Richard Rhodes - The Making of the Atomic Bomb

Bohr may have found his way through his youthful emotional crisis in part by calling up his childhood gift of literal-mindedness. He famously insisted on anchoring physics in fact and refused to carry argument beyond physical evidence. He was never a system-builder. “Bohr characteristically avoids such a word as ‘principle,’” says Rosenfeld; “he prefers to speak of ‘point of view’ or, better still, ‘argument,’ i.e. line of reasoning; likewise, he rarely mentions the ‘laws of nature,’ but rather refers to ‘regularities of the phenomena.’” 285Bohr was not displaying false humility with his choice of terms; he was reminding himself and his colleagues that physics is not a grand philosophical system of authoritarian command but simply a way, in his favorite phrase, of “asking questions of Nature.” 286He apologized similarly for his tentative, rambling habit of speech: “I try not to speak more clearly than I think.” 287

“He points out,” Rosenfeld adds, “that the idealized concepts we use in science must ultimately derive from common experiences of daily life which cannot themselves be further analysed; therefore, whenever any two such idealizations turn out to be incompatible, this can only mean that some mutual limitation is imposed upon their validity.” 288Bohr had found a solution to the spiraling flights of doubt by stepping out of what Kierkegaard called “the fairyland of the imagination” and back into the real world. 289In the real world material objects endure; their atoms cannot, then, ordinarily be unstable. In the real world cause and effect sometimes seem to limit our freedom, but at other times we know we choose. In the real world it is meaningless to doubt existence; the doubt itself demonstrates the existence of the doubter. Much of the difficulty was language, that slippery medium in which Bohr saw us inextricably suspended. “It is wrong,” he told his colleagues repeatedly, “to think that the task of physics is to find out how nature is” —which is the territory classical physics had claimed for itself. “Physics concerns what we can say about nature.” 290

Later Bohr would develop far more elaborately the idea of mutual limitations as a guide to greater understanding. It would supply a deep philosophical basis for his statecraft as well as for his physics. In 1913 he first demonstrated its resolving power. “It was clear,” he remembered at the end of his life, “and that was the point about the Rutherford atom, that we had something from which we could not proceed at all in any other way than by radical change. And that was the reason then that [I] took it up so seriously.” 291

Otto Hahn cherished the day the Kaiser came to visit. The official dedication of the first two Kaiser Wilhelm Institutes, one for chemistry, one for physical chemistry, on October 23, 1912—Bohr in Copenhagen was approaching his quantized atom—was a wet day in the suburb of Dahlem southwest of Berlin. 292, 293The Kaiser, Wilhelm II, Victoria’s eldest grandson, wore a raincloak to protect his uniform, the dark collar of his greatcoat turned out over the lighter shawl of the cloak. The officials who walked the requisite paces behind him, his scholarly friend Adolf von Harnack and the distinguished chemist Emil Fischer foremost among them, made do with dark coats and top hats; those farther back in the procession who carried umbrellas kept them furled. Schoolboys, caps in hand, lined the curbs of the shining street like soldiers on parade. They stood at childish attention, awe dazing their dreamy faces, as this corpulent middle-aged man with upturned dark mustaches who believed he ruled them by divine right passed in review. They were thirteen, perhaps fourteen years old. They would be soldiers soon enough.

Officials in the Ministry of Culture had encouraged His Imperial Majesty to support German science. He responded by donating land for a research center on what had been a royal farm. Industry and government then lavishly endowed a science foundation, the Kaiser Wilhelm Society, to operate the proposed institutes, of which there would be seven by 1914. 294

The society began its official life early in 1911 with von Harnack, a theologian who was the son of a chemist, as its first president. The imperial architect, Ernst von Ihne, went briskly to work. The Kaiser came to Dahlem to dedicate the first two finished buildings, and the Institute for Chemistry especially must have pleased him. It was set back on a broad lawn at the corner of Thielallee and Faradayweg: three stories of cut stone filigreed with six-paned windows, a steep, gabled slate roof and at the roofline high above the entrance a classical pediment supported by four Doric columns. A wing angled off paralleling the cross street. Fitted between the main building and the wing like a hinge, a round tower rose up dramatically four stories high. Von Ihne had surmounted the tower with a dome. Apparently the dome was meant to flatter the Kaiser’s taste. A sense of humor was not one of Wilhelm II’s strong points and no doubt it did. The dome took the form of a giant Pickelhaube, the comic-opera spiked helmet that the Kaiser and his soldiers wore.

Leaving Ernest Rutherford in Montreal in 1906 Hahn had moved to Berlin to work with Emil Fischer at the university. Fischer was an organic chemist who knew little about radioactivity, but he understood that the field was opening to importance and that Hahn was a first-rate man. He made room for Hahn in a wood shop in the basement of his laboratories and arranged Hahn’s appointment as a Privatdozent, which stirred less forward-looking chemists on the faculty to wonder aloud at the deplorable decline in standards. A chemist who claimed to identify new elements with a gold-foil electroscope must be at least an embarrassment, if not in fact a fraud. 295

Hahn found the university’s physicists more congenial than its chemists and regularly attended the physics colloquia. At one colloquium at the beginning of the autumn term in 1907 he met an Austrian woman, Lise Meitner, who had just arrived from Vienna. 296Meitner was twenty-nine, one year older than Hahn. She had earned her Ph.D. at the University of Vienna and had already published two papers on alpha and beta radiation. Max Planck’s lectures in theoretical physics had drawn her to Berlin for postgraduate study.

Hahn was a gymnast, a skier and a mountain climber, boyishly goodlooking, fond of beer and cigars, with a Rhineland drawl and a warm, selfdeprecating sense of humor. He admired attractive women, went out of his way to cultivate them and stayed friends with a number of them throughout his happily married life. Meitner was petite, dark and pretty, if also morbidly shy. Hahn befriended her. When she found she had free time she decided to experiment. She needed a collaborator. So did Hahn. A physicist and a radiochemist, they would make a productive team.

They required a laboratory. Fischer agreed that Meitner could share the wood shop on condition that she never show her face in the laboratory upstairs where the students, all male, worked. 297For two years she observed the condition strictly; then, with the liberalization of the university, Fischer relented, allowed women into his classes and Meitner above the basement. Vienna had been only a little more enlightened. Meitner’s father, an attorney—the Meitners were assimilated Austrian Jews, baptized all around—had insisted that she acquire a teacher’s diploma in French before beginning to study physics so that she would always be able to support herself. Only then could she prepare for university work. With the diploma out of the way Meitner crammed eight years of Gymnasium preparation into two. She was the second woman ever to earn a Ph.D at Vienna. Her father subsidized her research in Berlin until at least 1912, when Max Planck, by now a warm supporter, appointed her to an assistantship. “The German Madame Curie,” Einstein would call her, characteristically lumping the Germanic peoples together and forgetting her Austrian birth.