Old Intelligencer

The Old Guard Under the N e w Order: Kurt Friedrichs on His Meeting with Felix Klein by David E. Rowe Constance Reid's recent tribute to K. O. Friedrichs

(Mathematical Intelligencer, Vol. 5, No. 3) undoubtedly brought back fond memories to those w h o knew the man and his many achievements. It was a great pleasure for me to interview Friedrichs in January 1982, only about a year before his death. He was already in very delicate health. His wife Nellie was kind enough to arrange the interview, but warned me beforehand that her husband tired rather easily and was somewhat hard of hearing. Nevertheless, he was extremely forthcoming in discussing his early career with me, and quick to dismiss some of my faulty misconceptions regarding G6ttingen mathematics in the 1920s, which was the main topic of conversation. Most of what Friedrichs spoke about can be found either in Reid's eulogistic article or in her book on Richard Courant. One particular incident he related to me, however, was only alluded to in her article, and because of its personal interest and the larger themes it suggests, it seems appropriate to repeat it here, in a somewhat embellished form. This is the story Friedrichs told me about the day he met Felix Klein. The date was June 24, 1922, well into the twilight of Klein's career. The aged Olympian rarely went out anymore and could only get about in a wheelchair. His main exercise was occasional excursions through the botanical garden that was located immediately between his home and the Auditoriumhaus, where he had taught for some thirty years. The winter before he did manage to attend the banquet honoring Hilbert on his 60th birthday, on which occasion he presented his colleague with a copy of the Vortrag Hilbert had delivered in Klein's Leipzig seminar of 1885. But at the birthday party that evening, Klein was noticeably absent, as his health could only w i t h s t a n d a certain amount of activity and excitement in one day. By this time, Klein also had greatly curtailed his administrative and organizational activities, most of 74

which, in any event, had been disrupted by the War. At the end of March 1922, he stepped down from his position as head of the subcommittee for mathematics, astronomy, and g e o d e s y of the Notgemeinschaft der Deutschen Wissenschaften. In the meantime, the second volume of his Gesammelte Mathematische Abhandlungen was published and, with the assistance of Erich BesselHagen, considerable progress already had been made in preparing the third and final volume for publication. The Notgemeinschaft originally authorized an expenditure of 50,000 Marks to s u p p o r t the publication of Klein's Collected Works, but spiralling inflation eventually forced the organization to lay out an additional 400,000 Marks in order to complete the project. This third volume, the culminating achievement of his career, presented for the first time Klein's correspondence of 1881-82 with Henri Poincar4, which documents their famous rivalry over the early development of the theory of automorphic functions. It was only a few months before meeting Friedrichs that Klein finally recovered Poincar6's half of this correspondence, which had been lost for over ten years. Ever since October 1914, w h e n he and 92 other German scholars signed the chauvanistic "Call to the Cultured World," Klein's international reputation had taken a precipitous slide downward, and losing the Poincar6 letters certainly had not helped. Numerous parties prodded him to produce them: Mittag-Leffier asked for the letters before the War broke out, as he was planning to dedicate a volume of Acta Mathematica to PoincarG who died in 1912. He, for one, was greatly miffed that Klein could have lost such important correspondence, and even suspected foul play on Klein's part. It was not until 1923 that the volume honoring Poincar6 (no. 39) finally appeared, containing the long lost Klein-Poincar6 correspondence. Probably little or n o n e of this b a c k g r o u n d was known to the 21-year old Friedrichs, as he approached his first and only meeting with Felix Klein with a mixture of excitement and trepidation. Certainly he had arranged for it carefully enough: his father was indirectly acquainted with Klein's brother Alfred, as they were both lawyers in Diisseldorf, and the latter agreed to write a short letter of introduction paving the way for the meeting. Still, the shy young mathematician was not at all sure how he would be received once he arrived at Wilhelm Weber Strasse 3.

