einstein

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 “½” 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 at the grave of the greatest and noblest man of our times.” And in 1953, for
the celebration of the hundredth anniversary of Lorentz’s birth, Einstein wrote an essay on his importance. “Whatever came from this supreme mind
was as lucid and beautiful as a good work of art,” he wrote. “He meant more to me personally than anybody else I have met in my lifetime.” 18
Mari was unhappy about moving to Prague. “I am not going there gladly and I expect very little pleasure,” she wrote a friend. But initially, until the
city’s dirtiness and snobbishness became oppressive, their life there was nice enough. They had electric lighting in their home for the first time, and
both the space and money for a live-in maid. “The people are haughty, shabby-genteel, or subservient, depending on their lot in life,” Einstein said.
“Many of them possess a certain grace.” 19
From Einstein’s office at the university he could look down on a beautiful park with shady trees and manicured gardens. In the morning, it would
be filled just with women, and in the afternoon just with men. Some walked alone as if deep in thought, Einstein noticed, while others clustered in
groups holding animated arguments. Eventually, Einstein asked what the park was. It belonged, he was told, to an insane asylum. When he showed
his friend Philipp Frank the view, Einstein commented ruefully, “Those are the madmen who do not occupy themselves with the quantum theory.” 20
The Einsteins became acquainted with Bertha Fanta, a delightfully cultured woman who hosted at her home a literary and musical salon for
Prague’s Jewish intelligentsia. Einstein was the ideal catch: a rising scholar who was willing, with equal gusto, to play the violin or discuss Hume
and Kant, depending on the spirit of the occasion. Other habitués included the young writer Franz Kafka and his friend Max Brod.
In his book The Redemption of Tycho Brahe, Brod seemed to use (though he sometimes denied it) Einstein as the model for the character of
Johannes Kepler, the brilliant astronomer who had been Brahe’s assistant in Prague in 1600. The character is devoted to his scientific work and is
always willing to throw away conventional thinking. But in the realm of the personal, he is protected from “the aberrations of feeling” by his aloof and
abstracted air. “He had no heart and therefore nothing to fear from the world,” Brod wrote. “He was not capable of emotion or love.” When the novel
came out, a fellow scientist, Walther Nernst, said to Einstein, “You are this man Kepler.” 21
Not really. Despite the image he sometimes cast as a loner, Einstein continued to establish, as he had back in Zurich and Bern, intimate
friendships and emotional bonds, particularly with fellow thinkers and scientists. One such friend was Paul Ehrenfest, a young Jewish physicist from
Vienna who was teaching at the University of St. Petersburg but feeling professionally stymied there because of his background. In early 1912, he
embarked on a trip through Europe looking for a new job, and on his way toward Prague contacted Einstein, with whom he had been
corresponding about gravity and radiation. “Do stay at my house so that we can make good use of the time,” Einstein responded. 22
When Ehrenfest arrived one rainy Friday afternoon in February, a cigar-puffing Einstein and his wife were at the train station to meet him. They all
walked to a café, where they compared the great cities of Europe. When Mari left, the discussion turned to science, most notably statistical
mechanics, and they continued talking as they walked to Einstein’s office. “On the way to the institute, first argument about everything,” Ehrenfest
recorded in his diary of the seven days he spent in Prague.
Ehrenfest was a mousy and insecure man, but his eagerness for friendship and his love of physics made it easy for him to forge a bond with
Einstein. 23 They both seemed to crave arguing about science, and Einstein later said that “within a few hours we were friends as if Nature created
us for each other.”Their intense discussions continued the next day, as Einstein explained his efforts to generalize his theory of relativity. On Sunday
evening, they relaxed a bit by performing Brahms, with Ehrenfest on piano, Einstein on violin, and 7-year-old Hans Albert singing. “Yes we will be
friends,” Ehrenfest wrote in his diary that night. “Was awfully happy.” 24
Einstein was already thinking of leaving Prague, and he suggested Ehrenfest as a possible successor. But he “adamantly refuses to profess any
religious affiliation,” Einstein lamented. Unlike Einstein, who was willing to relent and write “Mosaic” on his official forms, Ehrenfest had abandoned
Judaism and would not profess otherwise. “Your stubborn refusal to acknowledge any religious affiliation really bugs me,” Einstein wrote him in
April. “Drop it for your children’s sake. After all, after becoming a professor here you could revert to this strange hobby horse of yours.” 25
Matters eventually came to a happy resolution when Ehrenfest accepted an offer, which Einstein had earlier received but declined, to replace the
revered Lorentz, who was cutting back from full-time teaching at the University of Leiden. Einstein was thrilled, for it meant he would now have two
friends there to visit regularly. It became, for Einstein, almost a second academic home and a way to escape the oppressive atmosphere he later
found in Berlin. Almost every year for the next two decades, until 1933 when Ehrenfest committed suicide and Einstein moved to America, Einstein
would make regular pilgrimages to see him and Lorentz in Leiden or at the seaside resorts nearby. 26
The 1911 Solvay Conference
Ernest Solvay was a Belgian chemist and industrialist who reaped a fortune by inventing a method for making soda. Because he wanted to do