The first subway on the European continent was dug not in Paris or Berlin but in Budapest. Two miles long, completed in 1896, it connected the thriving Hungarian capital with its northwestern suburbs. During the same year the rebuilding of the grand palace of Franz Josef I, in one of his Dual-Monarchial manifestations King of Hungary, enlarged that structure to 860 rooms. Across the wide Danube rose a grandiose parliament, its dimensions measured in acres, six stories of Victorian mansard-roofed masonry bristling with Neo-Gothic pinnacles set around an elongated Renaissance dome braced by flying buttresses. The palace in hilly, quiet Buda confronted the parliament eastward in flat, bustling Pest. “Horse-drawn droshkies,” Hungarian physicist Theodor von Kármán remembers of that time, carried “silk-gowned women and their Hussar counts in red uniforms and furred hats through the ancient war-scarred hills of Buda.”382 But “such sights hid deeper social currents,” von Kármán adds.
From the hills of Buda you could look far beyond Pest onto the great Hungarian plain, the Carpathian Basin enclosed 250 miles to the east by the bow of the Carpathian Mountains that the Magyars had crossed to found Hungary a thousand years before. Pest expanded within rings of boulevards on the Viennese model, its offices busy with banking, brokering, lucrative trade in grain, fruit, wine, beef, leather, timber and industrial proauction only lately established in a country where more than 96 percent of the population had lived in settlements of fewer than 20,000 persons as recently as fifty years before. Budapest, combining Buda, Óbuda and Pest, had grown faster than any other city on the Continent in those fifty years, rising from seventeenth to eighth in rank—almost a million souls. Now coffeehouses, “the fountain of illicit trading, adultery, puns, gossip and poetry,” a Hungarian journalist thought, “the meeting places for the intellectuals and those opposed to oppression,” enlivened the boulevards; parks and squares sponsored a cavalry of equestrian bronzes; and peasants visiting for the first time the Queen City of the Danube gawked suspiciously at blocks of mansions as fine as any in Europe.383
Economic take-off, the late introduction of a nation rich in agricultural resources to the organizing mechanisms of capitalism and industrialization, was responsible for Hungary’s boom. The operators of those mechanisms, by virtue of their superior ambition and energy but also by default, were Jews, who represented about 5 percent of the Hungarian population in 1910. The stubbornly rural and militaristic Magyar nobility had managed to keep 33 percent of the Hungarian people illiterate as late as 1918 and wanted nothing of vulgar commerce except its fruits.384 As a result, by 1904 Jewish families owned 37.5 percent of Hungary’s arable land; by 1910, although Jews comprised only 0.1 percent of agricultural laborers and 7.3 percent of industrial workers, they counted 50.6 percent of Hungary’s lawyers, 53 percent of its commercial businessmen, 59.9 percent of its doctors and 80 percent of its financiers.385, 386 The only other significant middle class in Hungary was a vast bureaucracy of impoverished Hungarian gentry that came to vie with the Jewish bourgeoisie for political power. Caught between predominantly Jewish socialists and radicals on one side and the entrenched bureaucracy on the other, both sides hostile, the Jewish commercial elite allied itself for survival with the old nobility and the monarchy; one measure of that conservative alliance was the dramatic increase in the early twentieth century of ennobled Jews.
George de Hevesy’s prosperous maternal grandfather, S. V. Schossberger, became in 1863 the first unconverted Jew ennobled since the Middle Ages, and in 1895 de Hevesy’s entire family was ennobled.387 Max Neumann, the banker father of the brilliant mathematician John von Neumann, was elevated in 1913. Von Kármán’s father’s case was exceptional. Mór Kármán, the founder of the celebrated Minta school, was an educator rather than a wealthy businessman. In the last decades of the nineteenth century he reorganized the haphazard Hungarian school system along German lines, to its great improvement—and not incidentally wrested control of education from the religious institutions that dominated it and passed that control to the state. That won him a position at court and the duty of planning the education of a young archduke, the Emperor’s cousin. As a result, writes von Kármán:
One day in August 1907, Franz Joseph called him to the Palace, and said he wished to reward him for his fine job. He offered to make my father an Excellency.388
My father bowed slightly and said: “Imperial Majesty, I am very flattered. But I would prefer something which I could hand down to my children.”
The Emperor nodded his agreement and ordained that my father be given a place in the hereditary nobility. To receive a predicate of nobility, my father had to be landed. Fortunately he owned a small vineyard near Budapest, so the Emperor bestowed upon him the predicate “von Szolloskislak” (small grape). I have shortened it to von, for even to me, a Hungarian, the full title is almost unpronounceable.
Jewish family ennoblements in the hundred years prior to 1900 totaled 126; in the short decade and a half between 1900 and the outbreak of the Great War the insecure conservative alliance bartered 220 more.389 Some thousands of men in these 346 families were ultimately involved. They were thus brought into political connection, their power of independent action siphoned away.
Out of the prospering but vulnerable Hungarian Jewish middle class came no fewer than seven of the twentieth century’s most exceptional scientists: in order of birth, Theodor von Kármán, George de Hevesy, Michael Polanyi, Leo Szilard, Eugene Wigner, John von Neumann and Edward Teller. All seven left Hungary as young men; all seven proved unusually versatile as well as talented and made major contributions to science and technology; two among them, de Hevesy and Wigner, eventually won Nobel Prizes.
The mystery of such a concentration of ability from so remote and provincial a place has fascinated the community of science. Recalling that “galaxy of brilliant Hungarian expatriates,” Otto Frisch remembers that his friend Fritz Houtermans, a theoretical physicist, proposed the popular theory that “these people were really visitors from Mars; for them, he said, it was difficult to speak without an accent that would give them away and therefore they chose to pretend to be Hungarians whose inability to speak any language without accent is well known; except Hungarian, and [these] brilliant men all lived elsewhere.”390 That was amusing to colleagues and flattering to the Hungarians, who liked the patina of mystery that romanticized their pasts. The truth is harsher: the Hungarians came to live elsewhere because lack of scientific opportunity and increasing and finally violent anti-Semitism drove them away. They took the lessons they learned in Hungary with them into the world.
They all began with talent, variously displayed and remembered. Von Kármán at six stunned his parents’ party guests by quickly multiplying sixfigure numbers in his head.391 Von Neumann at six joked with his father in classical Greek and had a truly photographic memory: he could recite entire chapters of books he had read.392 Edward Teller, like Einstein before him, was exceptionally late in learning—or choosing—to talk.393 His grandfather warned his parents that he might be retarded, but when Teller finally spoke, at three, he spoke in complete sentences.
Von Neumann too wondered about the mystery of his and his compatriots’ origins. His friend and biographer, the Polish mathematician Stanislaw Ulam, remembers their discussions of the primitive rural foothills on both sides of the Carpathians, encompassing parts of Hungary, Czechoslovakia and Poland, populated thickly with impoverished Orthodox villages. “Johnny used to say that all the famous Jewish scientists, artists and writers who emigrated from Hungary around the time of the first World War came, either directly or indirectly, from those little Carpathian communities, moving up to Budapest as their material conditions improved.”394 Progress, to people of such successful transition, could be a metaphysical faith. “As a boy,” writes Teller, “I enjoyed science fiction. I read Jules Verne. His words carried me into an exciting world. The possibilities of man’s improvement seemed unlimited. The achievements of science were fantastic, and they were good.”395
Leo Szilard, long before he encountered the novels of H. G. Wells, found another visionary student of the human past and future to admire. Szilard thought in maturity that his “addiction to the truth” and his “predilection for ‘Saving the World’ ” were traceable first of all to the stories his mother told him.396 But apart from those, he said, “the most serious influence on my life came from a book which I read when I was ten years old. It was a Hungarian classic, taught in the schools, The Tragedy of Man.”
A long dramatic poem in which Adam, Eve and Lucifer are central characters, The Tragedy of Man was written by an idealistic but disillusioned young Hungarian nobleman named Imre Madach in the years after the failed Hungarian Revolution of 1848. A modern critic calls the work “the most dangerously pessimistic poem of the 19th century.”397 It runs Adam through history with Lucifer as his guide, rather as the spirits of Christmas lead Ebenezer Scrooge, enrolling Adam successively as such real historical personages as Pharaoh, Miltiades, the knight Tancred, Kepler. Its pessimism resides in its dramatic strategy. Lucifer demonstrates to Adam the pointlessness of man’s faith in progress by staging not imaginary experiences, as in Faust or Peer Gynt, but real historical events. Pharaoh frees his slaves and they revile him for leaving them without a dominating god; Miltiades returns from Marathon and is attacked by a murderous crowd of citizens his enemies have bribed; Kepler sells horoscopes to bejewel his faithless wife. Adam sensibly concludes that man will never achieve his ultimate ideals but ought to struggle toward them anyway, a conclusion that Szilard continued to endorse as late as 1945. “In [Madach’s] book,” he said then, “the devil shows Adam the history of mankind, [ending] with the sun dying down.398 Only a few Eskimos are left and they worry chiefly because there are too many Eskimos and too few seals [the last scene before Adam returns to the beginning again]. The thought is that there remains a rather narrow margin of hope after you have made your prophecy and it is pessimistic.”
