The Human Side of Science: Edison and Tesla, Watson and Crick, and Other Personal Stories behind Science's Big Ideas (2016)


Einstein's torrent of papers and book reviews continued past his monumental year of 1905. Fortunately, they generated attention in just the right place. His thesis adviser, Alfred Kleiner, had been the lone physicist on the staff of the University of Zurich for some time. He was finally coming into a spot in which he could get some help. He was about to become rector of the university, and he might be able to create another physics position. Although he had earlier encouraged Friedrich Adler to prepare for the position he was going to set up, Kleiner saw that Einstein's enthusiasm and theoretical interests would make him a better fit. Kleiner wrote Einstein and suggested he become a privatdozent (unsalaried lecturer) at the University of Bern as a first, preparatory step toward the eventual professorship at the University of Zurich. In short order, Einstein completed the necessary materials and was approved. Since he still worked at the Patent Office, he could offer classes only at odd times. This cut into his valuable research time as he worked to extend his special relativity to cover accelerated motion. Only the tantalizing possibility of a full-time job at the University of Zurich kept him going. Meanwhile, home life with Mileva suffered some serious neglect.


Alfred Kleiner (1849–1916). From Wikimedia Commons, user Tianxiaozhang~commonswiki.

Finally, after Einstein had delivered a pretty good lecture to the Physical Society of Zurich in February 1909, Kleiner was able to give Einstein a strong recommendation, and the committee voted to make him an offer. After an initial salary offer that Einstein thought was too low, the committee agreed to match Einstein's current remuneration. He accepted. Friedrich Haller was amazed when Einstein resigned from the Patent Office effective October 1909 to become a professor at the University of Zurich. Academe had beckoned, and Einstein heeded its call.


News of Einstein's acceptance of a position at the University of Zurich showed up in several newspapers and attracted the attention of Anna Schmid. Einstein had met Anna many years earlier when he was on holiday with his mother and sister at the Pension Paradise Hotel (see chapter 9 for his poem to her). Anna congratulated Einstein, told him of her marriage to George Meyer, and said they were living in Basel. Einstein wrote back and invited her to come see him in Zurich at the university. Anna responded positively, and her letter was somehow intercepted by Mileva. Immediately, Mileva became suspicious that her husband was having an affair and dashed off an angry note to Anna's husband, telling him how outraged she was that his wife and her husband were carrying on so. When Einstein found out about Mileva's letter, he was furious. He wrote a letter of apology to Meyer immediately, telling him he hadn't seen Anna in ten years, and nothing had happened between them even then. Somehow, the similar letter his mother had written to Mileva's parents must have come to his mind. Einstein wondered if either of those two primary women in his life trusted him. Lost trust is difficult to regain.


Einstein began his academic career lecturing at the University of Zurich in October 1909. He and Mileva thought that perhaps another child might get their relationship back on track. Mileva became pregnant almost immediately. Although teaching made him a bit nervous at first, Einstein soon relaxed and became a much less formal professor than his colleagues, which pleased the students enormously. They surrounded him, even after class, following him to the cafés in Zurich for discussions of science. He became more confident but remained humble and friendly. Students and colleagues loved him. Mileva, however, was still getting the short end of the stick.


After only about six months at Zurich, Einstein began to get feelers from the German University at Prague, which anticipated the opening of a full professorship at double his current salary, and with less teaching responsibilities. The offer sounded tempting, and negotiations continued. Meanwhile, Mileva gave birth to their second son, Eduard, aka Tete, in July 1910. Tete was a fussy baby. This served to increase Mileva's depression rather than alleviate it. In January 1911, Einstein was offered the faculty position in Prague, and he accepted it. The Einstein family arrived there in April. Prague was hot and buggy, the water was brown, the air was sooty, and the Germans (10 percent of the population) looked down on the Czechs (who were the majority at 90 percent). Further, about half of the Germans were Jewish, so the other half didn't mix well with them. Mileva was extremely unhappy, to say the least. Einstein was treated like a celebrity at the university, but his research was going badly. To extend his theory of special relativity, he was going to have to abandon normal Euclidean geometry for more exotic possibilities. In addition, the quantum was perplexing him, and he didn't have anybody to bounce ideas off, as he had with Besso.


In the fall, the first Solvay Conference was held in Brussels. Named for and instituted by Ernest Solvay, a wealthy chemical industrialist, these conferences brought together the best scientific minds so they could update each other and share ideas. Einstein met Marie Curie, who was rumored to be having an affair with French physicist Paul Langevin. Asked for a comment about this rumor by an eager press, Einstein said, “Madame Curie is a simple, honest woman, almost buried under her duties and obligations. She has sparkling intelligence but, despite her passionate nature, is not attractive enough to be a danger to anyone.”1 How's that for a left-handed compliment?


Prior to the conference, Einstein had taught a short course at Zurich. Meeting up with his old friend Marcel Grossmann, now a dean at the ETH, Einstein was asked if would be interested in a faculty position there. Einstein said yes indeed; he knew Mileva would have responded even more positively. Heinrich Zangger, now a dean of forensic medicine at Zurich, pressed the ETH administration even further to favor Einstein with an appointment. After the usual snags, an offer was made in February 1912, and Einstein accepted it. Before moving to Zurich, Einstein traveled to Berlin, where he visited his cousin Elsa (see chapter 9). Elsa was divorced in 1908 from Max Löwenthal, with whom she had two daughters, Margot and Ilse. The cousins reminisced about the old days and enjoyed each other's company tremendously.

