bulletins.”Footnote 64
Entirely Apolitical
The Time reporter was right about the radio. Hitler sent troops into Poland on September 1, 1939. The Harvard congress began on September 3, 1939, the same day that Britain declared war on Germany. The delegates spent the first night of the congress listening to President Franklin D. Roosevelt give a radio address about the outbreak of war in Europe.Footnote 65 Alfred Tarski had traveled from Warsaw to Massachusetts to deliver his talk; he ended up staying in the United States for good. Janina Hosiasson, the logician whom Tarski had recommended to Neurath for the very first Unity of Science congress, had also submitted a paper. In the end, she was not able to secure the necessary travel documents. Hosiasson was in Warsaw when the bombing began.Footnote 66
In the late 1930s, as more people tried to emigrate, Neurath's pleas for solidarity took on a new light. Neither logical empiricism nor the Unity of Science movement were popular in continental Europe.Footnote 67 Unifiers came in for virulent, often antisemitic criticism from right-wing nationalists.Footnote 68 Marxists were also none too pleased (Lenin had set the tone when he attacked Frank and other “Machians” for being insufficiently materialist).Footnote 69 Neurath's relentless striving did not make the movement more popular than the mainstream “school philosophy” which it claimed to supplant. The unifiers turned their attention to their own safety, but the situation made a mockery of a clear-thinking science validated by equally capable knowing subjects. Fascist regimes labeled people as leftists and Jews, then rejected their scholarship as tainted. Members of the movement had deep connections to each other, but it was hard for one drowning person to save another.
In April 1933, the newly empowered Nazi government dismissed civil servants whom it considered to be Jewish or otherwise dangerous to the regime. The mass firings included Reichenbach, who had held a professorship at the University of Berlin. He immigrated to Turkey.Footnote 70 Newly orphaned, the Berlin Society struggled to continue a fraction of its programming. In February 1934, a brief civil war in Austria ended in a right-wing coup. The new Catholic nationalist regime banned the Social Democratic Party, in which Neurath had been an active member. The Ernst Mach Society also had roots in the party. The regime banned it too.
Moritz Schlick, a professor at the University of Vienna who hosted the Vienna Circle's weekly discussions, was the society's honorary president and last best hope. A former student of Max Planck, Schlick held the Chair for the Natural Philosophy of the Inductive Sciences originally held by Mach (and later by Ludwig Boltzmann).Footnote 71 Alarmed by the police's interest in the society, he wrote the investigating precinct that the society's activities were “purely scientific” and “entirely apolitical.”Footnote 72 As a clear-thinking philosopher and professor, he would never join any political party, “let alone a socialist one!”—although he did simultaneously claim to be a long-time supporter of the new Catholic nationalist regime.Footnote 73
Schlick's efforts did not save the society, but he, the descendant of wealthy north-German Protestants, dodged further legal repercussions. Neurath, whose father had been born to Jewish peasants, had fewer options. In 1919, he had served as an economic official in the short-lived Bavarian Soviet Republic.Footnote 74 Following Germany's suppression of the Republic, the victorious state convicted him of high treason. Before he was extradited to Austria (a result that saved him a lengthy prison term, and possibly his life), Neurath finished his habilitation at the University of Heidelberg. With his conviction went his chances of a professorship. After the 1934 coup, his political commitments and Jewish ancestry made staying in Vienna untenable. The national police repeatedly searched his home and office, and his family and friends assumed he would have been arrested had he not been abroad.Footnote 75 He spent several months in Prague before relocating to The Hague.
Neurath's time in Prague was something of a Unity of Science reunion. Carnap and Frank were professors at the city's German University. Together with visiting colleagues, they began to discuss creating a Society for the Unity of Science. They planned to found branches in major cities (Prague, Vienna, Warsaw, Amsterdam, and Paris were all on the table), but without “foreign and politically-compromised people” in leadership positions.Footnote 76 Neurath could serve as organizational secretary—an interpersonal clearing house—but with extra layers of institutional cover. The desire for many branches reflected both the movement's longstanding commitment to internationalism and a practical concession to the actual geographic distribution of its members.
