A possible clue to Einstein’s character is an evident gulf between how women saw him and how men saw him. The men in his life, his friends and his sons, complained of his detachment. “For all his kindness, sociability and love of humanity,” the physicist Max Born wrote, “he was nevertheless totally detached from his environment and the human beings included in it.” But women saw in him “masculine good looks of the type that played havoc at the turn of the Century…. The lower half of his face might have belonged to a sensualist who found plenty of reasons to love life.” And there is plenty of evidence, from the stories of affairs lasting into old age and the letters between him and his women, that women continued to find him attractive.
Throughout his life, in fact, we see how important women were to him. His first marriage in 1903 to Mileva Maric�, a Serbian mathematician, began as a partnership between fellow students and soulmates. He risked a great deal for it, including his relationship with his parents. When it went bad, he might have stayed for the benefit of their children, but he gave it all up for a new love, that of his cousin Elsa Einstein. This cost him dearly in his relationships with his sons, as he wrote to Elsa:
I have carried these children around innumerable times day and night, taken them out in their pram, played with them, romped around and joked with them. They used to shout with joy when I came; the little one cheered even now, because he was still too small to grasp the situation. Now they will be gone forever, and their image of their father is being spoiled.
What he gained by this sacrifice was not just a life with Elsa, but a household of women, starting with Elsa’s two grown daughters—one of whom he apparently also proposed to. A decade later he added Helen Dukas, who became not only his personal assistant but a member of his household. In later years this circle of women came to include also his beloved sister Maja who, along with one of Elsa’s daughters, left her husband to live out her life with Einstein. But this household of women was not enough for him, for it seems Elsa did not interfere with his having many friendships—erotic or not—with women in Berlin.
Perhaps the stories of Einstein and others point to a kind of man who is most comfortable and engaged when in the company of women. Reading about his relations with them, we can ask whether there is an erotic component to some kinds of scientific and mathematical creativity.
This possibility challenges the stereotype that scientists and mathematicians tend to be nerds, out of touch with their bodies. Perhaps the notion that scientists are people of unworldly detachment is accepted uncritically because it supports the ancient idea that the mind and body are distinct entities. Some would prefer the myth of Stephen Hawking, who may seem to be a man with no body to speak of, in touch with only the universe (with his necessary support from a team of nurses and students hardly mentioned), than to think too much about Einstein seducing Berlin socialites in his sailboat, or Erwin Schrödinger inventing quantum mechanics during an erotic weekend with a lover and later showing up in Stockholm to receive the Nobel Prize with both his wife and his mistress.
The discrepancies in the myth of Einstein are important, not so much for their own sake but because they point to contradictions in the perception of his scientific legacy held by laypeople and scientists alike. Corresponding to the apparent contradictions between the character of the young and the old Einstein, and between the detached sage and the man deeply involved with women, we can find in much of the recent writing two scientists called Einstein. The early Einstein, according to legend, was brash and revolutionary. His thinking was closely tied to experimental science and engineering practice. It was intuitive, centered on a search for general principles, and done with a light hand that employed the bare minimum of mathematics.
Moreover, as Peter Galison convincingly shows in his 2003 book, Einstein’s Clocks, Poincaré’s Maps: Empires of Time, the young Einstein developed his science while being closely involved with the technology of his time. Einstein’s father and uncle were high-tech entrepreneurs, which in those days meant they took part in the electrification of cities. In the patent office he dealt every day with cutting-edge technology, and some of it had to do with the issue of defining time and establishing simultaneity. The problem of synchronizing clocks in distant places, leading to a definition of simultaneous time, is central to Einstein’s 1905 special theory of relativity. From Galison we learn that the same problem was crucial for coordinating railway timetables and more generally for the establishment of national and global systems of time, and that Einstein likely examined patents relevant to this problem in his work in the Swiss patent office.
Einstein’s later work, beginning in the early 1920s, was very different. It was an almost random search through catalogs of inelegant mathematical formulas, in the vain hope of discovering a unification of the different physical forces, including both gravity and the fundamental particles. I agree with Neffe that this work was “lacking something that had previously served him well on two occasions: a principle…. It also lacked any empirical foundation.” According to Banesh Hoffman, one of his assistants, “The search was not so much a search as a groping in the gloom of a mathematical jungle inadequately lit by physical intuition.” The ever-acerbic physicist Wolfgang Pauli wrote to him in 1929: “All that is left…is to congratulate you (or had I better say ‘express… condolences’?) on your having gone over to the pure mathematicians.”