In the summer of 1912, the Einsteins moved to Zurich, delighted to escape from Prague. One of the first things Einstein did was to call on Grossmann. He recalled that Grossmann's thesis dealt with more exotic non-Euclidean geometry, and Einstein had decided that in generalizing relativity he also needed more generalized geometry, but he was without a clue in that department. “Grossmann, you've got to help me,” he implored.2 Grossmann was eager to assist, but only with the mathematics; he wanted no part of the physics. Einstein was quite amenable to that arrangement. They wrote two papers together, with the mathematics and the physics clearly separated. The equations they came up with still didn't achieve what Einstein wanted: a simple mathematical formulation that related gravity to the fundamental curvature of space-time that was general enough that it didn't depend on whatever coordinate system the equations were formulated in.

This qualifies as save number three for Grossmann (see chapter 9 for the first two), because his help was just what Einstein needed. The reason the equations didn't work was because Einstein made an error when he checked them and didn't catch it at the time. In Einstein's defense, the calculations involved extremely complicated mathematical forms, and so it was easy to make a mistake. On the other hand, all those skipped classes at the ETH may have taken their toll. In Einstein's words, “Never before in my life have I troubled myself over anything so much, and that I have gained great respect for mathematics, whose more subtle parts I considered until now, in my ignorance, as pure luxury! Compared with this problem, the original theory of relativity is childish.”3


While the general relativity equations simmered, the rest of life continued at its merry pace. The Einsteins traveled to Paris, where they stayed with the Curies. The families became friendly, so the Einsteins planned to return in the summer for some hiking. Teaching and research continued at their normal pace, but then a big academic break came in the form of visitors from Berlin.

Max Planck and physicist Walther Nernst arrived with a directive from Fritz Haber, the new director of the Kaiser Wilhelm Institute of Physical and Electrochemistry: get Einstein. The offer they made was overwhelming. Einstein would be a full professor at the University of Berlin as well as the director of the Kaiser Wilhelm Institute of Theoretical Physics (when it was built). His salary would be the maximum allowed for any professor at the university, and he would have zero teaching duties.

The idea of returning to Germany didn't appeal to Einstein. He knew Mileva would hate it there. The directorship didn't interest him, but the lack of teaching duties did. He was beginning to feel worn down at the ETH, and he suspected he might be very close to finishing general relativity, his all-consuming interest at this time. His friend from undergraduate days, Louis Kollros, recalls Einstein saying, “The Berliner gentlemen speculate that I am an award-winning Chicken-hen, but I do not know if I can still lay eggs!”4 Einstein soon accepted but delayed the start time until the spring of 1914. This allowed him to attend conferences, travel, hike with the Curies, struggle with the general relativity equations, and arrange a secret meeting with Elsa. It also represented the calm before the storm.


The impending move to Berlin made Mileva even gloomier than ever. She didn't much care for Germans. In addition, Einstein's relatives would be in proximity, in particular his mother and that pesky cousin Elsa. In late December, Einstein sent Mileva to Berlin to find an apartment, since he had little interest in housing. She returned to Zurich even more unhappy and even a little suspicious of Elsa, who offered to help find housing close to her.

When moving time came in late March, Tete developed multiple illnesses, which led to his exhaustion. Doctors recommended recuperation at a spa, so Mileva and the boys left for Locarno, a resort town in the Italian colony of Switzerland. This left Einstein free to move to Berlin by himself. He canceled a physics meeting to arrive early and spend time with Elsa. At the university, Einstein was charting a somewhat different course than his sponsors—Haber, Nernst, and Planck—must have expected. Einstein wanted experimental tests of the general relativity theory, not a research program in quantum theory.

It was late April by the time Mileva and the boys arrived in Berlin. Einstein was uncommunicative at home, and Mileva felt like she was being ignored. Even Hans Albert complained that his father had become “nasty” since the move to Berlin. Mileva suspected Einstein was spending time with Elsa. They had a giant argument in July. As a result, Einstein moved out of the apartment to stay with his Uncle Jakob, and Mileva and the boys began living with Clara Haber. Their major form of communication became notes passed through Fritz Haber, a role Haber neither expected nor appreciated. Finally, a separation agreement was negotiated, with Mileva and the boys moving back to Zurich, and visitation of the boys taking place only on neutral ground, and never at Elsa's. Besso came to Berlin to accompany Mileva and the boys back to Zurich, and Fritz Haber went to the train station with Einstein to see the boys off.


As if the personal war between Einstein and Mileva wasn't bad enough, a far larger conflict broke out at the same time: World War I. With world opinion strongly against Germany, especially after its invasion of Belgium, ninety-three prominent German scholars, politicians, and authors signed a manifesto supporting Germany. One of Elsa's friends, Georg Nicolai, soon circulated a counter-petition urging a stop to the war, pointing out that there would be no victors, only victims. Einstein's pacifism kicked in, and he signed it, but not many others did, and it wasn't widely published.

