His scientific work, on the other hand, was giving him great pleasure, and he expressed excitement about his possible new opportunity. “It is most probable that I will be offered the position of full professor at a large university with a significantly better salary than I now have.”9
When word of Einstein’s possible move spread in Zurich, fifteen of his students, led by Hans Tanner, signed a petition urging officials there “to do your utmost to keep this outstanding researcher and teacher at our university.” They stressed the importance of having a professor in “this newly created discipline” of theoretical physics, and they extolled him personally in effusive terms. “Professor Einstein has an amazing talent for presenting the most difficult problems of theoretical physics so clearly and so comprehensibly that it is a great delight for us to follow his lectures, and he is so good at establishing a perfect rapport with his audience.”10
The Zurich authorities were so eager to keep him that they raised his salary from its current 4,500 francs, which was the same as he made as a patent examiner, to 5,500 francs. Those attempting to lure him to Prague, on the other hand, were having a more difficult time.
The faculty department at Prague had settled on Einstein as its first choice and forwarded the recommendation to the education ministry in Vienna. (Prague was then part of the Austro-Hungarian Empire, and such an appointment had to be approved by Emperor Franz Joseph and his ministers.) The report was accompanied by the highest possible recommendation from the best possible authority, Max Planck. Einstein’s theory of relativity “probably exceeds in audacity everything that has been achieved so far in speculative science,” Planck proclaimed. “This principle has brought about a revolution in our physical picture of the world that can be compared only to that produced by Copernicus.” In a comment that might later have seemed prescient to Einstein, Planck added, “Non- Euclidean geometry is child’s play by comparison.”11
Planck’s imprimatur should have been enough. But it wasn’t. The ministry decided that it preferred the second-place candidate, Gustav Jaumann, who had two advantages: he was Austrian, and he was not Jewish. “I did not get the call to Prague,” Einstein lamented to a friend in August. “I was proposed by the faculty, but because of my Semitic origin the ministry did not approve.”
Jaumann, however, soon discovered that he was the faculty’s second choice, and he erupted. “If Einstein has been proposed as the first choice because of the belief that he has greater achievements to his credit,” he declared, “then I will have nothing to do with a university that chases after modernity and does not appreciate merit.” So by October 1910, Einstein could confidently declare that his own appointment was “almost certain.”
There was one final hurdle, also dealing with religion. Being a Jew was a disadvantage; being a nonbeliever who claimed
As it turned out, Einstein’s desire for the job was greater than his ornery impracticality. He agreed to write “Mosaic” as his faith, and he also accepted Austro-Hungarian citizenship, with the proviso that he was allowed to remain a Swiss citizen as well. Along with the German citizenship that he had forsaken but that would soon be foisted back on him, that meant he had held, off and on, three citizenships by the age of 32. In January 1911, he was officially appointed to the post, with a pay twice what he had been making before his recent raise. He agreed to move to Prague that March.12
Einstein had two scientific heroes he had never met—Ernst Mach and Hendrik Lorentz—and he was able to visit them both before his move to Prague. When he went to Vienna for his formal presentation to the ministers there, he called on Mach, who lived in a suburb of that city. The aging physicist and preacher of empiricism, who so deeply influenced the Olympia Academy and instilled in Einstein a skepticism about unobservable concepts such as absolute time, had a gnarly beard and gnarlier personality. “Please speak loudly to me,” he barked when Einstein entered his room. “In addition to my other unpleasant characteristics I am also almost stone deaf.”
Einstein wanted to convince Mach of the reality of atoms, which the old man had long rejected as being imaginary constructs of the human mind. “Let us suppose that by assuming the existence of atoms in a gas we were able to predict an observable property of this gas that could not be predicted on the basis of non-atomistic theory,” Einstein asked. “Would you then accept such a hypothesis?”
“If with the help of the atomic hypothesis one could actually establish a connection between several observable properties which without it would remain isolated, then I should say that this hypothesis was an ‘economical’ one,” Mach grudgingly replied.
It was not a full acceptance, but it was enough for Einstein. “For the moment Einstein was satisfied,” his friend Philipp Frank noted. Nevertheless, Einstein began edging away from Mach’s skepticism about any theories of reality not built on directly observable data. He developed, said Frank, “a certain aversion to the Machist philosophy.”13 It was the beginning of an important conversion.
Just before moving to Prague, Einstein went to the Dutch town of Leiden to meet Lorentz. Mari accompanied him, and they accepted an invitation to stay with Lorentz and his wife. Einstein wrote that he was looking forward to having a conversation on “the radiation problem,” adding, “I wish to assure you in advance that I am not the orthodox light-quantizer for whom you take me.”14
Einstein had long idolized Lorentz from afar. Just before he went to visit, he wrote a friend: “I admire this man like no other; I might say, I love him.” The feeling was reinforced when they finally met. They stayed up late on Saturday night discussing such issues as the relationship between temperature and electrical conductivity.
Lorentz thought he had caught Einstein in a small mathematical mistake in one of his papers on light quanta, but in fact, as Einstein noted, it was simply “a one-time writing error” where he had left out a “?” that was included later in the paper.15 Both the hospitality and “scientific stimulus” made Einstein effusive in his next letter. “You radiate so much goodness and benevolence,” he wrote, “that the troubling conviction that I did not deserve the great kindness and honors could not even enter my mind during my stay at your house.”16
Lorentz became, in the words of Abraham Pais, “the one father figure in Einstein’s life.” After his pleasant visit to Lorentz’s study in Leiden, he would return whenever he could find an excuse. The atmosphere of such meetings was captured by their colleague Paul Ehrenfest:
The best easy chair was carefully pushed in place next to the large work table for his esteemed guest. A cigar was given to him, and then Lorentz quietly began to formulate questions concerning Einstein’s theory of the bending of light in a gravitational field . . . As Lorentz spoke on, Einstein began to puff less frequently on his cigar, and he sat more intently in his armchair. And when Lorentz had finished, Einstein bent over the slip of paper on which Lorentz had written mathematical formulas. The cigar was out, and Einstein pensively twisted his finger in a lock of hair over his right ear. Lorentz sat smiling at an Einstein completely lost in meditation, exactly the way that a father looks at a particularly beloved son—full of confidence that the youngster will crack the nut he has given him, but eager to see how. Suddenly, Einstein’s head sat up joyfully; he had it. Still a bit of give and take, interrupting one another, a partial disagreement, very quick clarification and a complete mutual understanding, and then both men with beaming eyes skimming over the shining riches of the new theory.
17
When Lorentz died in 1928, Einstein would say in his eulogy, “I stand