The recent past showed the benefits of a distributed model. A few years previously, as Neurath had nervously eyed the political news from Germany, he filed paperwork with the Dutch government to register a Mundaneum Institute in The Hague.Footnote 77 The Institute rented office space in Vienna, and a number of documents from the Social and Economic Museum made their way down the street. Outside flew the Dutch flag. The Austrian police left the office alone. When Otto Neurath and Olga Hahn-Neurath (a mathematician married to Neurath, and also Hans Hahn's sister) fled Vienna with several museum staff, their documents came along.
Despite the utility of branch offices, no Unity of Science societies came out of the Prague group's discussions. Schlick, who had not been particularly keen on the movement in the first place, categorically refused to have anything to do with any organization that had “Unity of Science” in its name.Footnote 78 As the Prague group was still trying to actualize their plans, Hans Hahn, the professor of mathematics who had cowritten the manifesto, died. Philipp Frank wrote an obituary for Erkenntnis.Footnote 79 Whereas the movement had once had strong footholds in both Vienna and Berlin, it now appeared in danger of slipping from both. Most of its leadership was in exile. Its publications instantiated the movement, and they existed only as long as publishers honored their contracts.
In the fall of 1934, Neurath had resettled in The Hague, Carnap was planning a move across the Atlantic, and Frank decided to order a copy of one of Hahn's books. He contacted a bookstore in Czechoslovakia, but the Vienna-based Gerold and Company was unable to fill the order. The Austrian police had confiscated the entire print run.Footnote 80 Hahn had written the book from a lecture that he had delivered at the Ernst Mach Society, and the society had published the book under its imprint. Austria's government had banned the organization; it might as well ban all its publications, too.
The political situation deteriorated further. While members of the movement were beginning their 1936 congress with Bohr in Copenhagen, Schlick was shot by a former student in Vienna.Footnote 81 For the second time in two years, Frank wrote an obituary for Erkenntnis.Footnote 82 The murder had to do with personal and professional jealousies, but the press spun a political narrative that painted Schlick as an amoral, philosemitic corrupter of Austrian youth.Footnote 83 There had previously been no love lost between Neurath and Schlick. Nevertheless, the murder was a brutal shock. Neurath sadly wrote that the time in Vienna had been “our best period of cooperation” because “Schlick and Hahn both created an associational effect.”Footnote 84
After the summer's tumult, Neurath created the “Unity of Science Institute,” which was actually a sub-department of his Hague-based Mundaneum Institute. Not founding a new organization meant no new paperwork; the movement's organizers got two letterheads for the price of one.Footnote 85 Such cover—the ability to send a letter on behalf of the Unity of Science Institute rather than as one's lowly self—became more important as the German and Austrian governments continued to crack down on their perceived enemies.
Erkenntnis faced the stiffest headwinds. In November 1936, the Nazi government asked the journal's publisher to confirm the racial status of its editors. Carnap conferred with Neurath about what to do: switch to the University of Chicago Press? Neurath argued for maintaining a foothold in Europe. People who wanted to publish in the United States would always have other options, but it had been “a necessity” to found Erkenntnis in Europe.Footnote 86 They agreed to let Felix Meiner take Reichenbach off the masthead. In the summer of 1937, Meiner, under further pressure from unnamed “authorities,” revisited the question of the journal's editorship, this time indicating that removing Reichenbach might not be enough. He blamed Reichenbach's political activities in the wake of the Great War—he had been a pacifist and joined an outspoken socialist youth organization—further noting that the “direction which Erkenntnis was going” did not have many followers in Germany.Footnote 87
Two months later, Meiner and Carnap met in Dresden. Unlike Reichenbach and Neurath, Carnap had four Protestant grandparents; Germany would have been off-limits to his co-editors. Meiner bluntly stated that the number of Jews who submitted to the journal made it untenable for him to continue its publication. Pleading his own commercial viability, he explained that “certain circles find it impossible to work with a publisher who still has any kind of connection to Jews.”Footnote 88 For Erkenntnis to continue, its editors needed to find a new publisher.