Szilard’s qualified faith in progress and his liberal political values ultimately set him apart from his Hungarian peers. He believed that group was shaped by the special environment of Budapest at the turn of the century, “a society where economic security was taken for granted,” as a historian paraphrases him, and “a high value was placed on intellectual achievement.”399 The Minta that Szilard and Teller later attended deeply gratified von Kármán when he went there in the peaceful 1890s. “My father [who founded the school],” he writes, “was a great believer in teaching everything—Latin, math, and history—by showing its connection with everyday living.” To begin Latin the students wandered the city copying down inscriptions from statues and museums; to begin mathematics they looked up figures for Hungary’s wheat production and made tables and drew graphs. “At no time did we memorize rules from a book. Instead we sought to develop them ourselves.”400 What better basic training for a scientist?
Eugene Wigner, small and trim, whose father managed a tannery and who would become one of the leading theoretical physicists of the twentieth century, entered the Lutheran Gimnásium in 1913; John von Neumann followed the next year. “We had two years of physics courses, the last two years,” Wigner remembers. “And it was very interesting. Our teachers were just enormously good, but the mathematics teacher was fantastic. He gave private classes to Johnny von Neumann. He gave him private classes because he realized that this would be a great mathematician.”401
Von Neumann found a friend in Wigner. They walked and talked mathematics. Wigner’s mathematical talent was exceptional, but he felt less than first-rate beside the prodigious banker’s son. Von Neumann’s brilliance impressed colleagues throughout his life. Teller recalls a truncated syllogism someone proposed to the effect that (a) Johnny can prove anything and (b) anything Johnny proves is correct.402 At Princeton, where in 1933 von Neumann at twenty-nine became the youngest member of the newly established Institute for Advanced Study, the saying gained currency that the Hungarian mathematician was indeed a demigod but that he had made a thorough, detailed study of human beings and could imitate them perfectly.403 The story hints at a certain manipulative coldness behind the mask of bonhomie von Neumann learned to wear, and even Wigner thought his friendships lacked intimacy.404 To Wigner he was nevertheless the only authentic genius of the lot.405
These earlier memories of Gimnásium days contrast sharply with the turmoil that Teller experienced. Part of the difference was personal. Teller was bored in first-year math at the Minta and quickly managed to insult his mathematics teacher, who was also the principal of the school, by improving on a proof. The principal took the classroom display unkindly. “So you are a genius, Teller? Well, I don’t like geniuses.”406 But whatever Teller’s personal difficulties, he was also confronted directly, as a schoolboy of only eleven years, with revolution and counterrevolution, with riots and violent bloodletting, with personal fear. What had been usually only implicit for the Martians who preceded him was made explicit before his eyes. “I think this was the first time I was deeply impressed by my father,” he told his biographers. “He said anti-Semitism was coming. To me, the idea of anti-Semitism was new, and the fact that my father was so serious about it impressed me.”407
Von Kármán studied mechanical engineering at the University of Budapest before moving on to Göttingen in 1906; de Hevesy tried Budapest in 1903 before going to the Technische Hochschule in Berlin in 1904 and on to work with Fritz Haber and then with Ernest Rutherford; Szilard had studied at the Technology Institute in Budapest and served in the Army before the post-Armistice turmoil made him decide to leave. In contrast, Wigner, von Neumann and particularly Teller experienced the breakdown of Hungarian society as adolescents—Teller at the impressionable beginning of puberty—and at first hand.
“The Revolution arrived as a hurricane,” an eyewitness to the Hungarian Revolution of October 1918 recalls. “No one prepared it and no one arranged it; it broke out by its own irresistible momentum.”408 But there were antecedents: a general strike of half a million workers in Budapest and other Hungarian industrial centers in January 1918; another general strike of similar magnitude in June. In the autumn of that year masses of soldiers, students and workers gathered in Budapest. This first brief revolution began with anti-military and nationalistic claims. By the time the Hungarian National Council had been formed under Count Mihály Károli (“We can’t even manage a revolution without a count,” they joked in Budapest), in late October, there was expectation of real democratic reform: the council issued a manifesto calling for Hungarian independence, an end to the war, freedom of the press, a secret ballot and even female suffrage.
The Austro-Hungarian Dual Monarchy collapsed in November. Austrian novelist Robert Musil explained that collapse as well as anybody in a dry epitaph: Es ist passiert (“It sort of happened”).409 Hungary won a new government on October 31 and ecstatic crowds filled the streets of Budapest waving chrysanthemums, which had become the symbol of the revolution, and cheering the truckloads of soldiers and workers that pushed through.
The victory was not easy after all. The revolution hardly extended beyond Budapest. The new government was unable to negotiate anything better than a national dismembering. The founding of the Republic of Hungary, proclaimed on November 16, 1918, was shadowed by another founding on November 20: of the Hungarian Communist Party, by soldiers returning from Russian camps where they had been radicalized as prisoners of war. On March 21, 1919, four months after it began, the Republic of Hungary bloodlessly metamorphosed into the Hungarian Soviet Republic, its head a former prisoner of war, disciple of Lenin, journalist, Jew born in the Carpathians of Transylvania: Béla Kun. Arthur Koestler, a boy of fourteen then in Budapest, heard for the first time “the rousing tunes of the Marseillaise and of the Internationale which, during the hundred days of the Commune, drowned the music-loving town on the Danube in a fiery, melodious flood.”410
It was a little more than a hundred days: 133. They were days of confusion, hope, fear, comic ineptitude and some violence. Toward the end of the war von Kármán had returned to Budapest from aeronautics work with the Austro-Hungarian Air Force, where he had participated in the development of an early prototype of the helicopter. De Hevesy had also returned. Von Kármán helped reorganize and modernize the university in the brief days of the Republic and even served as undersecretary for universities during the Kun regime. He remembered its naïveté more than its violence: “So far as I can recall, there was no terrorism in Budapest during the one hundred days of the Bolsheviks, although I did hear of some sadistic excesses.”411 Lacking a qualified physicist, the university hired de Hevesy as a lecturer on experimental physics during the winter of 1918–19. Undersecretary von Kármán appointed him to a newly established professorship of physical chemistry in March, but de Hevesy found Commune working conditions unsatisfactory and went off in May to Denmark to visit Bohr. The two old friends agreed he would join Bohr’s new institute in Copenhagen as soon as it was built.
Arthur Koestler remembers that food was scarce, especially if you tried to buy it with the regime’s ration cards and nearly worthless paper money, but for some reason the same paper would purchase an abundance of Commune-sponsored vanilla ice cream, which his family therefore consumed for breakfast, lunch and dinner. He mentions this curiosity, he remarks, “because it was typical of the happy-go-lucky, dilettantish, and even surrealistic ways in which the Commune was run.” It was, Koestler thought, “all rather endearing—at least when compared to the lunacy and savagery which was to descend upon Europe in years to come.”412
The Hungarian Soviet Republic affected von Neumann and Teller far more severely. They were not admirers like young Koestler nor yet members of the intellectual elite like de Hevesy and von Kármán. They were children of businessmen—Max Teller was a prosperous attorney. Max von Neumann took his family and fled to Vienna. “We left Hungary,” his son testified many years later, “very soon after the Communists seized power. . . . We left essentially as soon as it was feasible, which was about 30 or 40 days later, and we returned about 2 months after the Communists had been put down.”413 In Vienna the elder von Neumann joined the group of Hungarian financiers working with the conservative nobility to overthrow the Commune.414
Lacking protective wealth, the Tellers stuck it out grimly in Budapest, living with their fears. They made forays into the country to barter with the peasants for food. Teller heard of corpses hung from lampposts, though as with von Kármán’s “sadistic excesses” he witnessed none himself.415 Faced with an overcrowded city, the Commune had socialized all housing. The day came for the Koestlers as for the Tellers when soldiers charged with requisitioning bourgeois excesses of floor space and furniture knocked on their doors. The Koestlers, who occupied two threadbare rooms in a boarding house, were allowed to keep what they had, Arthur discovering in the meantime that working people were interesting and different. The Tellers acquired two soldiers who slept on couches in Max Teller’s two office rooms, connected to the Teller apartment.416 The soldiers were courteous; they sometimes shared their food; they urinated on the rubber plant; but because they searched for hoarded money (which was safely stashed in the cover linings of Max Teller’s law books) or simply because the Tellers felt generally insecure, their alien presence terrified.