It is true that many mathematicians and physicists do their best work when young. But in Einstein’s later work we see something much more extreme than the usual falling off. It is as if Thelonious Monk or John Coltrane turned into an obscure twelve-tone composer. How did the greatest physicist since Newton turn into a failed player of mathematical games? All the biographers ask this question; none gives an answer that seems remotely plausible to me as a working scientist.
The key issue in the assessment of Einstein’s later years is his conviction that quantum mechanics could not be correct. Although in 1905 he had been the first to identify the need for a new quantum physics, he dissented strongly from the view that our understanding of quantum phenomena was put in final form by the invention of quantum mechanics in 1926 and 1927. In particular, he argued that quantum mechanics, while making predictions that agreed with experiments, could only provide an incomplete and approximate description of phenomena at the level of the atom. His objection was partly based on the fact that quantum mechanics gives only statistical predictions for many experiments, and partly on the fact that it gives no physical picture of precisely what occurs in individual atomic processes. For him then, quantum mechanics was at best a provisional step on the way to the right theory of atomic physics. A major motivation for his search for a unified field theory was his belief that it might lead to that correct theory. He was not alone; among the inventors of quantum physics, Louis de Broglie, Erwin Schrödinger, and others shared his skepticism about the theory.
As Freeman Dyson has described in these pages, Einstein was a leader of a generation of revolutionaries, every one of whom “had a crazy theory that he thought would be the key to understanding everything.”2 Like some of his fellow European refugees, such as Kurt Gödel, Einstein represented an older, philosophical approach to science that was based on attempts to think radically about the foundations of reality such as the nature of space, time, and causality. In America, however, he found a new generation of conservatives, among whom Dyson numbers himself. As Dyson saw it,
The old revolutionaries…believed that physics needed another revolution as profound as the quantum revolution…. Young people like me saw all these famous old men making fools of themselves, and so we became conservatives.
They were conservative because they thought the revolution was over and their task was to develop the applications of quantum physics, which they took to be the prime legacy of the revolution. “The physical ideas were basically correct,” Dyson wrote. His contemporaries
did not need to start another revolution. They only needed to take the existing physical theories and clean up the details. I helped them with the later stages of the cleanup. The result of our efforts was the modern theory of quantum electrodynamics, the theory that accurately describes the way atoms and radiation behave.
But for Einstein and others, who did not accept quantum mechanics, the revolution was not yet over. By the time Einstein moved to Princeton in 1933, he had already parted ways with most of his colleagues. As a result, although all the subsequent developments of twentieth-century physics were entirely based on Einstein’s early work, it can also be said that Einstein left very little legacy from his work at Princeton within the scientific community. His later views were for the most part not taken seriously, and those who followed him and worked with him during that period did not flourish. Indeed, his most important contribution of all, general relativity—which he had developed between 1909 and 1915, following his early work on special relativity—was mostly ignored from the 1930s to the 1960s as physics focused on the rapidly expanding sphere of applications of the quantum theory.
By the time Newton died the Royal Society was filled with Newtonians. But after Einstein’s death in 1955, to be an Einsteinian was to be in a decidedly marginalized position in the physics world, if by Einsteinian one meant someone who agreed with Einstein’s strongest convictions and consequently approached physics in the same style he did. The big question that any assessment of Einstein’s later period then hinges on is whether Einstein’s later views were correct or not. The least that can be said is that there is an entire field now devoted to questions raised by the counterintuitive aspects of quantum mechanics called the foundations of quantum mechanics. Most experts agree that the questions raised by Einstein have not been resolved, and a fair fraction of them suspect that in the end Einstein’s view that quantum mechanics is just a step on the way to the right theory will turn out to have been correct.
Nonetheless, for most of Einstein’s biographers, who have been either nonphysicists or, like Pais, particle physicists firmly in the dominant quantum theory camp, the question is closed. To them one of very greatest scientists in history was completely wrong about the truth of a theory whose development he initiated. Isaacson asks, “So what made Einstein cede the revolutionary road to younger radicals and spin into a defensive crouch?” The simple truth is that Einstein ceded nothing because he had well-thought-out and principled objections to the quantum theory.