Einstein found a bachelor apartment near Elsa's, but not too near. The occasional square meal and delightful company were great, but her mothering instincts became a bit much at times. Much as he missed the boys, he didn't miss Mileva, and the quiet allowed him to plunge into his work full bore. He pursued general relativity so relentlessly that he cared little about his own health. He was living the way he had described to Elsa in a letter from several months earlier, “I have firmly decided to bite into the grass with a minimum of medical help when my little hour has come. But until then, I plan to sin away as my wicked soul bids me. Diet, smoking like a chimney, working like a horse.”5Unfortunately, the horse was pulling a faulty load. When Einstein and Grossmann worked together more than two years earlier, they'd had to choose between two fundamentally different mathematical techniques to formulate their equations. Their first choice was eliminated by Einstein on the basis of a lengthy calculation, in which he had made an error. Thus, he labored away using the other tensor, which required many adjustments, but he still couldn't make it fit. Besides, he was no longer in close touch with Grossmann, who was still in Zurich at the ETH. Fortunately, Einstein piqued the curiosity of Germany's greatest mathematician, David Hilbert.


David Hilbert (1862–1943). From Wikimedia Commons, user Mschlindwein.

In June 1915, Einstein traveled to Göttingen to present a series of talks and had a very pleasant time with David Hilbert. Unlike Marcel Grossmann, who harbored a certain distaste for physics, Hilbert liked it and had been following Einstein's career with interest. Besides, Hilbert was one of the few besides Einstein who had signed Nicolai's antiwar petition. When Einstein outlined his struggles to generalize relativity, Hilbert, who was familiar with the tensors, instantly understood what Einstein was trying to accomplish. One of Hilbert's colleagues, Felix Klein, wondered about Einstein's ability to carry out his ambitious plans. “Einstein is not innately a mathematician, but works rather under the influence of obscure physical-philosophical impulses.”6

Einstein spent a restless summer with a nagging feeling of something amiss in his analysis. Hilbert spent some of his summer vacation on Einstein's equations and also realized something must be wrong. Hilbert took the additional step of encouraging one of his brightest assistants, Emmy Noether, to work on a generalization of similar equations, and she formulated and proved Noether's first theorem. This very general theorem shows that for every symmetry of a physical system, there is a corresponding conservation law. In a very elegant way, she demonstrated that Einstein's general relativity automatically included energy and momentum conservation. Before her work, there was some concern about whether energy would be conserved, and it could only be answered by lengthy, laborious calculations. Einstein wrote to Hilbert: “Yesterday I received from Miss Noether a very interesting paper on invariants. I'm impressed that such things can be understood in such a general way. The old guard at Göttingen should take some lessons from Miss Noether! She seems to know her stuff.”7


Then, Einstein went back to work and discovered his calculation error from almost three years earlier that seemed to make the second formulation preferable to the first one. Next, he repeated the calculation that knocked out the first choice and found another error. Finally, he was able to return to the first choice that he and Grossmann had made. With great effort, he reformulated his equations to present to the Prussian Academy of Sciences. Acknowledging the giant difference from the equations he presented to the same group the prior year, he said, “No one who has really grasped it can escape the magic of this theory.”8 Writing to his friend Paul Ehrenfest about what academy members must have thought, Einstein said, “That fellow Einstein suits his convenience. Every year, he retracts what he wrote the year before.”9

Having equations is a good start, but next must come solutions to these equations. Einstein was able to show that his equations predicted a small deviation in the orbit of Mercury. That small effect matched experimental results almost exactly. More support was needed, but this would take a while. Meanwhile, Hilbert published his own equations, which were quite similar. This caused a minor rift, and Hilbert claimed to understand Einstein's work better than Einstein himself. This may have been true, but Hilbert's paper acknowledged Einstein's priority, so the difficulty went no further.

Einstein had scored a major coup on the old Newtonian theory. Now, time and space not only depended on the observer; they were deformed by the presence of mass. Einstein's general theory of relativity says that throughout the entire universe, the presence of mass curves space-time. A two-dimensional analogy is provided by a stretched blanket: A small marble will roll straight across an empty blanket, but if a bowling ball is placed on the blanket, the marble's path will be curved by the presence of the ball.


Einstein was elated that his difficulties with formulating a general theory of relativity were finally over, and now he made a stab at resolving his difficulty with Mileva. Separation didn't seem to be a long-term solution, so he asked her for a divorce. Her response was to deny him access to the boys. She then proceeded to have a nervous breakdown. Einstein's friends in Zurich—Besso and Zangger—helped with the boys, but Einstein wasn't doing very well health-wise himself. What with all his nonstop working, his family struggles, the ongoing war, and the rising tide of anti-Semitism in Berlin, he developed horrible stomach pains and thought he was going to die. After a period of denial, followed by doctor visits and more denial, he came under Elsa's care by moving to an apartment next door to hers.


Meanwhile, Einstein's equations were being studied by astronomers. Karl Schwarzschild found solutions both inside and outside massive objects such as stars, and Willem de Sitter applied the equations to the universe as a whole.


Albert Einstein, far left, and Willem de Sitter (1872–1934), far right, about 1923. Photographed by H. van Batenburg, 1923. Leiden Archives, from Wikimedia Commons, user Mdd.