Yet it was not finally Hungarian communism that frightened Edward Teller’s parents most. The leaders of the Commune and many among its officials were Jewish—necessarily, since the only intelligentsia Hungary had evolved up to that time was Jewish. Max Teller warned his son that anti-Semitism was coming. Teller’s mother expressed her fears more vividly. “I shiver at what my people are doing,” she told her son’s governess in the heyday of the Commune.417 “When this is over there will be a terrible revenge.”
In the summer of 1919, as the Commune faltered, eleven-year-old Edward and his older sister Emmi were packed off to safety at their maternal grandparents’ home in Rumania. They returned in the autumn; by then Admiral Nicholas Horthy had ridden into Budapest on a white horse behind a new national army to install a violent fascist regime, the first in Europe. The Red Terror had come and gone, resulting in some five hundred deaths by execution.418 The White Terror of the Horthy regime was of another order of magnitude: at least 5,000 deaths and many of those sadistic; secret torture chambers; a selective but unrelenting anti-Semitism that drove tens of thousands of Jews into exile.419 A contemporary observer, a socialist equally biased against either extreme, wrote that he had “no desire whatever to palliate the brutalities and atrocities of the proletarian dictatorship; its harshness is not to be denied, even if its terrorists operated more with insults and threats than with actual deeds. But the tremendous difference between the Red and the White Terror is beyond all question.”420 A friend of the new regime, Max von Neumann brought his family home.
In 1920 the Horthy regime introduced a numerus clausus law restricting university admission which required “that the comparative numbers of the entrants correspond as nearly as possible to the relative population of the various races or nationalities.”421 The law, which would limit Jewish admissions to 5 percent, a drastic reduction, was deliberately anti-Semitic. Though he was admitted to the University of Budapest and might have stayed, von Neumann chose instead to leave Hungary at seventeen, in 1921, for Berlin, where he came under the influence of Fritz Haber and studied first for a chemical engineering degree, awarded at the Technical Institute of Zürich in 1925. A year later he picked up a Ph.D. summa cum laude in mathematics at Budapest; in 1927 he became aPrivatdozent at the University of Berlin; in 1929, at twenty-five, he was invited to lecture at Princeton. He was professor of mathematics at Princeton by 1931 and accepted lifetime appointment to the Institute for Advanced Study in 1933.
Von Neumann experienced no personal violence in Hungary, only upheaval and whatever anxiety his parents communicated. He nevertheless felt himself scarred. His discussion with Stanislaw Ulam went on more ominously from identifying Carpathian villages as the ultimate places of origin of Hungary’s talented expatriates. “It will be left to historians of science,” Ulam writes, “to discover and explain the conditions which catalyzed the emergence of so many brilliant individuals from that area. . . . Johnny used to say that it was a coincidence of some cultural factors which he could not make precise: an external pressure on the whole society of this part of Central Europe, a feeling of extreme insecurity in the individuals, and the necessity to produce the unusual or else face extinction.”422
Teller was too young to leave Hungary during the worst of the Horthy years. This was the adolescent period, as Time magazine paraphrased Teller later, when Max Teller “dinned into his son two grim lessons: 1) he would have to emigrate to some more favorable country when he grew up and 2) as a member of a disliked minority he would have to excel the average just to stay even.”423 Teller added a lesson of his own. “I loved science,” he told an interviewer once. “But also it offered a possibility for escaping this doomed society.”424 Von Kármán embeds in his autobiography a similarly striking statement about the place of science in his emotional life. When the Hungarian Soviet Republic collapsed he retreated to the home of a wealthy friend, then found his way back to Germany. “I was glad to get out of Hungary,” he writes of his state of mind then. “I felt I had had enough of politicians and government upheavals. . . . Suddenly I was enveloped in the feeling that only science is lasting.”425
That science can be a refuge from the world is a conviction common among men and women who turn to it. Abraham Pais remarks that Einstein “once commented that he had sold himself body and soul to science, being in flight from the ‘I∍ and the ‘we’ to the‘it.’ ”426 But science as a means of escaping from the familiar world of birth and childhood and language when that world mounts an overwhelming threat—science as a way out, a portable culture, an international fellowship and the only abiding certitude—must become a more desperate and therefore a more total dependency. Chaim Weizmann gives some measure of that totality in the harsher world of the Russian Pale when he writes that “the acquisition of knowledge was not for us so much a normal process of education as the storing up of weapons in an arsenal by means of which we hoped later to be able to hold our own in a hostile world.”427 He remembers painfully that “every division of one’s life was a watershed.”428
Teller’s experience in Hungary before he left it in 1926, at seventeen, for the Technical Institute at Karlsruhe was far less rigorous than Weizmann’s in the Pale. But external circumstance is no sure measure of internal wounding, and there are not many horrors as efficient for the generation of deep anger and terrible lifelong insecurity as the inability of a father to protect his child.
* * *
“In the last few years,” Niels Bohr wrote the German theoretical physicist Arnold Sommerfeld at Munich in April 1922, “I have often felt myself scientifically very lonesome, under the impression that my effort to develop the principles of the quantum theory systematically to the best of my ability has been received with very little understanding.”429 Through the war years Bohr had struggled to follow, wherever it might lead, the “radical change” he had introduced into physics. It led to frustration. However stunning Bohr’s prewar results had been, too many older European scientists still thought his inconsistent hypotheses ad hoc and the idea of a quantized atom repugnant. The war itself stalled advance.
Yet he persisted, groping his way forward in the darkness. “Only a rare and uncanny intuition,” writes the Italian physicist Emilio Segrè, “saved Bohr from getting lost in the maze.”430 He guided himself delicately by what he called the correspondence principle. As Robert Oppenheimer once explained it, “Bohr remembered that physics was physics and that Newton described a great part of it and Maxwell a great part of it.” So Bohr assumed that his quantum rules must approximate, “in situations where the actions involved were large compared to the quantum, to the classical rules of Newton and of Maxwell.”431 That correspondence between the reliable old and the unfamiliar new gave him an outer limit, a wall to feel his way along.
Bohr built his Institute for Theoretical Physics with support from the University of Copenhagen and from Danish private industry, occupying it on January 18, 1921, after more than a year of delay—he struggled with the architect’s plans as painfully as he struggled with his scientific papers. The city of Copenhagen ceded land for the institute on the edge of the Faelledpark, broad with soccer fields, where a carnival annually marks the Danish celebration of Constitution Day. The building itself was modest gray stucco with a red tile roof, no larger than many private homes, with four floors inside that looked like only three outside because the lowest floor was built partly below grade and the top floor, which served the Bohrs at first as an apartment, extended into the space under the peaked roof (later, as Bohr’s family increased to five sons, he built a house next door and the apartment served as living quarters for visiting students and colleagues). The institute included a lecture hall, a library, laboratories, offices and a popular PingPong table where Bohr often played. “His reactions were very fast and accurate,” says Otto Frisch, “and he had tremendous will power and stamina. In a way those qualities characterized his scientific work as well.”432
In 1922, the year his Nobel Prize made him a Danish national hero, Bohr accomplished a second great theoretical triumph: an explanation of the atomic structure that underlies the regularities of the periodic table of the elements. It linked chemistry irrevocably to physics and is now standard in every basic chemistry text. Around the nucleus, Bohr proposed, atoms are built up of successive orbital shells of electrons—imagine a set of nested spheres—each shell capable of accommodating up to a certain number of electrons and no more. Elements that are similar chemically are similar because they have identical numbers of electrons in their outermost shells, available there for chemical combination. Barium, for example, an alkaline earth, the fifty-sixth element in the periodic table, atomic weight 137.34, has electron shells filled successively by 2, 8, 18, 18, 8 and 2 electrons. Radium, another alkaline earth, the eighty-eighth element, atomic weight 226, has electron shells filled successively by 2, 8, 18, 32, 18, 8 and 2 electrons. Because the outer shell of each element has two valence electrons, barium and radium are chemically similar despite their considerable difference in atomic weight and number. “That [the] insecure and contradictory foundation [of Bohr’s quantum hypotheses],” Einstein would say, “was sufficient to enable a man of Bohr’s unique instinct and perceptiveness to discover the major laws of spectral lines and of the electron shells of the atom as well as their significance for chemistry appeared to me like a miracle. . . . This is the highest form of musicality in the sphere of thought.”433
Confirming the miracle, Bohr predicted in the autumn of 1922 that element 72 when discovered would not be a rare earth, as chemists expected and as elements 57 through 71 are, but would rather be a valence 4 metal like zirconium. George de Hevesy, now settled in at Bohr’s institute, and a newly arrived young Dutchman, Dirk Coster, went to work using X-ray spectroscopy to look for the element in zircon-bearing minerals. They had not finished their checking when Bohr went off with Margrethe in early December to claim his Nobel Prize. They called him in Stockholm the night before his Nobel lecture, only just in time: they had definitely identified element 72 and it was chemically almost identical to zirconium. They named the new element hafnium after Hafnia, the old Roman name for Copenhagen. Bohr announced its discovery with pride at the conclusion of his lecture the next day.