Eight members of the movement who had agreed to editorial positions discussed how to proceed. They were trying to sort out Erkenntnis when the next blow struck. Days after crowds of cheering Austrians welcomed German troops into Vienna, Gerold and Company tersely declared that they would no longer publish Neurath's Unity of Science series.Footnote 89 The press had been about to print a monograph by the mathematician Richard von Mises, who, like Reichenbach, had been a professor in Berlin until 1933 before relocating to Turkey (von Mises, too, had Jewish ancestry). Now his proofs were on the way back to him in Istanbul. Neurath, the series’ sole editor, acted quickly. Within a month, he arranged a contract with the Dutch publisher Van Stockum and Zoon.Footnote 90 Von Mises’ book came out later that same year.Footnote 91
Divided into three possible editorial committees, but acting as one (unofficial) leadership committee, the eight unifiers took more than half a year to sort out the situation with Meiner. At one point, fearful of lost letters and delays, the committee considered it best practice to send two copies of their transatlantic circular letters by ship and a third by airmail (to save on postage, Neurath combined letters to Carnap and their American colleague Charles W. Morris, who were both at the University of Chicago).Footnote 92 As a result of their negotiations, the committee agreed to rename “our organ” from Erkenntnis to The Journal of Unified Science.Footnote 93 Neurath had already moved the publication of his Unity of Science series from Vienna to The Hague, and he did the same for the journal formerly known as Erkenntnis. Its last volume (1939/1940) appeared with Van Stockum and Zoon. Carnap and Reichenbach were back as co-editors, with Philipp Frank, Jørgen Jørgensen, Charles W. Morris, Otto Neurath, Louis Rougier, and L. Susan Stebbing as “associate editors.”Footnote 94 While continuing in his uncredited leadership role, Neurath revived the project's collective spirit. Stebbing, agreeing to review the encyclopedia for “your journal,” received a playful rebuke.Footnote 95 It was “our Journal.”Footnote 96
Looking the Anglo-Saxons in the Eyes
The unifiers built their science on publications. They pushed Neurath to publish other people's articles so that they could cite them. They pushed him to publish their own articles so that they could be cited. They had always needed to wrap their ideas in paper, but fascist oppression and street violence upped the ante. Throughout the 1930s, and especially after the pogroms in the fall of 1938, those looking to emigrate became especially sensitive to the physical side of their publications: how far and under what conditions their manuscripts would travel, how quickly an editor would print their article, how many copies the publisher would give them.
In other contexts, a desire to publish quickly might have stemmed from priority claims, the commercial viability of breaking news, or the needs of military intelligence.Footnote 97 Credit and recognition were one thing. It was another to present oneself as a scholar of sufficient standing to be granted an increasingly rare post at a foreign university. Because several aspects of the system focused on letters and affidavits, those with preexisting personal connections in target countries fared better.Footnote 98 Unifiers who needed to emigrate understood publications not only as ends in themselves, but also as ways of leveraging direct personal contact with British and American colleagues.
Anyone trying to escape the growing Reich faced a complicated regime of passports, travel permits, and visas, all of which depended on would-be emigrants’ ability to convince public and private authorities of their need to travel and their ability to provide for themselves.Footnote 99 For the academic job market, would-be emigrants asked British and American citizens for letters of recommendation that extolled their genius. For consular permission to enter those countries, they sometimes had to ask the same people for affidavits promising financial support, lest they become destitute burdens on the public purse. Nazi policies worsened matters by confiscating emigrants’ savings and property. Whether or not they intended to overstay their sanctioned time, those who arranged short-term trips struggled to match the dates on exit, transit, and entry visas to available train and steamship tickets, and all had to align with the official purpose for travel—like to attend an International Congress for the Unity of Science.