Even though Einstein battled stomach and family problems, he and de Sitter carried on a two-year running debate about the nature of the entire universe in relationship to the field equations of general relativity. Others, especially the mathematicians from Göttingen, joined the debate, and papers and presentations flew back and forth with details, arguments, and counterarguments, all quite civil. The biggest problem turned out to be the status of the universe in terms of expansion, contraction, or remaining static. Einstein finally added a term to his equations in order to keep the universe static, because de Sitter convinced him that the fundamental equations implied expansion. Einstein called the term the cosmological constant, and its addition annoyed him because it marred the equation's simplicity (more on this constant in chapter 11).


In scientific circles, Einstein's reputation and notoriety grew, but the war droned on. Jewish refugees from the Eastern front flooded into Germany, unleashing a tide of anti-Semitism. Since Einstein was so prominently antiwar, his support for refugees marked him as vaguely anti-German, and because he was Jewish, his scientific standing among right-wingers was tarnished. At first, he was too busy to notice much other than his work, but the situation became hard to ignore. The war ended in November 1918, but anti-Semitism was just barely hitting its stride.


Early in 1919, with perfect timing, Kurt Blumenfeld showed up at Einstein's door. He wanted to speak to Einstein about the Zionist cause. Einstein had been exposed to Zionism before and had not displayed much interest, but he was especially vulnerable at this time. Stomach problems, the completion of his general relativity project, his pending divorce, the plight of war refugees, the end of the war, the rising tide of anti-Semitism, and the establishment of Palestine as a Jewish state by the Balfour Declaration all conspired to make Einstein receptive to Blumenfeld's ideas. Blumenfeld quotes Einstein's reaction: “I am against nationalism but in favor of Zionism. The reason has become clear to me today. When a man has both arms and he is always saying I have a right arm, then he is a chauvinist. However, when the right arm is missing, then he must do something to make up for the missing limb. Therefore, I am, as a human being, an opponent of nationalism. But as a Jew I am from today a supporter of the Jewish Zionist efforts.”10 Einstein's change of heart that day led to several later consequences, as we will see.


Kurt Blumenfeld (1884–1963). bpk, Berlin / Central Zionist Archives, Jerusalem / Art Resource, NY.


The world war ended only a few months before the personal one between Einstein and Mileva did. For more than a year, negotiations between the two dragged on by letter. The process was interrupted by illnesses, hospitalizations, hyper-inflation in German currency, even a joint offer of employment from the University of Zurich and the ETH—both of which were the work of Zangger. At long last, the divorce agreement was sealed. The final terms included a deposit of forty thousand marks in a Swiss bank from which Mileva could draw the interest but not the principal, and the proceeds from the Nobel Prize if Einstein won it.

The source of the forty thousand marks is unknown, and the Nobel Prize proceeds require a little more explanation. It might seem presumptuous on Einstein's part, but he had been nominated for the Nobel Prize eight times since 1910, and his recent completion of the general relativity theory seemed like it would make him a shoo-in. Actually, the story of why Einstein didn't win the Nobel Prize earlier is rather lengthy and quite political, involving prejudices against Jews, pacifists, as well as judging densely mathematical theoretical physics in comparison with easier-to-understand experiments.

With the divorce finalized in February, Einstein, currently living with Elsa and her two daughters, Margot and Ilse, was free to marry. But then a curious thing happened. An odd discussion took place. The question was first suggested by Ilse's boyfriend in a half-joking way, should Einstein marry Elsa or Ilse? The matter was discussed, and Einstein graciously said he would be agreeable to marry either one, and they should be the ones to choose. After unrecorded discussions between mother and daughter, Einstein and Elsa were married in June. They had separate bedrooms at opposite ends of the apartment because Einstein “snored too much.”


Much of the rest of 1919 was spent in eager anticipation of solar events. The next eclipse of the sun, which would occur May 29, provided an opportunity to test general relativity. According to Einstein's theory, stars sending out light rays that traveled close to our sun would be bent by its mass, and the star's apparent direction would shift. The predicted effect was quite small. It could only be measured by high-quality astronomical equipment, only a small swath of Earth's landmass would be able to see the eclipse, and bad weather could negate the whole effort. The world's astronomers relished the chance to have an impact on Einstein's new theory, many hoping to disprove it. Only one country was in the position of being able to fund an expedition that would get the right equipment to the right place at the right time: England.

Arthur Eddington was just the right fellow to perform this experiment. His skills were a rare combination: high mathematics and practical astronomy. Willem de Sitter had sent him a copy of Einstein's work, and he grasped it immediately. Eddington explained general relativity to his colleagues in England, although ideas from Germans were not easily accepted in those war years. The story goes that he was congratulated on being one of three people who understood the theory. Eddington hesitated and was accused of false modesty. He then said, “On the contrary, I was trying to imagine who the third person was.”11


Sir Arthur Eddington (1882–1944). From Wikimedia Commons, user Mu.