Despite his success with it, quantum theory needed a more solid foundation than Bohr’s intuition. Arnold Sommerfeld in Munich was an early contributor to that work; after the war the brightest young men, searching out the growing point of physics, signed on to help. Bohr remembered the period as “a unique cooperation of a whole generation of theoretical physicists from many countries,” an “unforgettable experience.”434 He was lonesome no more.
Sommerfeld brought with him to Göttingen in the early summer of 1922 his most promising student, a twenty-year-old Bavarian named Werner Heisenberg, to hear Bohr as visiting lecturer there. “I shall never forget the first lecture,” Heisenberg wrote fifty years later, the memory still textured with fine detail. “The hall was filled to capacity. The great Danish physicist . . . stood on the platform, his head slightly inclined, and a friendly but somewhat embarrassed smile on his lips.435 Summer light flooded in through the wide-open windows. Bohr spoke fairly softly, with a slight Danish accent. . . . Each one of his carefully formulated sentences revealed a long chain of underlying thoughts, of philosophical reflections, hinted at but never fully expressed. I found this approach highly exciting.”
Heisenberg nevertheless raised pointed objection to one of Bohr’s statements. Bohr had learned to be alert for bright students who were not afraid to argue. “At the end of the discussion he came over to me and asked me to join him that afternoon on a walk over the Hain Mountain,” Heisenberg remembers. “My real scientific career only began that afternoon.”436 It is the memory of a conversion. Bohr proposed that Heisenberg find his way to Copenhagen eventually so that they could work together. “Suddenly, the future looked full of hope.”437 At dinner the next evening Bohr was startled to be challenged by two young men in the uniforms of the Göttingen police. One of them clapped him on the shoulder: “You are arrested on the charge of kidnapping small children!” They were students, genial frauds.438 The small child they guarded was Heisenberg, boyish with freckles and a stiff brush of red hair.
Heisenberg was athletic, vigorous, eager—“radiant,” a close friend says. “He looked even greener in those days than he really was, for, being a member of the Youth Movement . . . he often wore, even after reaching man’s estate, an open shirt and walking shorts.”439 In the Youth Movement young Germans on hiking tours built campfires, sang folk songs, talked of knighthood and the Holy Grail and of service to the Fatherland. Many were idealists, but authoritarianism and anti-Semitism already bloomed poisonously among them. When Heisenberg finally got to Copenhagen at Eastertime in 1924 Bohr took him off on a hike through north Zealand and asked him about it all. “‘But now and then our papers also tell us about more ominous, anti-Semitic, trends in Germany, obviously fostered by demagogues,’ ” Heisenberg remembers Bohr questioning. “ ‘Have you come across any of that yourself?’ ” That was the work of some of the old officers embittered by the war, Heisenberg said, “but we don’t take these groups very seriously.”440
Now, as part of the “unique cooperation” Bohr would speak of, they went freshly to work on quantum theory. Heisenberg seems to have begun with a distaste for visualizing unmeasurable events. As an undergraduate, for example, he had been shocked to read in Plato’s Timaeus that atoms had geometric forms: “It saddened me to find a philosopher of Plato’s critical acumen succumbing to such fancies.”441 The orbits of Bohr’s electrons were similarly fanciful, Heisenberg thought, and Max Born and Wolfgang Pauli, his colleagues at Göttingen, concurred. No one could see inside an atom. What was known and measurable was the light that came out of the atomic interior, the frequencies and amplitudes associated with spectral lines. Heisenberg decided to reject models entirely and look for regularities among the numbers alone.
He returned to Göttingen as a Privatdozent working under Born. Toward the end of May 1925 his hay fever flared; he asked Born for two weeks’ leave of absence and made his way to Heligoland, a stormy sliver of island twenty-eight miles off the German coast in the North Sea, where very little pollen blew. He walked; he swam long distances in the cold sea; “a few days were enough to jettison all the mathematical ballast that invariably encumbers the beginning of such attempts, and to arrive at a simple formulation of my problem.”442 A few days more and he glimpsed the system he needed. It required a strange algebra that he cobbled together as he went along where numbers multiplied in one direction often produced different products from the same numbers multiplied in the opposite direction. He worried that his system might violate the basic physical law of the conservation of energy and he worked until three o’clock in the morning checking his figures, nervously making mistakes. By then he saw that he had “mathematical consistency and coherence.” And so often with deep physical discovery, the experience was elating but also psychologically disturbing:
At first, I was deeply alarmed. I had the feeling that, through the surface of atomic phenomena, I was looking at a strangely beautiful interior, and felt almost giddy at the thought that I now had to probe this wealth of mathematical structures nature had so generously spread out before me. I was far too excited to sleep, and so, as a new day dawned, I made for the southern tip of the island, where I had been longing to climb a rock jutting out into the sea. I now did so without too much trouble, and waited for the sun to rise.
Back in Göttingen Max Born recognized Heisenberg’s strange mathematics as matrix algebra, a mathematical system for representing and manipulating arrays of numbers on matrices—grids—that had been devised in the 1850s and that Born’s teacher David Hilbert had extended in 1904. In three months of intensive work Born, Heisenberg and their colleague Pascual Jordan then developed what Heisenberg calls “a coherent mathematical framework, one that promised to embrace all the multifarious aspects of atomic physics.”443 Quantum mechanics, the new system was called. It fit the experimental evidence to a high degree of accuracy. Pauli managed with heroic effort to apply it to the hydrogen atom and derive in a consistent way the same results—the Balmer formula, Rydberg’s constant—that Bohr had derived from inconsistent assumptions in 1913. Bohr was delighted. At Copenhagen, at Göttingen, at Munich, at Cambridge, the work of development went on.
* * *
The bow of the Carpathians as they curve around northwestward begins to define the northern border of Czechoslovakia. Long before it can complete that service the bow bends down toward the Austrian Alps, but a border region of mountainous uplift, the Sudetes, continues across Czechoslovakia. Some sixty miles beyond Prague it turns southwest to form a low range between Czechoslovakia and Germany that is called, in German, the Erzgebirge: the Ore Mountains. The Erzgebirge began to be mined for iron in medieval days. In 1516 a rich silver lode was discovered in Joachimsthal (St. Joachim’s dale), in the territory of the Count von Schlick, who immediately appropriated the mine. In 1519 coins were first struck from its silver at his command. Joachimsthaler, the name for the new coins, shortened to thaler, became “dollar” in English before 1600. Thereby the U.S. dollar descends from the silver of Joachimsthal.
The Joachimsthal mines, ancient and cavernous, shored with smoky timbers, offered up other unusual ores, including a black, pitchy, heavy, nodular mineral descriptively named pitchblende. A German apothecary and self-taught chemist, Martin Heinrich Klaproth, who became the first professor of chemistry at the University of Berlin when it opened its doors in 1810, succeeded in 1789 in extracting a grayish metallic material from a sample of Joachimsthal pitchblende. He sought an appropriate name. Eight years previously Sir William Herschel, the German-born English astronomer, had discovered a new planet and named it Uranus after the earliest supreme god of Greek mythology, son and husband of Gaea, father of Titans and Cyclopes, whose son Chronus with Gaea’s help castrated him and from whose wounded blood, falling then on Earth, the three vengeful Furies sprang. To honor Herschel’s discovery Klaproth named his new metal uranium. It was found to serve, in the form of sodium and ammonium diuranates, as an excellent coloring agent of ceramic glazes, giving a good yellow at 0.006 percent and with higher percentages successively orange, brown, green and black. Uranium mining for ceramics, once begun, continued modestly at Joachimsthal into the modern era. It was from Joachimsthal pitchblende residues that Marie and Pierre Curie laboriously separated the first samples of the new elements they named radium and polonium. The radioactivity of the Erzgebirge ores thus lent glamour to the region’s several spas, including Carlsbad and Marienbad, which could now announce that their waters were not only naturally heated but dispersed tonic radioactivity as well.
