"Albert is an old fool": Einstein vs Schrödinger in battle of the Nobel laureates

Einstein & Schrödinger were friends then competitors in hunt for Grand Unified Theory. A media war tore them apart

Published April 18, 2015 7:30PM (EDT)


Excerpted from "Einstein's Dice and Schrödinger's Cat"

This is the tale of two brilliant physicists, the 1947 media war that tore apart their decades-long friendship, and the fragile nature of scientific collaboration and discovery.


When they were pitted  against each other, each scientist was a Nobel laureate, well into middle age, and certainly past the peak of his major work. Yet the international press largely had a different story to tell. It was a familiar  narrative of a seasoned  fighter still going strong versus an upstart contender hungry to seize the trophy. While Albert Einstein was extraordinarily famous, his every pronouncement covered by the media, relatively few readers  were conversant with the work  of Austrian physicist Erwin Schrödinger.

Those following  Einstein’s career knew that  he been working  for decades on a unified field theory.  He hoped to extend the work of nineteenth-century British physicist James Clerk Maxwell in uniting the forces of nature  through a simple set of equations. Maxwell had provided a unified explanation for electricity and magnetism,  called electromagnetic fields, and identified them as light waves. Einstein’s own general theory  of relativity  described gravity as a warping  of the geometry of space and time. Confirmation of the theory had won him fame. However,  he didn’t want  to stop there. His dream was to incorporate  Maxwell’s results into an extended  form of general relativity and thereby unite electromagnetism with gravity.

Every few years, Einstein had announced a unified theory to great fanfare, only to have it quietly fail and be replaced by another. Starting in the late 1920s,  one of his primary  goals was a deterministic alternative to probabilistic quantum theory,  as developed  by Niels Bohr, Werner  Heisenberg,  Max  Born, and others. Although  he realized that quantum theory was experimentally successful, he judged it incomplete. In his heart he felt that “God  did not play dice,” as he put it, couching the issue in terms of what an ideal mechanistic creation would be like. By “God” he meant  the deity described by seventeenth-century Dutch philosopher Baruch Spinoza: an emblem of the best possible natural order.  Spinoza  had argued  that  God, synonymous with  nature, was immutable and eternal, leaving no room for chance. Agreeing with Spinoza, Einstein sought  the invariant rules governing  nature’s  mechanisms. He was absolutely determined to prove that  the world  was absolutely  determined.

Exiled in Ireland in the 1940s after the Nazi annexation of Austria,  Schrödinger  shared  Einstein’s disdain  for the orthodox interpretation of quantum mechanics  and  saw him as a natural co laborator. Einstein  similarly found  in Schrödinger  a kindred spirit. After sharing ideas for unification  of the forces, Schrödinger  suddenly announced success, generating  a storm of attention and opening a rift between the men.

You may have heard  of Schrödinger’s  cat—the  feline thought experiment  for which the general public knows him best. But back when this feud took place, few people outside of the physics community had heard of the cat conundrum or of him. As depicted in the press, he was just an ambitious scientist residing in Dublin  who might have landed a knockout punch on the great one.

The leading announcer was the Irish Press, from which the international  community learned  about Schrödinger’s challenge. Schrödinger had sent them an extensive press release describing his new “theory of everything,” immodestly placing his own work  in the context  of the achievements  of the Greek sage Democritus (the coiner of the term “atom”), the Roman  poet Lucretius, the French philosopher Descartes, Spinoza, and Einstein himself. “It is not a very becoming  thing for a scientist to advertise his own discoveries,” Schrödinger told them. “But since the Press wishes it, I submit to them.”

The New York Times cast the announcement as a battle  between a maverick’s mysterious  methods  and the establishment’s  lack of progress. “How Schrödinger  has proceeded  we are not told,” it reported.

For a fleeting moment  it seemed that  a Viennese physicist whose name was then little known  to the general public had beaten the great Einstein  to a theory  that  explained  everything  in the universe. Perhaps it was time, puzzled readers  may have thought, to get to know Schrödinger  better.