The eclipse's path of totality ranged across the south Atlantic from South America to Africa, so Eddington and his assistant E. Cottingham were dispatched to the island of Principe, off the west coast of Africa. Andrew Crommelin and Charles Davidson were sent to Sobral, Brazil, in case weather spoiled the data from Eddington's efforts. The Newtonian conception of gravity predicted a shift of a star's position of 0.86 second of arc, and Einstein's general relativity predicted a 1.74-second shift. The anticipated eclipse finally occurred, the telescopes (four-inch-diameter models) were ready, and the clouds parted reluctantly to yield some data. It took some time to return to England and analyze the data, but the final result was 1.79 seconds. Close enough, within experimental uncertainty, to support Einstein's general theory of relativity.

The London Times headline read: “Revolution in Science—New Theory of the Universe—Newton's Ideas Overthrown.” The story was picked up in the United States, and before long, Einstein became a worldwide celebrity. He joked to reporters, “Today in Germany, I am called a German man of science and in England I am represented as a Swiss Jew. If I come to be regarded as a bête noir, the description will be reversed, and I shall become a Swiss Jew for the Germans and a German man of science for the English.”12


He didn't have long to wait for the latter to occur. After the war, the German mark dropped to an all-time low, and unemployment was rampant. A scapegoat was found close at hand: Jews—and Einstein represented a prominent example. A group calling itself German Scientists for the Preservation of Pure Science organized a rally at which relativity was dismissed as a “publicity stunt,” and Einstein called a plagiarist. Oddly, Einstein attended the rally and later wrote a letter to the editor of Berliner Tageblatt, a liberal German newspaper, saying that the criticisms were superficial and made little sense. Further, he pointed out that one of the rally's behind-the-scenes organizers, the Nobel Laureate Phillip Lenard, had never achieved anything in theoretical physics. Later, Einstein regretted his loss of temper, saying, “Everyone is entitled to one act of stupidity.”13 Ironically, Mileva had attended Lenard's lectures in Heidelberg in 1897 and had written to Einstein about his experiments with the photoelectric effect. Further, one of Einstein's 1905 papers explained the photoelectric effect in terms of the quantum. To top all, as we'll see shortly, Einstein's Nobel Prize was awarded for…you guessed it, the photoelectric effect. Lenard's anti-Semitic views became even stronger. He created more trouble for Einstein with his book One Hundred Authors against Einstein. Eventually, Lenard became a Nazi with direct access to Hitler.


In 1920, Einstein participated in a colloquium along with German physicist Max von Laue and Max Planck at the University of Berlin's Institute of Physics. One of the younger colloquium members was Leo Szilárd.


Leo Szilárd (1898–1964). From Wikimedia Commons, user Panoptik~commonswiki.

Although Leo Szilárd was almost twenty years younger than Einstein, the two of them became friends, walking home together after colloquia, with Szilárd often stopping over for tea. After hearing that a German family had perished when a refrigerator leaked toxic chemicals in their apartment, the two of them brainstormed a refrigerator that had no moving parts and eventually patented it. A working model of their refrigerator was actually built, but it wailed like a banshee and was never a practical success. As we'll see in chapter 12, Szilárd played a strong role in Einstein's activities in World War II.


Early in 1921, Einstein heard from Kurt Blumenfeld again, this time with an invitation. Blumenfeld carried a telegram from World Zionist Organization president Chaim Weizmann.


Chaim Weizmann (1874–1952). From Wikimedia Commons, user Jappalang.

Weizmann was a biochemist who emigrated from Russia to England and had deep commitments to Zionism. He invited Einstein to join him on a trip to America to raise funds for settling Palestine, and especially for the Hebrew University of Jerusalem. To their surprise, Einstein accepted, and he and Elsa set sail for America in March 1921. During the trip, Einstein tried to explain the theory of relativity to Weizmann. Upon arrival in New York, Weizmann said, “Einstein explained his theory to me every day, and by the time we arrived I was fully convinced that he really understands it.”14


The Nobel committee was hamstrung by indecision in 1921, thanks partly to Philip Lenard, who opposed Einstein at every turn. The following year, however, changes were made to the committee membership, and Einstein was awarded the prize, officially stated as 1921's prize. The citation read, “Services to theoretical physics, and especially for his discovery of the law of the photoelectric effect.” When the prize was announced, Einstein and Elsa were on a trip to the Far East, which included Palestine. Besides the honor of the prize, there was an extremely practical side to this award. The money, about ten times an average professor's annual salary, went to Mileva, even though the divorce agreement said she only got the interest. (Einstein hid this fact for a long time.) She promptly bought three apartment houses in Zurich and lived on the top floor of one of them.


Einstein was one of the first to take Planck's quantum as a valid representation of reality, even though Planck himself had regarded it as a mathematical convenience. He was equally quick to embrace Niels Bohr's use of the quantum to explain the radiation of light from the hydrogen atom in 1913. Quantum mechanics, however, had taken some unsatisfactory turns in Einstein's view, partly due to Danish physicist Niels Bohr.

Einstein's difficulty with quantum mechanics was rooted in cause and effect. Bohr, Werner Heisenberg, Wolfgang Pauli, Erwin Schrödinger, and Paul Dirac had developed equations that injected an element of uncertainty into the fundamental description of reality, typified by Heisenberg's uncertainty principle: It is impossible to measure exactly the position and momentum of any particle at the same time. Although this principle flows directly from the dualistic wave/particle nature of particles, it implies that probabilities are involved at a very fundamental level. Einstein couldn't buy this. Although this is a significant philosophical idea, a way to express his view is a quote from him: “I can't conceive of God playing dice.”15


Niels Bohr (1885–1962). From Wikimedia Commons, user Craigboy.