In the summer of 1921 a wealthy seventeen-year-old American student, a recent graduate of the Ethical Culture School of New York, made his way to Joachimsthal on an amateur prospecting trip. Young Robert Oppenheimer had begun collecting minerals when his grandfather, who lived in Hanau, Germany, had given him a modest starter collection on a visit there when Robert was a small boy, before the Great War. He dated his interest in science from that time. “This was certainly at first a collector’s interest,” he told an interviewer late in life, “but it began to be also a bit of a scientist’s interest, not in historical problems of how rocks and minerals came to be, but really a fascination with crystals, their structure, birefringence, what you saw in polarized light, and all the canonical business.” The grandfather was “an unsuccessful businessman, born himself in a hovel, really, in an almost medieval German village, with a taste for scholarship.”444 Oppenheimer’s father had left Hanau for America at seventeen, in 1898, worked his way to ownership of a textile-importing company and prospered importing lining fabrics for men’s suits at a time when ready-made suits were replacing hand tailoring in the United States. The Oppenheimers—Julius; his beautiful and delicate wife Ella, artistically trained, from Baltimore; Robert, born April 22, 1904; and Frank, Robert’s sidekick brother, eight years younger—could afford to summer in Europe and frequently did so.
Julius and Ella Oppenheimer were people of dignity and some caution, nonpracticing Jews. They lived in a spacious apartment on Riverside Drive near 88th Street overlooking the Hudson River and kept a summer house at Bay Shore on Long Island. They dressed with tailored care, practiced cultivation, sheltered themselves and their children from real and imagined harm. Ella Oppenheimer’s congenitally unformed right hand, hidden always in a prosthetic glove, was not discussed, not even by the boys out of earshot among their friends. She was loving but formal: in her presence only her husband presumed to raise his voice. Julius Oppenheimer, according to one of Robert’s friends a great talker and social arguer, according to another was “desperately amiable, anxious to be agreeable,” but also essentially kind.445, 446 He belonged to Columbia University educator Felix Adler’s Society for Ethical Culture, of which Robert’s school was an extension, which declared that “man must assume responsibility for the direction of his life and destiny”: man, as opposed to God. Robert Oppenheimer remembered himself as “an unctuous, repulsively good little boy.” His childhood, he said, “did not prepare me for the fact that the world is full of cruel and bitter things. It gave me no normal, healthy way to be a bastard.”447 He was a frail child, frequently ill. For that reason, or because she had lost a middle son shortly after birth, his mother did not encourage him to run in the streets. He stayed home, collected minerals and at ten years of age wrote poems but still played with blocks.
He was already working up to science. A professional microscope was a childhood toy. He did laboratory experiments in the third grade, began keeping scientific notebooks in the fourth, began studying physics in the fifth, though for many years chemistry would interest him more. The curator of crystals at the American Museum of Natural History took him as a pupil. He lectured to the surprised and then delighted members of the New York Mineralogical Club when he was twelve—from the quality of his correspondence the membership had assumed he was an adult.
When he was fourteen, to get him out of doors and perhaps to help him find friends, his parents sent him to camp. He walked the trails of Camp Koenig looking for rocks and discoursing with the only friend he found on George Eliot, emboldened by Eliot’s conviction that cause and effect ruled human affairs. He was shy, awkward, unbearably precious and condescending and he did not fight back. He wrote his parents that he was glad to be at camp because he was learning the facts of life. The Oppenheimers came running. When the camp director cracked down on dirty jokes, the other boys, the ones who called Robert “Cutie,” traced the censorship to him and hauled him off to the camp icehouse, stripped him bare, beat him up—“tortured him,” his friend says—painted his genitals and buttocks green and locked him away naked for the night.448 Responsibly he held out to the end of camp but never went back. “Still a little boy,” another childhood friend, a girl he liked more than she knew, remembers him at fifteen; “ . . . very frail, very pink-cheeked, very shy, and very brilliant of course. Very quickly everybody admitted that he was different from all the others and very superior. As far as studies were concerned he was good in everything. . . . Aside from that he was physically—you can’t say clumsy exactly—he was rather undeveloped, not in the way he behaved but the way he went about, the way he walked, the way he sat. There was something strangely childish about him.”449
He graduated as Ethical Culture’s valedictorian in February 1921. In April he underwent surgery for appendicitis. Recovered from that, he traveled with his family to Europe and off on his side trip to Joachimsthal. Somewhere along the way he “came down with a heavy, almost fatal case of trench dysentery.” He was supposed to enter Harvard in September, but “I was sick abed—in Europe, actually, at the time.”450 Severe colitis following the bout of dysentery laid him low for months. He spent the winter in the family apartment in New York.
To round off Robert’s convalescence and toughen him up, his father arranged for a favorite English teacher at Ethical Culture, a warm, supportive Harvard graduate named Herbert Smith, to take him out West for the summer. Robert was then eighteen, his face still boyish but steadied by arresting blue-gray eyes. He was six feet tall, on an extremely narrow frame; he never in his life weighed more than 125 pounds and at times of illness or stress could waste to 115. Smith guided his charge to a dude ranch, Los Piños, in the Sangre de Cristo Mountains northeast of Santa Fe, and Robert chowed down, chopped wood, learned to ride horses and live in rain and weather.
A highlight of the summer was a pack trip. It started in Frijoles, a village within sheer, pueblo-carved Cañon de los Frijoles across the Rio Grande from the Sangre de Cristos, and ascended the canyons and mesas of the Pajarito Plateau up to the Valle Grande of the vast Jemez Caldera above 10,000 feet. The Jemez Caldera is a bowl-shaped volcanic crater twelve miles across with a grassy basin inside 3,500 feet below the rim, the basin divided by mountainous extrusions of lava into several high valleys. It is a million years old and one of the largest calderas in the world, visible even from the moon. Northward four miles from the Cañon de los Frijoles a parallel canyon took its Spanish name from the cottonwoods that shaded its washes: Los Alamos. Young Robert Oppenheimer first approached it in the summer of 1922.
Like Eastern semi-invalids in frontier days, Oppenheimer’s encounter with wilderness, freeing him from overcivilized restraints, was decisive, a healing of faith. From an ill and perhaps hypochondriac boy he weathered across a vigorous summer to a physically confident young man. He arrived at Harvard tanned and fit, his body at least in shape.
At Harvard he imagined himself a Goth coming into Rome.451 “He intellectually looted the place,” a classmate says.452 He routinely took six courses for credit—the requirement was five—and audited four more. Nor were they easy courses. He was majoring in chemistry, but a typical year might include four semesters of chemistry, two of French literature, two of mathematics, one of philosophy and three of physics, these only the courses credited.453 He read on his own as well, studied languages, found occasional weekends for sailing the 27-foot sloop his father had given him or for allnight hikes with friends, wrote short stories and poetry when the spirit moved him but generally shied from extracurricular activities and groups. Nor did he date; he was still unformed enough to brave no more than worshiping older women from afar. He judged later that “although I liked to work, I spread myself very thin and got by with murder.”454 The murder he got by with resulted in a transcript solid with A’s sprinkled with B’s; he graduated summa cum laude in three years.
There is something frantic in all this grinding, however disguised in traditional Harvard languor. Oppenheimer had not yet found himself—is that more difficult for Americans than for Europeans like Szilard or Teller, who seem all of a piece from their earliest days?—and would not manage to do so at Harvard. Harvard, he would say, was “the most exciting time I’ve ever had in my life. I really had a chance to learn. I loved it. I almost came alive.”455 Behind the intellectual excitement there was pain.
He was always an intensely, even a cleverly, private man, but late in life he revealed himself to a group of sensitive friends, a revelation that certainly reaches back all the way to his undergraduate years. “Up to now,” he told that group in 1963, “and even more in the days of my almost infinitely prolonged adolescence, I hardly took an action, hardly did anything or failed to do anything, whether it was a paper in physics, or a lecture, or how I read a book, how I talked to a friend, how I loved, that did not arouse in me a very great sense of revulsion and of wrong.”456 His friends at Harvard saw little of this side—an American university is after all a safe-house—but he hinted of it in his letters to Herbert Smith:
Generously, you ask what I do. Aside from the activities exposed in last week’s disgusting note, I labor, and write innumerable theses, notes, poems, stories, and junk; I go to the math lib[rary] and read and to the Phil lib and divide my time between Meinherr [Bertrand] Russell and the contemplation of a most beautiful and lovely lady who is writing a thesis on Spinoza—charmingly ironic, at that, don’t you think? I make stenches in three different labs, listen to Allard gossip about Racine, serve tea and talk learnedly to a few lost souls, go off for the weekend to distill the low grade energy into laughter and exhaustion, read Greek, commit faux pas, search my desk for letters, and wish I were dead. Voila.457
Part of that exaggerated death wish is Oppenheimer making himself interesting to his counselor, but part of it is pure misery—considering its probable weight, rather splendidly and courageously worn.
