Walter Isaacson - Einstein - His Life and Universe

She would write the new equations on a blackboard so they could ponder them together, and point out problems. Einstein would then try to counter them.“He had certain criteria by which to judge whether this is relevant to physical reality or not,” she recounted. Even when they were defeated by the obstacles to a new approach, as they invariably were, Einstein remained optimistic. “Well, we’ve learned something,” he would say as the clock ticked down. 10

In the evening, he would often explain his last-ditch efforts to his companion, Johanna Fantova, and she would record them in her journal. The entries for 1954 were littered with hopes raised and dashed. February 20: “Thinks he found a new angle to his theory, something very important that would simplify it. Hopes he won’t find any errors.” February 21: “Didn’t find any errors, but the new work isn’t as exciting as he had thought the day before.” August 25: “Einstein’s equations are looking good—maybe something will come of them—but it’s damned hard work.” September 21: “He’s making some progress with what was at first only a theory but is now looking good.” October 14: “Found an error in his work today, which is a setback.” October 24: “He calculated like crazy today but accomplished nothing.” 11

That year Wolfgang Pauli, the quantum mechanics pioneer, came to visit. Again the old debate over whether God would play dice was reengaged, as it had been a quarter-century earlier at the Solvay Conferences. Einstein told Pauli that he still objected to the fundamental tenet in quantum mechanics that a system can be defined only by specifying the experimental method of observing it. There was a reality, he insisted, that was independent of how we observed it. “Einstein has the philosophical prejudice that a state, termed ‘real,’ can be defined objectively under any circumstances, that is, without specification of the experimental arrangement used to examine the system,” Pauli marveled in a letter to Max Born. 12

He also clung to his belief that physics should be based, as he told his old friend Besso, “on the field concept, i.e., on continuous structures.” Seventy years earlier, his awe at contemplating a compass caused him to marvel at the concept of fields, and they had guided his theories ever since. But what would happen, he worried to Besso, if field theory turned out to be unable to account for particles and quantum mechanics? “In that case nothing remains of my entire castle in the air, gravitation theory included.” 13

So even as Einstein apologized for his stubbornness, he proudly refused to abandon it. “I must seem like an ostrich who forever buries its head in the relativistic sand in order not to face the evil quanta,” he wrote Louis de Broglie, another of his colleagues in the long struggle. He had found his gravitational theories by trusting an underlying principle, and that made him a “fanatic believer” that comparable methods would eventually lead to a unified field theory. “This should explain the ostrich policy,” he wryly told de Broglie. 14

He expressed this more formally in the concluding paragraph of his final updated appendix to his popular book, Relativity: The Special and General Theory. “The conviction prevails that the experimentally assured duality (corpuscular and wave structure) can be realized only by such a weakening of the concept of reality,” he wrote. “I think that such a far-reaching theoretical renunciation is not for the present justified by our actual knowledge, and that one should not desist from pursuing to the end the path of the relativistic field theory.” 15

Bertrand Russell encouraged him to continue, in addition, the search for a structure that would ensure peace in the atomic age. They had both opposed the First World War, Russell recalled, and supported the Second. Now it was imperative to prevent a third. “I think that eminent men of science ought to do something dramatic to bring home to the governments the disasters that may occur,” Russell wrote. Einstein replied by proposing a “public declaration” that they and perhaps a few other eminent scientists and thinkers could sign. 16

Einstein set to work enlisting his old friend and sparring partner, Niels Bohr. “Don’t frown like that!” Einstein joked, as if he were face-to-face with Bohr rather than writing to him in Copenhagen. “This has nothing to do with our old controversy on physics, but rather concerns a matter on which we are in complete agreement.” Einstein admitted that his own name might carry some influence abroad, but not in America,“where I am known as a black sheep (and not merely in scientific matters).” 17

Alas, Bohr declined, but nine other scientists, including Max Born, agreed to join the effort. Russell concluded the proposed document with a simple plea: “In view of the fact that in any future world war nuclear weapons will certainly be employed, and that such weapons threaten the continued existence of mankind, we urge the governments of the world to realize, and to acknowledge publicly, that their purpose cannot be furthered by a world war, and we urge them, consequently, to find peaceful means for the settlement of all matters of dispute between them.” 18

Einstein made it to his seventy-sixth birthday, but he was not well enough to come outside to wave to the reporters and photographers gathered in front of 112 Mercer Street. The mailman delivered presents, Oppenheimer came by with papers, the Bucky family brought some puzzles, and Johanna Fantova was there to record the events.

Among the presents was a tie sent by the fifth grade of the Farmingdale Elementary School in New York, which presumably had seen pictures of him and thought he could use one. “Neckties exist for me only as remote memories,” he admitted politely in his letter of thanks. 19

A few days later, he learned of the death of Michele Besso, the personal confessor and scientific sounding board he had met six decades earlier upon arriving as a student in Zurich. As if he knew that he had only a few more weeks, Einstein ruminated on the nature of death and time in the condolence letter he wrote to Besso’s family. “He has departed from this strange world a little ahead of me. That means nothing. For us believing physicists, the distinction between past, present and future is only a stubborn illusion.”

Einstein had introduced Besso to his wife, Anna Winteler, and he marveled as his friend made the marriage survive despite some difficult patches. Besso’s most admirable personal trait, Einstein said, was to live in harmony with a woman, “an undertaking in which I twice failed rather miserably.” 20

One Sunday in April, the Harvard historian of science I. Bernard Cohen went to see Einstein. His face, deeply lined, struck Cohen as tragic, yet his sparkling eyes made him seem ageless. He spoke softly yet laughed loudly. “Every time he made a point that he liked,” Cohen recalled, “he would burst into booming laughter.”

Einstein was particularly amused by a scientific gadget, designed to show the equivalence principle, that he had recently been given. It was a version of the old-fashioned toy in which a ball that hangs by a string from the end of a stick has to be swung up so that it lands in a cup atop the stick. This one was more complex; the string tied to the ball went through the bottom of the cup and was attached to a loose spring inside the handle of the contraption. Random shaking would get the ball in the cup every now and then. The challenge: Was there a method that would get the ball in the cup every time?

As Cohen was leaving, a big grin came over Einstein’s face as he said he would explain the answer to the gadget. “Now the equivalence principle!” he announced. He poked the stick upward until it almost touched the ceiling. Then he let it drop straight down. The ball, while in free fall, behaved as if it was weightless. The spring inside the contraption instantly pulled it into the cup. 21