Niels Bohr provided the counterpoint to Einstein's argument by saying, “Einstein, stop telling God what to do with his dice.”16 The serious parts to the Einstein/Bohr debates took place over many years, and in many different public and private forums, starting with the 1927 Solvay Conference. The discussions often followed this format: Einstein comes up with an argument to cast doubt on the quantum mechanical theory; Bohr thinks about it for a while, then demolishes the argument. Supposedly, one such debate took place on a streetcar. They were so engaged that they missed their stop and went to the end of the line. They got back on the car, started arguing again, then missed the stop again going the other way.

Bonus Material: Bohr/Einstein Internet interview. See To Dig Deeper for details.

The debates between Einstein and Bohr were quite civil, and the two had the greatest mutual respect and were quite good friends. In a letter to Bohr, Einstein said, “Not often in life has a human being caused me such joy by his mere presence as you did.”17 Bohr became involved in World War II, and will appear again in chapter 12.


Niels Bohr and Albert Einstein, about 1925. From Wikimedia Commons, user Craigboy.


Besides the first Einstein/Bohr debate at the Solvay Conference, 1927 saw a signal family event for the Einsteins: Hans Albert graduated from the ETH with a degree in civil engineering. But then the other shoe dropped. Hans Albert announced he was going to marry Freida Knecht. Einstein hit the roof. Freida was nine years older than Hans Albert and was only four feet eleven inches tall. Ironically, Einstein reacted in the same way his mother had about Mileva, and Hans Albert reacted like his father had—stubbornly. The marriage took place on May 7, 1927; the children of the marriage were not dwarfs; and Einstein later admitted, reluctantly, that Hans Albert's marriage was happier than either of his.


It wasn't long after general relativity that Einstein began thinking about his next project. His goal was to unify gravity and electromagnetism into what he called a unified field. But action followed thought slowly in this case. Family events, the experimental support of general relativity, his newfound celebrity status, his travels, and even some health issues delayed his work substantially. Further, he was not alone in his pursuit of unification. Other theorists proposed ideas, none of which reached the level Einstein sought. Finally, in 1929, Einstein pursued a variation on a theory proposed by Hermann Weyl and decided he was on the right track.

As he prepared his paper, word somehow leaked out, and reporters gathered outside his house. The paper was published by the New York Times, dense equations and all. Within months, Einstein abandoned that particular theory on mathematical grounds, but he pursued this holy grail of the unified field theory the rest of his life. He never stopped thinking about it, but he recognized the frustration, saying, “Most of my intellectual offspring end up very young in the graveyard of disappointed hopes.”18

The year 1929 also marked a significant birthday for Einstein: he turned fifty. Several of his friends went in together and bought him a twenty-three-foot sailboat, which he called Tümmler, German for “porpoise.” He and Elsa then sank much of their life savings into building a cottage on a lake at Caputh, near Potsdam, only a short drive from Berlin. It was quiet and peaceful at Caputh, and the Einsteins loved it as an escape from the ever-increasing difficulties in Berlin.


The Einstein lake cottage at Caputh. From Wikimedia Commons, user Oursana.


Perhaps the relaxation at the lake house was a little more than Elsa bargained for. Several wealthy widows came for visits in their chauffeur-driven cars, and Einstein would go away with them to concerts and perhaps stay the night. Elsa saw many women throw themselves at Einstein. She was a good sport about it for the most part. But when Einstein asked Elsa, who controlled finances, for spending money for incidentals on one of these outings, Elsa balked and refused to give him money for his “hussy.” Einstein lost his temper and took the “hussy” sailing. The next day, Elsa became even more angry when she found a skimpy bathing suit on the boat. As a live-in maid put it, “Einstein loved beautiful women, and they loved him in return.”19


In a visit to Caltech in 1931, Einstein was delighted to meet Edwin Hubble (see chapter 12). Hubble had telescopic evidence that the universe was expanding, which allowed Einstein to remove the cosmological constant from his general relativity equations. In California, Einstein had lunch with the Hollywood actor Charlie Chaplin and attended the premier of his movie City Lights with him. Einstein later said, “Just as in his films, Chaplin is an enchanting person.”20

Travels, visiting professorships, and extended weekends at Caputh were becoming more commonplace as the anti-Semitism in Berlin increased. Finally, in 1932, Einstein could see the handwriting on the wall. He accepted an offer from Abraham Flexner to conduct pure research at the Institute for Advanced Study in Princeton, New Jersey, but he anticipated only half-time there and half-time in Berlin. Meanwhile, German anti-Semitism was stronger than ever, and Einstein became more politically active, speaking out strongly against the Nazis. Before they left for a speaking tour of the United States in December 1932, Einstein said to Elsa, “Before you leave our villa this time have a close look at it.” “Why?” asked Elsa. Einstein answered: “You'll never see it again.”21


Sure enough, while the Einsteins were in America, Adolf Hitler became chancellor, and Einstein's apartment in Berlin and the lake house were searched and his beloved sailboat confiscated. With some assistance from Philip Lenard and other prominent anti-Semites, Einstein had become number one on Hitler's hit list. There was a price on his head in Germany. One of the milder things Einstein said about Hitler was “The world needs heroes and it's better they be harmless men like me than villains like Hitler.”22


Since the Institute for Advanced Study job didn't begin until October, the Einsteins left the United States for Belgium, staying with the royal family under guard. Much to his dismay, Einstein learned that Tete had had a nervous breakdown, and so he traveled to Zurich at great personal danger. Tete told his father he hated him, and that he had “cast a shadow over his life.”23 Heinrich Zangger thought Tete might be able to recover enough to live a normal life, but that didn't occur. Tete's schizophrenia kept him in and out of sanitariums for the rest of his life. Einstein left Zurich depressed, never to see Tete or Mileva again.