Both of Oppenheimer’s closest college friends, Francis Fergusson and Paul Horgan, agree that he was prone to baroque exaggeration, to making more of things than things could sustain on their own.458 Since that tendency would eventually ruin his life, it deserves to be examined. Oppenheimer was no longer a frightened boy, but he was still an insecure and uncertain young man. He sorted among information, knowledge, eras, systems, languages, arcane and apposite skills in the spirit of trying them on for size. Exaggeration made it clear that he knew you knew how awkwardly they fit (and self-destructively at the same time supplied the awkwardness). That was perhaps its social function. Deeper was worse. Deeper was self-loathing, “a very great sense of revulsion and of wrong.” Nothing was yet his, nothing was original, and what he had appropriated through learning he thought stolen and himself a thief: a Goth looting Rome. He loved the loot but despised the looter. He was as clear as Harry Moseley was clear in his last will about the difference between collectors and creators. At the same time, intellectual controls were the only controls he seems to have found at that point in his life, and he could hardly abandon them.
He tried writing, poems and short stories. His college letters are those of a literary man more than of a scientist. He would keep his literary skills and they would serve him well, but he acquired them first of all for the access he thought they might open to self-knowledge. At the same time, he hoped writing would somehow humanize him. He read The Waste Land, newly published, identified with its Weltschmerz and began to seek the stern consolations of Hindu philosophy. He worked through the rigors of Bertrand Russell’s and Alfred North Whitehead’s three-volume Principia Mathematica with Whitehead himself, newly arrived—only one other student braved the seminar—and prided himself throughout his life on that achievement. Crucially, he began to find the physics that underlay the chemistry, as he had found crystals emerging in clarity from the historical complexity of rocks: “It came over me that what I liked in chemistry was very close to physics; it’s obvious that if you were reading physical chemistry and you began to run into thermodynamical and statistical mechanical ideas you’d want to find out about them. . . . It’s a very odd picture; I never had an elementary course in physics.”459
He worked in the laboratory of Percy Bridgman, many years later a Nobel laureate, “a man,” says Oppenheimer, “to whom one wanted to be an apprentice.”460 He learned much of physics, but haphazardly. He graduated a chemist and was foolhardy enough to imagine that Ernest Rutherford would welcome him at Cambridge, where the Manchester physicist had moved in 1919 to take over direction of the Cavendish from the aging J. J. Thomson. “But Rutherford wouldn’t have me,” Oppenheimer told a historian later. “He didn’t think much of Bridgman and my credentials were peculiar and not impressive, and certainly not impressive to a man with Rutherford’s common sense. . . . I don’t even know why I left Harvard, but I somehow felt that [Cambridge] was more near the center.”461 Nor would Bridgman’s letter of recommendation, though well meant, have helped with Rutherford. Oppenheimer had a “perfectly prodigious power of assimilation,” the Harvard physicist wrote, and “his problems have in many cases shown a high degree of originality in treatment and much mathematical power.” But “his weakness is on the experimental side. His type of mind is analytical, rather than physical, and he is not at home in the manipulations of the laboratory.” Bridgman said honestly that he thought Oppenheimer “a bit of a gamble.”462 On the other hand, “if he does make good at all, I believe that he will be a very unusual success.” After another healing summer in New Mexico with Paul Horgan and old friends from the summer of 1921, Oppenheimer went off to Cambridge to attack the center where he could.
J. J. Thomson still worked at the Cavendish. He let Oppenheimer in. “I am having a pretty bad time,” Oppenheimer wrote to Francis Fergusson at Oxford on November 1. “The lab work is a terrible bore, and I am so bad at it that it is impossible to feel that I am learning anything. . . . The lectures are vile.” Yet he thought “the academic standard here would depeople Harvard overnight.”463 He worked in one corner of a large basement room at the Cavendish (the Garage, it was called); Thomson worked in another. He labored painfully to make thin films of beryllium for an experiment he seems never to have finished—James Chadwick, who had moved down from Manchester and was now Rutherford’s assistant director of research, later put them to use. “The business of the laboratory was really quite a sham,” Oppenheimer recalled, “but it got me into the laboratory where I heard talk and found out a good deal of what people were interested in.”464
Postwar work on quantum theory was just then getting under way. It excited Oppenheimer enormously. He wanted to be a part of it. He was afraid he might be too late. All his learning had come easily before. At Cambridge he hit the wall.
It was as much an emotional wall as an intellectual, probably more. “The melancholy of the little boy who will not play because he has been snubbed,” he described it three years later, after he broke through.465 The British gave him the same silent treatment they had given Niels Bohr, but he lacked Bohr’s hard-earned self-confidence. Herbert Smith sensed the approaching disaster. “How is Robert doing?” he wrote Fergusson. “Is frigid England hellish socially and climatically, as you found it? Or does he enjoy its exoticism? I’ve a notion, by the way, that your ability to show him about should be exercised with great tact, rather than in royal profusion. Your [two] years’ start and social adaptivity are likely to make him despair. And instead of flying at your throat . . . I’m afraid he’d merely cease to think his own life worth living.”466 Oppenheimer wrote Smith in December that he had not been busy “making a career for myself. . . . Really I have been engaged in the far more difficult business of making myself for a career.”467 It was worse than that. He was in fact, as he later said, “on the point of bumping myself off. This was chronic.”468 He saw Fergusson at Christmastime in Paris and reported despair at his lab work and frustration with sexual ventures. Then, contradicting Smith’s prediction, he flew at Fergusson’s throat and tried to strangle him. Fergusson easily set him aside. Back at Cambridge Oppenheimer tried a letter of explanation. He wrote that he was sending Fergusson a “noisy” poem. “I have left out, and that is probably where the fun came in, just as I did in Paris, the awful fact of excellence; but as you know, it is that fact now, combined with my inability to solder two copper wires together, which is probably succeeding in getting me crazy.”469
The awful fact of excellence did not continue to elude him. As he approached a point of psychological crisis he also drove hard to extend himself, understanding deeply that his mind must pull him through. He was “doing a tremendous amount of work,” a friend said, “thinking, reading, discussing things, but obviously with a sense of great inner anxiety and alarm.”470 A crucial change that year was his first meeting with Bohr. “When Rutherford introduced me to Bohr he asked me what I was working on. I told him and he said, ‘How is it going?’ I said, ‘I’m in difficulties.’ He said, ‘Are the difficulties mathematical or physical?’ I said, ‘I don’t know.’ He said, ‘That’s bad.’ ”471 But something about Bohr—his avuncular warmth at least, what C. P. Snow calls his simple and genuine kindness, his uninsipid “sweetness”—helped release Oppenheimer to commitment: “At that point I forgot about beryllium and films and decided to try to learn the trade of being a theoretical physicist.”472, 473
Whether the decision precipitated the crisis or began to relieve it is not clear from the record. Oppenheimer visited a Cambridge psychiatrist. Someone wrote his parents about his problems and they hurried over as they had hurried to Camp Koenig years before. They pushed their son to see a new psychiatrist. He found one in London on Harley Street. After a few sessions the man diagnosed dementia praecox, the older term for what is now called schizophrenia, a condition characterized by early adult onset, faulty thought processes, bizarre actions, a tendency to live in an inner world, incapacity to maintain normal interpersonal relationships and an extremely poor prognosis. Given the vagueness of the symptomatology and Oppenheimer’s intellectual dazzle and profound distress, the psychiatrist’s mistake is easy enough to understand. Fergusson met Oppenheimer in Harley Street one day and asked him how it had gone. “He said . . . that the guy was too stupid to follow him and that he knew more about his troubles than the [doctor] did, which was probably true.”474
Resolution began before the consultations on Harley Street, in the spring, on a ten-day visit to Corsica with two American friends. What happened to bring Oppenheimer through is a mystery, but a mystery important enough to him that he deliberately emphasized it—tantalizingly and incompletely—to one of the more sensitive of his profilers, Nuel Pharr Davis. Corsica, Oppenheimer wrote his brother Frank soon after his visit, was “a great place, with every virtue from wine to glaciers, and from langouste to brigantines.”475To Davis, late in life, he emphasized that although the United States Government had assembled hundreds of pages of information about him across the years, so that some people said his entire life was recorded there, the record in fact contained almost nothing of real importance. To prove his point, he said, he would mention Corsica. “The [Cambridge] psychiatrist was a prelude to what began for me in Corsica. You ask whether I will tell you the full story or whether you must dig it out. But it is known to few and they won’t tell. You can’t dig it out. What you need to know is that it was not a mere love affair, not a love affair at all, but love.”476 It was, he said, “a great thing in my life, a great and lasting part of it.”477
Whether a love affair or love, Oppenheimer found his vocation in Cambridge that year: that was the certain healing. Science saved him from emotional disaster as science was saving Teller from social disaster. He moved to Göttingen, the old medieval town in Lower Saxony in central Germany with the university established by George II of England, in the autumn of 1926, late Weimar years. Max Born headed the university physics department, newly installed in institute buildings on Bunsenstrasse funded by the Rockefeller Foundation. Eugene Wigner traveled to Göttingen to work with Born, as had Werner Heisenberg and Wolfgang Pauli and, less happily, the Italian Enrico Fermi, all future Nobel laureates. James Franck, having moved over from Haber’s institute at the KWI, a Nobelist as of 1925, supervised laboratory classes. The mathematicians Richard Courant, Herman Weyl and John von Neumann collaborated. Edward Teller would show up later on an assistantship.