Formal congress invitations allowed attendees to travel and to move money across state lines.Footnote 100 Stebbing and Neurath were planning the 1938 Cambridge congress when Germany annexed Austria. Neurath, “formerly Austrian and a fresh German” joked to Stebbing, “an English lady,” that “a letter from you with an official letterhead” would be more useful for attendees who needed British entry permits than anything he could generate.Footnote 101 The next year, he apologetically asked Stebbing for an invitation on official letterhead so that he could travel to Britain. He hoped to set up a branch office for his visual education institute: “the man of your home office likes invitation letters from English friends. I know it. He believes in the explanations of a Gentleman, but a letter is always the best introduction.”Footnote 102 By then, many of the unifiers needed the official imprimatur of invited lectures and congress presentations in order to leave the country in which they lived (and were trapped).
Emigrants fled regimes that had stolen or stalled their careers. The same regimes stripped them of the very qualifications they needed to emigrate. When Neurath fled Austria in 1934, he left his museum career behind him. He read the manuscript of Carnap's new book, The Logical Syntax of Language, in Prague while he planned his next move.Footnote 103 He wrote to its author with praise for how he managed to bring things to a unified whole, but then shifted gears to a “humane” request: “I must arrange a new place for myself in the world, and I have a concrete interest that my personal achievements be somewhat more precisely fixed in your book.”Footnote 104 At issue was credit for Neurath's contributions to developing physicalist language, a way of talking about objects in the world that allowed one person to convey knowledge to another. Neurath denied the absolute truth of such statements. There was no language outside of language; one could only compare statements with other statements. He suggested a few articles of his that Carnap could revisit and perhaps cite.Footnote 105 Privately, Carnap grumbled about needing to “quiet” and “soften” Neurath, but he added a paragraph to the manuscript that allocated Neurath partial credit.Footnote 106
Travel restrictions, missing credit for “personal achievements,” and weak professional connections hindered people who wanted to emigrate. Anyone seeking to work in the United States needed a visa. You could apply for a quota visa, allocated by country of origin. In the 1930s, quota visa waiting lists for Central European countries stretched several years into the future. Alternatively, if you had worked as a clergyman or professor for at least two years prior to your emigration, you could apply for a non-quota visa.Footnote 107 The United States did not limit non-quota visas, but you needed to prove that you were immigrating to take up a professorship (or a ministry). Britain also restricted immigrants based on their jobs, but it wanted manual workers.Footnote 108 Its academic rescue organizations focused their efforts on providing immigrants with transit visas and the cost of steamer tickets to America. Regardless of country, what had been true in the 1920s was true in the 1930s: people who wanted academic jobs had to navigate the academic job market. The difference was, once again, the stakes.
More had changed for the applicants than for the departments looking to hire. Applicants wanted to stand out from the crowd, and they used their publications to enlist contacts who could advocate for them. People who needed help swamped the number of would-be helpers—both individuals and organizations. To break through the surface, Neurath always advised face-to-face appeals: “the Anglo-Saxons want to look you in the eyes.”Footnote 109 In 1939, the former Vienna Circle member Rose Rand made it to Britain by promising to work as a domestic servant or hospital nurse. She lived with Stebbing for a short time after her arrival, and Stebbing also arranged a home placement where Rand could improve her English.Footnote 110 A generation younger than Carnap, Reichenbach, and the movement's other leaders, Rand had not previously worked as a professor. Nevertheless, she wanted to apply for academic positions in the United States. She hoped that her “articles published in the near future [would] give her an opportunity to come in closer contact with scientific people.”Footnote 111 That plan did not work out. She spent the rest of the war performing exhausting and demoralizing manual labor in Britain, too busy to write or even read.Footnote 112
Would-be emigrants like Rand frequently expressed a desire for separata (separately printed journal articles).Footnote 113 They wanted to get their work in front of as many people as possible. For academics without access to free secretarial labor—like that of a wife or girlfriend—that meant either spending precious time typing multiple copies or scrounging up enough money for a professional to do the job.Footnote 114 Separata solved that concern. Unlike the popular press, academic journals rarely paid for submissions, but most provided authors with copies of their work—anywhere from around a dozen to a few hundred. When Carnap and Hans Reichenbach printed the congresses’ proceedings in Erkenntnis, they had to allocate a significant portion of each congress’ budget to paying for the copies that they gave to the participants.Footnote 115 Authors could mail their separata for less than it would have cost to mail the entire issue, and they did not have to wait for the rest of the issue to be printed (let alone for the whole volume to come out).
