More on this book
Community
Kindle Notes & Highlights
he applied Bose’s counting method, later called “Bose-Einstein statistics,” to actual gas molecules, thus becoming the primary inventor of quantum-statistical mechanics.
Despite his discomfort with the direction quantum theory was heading, Einstein was still helping, at
Born proposed that the wave did not describe the behavior of the particle. Instead, he said that it described the probability of its location at any moment.55 It was an approach that revealed quantum mechanics as being, even more than previously thought, fundamentally based on chance rather than causal certainties, and it made Einstein even more squeamish.
It is impossible to know, Heisenberg declared, the precise position of a particle, such as a moving electron, and its precise momentum (its velocity times its mass) at the same instant. The more precisely the position of the particle is measured, the less precisely it is possible to measure its momentum. And the formula that describes the trade-off involves (no surprise) Planck’s constant. The very act of observing something—of allowing photons or electrons or any other particles or waves of energy to strike the object— affects the observation. But Heisenberg’s theory went beyond that. An
...more
“It is wrong to think that the task of physics is to find out how nature is,” Bohr declared. “Physics concerns what we can say about nature.”62
This inability to know a so-called “underlying reality” meant that there was no strict determinism in the classical sense. “When one wishes to calculate ‘the future’ from ‘the present’ one can only get statistical results,” Heisenberg said, “since one can never discover every detail of the present.”
The belief in an external world independent of the person observing it, he repeatedly said, was the basis of all science.66
There is no real reason—other than either a metaphysical faith or a habit ingrained in the mind—to believe that nature must operate with absolute certainty. It is just as reasonable, though perhaps less satisfying, to believe that some things simply happen by chance. Certainly, there was mounting evidence that on the subatomic level this was the case.
The Kaluza-Klein theories were put aside, although Einstein over the years would return to some of the concepts. In fact, physicists still do today. Echoes of these ideas, particularly in the form of extra compact dimensions, exist in string theory.
“Even if his attempt does not succeed, it will have forced us to think about the great questions at the foundation of science.”24
Einstein’s own remarks, given on the last day of the conference, show that the uncertainty principle was not the only aspect of quantum mechanics that concerned him. He was also bothered—and later would become even more so—by the way quantum mechanics seemed to permit action at a distance. In other words, something that happened to one object could, according to the Copenhagen interpretation, instantly determine how an object located somewhere else would be observed. Particles separated in space are, according to relativity theory, independent. If an action involving one can immediately affect
...more
converted him to a faith in a mathematical approach, one that emphasized the simplicity and elegance of equations more than the role of experience. The fact that this method paid off in general relativity, he said, “justifies us in believing that nature is the realization of the simplest conceivable mathematical ideas.”45 That is an elegant—and also astonishingly interesting—creed.
Hubble confirmed that, in general, the galaxies were moving away from us at a speed that was proportional to their distance from us. Those twice as far moved away twice as fast, and those three times as far moved away three times as fast.
Of course, it would have been even more exciting if Einstein had trusted his original equations and simply announced that his general theory of relativity predicted that the universe is expanding. If he had done that, then Hubble’s confirmation of the expansion more than a decade later would have had as great an impact as when Eddington confirmed his prediction of how the sun’s gravity would bend rays of light. The Big Bang might have been named the Einstein Bang, and it would have gone down in history, as well as in the popular imagination, as one of the most fascinating theoretical
...more
As it was, Einstein merely had the pleasure of renouncing the cosmological constant, which he had never liked.
“When I was discussing cosmological problems with Einstein,” George Gamow later recalled, “he remarked that the introduction of the cosmological term was the biggest blunder he ever made in his life.”55
In fact, Einstein’s blunders were more fascinating and complex than even the triumphs of lesser scientists.
“The genius of Albert Einstein, who added a ‘cosmological constant’ to his equation for the expansion of the universe but then retracted it, may be vindicated by new research.”58
I instinctively avoid meeting him, because I cannot show him a happy face.”23
“Even a genius like Schopenhauer was crushed by unemployment,” he wrote. “Life is like riding a bicycle. To keep your balance you must keep moving.”30
Einstein’s advocacy of war resistance reached its peak in 1932, the year before the Nazis seized power.
Einstein’s pacifism, world federalism, and aversion to nationalism were part of a political outlook that also included a passion for social justice, a sympathy for underdogs, an antipathy toward racism, and a predilection toward socialism.
This wariness of authority reflected the most fundamental of all of Einstein’s moral principles: Freedom and individualism are necessary for creativity and imagination to flourish.
He approved of a combination of capitalism and socialism.
Despite his association with the Zionist cause, Einstein’s sympathies extended to the Arabs who were being displaced by the influx of Jews into what would eventually be Israel. His message was a prophetic one. “Should we be unable to find a way to honest cooperation and honest pacts with the Arabs,” he wrote Weizmann in 1929, “then we have learned absolutely nothing during our 2,000 years of suffering.”
If the Jews did not assure that both sides lived in harmony, he warned friends in the Zionist movement, the struggle would haunt them in decades to come.78 Once again, he was labeled naïve.
