Authors: Walter Isaacson
That conflicting admixture of playfulness and seriousness, of insouciance and intensity, of intimacy and detachment—so peculiar yet also so evident in Einstein as well—must have appealed to him. He urged her to return to Zurich. By February 1898, she had made up her mind to do so, and he was thrilled. “I’m sure you won’t regret your decision,” he wrote. “You should come back as soon as possible.”
He gave her a thumbnail of how each of the professors was performing (admitting that he found the one teaching geometry to be “a little impenetrable”), and he promised to help her catch up with the aid of the lecture notes he and Marcel Grossmann had kept. The one problem was that she would probably not be able to get her “old pleasant room” at the nearby pension back. “Serves you right, you little runaway!”
32
By April she was back, in a boarding house a few blocks from his, and now they were a couple. They shared books, intellectual enthusiasms, intimacies, and access to each other’s apartments. One day, when he again forgot his key and found himself locked out of his own place, he went to hers and borrowed her copy of a physics text. “Don’t be angry with me,” he said in the little note he left her. Later that year, a
similar note left for her added, “If you don’t mind, I’d like to come over this evening to read with you.”
33
Friends were surprised that a sensuous and handsome man such as Einstein, who could have almost any woman fall for him, would find himself with a short and plain Serbian who had a limp and exuded an air of melancholy. “I would never be brave enough to marry a woman unless she were absolutely healthy,” a fellow student said to him. Einstein replied, “But she has such a lovely voice.”
34
Einstein’s mother, who had adored Marie Winteler, was similarly dubious about the dark intellectual who had replaced her. “Your photograph had quite an effect on my old lady,” Einstein wrote from Milan, where he was visiting his parents during spring break of 1899. “While she studied it carefully, I said with the deepest sympathy: ‘Yes, yes, she certainly is a clever one.’ I’ve already had to endure much teasing about this.”
35
It is easy to see why Einstein felt such an affinity for Mari
. They were kindred spirits who perceived themselves as aloof scholars and outsiders. Slightly rebellious toward bourgeois expectations, they were both intellectuals who sought as a lover someone who would also be a partner, colleague, and collaborator. “We understand each other’s dark souls so well, and also drinking coffee and eating sausages, etcetera,” Einstein wrote her.
He had a way of making the
etcetera
sound roguish. He closed another letter: “Best wishes etc., especially the latter.” After being apart for a few weeks, he listed the things he liked to do with her: “Soon I’ll be with my sweetheart again and can kiss her, hug her, make coffee with her, scold her, study with her, laugh with her, walk with her, chat with her, and ad infinitum!” They took pride in sharing a quirkiness. “I’m the same old rogue as I’ve always been,” he wrote, “full of whims and mischief, and as moody as ever!”
36
Above all, Einstein loved Mari
for her mind. “How proud I will be to have a little Ph.D. for a sweetheart,” he wrote to her at one point. Science and romance seemed to be interwoven. While on vacation with his family in 1899, Einstein lamented in a letter to Mari
, “When I read Helmholtz for the first time I could not—and still cannot—believe
that I was doing so without you sitting next to me. I enjoy working together and I find it soothing and also less boring.”
Indeed, most of their letters mixed romantic effusions with scientific enthusiasms, often with an emphasis on the latter. In one letter, for example, he foreshadowed not only the title but also some of the concepts of his great paper on special relativity. “I am more and more convinced that the electrodynamics of moving bodies as it is presented today does not correspond to reality and that it will be possible to present it in a simpler way,” he wrote. “The introduction of the term ‘ether’ into theories of electricity has led to the conception of a medium whose motion can be described without, I believe, being able to ascribe physical meaning to it.”
37
Even though this mix of intellectual and emotional companionship appealed to him, every now and then he recalled the enticement of the simpler desire represented by Marie Winteler. And with the tactlessness that masqueraded for him as honesty (or perhaps because of his puckish desire to torment), he let Mari
know it. After his 1899 summer vacation, he decided to take his sister to enroll in school in Aarau, where Marie lived. He wrote Mari
to assure her that he would not spend much time with his former girlfriend, but the pledge was written in a way that was, perhaps intentionally, more unsettling than reassuring. “I won’t be going to Aarau as often now that the daughter I was so madly in love with four years ago is coming back home,” he said. “For the most part I feel quite secure in my high fortress of calm. But I know that if I saw her a few more times, I would certainly go mad. Of that I am certain, and I fear it like fire.”
But the letter goes on, happily for Mari
, with a description of what they would do when they met back in Zurich, a passage in which Einstein showed once again why their relationship was so special. “The first thing we’ll do is climb the Ütliberg,” he said, referring to a high point just out of town. There they would be able to “take pleasure in unpacking our memories” of the things they had done together on other hiking trips. “I can already imagine the fun we will have,” he wrote. Finally, with a flourish only they could have fully appreciated, he concluded, “And then we’ll start in on Helmholtz’s electromagnetic theory of light.”
38
In the ensuing months, their letters became even more intimate and passionate. He began calling her Doxerl (Dollie), as well as “my wild little rascal” and “my street urchin”; she called him Johannzel (Johnnie) and “my wicked little sweetheart.” By the start of 1900, they were using the familiar
du
with one another, a process that began with a little note from her that reads, in full:
My little Johnnie,
Because I like you so much, and because you’re so far away that I can’t give you a little kiss, I’m writing this letter to ask if you like me as much as I do you? Answer me immediately.
A thousand kisses from your Dollie
39
Academically, things were also going well for Einstein. In his intermediate exams in October 1898, he had finished first in his class, with an average of 5.7 out of a possible 6. Finishing second, with a 5.6, was his friend and math note-taker Marcel Grossmann.
40
To graduate, Einstein had to do a research thesis. He initially proposed to Professor Weber that he do an experiment to measure how fast the earth was moving through the ether, the supposed substance that allowed light waves to propagate through space. The accepted wisdom, which he would famously destroy with his special theory of relativity, was that if the earth were moving through this ether toward or away from the source of a light beam, we’d be able to detect a difference in the observed speed of the light.
During his visit to Aarau at the end of his summer vacation of 1899, he worked on this issue with the rector of his old school there. “I had a good idea for investigating the way in which a body’s relative motion with respect to the ether affects the velocity of the propagation of light,” he wrote Mari
. His idea involved building an apparatus that would use angled mirrors “so that light from a single source would be reflected in two different directions,” sending one part of the beam in the direction of the earth’s movement and the other part of the beam perpendicular to it. In a lecture on how he discovered relativity, Einstein
recalled that his idea was to split a light beam, reflect it in different directions, and see if there was “a difference in energy depending on whether or not the direction was along the earth’s motion through the ether.” This could be done, he posited, by “using two thermoelectric piles to examine the difference of the heat generated in them.”
41