THE M A T H E M A T I C A L INTELLIGENCER VOL. 6, NO. 2 9 1984Springer-VerlagNew York

But whatever his misgivings, the reception he was a c c o r d e d - - a n d Friedrichs spoke about it vividly and with great animation--exceeded all his hopes and expectations. "I was a m a z e d , " he told me, " s i m p l y swept off my feet by Klein's grace and charm. I was just a student--completely u n k n o w n - - b u t he treated me like I was some kind of big-shot from Paris." Klein inquired about Friedrichs' study plans in G6ttingen, offered his considered advice, and gave his complete attention to what the aspiring young student had to say. Friedrichs was "simply astounded by his performance," not he told me that he was unaware of the other side of Klein's personality: "He could be very charming and gentlemanly when all went his way, but with anyone who crossed him, he was a tyrant!" And to reinforce this point he mentioned some of the familiar anecdotes about Klein's run-ins with Max Born, and the unpleasant time Carl Ludwig Siegel had living in Klein's home. Nor did Friedrichs have much respect for the circle around Klein at the end of his career: "Most were good second-rate mathematicians, not so much research-oriented as they were educators. Klein wanted to place them in the schools in order to upgrade educational staridards, but his people were not really effective enough." This negative judgement extended to Klein's n e p h e w and close collaborator, Robert Fricke, with w h o m he co-authored the four large volumes devoted to Elliptic Modular Functions and Automorphic Functions. Friedrichs succeeded him at the Technische Hochschule in Braunschweig, a few days after his death in 1930. Although Fricke's work has been regarded with esteem by other contemporary mathematicians, it is easy to see w h y it appeared old-fashioned to Friedrichs, a man who grew up reading the latest works of people like Hermann Weyl and John von Neumann. The exact date of this meeting--June 25, 1922 (not during the autumn as reported by Reid)--is known because of another recollection Friedrichs had from his conversation with Klein: their discussion about the assassination of the German Foreign Minister, Walter Rathenau, one day earlier. It was Klein's reaction to this event that Friedrichs remembered most vividly: "He was very upset about it; you could tell it was really bothering him that this had happened. He felt it was a terrible blow to the Republic, and he was deeply c o n c e r n e d and w o r r i e d a b o u t G e r m a n y ' s f u t u r e . " Walter Rathenau has since become something of a symbol of the fragility of the Weimar Republic. A Jewish intellectual w h o had studied mathematics, physics, and chemistry before assuming leadership of the Allgemeine Elektrizit~ts-Gesellschafl (AEG) founded by his father, he went on to organize and direct the Raw War Materials Department, which managed to keep the German army supplied during the critical first stages of World War I. He was an expert on economic questions and one of the strongest advocates for ful-

K. O . F r i e d r i c h s

Felix Klein THE MATHEMATICALINTELLIGENCERVOL. 6, NO. 2, 1984 75

Wilhelm Weber Strasse 3: Klein's Home in G6ttingen (upper left); The Auditorium Building was the Citadel of G6ttingen Mathematics During the Klein Era (lower left); The Botanical Garden Between Klein's House and the Auditorium Building (upper right).

fillment of the terms of the Versailles Treaty. His assassination at the hands of right-wing terrorists took place less than five months after he was appointed Foreign Minister. Felix Klein, on the other hand, was one of the most influential figures in educational affairs (which had especially strong social a n d political overtones) throughout the Wilhelmian era. Moreover, his politics were marked by much the same kind of ambivalence that was characteristic of that period: he was certainly progressive regarding technical education, women, Jews, and most of the other concomitants of modernity. At the same time he was an ardent nationalist, an imperialist sympathizer, and he had strong predilections for autocratic rather than democratic power structures. How did Klein react to the whirlwind events of the Weimar era? Friedrichs at least gives a glimpse of his reaction at a critical point in its history, and in fact little else seems to be known. It is true that Courant was enjoined by Klein to run for office (which he successfully did) as a member of the Social Democratic Party, but this was most likely a purely pragmatic decision, as Klein wanted someone at the University to be in touch with the local political scene. Probably his 76

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own views were closer to the liberal-oriented German Democratic Party, in which his daughter Elisabeth was an active member. It may also well be that Klein eventually succumbed to the fatalism that was so endemic during this period in Germany. In his Autobiographical Sketch, written in early 1923, he ends with the reflection: In the course of time it has become ever clearer to me, that it is only possible in a very limited sense for h u m a n beings to control their own fate, as outer circumstances independent of our will are in large measure always stepping in between. And Norbert Wiener, who visited Klein only a few months before his death, said that when he spoke "the great names of the past ceased to be mere shadowy [ f i g u r e s ] . . . [ w h i l e ] . . . there was a timelessness about him which became a man to w h o m time no longer had a meaning."

Theaterstr. 2 3400 G6ttingen West Germany