Jan Potters is a postdoctoral researcher at the University of Antwerp in Belgium and is currently writing a book about the philosopher Thomas Kuhn’s work on the history of quantum mechanics. Among the issues this will cover are the connections between Kuhn’s extensive oral histories with quantum physicists and his soon-to-be-famous ideas about scientific paradigms and revolutions. Of course, Kuhn’s interviews were themselves extremely influential, not least by becoming a cornerstone of AIP’s own oral history collection and a model for our interviewing program. For this week’s edition, we asked Potters to write a short piece looking at this foundational episode in the scholarly study of physics history.

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AIP’s renowned oral history collection can trace its origins back to a project called Sources for History of Quantum Physics (SHQP), which ran from 1961 to 1964—separate from, but parallel with, the origins of AIP’s history program. To date, the only extensive scholarship on the history of SHQP has been conducted by Anke te Heesen, a historian at Humboldt University in Berlin.¹ Here, my focus will be on how the project’s leader, Thomas Kuhn, experienced the interviews.

High hopes for an ambitious history project

SHQP was an initiative of the American Philosophical Society and the American Physical Society that was funded by the National Science Foundation and grew out of conversations between physicists and historians, including John Wheeler, John Van Vleck, Gerald Holton, and Edward Purcell. Near the end of the 1950s, they noted that little was known about the historical development of quantum physics. As Wheeler stated in the final report on SHQP:²

“One might anticipate that developments so central to modern civilization and so much to the glory of the human spirit would by now have been fully documented and described. Few expectations could be further from the facts. If it is true that ninety per cent of the physicists who ever lived are now alive, then conversely it is also probable that ninety per cent of the literature on the history of physics deals with work done by men now dead.”

SHQP, on the other hand, would include those physicists still very much alive. The project would not only collect archival materials, but also conduct interviews to collect memories about the development of quantum physics. This ambition rendered the project quite urgent, since Einstein had passed away in 1955, von Neumann in 1957, Pauli in 1958, Schrödinger died just before the project started in 1961, and then Bohr died in November 1962 between two interview sessions. Everything collected would be copied onto microfilm for future historians to consult.

From a list of people including Holton, Martin Klein, and I. Bernard Cohen, Kuhn was chosen as project leader because of his PhD in quantum physics, supervised by Van Vleck, and his experience as a historian of physics. Kuhn’s collaborators were John Heilbron, Paul Forman, and Lini Allen. Kuhn and Heilbron focused on the interviews, Heilbron and Forman collected archival materials, and Forman was also responsible for interview transcription. Allen was the project’s secretary. She was hired, among other reasons, because of her knowledge of several foreign languages, which was to prove useful since the project was partially to take place in Europe, with Niels Bohr’s institute in Copenhagen as headquarters.

While interviews had already been used in the human and social sciences—e.g. at the Columbia Center for Oral History and by social psychologist Ann Roe—SHQP was the first oral history of science project of this scale. Kuhn and his collaborators therefore mostly had to develop their interviewing style through practice. Looking back, Heilbron described it as putting “ridiculously detailed questions about the intellectual history of quantum physics” to their interviewees.³

Kuhn’s disappointment

In total, they conducted over 200 interviews with 100 interviewees.⁴ Among those interviewed were Bohr, Heisenberg, Dirac, Born, Jordan, Franck, Goudsmit, and Uhlenbeck.

Notwithstanding these results, Kuhn was quite disappointed with the interviews. In the reports submitted to NSF, he frequently complained about how difficult it was to obtain insightful information. In the 1962 report, he wrote that “we so very seldom get useful answers in response to questions on historical matters of technical substance.” A year later, he stated that “almost no one is able to tell us very much about the sources of new ideas and problems, the difficulties encountered in developing them, and their reception by the physics community.” Even thirty years later, Kuhn still primarily expressed disappointment:⁵

“Interviewing was frustrating as hell! Some of the interviews are really good. But the physicists, including the ones sponsoring the project, really wanted to get the development of ideas, and that’s of course what I wanted also. I knew from experience as a historian that scientific biographies are invariably inaccurate, they tell the wrong story. ... What I hadn’t anticipated was the number of times people would say, ‘I don’t know, I can’t remember; how, why would you expect me to remember that?’”

That many interviewees did not remember much should come as no surprise: most were already in their seventies or eighties, and the developments discussed had taken place over forty years earlier. Frustration also arose because Kuhn and Heilbron were, in a sense, too prepared. Because of this, they were sometimes able to spot that the response given was colored by later events. One interview where this happened was with Bohr:⁶

“[Before the interviews,] one of us had conjectured … from hints in [Bohr’s] correspondence and in Part I of his [published paper], that he had developed a detailed, non-spectroscopic, quantized version of Rutherford’s atom some time before he saw the relevance of the Balmer formula. In early interviews, therefore, we repeatedly asked him for information about his work on atom models in the months before he first related the models to spectra. Bohr found such questions merely “silly” and insisted that, in the absence of the Balmer formula, he could have done no significant work on models. He consistently denied … the very possibility of the sort of research which [archival documents that were found later] ultimately documented. … Tricks of memory like this were, we should add, typical in our experience as interviewers. Bohr was by no means the only scientist unable to recall, or even to conceive as possible, participation in work which subsequent developments had removed from the corpus of proper physics.”