“I believe in Spinoza’s God, who reveals himself in the lawful harmony of all that exists, but not in a God who concerns himself with the fate and the doings of mankind.”9
The idea of an impersonal God, whose hand is reflected in the glory of creation but who does not meddle in daily existence, is part of a respectable tradition in both Europe and America. It is to be found in some of Einstein’s favorite philosophers, and it generally accords with the religious beliefs of many of America’s founders, such as Jefferson and Franklin.
This belief in causal determinism, which was inherent in Einstein’s scientific outlook, conflicted not only with the concept of a personal God. It was also, at least in Einstein’s mind, incompatible with human free will. Although he was a deeply moral man, his belief in strict determinism made it difficult for him to accept the idea of moral choice and individual responsibility that is at the heart of most ethical systems.
For Born, quantum uncertainty provided an escape from this dilemma. Like some philosophers of the time, he latched on to the indeterminacy that was inherent in quantum mechanics to resolve “the discrepancy between ethical
He was generally kind, good-natured, gentle, and unpretentious.
Early in April 1933, the German government passed a law declaring that Jews (defined as anyone with a Jewish grandparent) could not hold an official position, including at the Academy or at the universities. Among those forced to flee were fourteen Nobel laureates and twenty-six of the sixty professors of theoretical physics in the country. Fittingly, such refugees from fascism who left Germany or the other countries it came to dominate—Einstein, Edward Teller, Victor Weisskopf, Hans Bethe, Lise Meitner, Niels Bohr, Enrico Fermi, Otto Stern, Eugene Wigner, Leó Szilárd, and others—helped to
...more
For a scientist, altering your doctrines when the facts change is not a sign of weakness.
cared passionately about humanity and sometimes about people.
Einstein also became a supporter of racial tolerance. When Marian Anderson, the black contralto, came to Princeton for a concert in 1937, the Nassau Inn refused her a room. So Einstein invited her to stay at his house on Mercer Street, in what was a deeply personal as well as a publicly symbolic gesture.
One remark he made turned out to be very prescient. “If and when war comes,” he said, “Hitler will realize the harm he has done Germany by driving out the Jewish scientists.”66
Over the years, Einstein had increasingly come to embrace the concept of realism, the belief that there is, as he put it, “a real factual situation” that exists “independent of our observations.”2 This belief was one aspect of his discomfort with Heisenberg’s uncertainty principle and other tenets of quantum mechanics that assert that observations determine realities.
The only way an action on one system can affect a distant one is if some wave or signal or information traveled between them—a process that would have to obey the speed limit of light. That was even true of gravity. If the sun suddenly disappeared, it would not affect the earth’s orbit for about eight minutes, the amount of time it would take the change in the gravitational field to ripple to the earth at the speed of light.
Einstein’s argument is based on what appears to be common sense. However, sometimes what seems to make sense turns out not to be a good description of nature.
One can show by thought experiments that quantum entanglement cannot be used to send information instantaneously. “In short,” says physicist Brian Greene, “special relativity survives by the skin of its teeth.”
Murray Gell-Mann and James Hartle, have adopted a view of quantum mechanics that differs in some ways from the Copenhagen interpretation and provides an easier explanation of the EPR thought experiment. Their interpretation is based on alternative histories of the universe, coarse-grained in the sense that they follow only certain variables and ignore (or average over) the rest. These “decoherent” histories form a tree-like structure, with each of the alternatives at one time branching out into alternatives at the next time and so forth.
Einstein’s fundamental dispute with the Bohr-Heisenberg crowd over quantum mechanics was not merely about whether God rolled dice or left cats half dead. Nor was it just about causality, locality, or even completeness. It was about reality.36 Does it exist? More specifically, is it meaningful to speak about a physical reality that exists independently of whatever observations we can make? “At the heart of the problem,” Einstein said of quantum mechanics, “is not so much the question of causality but the question of realism.”
Thus the search was not so much a search as a groping in the gloom of a mathematical jungle inadequately lit by physical intuition.”
“From what I have seen of Americans, I think that life would not be worth living to them without this freedom of self expression.”26 The depth of his appreciation for America’s core value would help explain Einstein’s cold public anger and dissent when, during the McCarthy era a few years later, the nation lapsed into a period marked by the intimidation of those with unpopular views.
For the remaining ten years of his life, his passion for advocating a unified governing structure for the globe would rival that for finding a unified field theory that could govern all the forces of nature. Although distinct in most ways, both quests reflected his instincts for transcendent order. In addition, both would display Einstein’s willingness to be a nonconformist, to be serenely secure in challenging prevailing attitudes.
“No, as long as there will be man, there will be war.”
Pacifists liked to think that Einstein’s break with their philosophy in the 1930s was an aberration caused by the unique threat posed by the Nazis, and some biographers likewise treat it as a temporary anomaly.31 But that minimizes the shift in Einstein’s thinking. He was never again a pure pacifist.
“Disarmament cannot be effective unless all countries participate,” he lectured. “If even one nation continues to arm, openly or secretly, the disarmament of the others will involve disastrous consequences.”
Any expressions of excess nationalism and militarism had always made him uncomfortable,
“I can escape the feeling of complicity in it only by speaking out.”46
Brilliant line.