Such copies also helped the journals themselves, as was the case with Max Horkheimer's Zeitschrift für Sozialforschung: Walter Benjamin, having fled Berlin for Paris in 1933, entered extensive negotiations about the number and quality of separata he would get for publishing “The Work of Art in the Age of Mechanical Reproduction” in Horkheimer's journal.Footnote 116 Its managing editor offered Benjamin an “exceptional” 200 copies due to “the great propagandistic value of this article for the journal”—and promised that the copies would get special high-quality paper covers, the better to send as stand-alone documents.Footnote 117
As the situation in Central Europe deteriorated further, authors used separata for additional purposes. People on the run were not usually able to bring their book collections with them. Nor could those still in Germany borrow what they needed: Nazi race laws stripped people of their access to libraries.Footnote 118 Even those allowed in the door discovered that “Aryan” staff had stocked the shelves with government-approved materials.Footnote 119 Neurath tried to compensate by founding a postal lending library. He asked his contacts for two copies of their publications, separata or even entire books, that he could collect and then circulate among his colleagues. He specified that contributors should send two copies because materials tended to go missing.Footnote 120 Perhaps the unreliable mail system was the culprit, but maybe some people just wanted to reclaim the convenience of a personal copy.
Access to publications helped displaced academics continue their own work. It also allowed them to build socio-intellectual connections. In Benjamin's case, the separata for his new article gave him a French-language calling card that he could use to spread his name in Paris.Footnote 121 For Hilda Geiringer, separata rebuilt her network and her library. In 1933, she had been about to take up a professorship in applied mathematics in Berlin.Footnote 122 She would have been the first woman in Germany to do so. Instead, the Nazis fired her for being Jewish. She joined a disproportionate number of female civil servants who lost their jobs. No women had served in the Great War or gotten their professorships before 1914, so they could not access the dispensations afforded to men in those categories.Footnote 123
Geiringer relocated to Belgium and then immigrated to Istanbul, joining von Mises and Reichenbach. In 1939, fearing deportation from Turkey, she began to plan a move to the United States. The two men had already made the journey (Philipp and Hania Frank, also already in the United States, went to New York harbor to greet von Mises).Footnote 124 Geiringer asked for copies of other people's work to supplement her university's “rather basic” library, and she also repeatedly requested separata of her own forthcoming Erkenntnis article.Footnote 125 Her letters to Neurath explicitly connected the separata to her ability to immigrate. They would serve a different purpose than, for example, the mathematics textbook she co-authored in Turkish, a condition of her permission to teach in that country.Footnote 126
Neurath acknowledged Geiringer's situation and recommended that she send him a short piece in English (because the Anglo-Saxons had bad German) that he could publish in the coming month's Unity of Science Forum.Footnote 127 Neurath had launched the Forum in the Dutch journal Synthese the previous summer. The yearly Erkenntnis was “overfull,” and the Forum could “serve as a monthly organ for us.”Footnote 128 As with his Unified Science series, Neurath alone had editorial control. His position as sole arbiter maximized speed in the publication process, at least when he was not traveling on other business. Impressed by how quickly Neurath said that he could publish her piece, Geiringer agreed to his suggestion. She again underscored the importance of separata for her emigration: “it would be enormously nice if you could give me a few tips as to whom I should send the separata (both from the perspective of who would be interested but also who might be useful to me).”Footnote 129
Karel Reach, who had been Carnap's student at the German University in Prague, was also looking to emigrate. Like Rand, he had never worked as a professor. A British academic aid organization told him he needed more publications. He had a few forthcoming, one in Analysis and one in the Forum, and some others in preparation.Footnote 130 He asked Stebbing for an invitation to London.Footnote 131 He hoped the trip would allow him to make further personal contacts (“it's all a protection racket”) and give him a few weeks of precious safety while he waited for his articles to come out.Footnote 132 In a letter to Carnap, Neurath reported that “for now, everyone who is connected with us, and who must get away, is out”; they just needed to “take care of” Reach's case.Footnote 133 Neurath and Stebbing conferred about what to do, agreeing that “if a man is abroad—he is saved in a certain sense.”Footnote 134 What happened with the London invitation is not clear. In August of 1939, Reach was still trying to arrange a way out of the Reich-controlled Protectorate.