A final source of Kuhn’s disappointment was that Kuhn and Heilbron mainly focused on intellectual developments. Regarding these topics, however, they noted that the interviewees often “stuttered when asked to recapitulate the origin, development, or reception of a scientific concept or experiment.” This was not the case with other topics: to their surprise, many interviewees provided “a living and often a moving picture of the social and institutional milieu within which quantum physics developed.” In this way, the interviews sometimes offered “information of a sort that … the historian can seldom capture in other ways.”⁷

What interviews can reveal

Because they had not expected such information, however, Kuhn and his collaborators often did not probe these responses further. For example, on July 10, 1962, in his second interview with James Franck and his wife, experimental physicist Hertha Sponer-Franck, Kuhn asked Franck about his first encounter with Bohr’s atomic model. Kuhn’s motivation was that experiments by Franck with Gustav Hertz in 1914 were often seen as the first experimental confirmation of Bohr’s model, even though Hertz and Franck did not mention Bohr in their paper.

During the interview, Franck stated that he had learned about Bohr’s paper while in the hospital as a soldier during World War I. Kuhn more or less ignored this remark about the war, however, and continued asking about Bohr’s work:

Franck: … when we were in the hospital I learned it. Hertz was too ill. When I was paralyzed, but otherwise quite all right, I read literature, and I found Bohr’s paper … That was 1916. As soon as the war broke out, we had become soldiers. So, there was no more possibility to do anything.

Kuhn: But you think that you had not even heard of the Bohr atom, of Bohr’s idea, when you went into the army?

Franck: I must say I do not know that. I know that I have not heard of Bohr’s paper when we wrote our article. Whether I had in the meantime heard about it, I don’t know. I know only that there was no possibility to do something about it, and then we both went into the army.

[Franck continues about the war, and then turns to his first meeting with Bohr]

Kuhn: Your first actual contacts with Bohr were after the war?

Franck: Yes, yes.

This excerpt illustrates how Kuhn often had a very specific focus on the development of theoretical and experimental views. Because of this, he sometimes did not inquire further into the broader, societal factors that shaped these developments, such as how Franck got a hold of Bohr’s work in the hospital in wartime France, or whether his wartime experience influenced his scientific work in any way.

Kuhn’s disappointment thus in part grew out of how the interviews were conducted. Important to remember, however, is that Kuhn and his collaborators had to learn interviewing while doing it. Given the number of interviews conducted, and how extensively their materials have been used, we cannot but recognize the work of Kuhn, Heilbron, Forman, and Allen as a significant and impressive contribution to the oral history of science.

References

1. Anke te Heesen, “Thomas S. Kuhn, Earwitness: Interviewing and the Making of a New History of Science,” Isis 111, no. 1 (2020): 86-97, doi:10.1086/708277; Anke te Heesen, “Spoken Words, Written Memories: Early Oral History and Elite Interviews,” History of Humanities 6, no. 1 (2021): 163-178, doi:10.1086/713261; Anke te Heesen, Revolutionäre im Interview: Thomas Kuhn, Quantenphysik und Oral History (Klaus Wagenbach, 2022).
2. Thomas S. Kuhn, John L. Heilbron, Paul Forman, and Lini Allen, Sources for History of Quantum Physics: An Inventory and Report (American Philosophical Society, 1967), on vi, online at https://www.amphilsoc.org/guides/ahqp/index.htm.
3. J. L. Heilbron, “Cold War Culture, History of Science, and Postmodernity: Engagement of an Intellectual in a Hostile Academic Environment,” in Weimar Culture and Quantum Mechanics: Selected Papers by Paul Forman and Contemporary Perspectives on the Forman Thesis, ed., Cathryn Carson, Alexei Kojevnikov, and Helmuth Trischler (Imperial College Press, 2011), 7–20, on 7, doi:10.1142/9789814293129_0002.
4. J. L. Heilbron, “Quantum Historiography and the Archive for History of Quantum Physics,” History of Science 7, no. 1 (1968): 90-111, on 98, doi:10.1177/007327536800700103.
5. Aristides Baltas, Kostas Gavroglu, and Vassiliki Kindi, “A Discussion with Thomas S. Kuhn,” in The Road since Structure: Thomas S. Kuhn, ed., James Conant and John Haugeland (University of Chicago Press, 2000), 255–323, on 303,
6. John L. Heilbron and Thomas S. Kuhn, “The Genesis of the Bohr Atom,” Historical Studies in the Physical Sciences 1 (1969): 211-290, on 255, doi:10.2307/27757291.
7. Kuhn et al., Sources, on 5.

Jan Potters
University of Antwerp
Jan.Potters@uantwerpen.be

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