einstein

Zurich, 1909
CHAPTER EIGHT
THE WANDERING PROFESSOR
1909–1914
As a self-assured 17-year-old, Einstein had enrolled at the Zurich Polytechnic and met Mileva Mari , the woman he would marry. Now, in October
1909, at age 30, he was returning to that city to take up his post as a junior professor at the nearby University of Zurich.
Their homecoming restored, at least temporarily, some of the romance to their relationship. Mari was thrilled to be back in their original nesting
ground, and by the end of their first month there she became pregnant again.
The apartment they rented was in a building where, they happily discovered, Friedrich Adler and his wife lived, and the couples became even
closer friends. “They run a bohemian household,” Adler wrote his father approvingly. “The more I talk to Einstein, the more I realize that my favorable
opinion of him was justified.”
The two men discussed physics and philosophy most evenings, often retreating to the attic of the three-story building so they would not be
disturbed by children or spouses. Adler introduced Einstein to the work of Pierre Duhem, whose 1906 book La Théorie Physique Adler had just
published in German. Duhem offered a more holistic approach than Mach did to the relationship between theories and experimental evidence, one
that seemed to influence Einstein as he staked out his own philosophy of science. 1
Adler particularly respected Einstein’s “most independent” mind. There was, he told his father, a nonconformist streak in Einstein that reflected
an inner security but not an arrogance. “We find ourselves in agreement on questions that the majority of physicists would not even understand,”
Adler boasted. 2
Einstein tried to persuade Adler to focus on science rather than be enticed into politics. “Be a little patient,” he said. “You will certainly be my
successor in Zurich one day.” (Einstein was already assuming that he would move on to a more prestigious university.) But Adler ignored the
advice and decided to become an editor at the Social Democratic Party newspaper. Loyalty to a party, Einstein felt, meant surrendering some
independence of thought. Such conformity confounded him. “How an intelligent man can subscribe to a party I find a complete mystery,” Einstein
later lamented about Adler. 3
Einstein was also reunited with his former classmate and note-taker Marcel Grossmann, who had helped him get his job at the patent office and
was now a professor of math at their old Polytechnic. Einstein would often visit Grossmann after lunch for help with the complex geometry and
calculus he needed to extend relativity into a more general field theory.
Einstein was even able to forge a friendship with the other distinguished math professor at the Polytechnic, Adolf Hurwitz, whose classes he had
often skipped and who had spurned his plea for a job. Einstein became a regular at the Sunday music recitals at Hurwitz’s home. When Hurwitz told
him during a walk one day that his daughter had been given a math homework problem she did not understand, Einstein showed up that afternoon
to help her solve it. 4
As Kleiner predicted, Einstein’s teaching talents improved. He was not a polished lecturer, but instead used informality to his advantage. “When
he took his chair in shabby attire with trousers too short for him, we were skeptical,” recalled Hans Tanner, who attended most of Einstein’s Zurich
lectures. Instead of prepared notes, Einstein used a card-sized strip of paper with scribbles. So the students got to watch him develop his thoughts
as he spoke. “We obtained some insight into his working technique,” said Tanner. “We certainly appreciated this more than any stylistically perfect
lecture.”
At each step of the way, Einstein would pause and ask the students if they were following him, and he even permitted interruptions. “This
comradely contact between teacher and student was, at that time, a rare occurrence,” according to Adolf Fisch, another who attended the lectures.
Sometimes he would take a break and let the students gather around him for casual conversation. “With an impulsiveness and naturalness he
would take students by the arm to discuss things,” recalled Tanner.
During one lecture, Einstein found himself momentarily stumped about the steps needed to complete a calculation. “There must be some silly
mathematical transformation that I can’t find for a moment,” he said. “Can one of you gentlemen see it?” Not surprisingly, none of them could. So
Einstein continued: “Then leave a quarter of a page. We won’t lose any time.”Ten minutes later, Einstein interrupted himself in the middle of another
point and exclaimed, “I’ve got it.” As Tanner later marveled, “During the complicated development of his theme he had still found time to reflect upon
the nature of that particular mathematical transformation.”
At the end of many of his evening lectures, Einstein would ask, “Who’s coming to the Café Terasse?” There, with an informal cadre on a terrace
overlooking the Limmat River, they would talk until closing time.
On one occasion, Einstein asked if anyone wanted to come back to his apartment. “This morning I received some work from Planck in which
there must be a mistake,” he said. “We could read it together.” Tanner and another student took him up on the offer and followed him home. There
they all pored over Planck’s paper. “See if you can spot the fault while I make some coffee,” he said.
After a while, Tanner replied, “You must be mistaken, Herr Professor, there is no error in it.”
“Yes, there is,” Einstein said, pointing to some discrepancies in the data, “for otherwise that and that would become that and that.” It was a vivid
example of Einstein’s great strength: he could look at a complex mathematical equation, which for others was merely an abstraction, and picture
the physical reality that lay behind it.
Tanner was astounded. “Let’s write to Professor Planck,” he suggested, “and tell him of the mistake.”
Einstein had by then become slightly more tactful, especially with those he placed on a pedestal, such as Planck and Lorentz. “We won’t tell him
he made a mistake,” he said. “The result is correct, but the proof is faulty. We’ll simply write and tell him how the real proof should run. The main
thing is the content, not the mathematics.” 5
Despite his work on his machine to measure electrical charges, Einstein had become a confirmed theorist rather than experimental physicist.
When he was asked during his second year as a professor to supervise laboratory work, he was dismayed. He hardly dared, he told Tanner, “pick
up a piece of apparatus for fear it might blow up.” To another eminent professor he confided, “My fears regarding the laboratory were rather well
founded.” 6
As he was finishing his first academic year at Zurich, in July 1910, Mari gave birth, again with difficulty, to their second son, named Eduard and