A Gruesome Conundrum

Today, what comes to mind for most people who have heard of Schrödinger  are a cat, a box, and a paradox. His famous  thought experiment, published  as part  of a 1935  paper, “The  Present Situation in Quantum Mechanics,” is one of the most gruesome  devised in the history of science. Hearing about  it for the first time is bound to trigger gasps of horror, followed  by relief that  it is just a hypothetical experiment that presumably has never been attempted on an actual feline subject.

Schrödinger proposed the thought experiment in 1935 as part of a paper that investigated the ramifications of entanglement in quantum physics. Entanglement (the term was coined by Schrödinger) is when the condition of two or more particles is represented by a single quantum state, such that if something happens to one particle the others are instantly  affected.

Inspired in part by dialogue with Einstein, the conundrum of Schrödinger’s cat presses the implications  of quantum physics to their very limits by asking us to imagine the fate of a cat becoming entangled with the state of a particle. The cat is placed in a box that contains  a radioactive substance,  a Geiger counter,  and a sealed vial of poison. The box is closed, and a timer is set to precisely the interval at which the substance would  have a 50–50 chance of decaying by releasing a particle. The researcher has rigged the apparatus so that if the Geiger counter registers the click of a single decay particle, the vial would be smashed, the poison released, and the cat dispatched. However, if no decay occurs, the cat would be spared.

According to quantum measurement theory, as Schrödinger pointed out, the state of the cat (dead or alive) would be entangled with the state of the Geiger counter’s reading (decay or no decay) until the box is opened. Therefore, the cat would be in a zombielike quantum superposition of deceased and living until the timer went off, the researcher opened the box, and the quantum state of the cat and counter  “collapsed” (distilled itself) into one of the two possibilities.

From the late 1930s until the early 1960s the thought experiment was little mentioned, except sometimes as a classroom anecdote. For instance,  Columbia University professor  and Nobel  laureate  T. D. Lee would  tell the tale to his students to illustrate the strange nature  of quantum collapse. In 1963,  Princeton  physicist Eugene Wigner mentioned the thought experiment in a piece he wrote about  quantum measurement  and extended it into what is now referred to as the “Wigner’s friend” paradox.

Renowned  Harvard philosopher Hilary  Putnam—who learned about  the  conundrum from  physicist  colleagues—was  one  of the first scholars outside of the world of physics to analyze and discuss Schrödinger’s  thought experiment. He described  its implications  in his classic 1965 paper “A Philosopher Looks at Quantum Mechanics,” published  as a book chapter.  When the paper was mentioned  the same year in a Scientific American book review, the term “Schrödinger’s  cat” entered  the realm of popular science. Over the decades that  followed, it crept into culture as a symbol of ambiguity  and has been mentioned in stories, essays, and verse.

Despite the public’s current  familiarity  with the cat paradox, the physicist who developed it still isn’t well known  otherwise.  While Einstein has been an icon since the 1920s, the very emblem of a brilliant scientist, Schrödinger’s life story is scarcely familiar. That is ironic because the adjective “Schrödinger’s”—in the sense of a muddled  existence— could well have applied to him.

A Man of Many Contradictions

The ambiguity of Schrödinger’s cat perfectly matched  the contradictory life of its creator. The bookish, bespectacled  professor  maintained a quantum superposition of contrasting views. His yin-yang existence began in his youth when he learned German and English from different family members and was raised bilingual. With ties to many countries but a supreme love of his native Austria, he never felt comfortable with either nationalism or internationalism and preferred  avoiding  politics altogether.

An enthusiast of fresh air and  exercise, he would  drown  others in the smoke from his omnipresent pipe. At formal  conferences,  he’d walk in dressed like a backpacker. He’d call himself an atheist and talk about  divine motivations. At one point  in his life he lived with both his wife and another woman  who was the mother  of his first child. His doctoral work was a mixture  of experimental and theoretical  physics. During  the early part  of his career he briefly considered  switching  to philosophy before veering back to science. Then came whirlwind shifts between numerous institutions in Austria, Germany,  and Switzerland.