The town was pleasant, for visiting Americans at least. They could drink frisches Bier at the fifteenth-century Schwartzen Bären, the Black Bears, and sit to crisp, delicate wiener Schnitzel at the Junkernschänke, the Junkers’ Hall, under a steel engraving of former patron Otto von Bismarck. The Junkernschänke, four hundred years old, occupied three stories of stained glass and flowered half-timber at the corner of Barefoot and Jew streets, which makes it likely that Oppenheimer dined there: he would have appreciated the juxtaposition. When a student took his doctorate at Göttingen he was required by his classmates to kiss the Goose Girl, a pretty, lifesize bronze maiden within a bronze floral arbor that decorates the fountain on the square in front of the medieval town hall. To reach the lips of the Gänseliesel required wading or leaping the fountain pool, the real point of the exercise, a baptism into professional distinction Oppenheimer must have welcomed.
The townspeople still suffered from the disaster of the war and the inflation. Oppenheimer and other American students lodged at the walled mansion of a Göttingen physician who had lost everything and was forced to take in boarders. “Although this society [at the university] was extremely rich and warm and helpful to me,” Oppenheimer says, “it was parked there in a very miserable German mood . . . bitter, sullen, and, I would say, discontent and angry and with all those ingredients which were later to produce a major disaster. And this I felt very much.”478 At Göttingen he first measured the depth of German ruin. Teller generalized it later from his own experience of lost wars and their aftermaths: “Not only do wars create incredible suffering, but they engender deep hatreds that can last for generations.”479
Two of Oppenheimer’s papers, “On the quantum theory of vibrationrotation bands” and “On the quantum theory of the problem of the two bodies,” had already been accepted for publication in the Proceedings of the Cambridge Philosophical Society when he arrived at Göttingen, which helped to pave the way. As he came to his vocation the papers multiplied. His work was no longer apprenticeship but solid achievement. His special contribution, appropriate to the sweep of his mind, was to extend quantum theory beyond its narrow initial ground. His dissertation, “On the quantum theory of continuous spectra,” was published in German in the prestigious Zeitschrift für Physik. Born marked it “with distinction”—high praise indeed. Oppenheimer and Born jointly worked out the quantum theory of molecules, an important and enduring contribution. Counting the dissertation, Oppenheimer published sixteen papers between 1926 and 1929. They established for him an international reputation as a theoretical physicist.
He came home a far more confident man. Harvard offered him a job; so did the young, vigorous California Institute of Technology at Pasadena. The University of California at Berkeley especially interested him because it was, as he said later, “a desert,” meaning it taught no theoretical physics yet at all.480 He decided to take Berkeley and Caltech both, arranging to lecture on the Bay Area campus in the autumn and winter and shift to Pasadena in the spring. But first he went back to Europe on a National Research Council fellowship to tighten up his mathematics with Paul Ehrenfest at Leiden and then with Pauli, now at Zurich, a mind more analytical and critical even than Oppenheimer’s, a taste in physics more refined. After Ehrenfest Oppenheimer had wanted to work in Copenhagen with Bohr. Ehrenfest thought not: Bohr’s “largeness and vagueness,” in Oppenheimer’s words, were not the proper astringent. “I did see a copy of the letter [Ehrenfest] wrote Pauli. It was clear that he was sending me there to be fixed up.”481
Before he left the United States for Leiden Oppenheimer visited the Sangre de Cristos with Frank. The two brothers found a cabin and a piece of land they liked—“house and six acres and stream,” in Robert’s terse description—up high on a mountain meadow.482 The house was rough-hewn timber chinked with caulk; it lacked even a privy. While Robert was in Europe his father arranged a long-term lease and set aside three hundred dollars for what Oppenheimer calls “restoration.” A summer in the mountains was restoration for the celebrated young theoretician as well.
* * *
At the end of that summer of 1927 the Fascist government of Benito Mussolini convened an International Physical Congress at Como on the southwestern end of fjord-like Lake Como in the lake district of northern Italy. The congress commemorated the centennial of the death in 1827 of Alessandro Volta, the Como-born Italian physicist who invented the electric battery and after whom the standard unit of electrical potential, the volt, is named. Everyone went to Como except Einstein, who refused to lend his prestige to Fascism.483 Everyone went because quantum theory was beleaguered and Niels Bohr was scheduled to speak in its defense.
At issue was an old problem that had emerged in a new and more challenging form. Einstein’s 1905 work on the photoelectric effect had demonstrated that light sometimes behaves as if it consists not of waves but of particles. Turning the tables, early in 1926 an articulate, cultured Viennese theoretical physicist named Erwin Schrödinger published a wave theory of matter demonstrating that matter at the atomic level behaves as if it consists of waves. Schrödinger’s theory was elegant, accessible and completely consistent. Its equations produced the quantized energy levels of the Bohr atom, but as harmonics of vibrating matter “waves” rather than as jumping electrons. Schrödinger soon thereafter proved that his “wave mechanics” was mathematically equivalent to quantum mechanics. “In other words,” says Heisenberg, “ . . . the two were but different mathematical formulations of the same structure.”484 That pleased the quantum mechanicists because it strengthened their case and because Schrödinger’s more straightforward mathematics simplified calculation.
But Schrödinger, whose sympathies lay with the older classical physics, made more far-reaching claims for his wave mechanics. In effect, he claimed that it represented the reality of the interior of the atom, that not particles but standing matter waves resided there, that the atom was thereby recovered for the classical physics of continuous process and absolute determinism. In Bohr’s atom electrons navigated stationary states in quantum jumps that resulted in the emission of photons of light. Schrödinger offered, instead, multiple waves of matter that produced light by the process known as constructive interference, the waves adding their peaks of amplitude together. “This hypothesis,” says Heisenberg dryly, “seemed to be too good to be true.”485 For one thing, Planck’s quantized radiation formula of 1900, by now exhaustively proven experimentally, opposed it. But many traditional physicists, who had never liked quantum theory, greeted Schrödinger’s work, in Heisenberg’s words, “with a sense of liberation.”486 Late in the summer, hoping to talk over the problem, Heisenberg turned up at a seminar in Munich where Schrödinger was speaking. He raised his objections. “Wilhelm Wien, [a Nobel laureate] who held the chair of experimental physics at the University of Munich, answered rather sharply that one must really put an end to quantum jumps and the whole atomic mysticism, and the difficulties I had mentioned would certainly soon be solved by Schrödinger.”487
Bohr invited Schrödinger to Copenhagen. The debate began at the railroad station and continued morning and night, says Heisenberg:
For though Bohr was an unusually considerate and obliging person, he was able in such a discussion, which concerned epistemological problems which he considered to be of vital importance, to insist fanatically and with almost terrifying relentlessness on complete clarity in all arguments. He would not give up, even after hours of struggling, [until] Schrödinger had admitted that [his] interpretation was insufficient, and could not even explain Planck’s law. Every attempt from Schrödinger’s side to get round this bitter result was slowly refuted point by point in infinitely laborious discussions.488
Schrödinger came down with a cold and took to his bed. Unfortunately he was staying at the Bohrs’. “While Mrs. Bohr nursed him and brought in tea and cake, Niels Bohr kept sitting on the edge of the bed talking at [him]: ‘But you must surely admit that . . .’ ”489Schrödinger approached desperation. “If one has to go on with these damned quantum jumps,” he exploded, “then I’m sorry that I ever started to work on atomic theory.” Bohr, always glad for conflicts that sharpened understanding, calmed his exhausted guest with praise: “But the rest of us are so grateful that you did, for you have thus brought atomic physics a decisive step forward.”490 Schrödinger returned home discouraged but unconvinced.