Edgar Zilsel had better luck, at least initially. Another Viennese philosopher trained in mathematics and physics, Zilsel had known Neurath and Frank since before the Great War. He studied the way that science had developed over time, arguing against the role of individual geniuses and highlighting the contributions of skilled craftspeople.Footnote 135 With the help of American and émigré colleagues, he successfully escaped Europe, securing a position at the relocated Institute for Social Research in New York. However, the contract was temporary, and he struggled with the uncertainty of his position. In need of “some publicity for his name,” Zilsel asked Carnap if he could be included in the letterhead and promotional material for the encyclopedia (Carnap, who supported the idea, passed the request on to Morris).Footnote 136
In 1943, Zilsel was hired at Mills College, a small women's college in California. That gave him a coveted faculty position, but little else. Although he continued to rack up publications and professional accolades, he grew increasingly depressed.Footnote 137 In the spring of 1944, he decided to kill himself. He wrote a note to his dean, insisting that “nobody must know of the suicide, everybody must be told that I died through a traffic accident,” adding “I am sorry to have inconvenienced you.”Footnote 138 He explained that he had set out ten dollars to compensate the janitor, should he be the one to find the body. He then took a lethal combination of pills. He died on the floor of his office, his head resting on a suit coat that he had folded into a pillow.
When Germany invaded Poland and Britain declared war, most of the movement's members were at the Harvard congress. Janina Hosiasson, the Polish logician, was not. In January 1940, she wrote to the British philosopher G. E. Moore from then still-independent Lithuania.Footnote 139 Like Reach, she was hoping to make it to Britain. In her letter, she first asked forgiveness; she had listed Moore as a reference in a refugee scholar aid application without asking his permission. Then, she recounted her escape from Warsaw. Under fire from the Luftwaffe, she and a few friends had fled north, first into the countryside, and then to Vilnius. She ended her letter with a question for him about the journal he edited: was Mind still being printed? It was both a polite inquiry—a form of small talk—and a grasp for any kind of hope.
One hope fulfilled: in the fall of 1941, an article of hers appeared in Mind.Footnote 140 Since arriving in Vilnius, Hosiasson had participated in a philosophical discussion group; its meetings continued illegally during the Soviet occupation.Footnote 141 Meanwhile, her friends and colleagues abroad were desperately trying to save her. She could not circulate her own CV, so they did it for her. Under “Additional Remarks,” they appended “starving; endangered.”Footnote 142 Tarski promised to find funds to support her, freeing universities from the obligation to pay her salary. A possible affiliation with the New School fell through, as did one with the University of Washington. After the Germans invaded the Baltic states, the Gestapo arrested Hosiasson. She continued to work while imprisoned. Her final article was published in Erkenntnis—but only in 2024, more than 80 years after her death.Footnote 143 She and other prisoners were marked “released” and then shot in the spring of 1942.Footnote 144
As for Geiringer, it was half a year before her piece for the Forum went to the printers. The outbreak of the war in Poland had put a spanner in the works, but by May 1940, Van Stockum and Zoon was back on track.Footnote 145 In the intervening months, Geiringer and her daughter had left Turkey, barely made it through Lisbon, and joined von Mises in the United States.Footnote 146 Less than a week after Neurath wrote to Geiringer to assure her that her article would soon be published, Germany invaded the Low Countries. Neurath fled across the Channel. The British interned him and several thousand other “enemy aliens.”Footnote 147 Erkenntnis—or rather The Journal of Unified Science—and the Forum went out of print shortly after.