Einstein traveled to Oxford and gave several lectures. During his stay there, he learned that his friend Paul Ehrenfest had shot his mentally deranged son and then committed suicide. With heavy heart, the couple sailed for America and had barely gotten settled in Princeton before more bad news arrived. Elsa's daughter Ilse was gravely ill with tuberculosis in Paris. Ilse died soon after her mother arrived, and Elsa returned to Princeton with Ilse's ashes, heartbroken. The bad news kept coming. The following year, Einstein got word that his friend Marcel Grossmann had died of multiple sclerosis. Immediately, Einstein wrote to his widow: “I remember our student days. He the irreproachable student, I myself disorderly and a dreamer. He on good terms with the teachers and understanding everything, I a pariah, discontent and little loved. But we were good friends.”24 Even closer to home, Elsa developed an eye problem. Doctors told Einstein her condition was far worse. She had heart and liver problems that wouldn't give her very long to live. She must have wondered at Einstein's attentiveness, but that didn't last long. Elsa died in 1936.

Einstein kept plugging away at his unified field theory with little success, although he had some collaborators at Princeton. His rejection of quantum mechanics played some part in his lack of progress. He acknowledged this by saying, “I must seem like an ostrich who forever buries his head in the relativistic sand in order not to face the evil quanta.”25 He also abandoned the physical insights he had relied on in his youth and became more dependent on formal mathematical arguments, never his strongest suit.


In 1939, the war in Europe again influenced Einstein's life. Mussolini moved to copycat Hitler's anti-Semitic laws, which put Maja and Paul Winteler at risk in Italy. The photo shows Maja and Paul in happier days with the rest of the Winteler family.


Maja Einstein (1881–1951) second from left, Paul Winteler (1882–1952) third from left, and the rest of the Winteler family, about 1900. From Wikimedia Commons, user Freigut.

They had lived in a pleasant villa near Florence and were patrons of the arts. Besides his law practice, Paul fancied himself a painter. Maja's piano talents were well-known, especially playing on the Blüthner piano Einstein had given her. They decided they had to leave Italy and reunite after the war. Einstein offered to host them at Princeton, but Paul's health wasn't good enough to make the trip. Paul went to Zurich to live with his sister Anna and her husband Michele Besso, Einstein's good friend. Maja came to Princeton to live with her brother. In later years, Maja and Albert had come to resemble each other to the point that, from the back, it was hard to tell them apart.


Not long after Einstein arrived in the United States, he applied for citizenship, realizing he could keep his Swiss credentials also. Citizenship was granted several years later, in 1940. Hans Albert left Switzerland in 1938, and settled in South Carolina, where he worked for the US Department of Agriculture studying sediment transport. The relationship between father and son was a complicated one, but improved as the years went on. Hans Albert had one son who survived to adulthood, Bernard, and an adopted daughter, Evelyn, born in Chicago in 1941.

Bernard eventually studied at the ETH and worked for defense contractors in the United States and Switzerland. He married Aude Ascher and they had five children: Thomas and Eduard, who live in California; Paul in France; Mira in Israel; and Charlie, who lives in Switzerland.


Bernard Einstein (1930–2008), about 2003. Courtesy of Thomaseinstein, from Wikimedia Commons.


Even in America, Einstein still had affairs with women. One particularly interesting one was Margarita Konenkova.

Margarita was a lawyer. She spoke five languages and was very intelligent. She was in Princeton in 1942, accompanying her artist husband, Sergei, who had been commissioned to sculpt a bust of Einstein. When Margarita and Sergei arrived at Einstein's home, there was apparently instant attraction between Margarita and Einstein, and she invited him to a weekend party at a friend's summer home on Long Island. Einstein accepted, and an interesting relationship began, which was discovered by the public only in the late 1990s when a Konenkova relative ran across some letters and pictures from the 1945–1946 era. Of particular interest was that Margarita had been listed as a spy in the memoirs of a Soviet spymaster. Could she have been picking Einstein's brain for details about the Manhattan Project? If so, these would have been slim pickings. As we'll see in chapter 12, Einstein's involvement with the A-bomb was only before the beginning of the project, and through his friend Leo Szilárd. Einstein did contribute to the war effort, but in a different way. He was asked if he would submit his original papers on relativity for auction. Since they had long ago been discarded, he offered to rewrite them. He did so, along with another paper. They fetched $11 million for the war bond campaign.


Einstein and Margarita Konenkova (1896–1980). © Sergey Konenkov/Sygma/Corbis.