Bohr and Heisenberg then went to work on the problem of reconciling the dualisms of atomic theory. Bohr hoped to formulate an approach that would allow matter and light to exist both as particle and as wave; Heisenberg argued consistently for abandoning models entirely and sticking to mathematics. In late February 1927, says Heisenberg, both of them “utterly exhausted and rather tense,” Bohr went off to Norway to ski.491 The young Bavarian tried, using quantum-mechanical equations, to calculate something so seemingly simple as the trajectory of an electron in a cloud chamber and realized it was hopeless. Facing that corner, he turned around. “I began to wonder whether we might not have been asking the wrong sort of question all along.”
Working late one evening in his room under the eaves of Bohr’s institute Heisenberg remembered a paradox Einstein had thrown at him in a conversation about the value of theory in scientific work. “It is the theory which decides what we can observe,” Einstein had said.492 The memory made Heisenberg restless; he went downstairs and let himself out—it was after midnight—and walked past the great beech trees behind the institute into the open soccer fields of the Faelledpark. It was early March and it would have been cold, but Heisenberg was a vigorous walker who did his best thinking outdoors. “On this walk under the stars, the obvious idea occurred to me that one should postulate that nature allowed only experimental situations to occur which could be described within the framework of the [mathematical] formalism of quantum mechanics.”493 The bald statement sounds wondrously arbitrary; its test would be its consistent mathematical formulation and, ultimately, its predictive power for experiment. But it led Heisenberg immediately to a stunning conclusion: that on the extremely small scale of the atom, there must be inherent limits to how precisely events could be known. If you identified the position of a particle—by allowing it to impact on a zinc-sulfide screen, for example, as Rutherford did—you changed its velocity and so lost that information. If you measured its velocity—by scattering gamma rays from it, perhaps—your energetic gamma-ray photons battered it into a different path and you could not then locate precisely where it was. One measurement always made the other measurement uncertain.
Heisenberg climbed back to his room and began formulating his idea mathematically: the product of the uncertainties in the measured values of the position and momentum cannot be smaller than Planck’s constant. So h appeared again at the heart of physics to define the basic, unresolvable granularity of the universe. What Heisenberg conceived that night came to be called the uncertainty principle, and it meant the end of strict determinism in physics: because if atomic events are inherently blurred, if it is impossible to assemble complete information about the location of individual particles in time and space, then predictions of their future behavior can only be statistical. The dream or bad joke of the Marquis de Laplace, the eighteenth-century French mathematician and astronomer, that if he knew at one moment the precise location in time and space of every particle in the universe he could predict the future forever, was thus answered late at night in a Copenhagen park: nature blurs that divine prerogative away.
Bohr ought to have liked Heisenberg’s democratization of the atomic interior.494 Instead it bothered him: he had returned from his ski trip with a grander conception of his own, one that reached back for its force to his earliest understanding of doubleness and ambiguity, to Poul Martin Møller and Søren Kierkegaard. He was particularly unhappy that his Bavarian protégé had not founded his uncertainty principle on the dualism between particles and waves. He trained on him the “terrifying relentlessness” he had previously directed at Schrödinger. Oskar Klein, Bohr’s amanuensis of the period, fortunately mediated. But Heisenberg was only twenty-six, however brilliant. He gave ground. The uncertainty principle, he agreed, was just a special case of the more general conception Bohr had devised. With that concession Bohr allowed the paper Heisenberg had written to go to the printer. And set to work composing his Como address.
At Como in pleasant September Bohr began with a polite reference to Volta, “the great genius whom we are here assembled to commemorate,” then plunged in. He proposed to try to develop “a certain general point of view” which might help “to harmonize the apparently conflicting views taken by different scientists.”495 The problem, Bohr said, was that quantum conditions ruled on the atomic scale but our instruments for measuring those conditions—our senses, ultimately—worked in classical ways. That inadequacy imposed necessary limitations on what we could know. An experiment that demonstrates that light travels in photons is valid within the limits of its terms. An experiment that demonstrates that light travels in waves is equally valid within its limits. The same is true of particles and waves of matter. The reason both could be accepted as valid is that “particles” and “waves” are words, are abstractions. What we know is not particles and waves but the equipment of our experiments and how that equipment changes in experimental use. The equipment is large, the interiors of atoms small, and between the two must be interposed a necessary and limiting translation.
The solution, Bohr went on, is to accept the different and mutually exclusive results as equally valid and stand them side by side to build up a composite picture of the atomic domain. Nur die Fülle führt zur Klarheit: only wholeness leads to clarity. Bohr was never interested in an arrogant reductionism. He called instead—the word appears repeatedly in his Como lecture—for “renunciation,” renunciation of the godlike determinism of classical physics where the intimate scale of the atomic interior was concerned.496The name he chose for this “general point of view” was complementarity, a word that derives from the Latin complementum, “that which fills up or completes.” Light as particle and light as wave, matter as particle and matter as wave, were mutually exclusive abstractions that complemented each other. They could not be merged or resolved; they had to stand side by side in their seeming paradox and contradiction; but accepting that uncomfortably non-Aristotelian condition meant physics could know more than it otherwise knew. And furthermore, as Heisenberg’s recently published uncertainty principle demonstrated within its limited context, the universe appeared to be arranged that way as far down as human senses would ever be able to see.
Emilio Segrè, who heard Bohr lecture at Como in 1927 as a young engineering student, explains complementarity simply and clearly in a history of modern physics he wrote in retirement: “Two magnitudes are complementary when the measurement of one of them prevents the accurate simultaneous measurement of the other.497 Similarly, two concepts are complementary when one imposes limitations on the other.”
Carefully Bohr then examined the conflicts of classical and quantum physics one at a time and showed how complementarity clarified them. In conclusion he briefly pointed to complementarity’s connection to philosophy. The situation in physics, he said, “bears a deep-going analogy to the general difficulty in the formation of human ideas, inherent in the distinction between subject and object.”498 That reached back all the way to the licentiate’s dilemma in Adventures of a Danish Student, and resolved it: the I who thinks and the I who acts are different, mutually exclusive, but complementary abstractions of the self.
In the years to come Bohr would extend the compass of his “certain general point of view” far into the world. It would serve him as a guide not only in questions of physics but in the largest questions of statesmanship as well. But it never commanded the central place in physics he hoped it would. At Como a substantial minority of the older physicists were predictably unpersuaded. Nor was Einstein converted when he heard. In 1926 he had written to Max Born concerning the statistical nature of quantum theory that “quantum mechanics demands serious attention. But an inner voice tells me that this is not the true Jacob. The theory accomplishes a lot, but it does not bring us closer to the secrets of the Old One. In any case, I am convinced that He does not play dice.”499Another physics conference, the annual Solvay Conference sponsored by a wealthy Belgian industrial chemist named Ernest Solvay, was held in Brussels a month after Como. Einstein attended, as did Bohr, Max Planck, Marie Curie, Hendrick Lorentz, Max Born, Paul Ehrenfest, Erwin Schrödinger, Wolfgang Pauli, Werner Heisenberg and a crowd of others. “We all stayed at the same hotel,” Heisenberg remembers, “and the keenest arguments took place, not in the conference hall but during the hotel meals. Bohr and Einstein were in the thick of it all.”500
Einstein refused to accept the idea that determinism on the atomic level was forbidden, that the fine structure of the universe was unknowable, that statistics rule. “ ‘God does not throw dice’ was a phrase we often heard from his lips in these discussions,” writes Heisenberg. “And so he refused point-blank to accept the uncertainty principle, and tried to think up cases in which the principle would not hold.” Einstein would produce a challenging thought experiment at breakfast, the debate would go on all day, “and, as a rule, by suppertime we would have reached a point where Niels Bohr could prove to Einstein that even his latest experiment failed to shake the uncertainty principle. Einstein would look a bit worried, but by next morning he was ready with a new imaginary experiment more complicated than the last.”501 This went on for days, until Ehrenfest chided Einstein—they were the oldest of friends—that he was ashamed of him, that Einstein was arguing against quantum theory just as irrationally as his opponents had argued against relativity theory. Einstein remained adamant (he remained adamant to the end of his life where quantum theory was concerned).
Bohr, for his part, supple pragmatist and democrat that he was, never an absolutist, heard once too often about Einstein’s personal insight into the gambling habits of the Deity. He scolded his distinguished colleague finally in Einstein’s own terms. God does not throw dice? “Nor is it our business to prescribe to God how He should run the world.”502