Conclusion
On October 21, 1941, Karel Reach finally left the city of his birth. It was not by choice. A few days prior, he, his parents, and thousands of other people—all Jewish under Nazi racial laws—had been ordered to assemble at the frigid grounds of the Trade Fair Palace, a large exhibition hall in the northern part of Prague. It served as a temporary prison for those awaiting deportation. After what would have been a relatively short but entirely unprovisioned stay at the fairgrounds, they boarded a train that carried them and 1,000 of their neighbors to the Łódź Ghetto.Footnote 148 The Reach family was dead within three years.Footnote 149
In Reach's last preserved letter to Neurath, he had written that he “could really use” the separata from his Forum piece.Footnote 150 Reach was not an émigré scholar; Hilda Geiringer was. Those classifications might seem self-evident, but what about Zilsel and Hosiasson? Both left one country for another, both continued their academic work, both died prematurely. Neither their lives nor their deaths were equivalent, which challenges us to account for when and how they stopped being similar to their colleagues. Both “émigré scholar” and “Holocaust victim” are historically-contingent labels. They belong in the same story.
The unifiers put words and objects to use. Those uses began with promoting their scholarship, but the rise of fascism forced them to end with promoting themselves. Institutions, publications, and congresses anchored the unifiers’ scholarship. People anchored the institutions, publications, and congresses. The people moved, and moved again. They lost their books, jobs, and savings. Some died, including Zilsel and Hosiasson, but also Stebbing of cancer in 1943 and Neurath of a stroke at the end of 1945. The “movement” was both more and less than a group of individuals who published articles and organized congresses. It never moved to America, but its surviving leaders did.Footnote 151
With their keen interest in precise language, the unifiers had much to say about the meaning of science. They had less to say about what it meant to be a movement. Looking to their actions provides some clues. They intended their promotional materials to face outwards, but the process of editing publications and planning congresses tied the movement together more than inherent ideological cohesion or participation in the resulting events. In the absence of human context, copies of articles were cheaply-bound sheets of paper. When Neurath sent separata, they were calling cards and recruitment tools. When Geiringer and Reach asked for them, they were certifications of scholarly talent and, they hoped, the first rung on a ladder to a safer life.
When members of the movement got jobs, got visas, and got out of Europe, they did so on the strength of their interpersonal networks. Established professors in Berlin and Vienna, those who had already been successful in the 1920s, had useful connections ready at hand. Recent graduates in Prague and Warsaw struggled to reach the same level of support, but that did not stop them from trying. The best-case scenario was knowing someone who could help. The next best was knowing someone who knew someone. A network of people, from end to end.
Acknowledgements
Comments from Edward Baring, Yaacob Dweck, Michael D. Gordin, Sebastián Murgueitio Ramírez, attendees of Princeton University's History of Science Program Seminar, and two anonymous peer reviewers improved earlier versions of this article. I am grateful for their engagement with my work.
Competing interests
The author declares none.
Funding information
Research for this article was funded by the Princeton University Department of History.
Austen Van Burns is a Collegiate Assistant Professor (Harper-Schmidt Fellow) at the University of Chicago. She researches the history of the physical and social sciences, focusing on the relationship between science and politics in modern Europe. She completed her doctorate at Princeton University in the summer of 2026.
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