After the war ended, Einstein's health wasn't very good. He seldom accepted honorary degrees, saying they were “ostentatious.” Yet, in 1946, Einstein traveled the sixty miles from Princeton to Lincoln University, near Oxford, Pennsylvania. Lincoln was the first degree-granting historically black university. He stood outdoors for hours, as there was no building on campus large enough to accommodate the crowd that showed up to hear him. In his address, he said, “There is separation of colored people from white people in the United States. That separation is not a disease of colored people. It is a disease of white people. And, I do not intend to be quiet about it.” This was only the tip of the iceberg of Einstein's civil rights activities.


Einstein at Lincoln University, 1946. Photographed by Peace Photo. From the Shelby White and Leon Levy Archives Center, Institute for Advanced Study, Princeton, NJ, USA.

It all started in 1931, when W. E. B. Du Bois wrote a letter to Einstein in Berlin, asking if he could write a small piece for the NAACP's journal The Crisis. Einstein did respond. Here's an excerpt: “It seems to be a universal fact that minorities, especially when their Individuals are recognizable because of physical differences, are treated by majorities among whom they live as an inferior class…. The determined effort of the American Negroes in this direction deserves every recognition and assistance.”

Subsequently, Einstein met and became friends with Paul Robeson in 1935 when Robeson came to perform on campus at Princeton. Robeson, born in Princeton, was the valedictorian at Rutgers University, became an All-American football player, got a law degree from Columbia, and played in the NFL briefly. He was a good singer and actor, and played in Broadway plays and Hollywood films such as “Emperor Jones,” the first film to star an African American. Robeson grew to be disenchanted with treatment of black Americans, and became sympathetic with communism. Subsequently, he was blacklisted in Hollywood and his passport was revoked. Nevertheless, Einstein invited Robeson to come for a visit in 1952, along with his friend Lloyd Brown. When Robeson briefly left the room, Brown told Einstein it was “an honor to meet a great man.” Einstein fired back, “You came here with a great man.”

Other highlights of Einstein's antiracism include his friendship with opera singer Marian Anderson. She performed on Princeton's campus in 1937 to rave reviews, but was turned away from the Nassau Inn because of her color. Einstein invited her to stay at his home, and she stayed there every time she traveled to Princeton. Einstein became a member of the NAACP in 1942 and was often seen strolling the streets in the black community, handing out candy to children.


Einstein's friend Chaim Weizmann had become the first president of Israel. When Weizmann died in 1952, Israel's prime minister, David Ben Gurion called Einstein “the greatest Jew on earth,” and offered him Israel's presidency. Einstein's answer was:

“I am deeply moved by the offer from our State of Israel (to serve as President), and at once saddened and ashamed that I cannot accept it. All my life I have dealt with objective matters, hence I lack both the natural aptitude and the experience to deal properly with people and to exercise official functions.” This answered the question in just the way Ben-Gurion hoped for. Before he received Einstein's answer, Ben-Gurion said to an aide: “Tell me what to do if he says yes! I've had to offer him the post because it was impossible not to, but if he accepts we are in for trouble!”


Albert Einstein and David ben Gurion (1886–1973). Used with permission from Science Source.


From 1942 on, Einstein had company of the highest order at the Institute for Advanced Study—mathematician Kurt Gödel.

Einstein and Gödel had met as early as 1931, but many things had occurred since then. When Gödel succumbed to Abraham Flexner's charms and decided to come to Princeton permanently, Einstein was delighted. The two men had large divergences in personality and opinion about almost everything, but there was a strong bond of mutual respect. Although Einstein might have found it more convenient to work from his home at 115 Mercer Street, he dutifully walked to and from the institute's office building every day. A colleague named Oskar Morgenstern said that Einstein told him he went to the office “just to have the privilege of walking home with Kurt Gödel.”


Kurt Gödel (1906–1978) and Albert Einstein at the Institute, about 1950. Photograph by Richard Arens, courtesy AIP Emilio Segre Visual Archive.

For Einstein, it must have brought back memories of walking home from the Bern patent office with Michele Besso. At Princeton, Einstein and Gödel were beginning to feel like museum pieces. Most of their colleagues would agree with their views out of deference or disagree silently. Gödel was such an introvert that the ideas of others weren't that important. On the other hand, Einstein thrived on interaction. Between the two of them, it was no-holds-barred. In the 1952 US presidential election, Einstein favored Adlai Stevenson, while, according to Einstein, “Gödel has gone extremely crazy. He voted for Eisenhower.” Closer to his scientific interests, Gödel came up with one solution to Einstein's equations in which time travel was possible and another in which there was no time at all. Gödel's brilliant mathematics made Einstein wonder. He wrote to Besso in 1954, “I consider it quite possible that physics cannot be based on the field principle, i.e., on continuous structures. In that case, nothing remains of my entire castle in the air, gravitation theory included…” Clearly, this odd couple thrived on their walks and talks.

For all his adventures, both intellectual and in other parts of his life, Einstein would seem to make a fascinating dinner companion. How could one fail to enjoy a fellow who said, “Whoever undertakes to set himself up as a judge of Truth and Knowledge is shipwrecked by the laughter of the gods.”


Albert Einstein. Image courtesy of the Observatories of the Carnegie Institution for Science Collection at the Huntington Library, San Marino, California.