As physicist Walter Thirring, who once worked with him, described, “It was like he was always being chased: from one problem  to another by his genius, from one country  to another by the political  powers  in the twentieth  century. He was a man full of contradictions.”

At one point in his career, he argued vehemently that causality should  be rejected in favor of pure chance. Several years later, after developing  the deterministic Schrödinger  equation, he had  second thoughts. Perhaps there are causal laws after all, he argued. Then physicist Max Born reinterpreted his equation probabilistically. After fighting that  reinterpretation, he started  to sway back toward the chance conception. Later in life, his philosophical roulette  wheel landed  once again in the direction  of causality.

In 1933,  Schrödinger  heroically  gave up an esteemed position  in Berlin because of the Nazis. He was the most prominent non-Jewish physicist to leave of his own accord. After working  in Oxford, he decided to move back to Austria  and became a professor  at the University of Graz. But then, strangely enough, after Nazi Germany  annexed Austria, he tried to cut a deal with the government  to keep his job. In a published  confession,  he apologized  for his earlier opposition and proclaimed his loyalty to the conquering power. Despite his pandering, he had to leave Austria  anyway,  moving on to a prominent position at the newly founded Dublin  Institute for Advanced  Studies. Once on neutral ground, he recanted  his self-renunciation.

“He  demonstrated impressive civil courage  after Hitler came to power in Germany  and . . . left the most prominent German  professorship in physics,” noted Thirring. “As the Nazis caught up with him, he was forced into a pathetic  show of solidarity  with the terror  regime.”

Quantum  Comrades

Einstein, who had been a colleague and dear friend in Berlin, stuck by Schrödinger all along and was delighted to correspond with him about their mutual  interests in physics and philosophy. Together they battled a common villain: sheer randomness, the opposite  of natural order.

Schooled in the writings  of Spinoza, Schopenhauer—for whom the unifying principle  was the force of will, connecting  all things in nature—and other  philosophers, Einstein  and Schrödinger  shared  a dislike for including  ambiguities  and subjectivity  in any fundamental description of the universe. While each played  a seminal  role in the development of quantum mechanics, both were convinced that the theory was incomplete. Though recognizing the theory’s experimental successes, they believed that  further  theoretical  work  would  reveal a timeless, objective reality.

Their alliance was cemented by Born’s reinterpretation of Schrödinger’s wave equation. As originally construed, the Schrödinger equation was designed to model  the continuous behavior  of tangible matter  waves, representing  electrons  in and out of atoms.  Much as Maxwell  constructed deterministic equations describing  light as electromagnetic waves traveling  through space, Schrödinger  wanted to create an equation that would detail the steady flow of matter waves. He thereby  hoped  to offer a comprehensive accounting of all of the physical properties of electrons.

Born shattered the exactitude of Schrödinger’s description, replacing matter waves with probability waves. Instead of physical properties being assessed directly, they needed to be calculated  through mathematical manipulations of the probability waves’ values. In doing so, he brought the Schrödinger equation in line with Heisenberg’s ideas about indeterminacy. In Heisenberg’s view, certain pairs of physical quantities, such as position  and momentum (mass times velocity) could not  be measured  simultaneously with high precision. He encoded such quantum fuzziness in his famous  uncertainty principle:  the more precisely a researcher  measures a particle’s position,  the less precisely he or she can know  its momentum—and the converse.

Aspiring to model the actual substance  of electrons and other particles, not just their likelihoods,  Schrödinger  criticized the intangible elements  of the Heisenberg-Born approach. He similarly  eschewed Bohr’s quantum philosophy, called “complementarity,” in which either wavelike or particlelike  properties reared their heads, depending on the experimenter’s  choice of measuring apparatus. Nature should be visualizable, he rebutted, not an inscrutable black box with hidden workings.

As Born’s, Heisenberg’s, and Bohr’s ideas became widely accepted among the physics community, melded into what became known  as the “Copenhagen interpretation” or orthodox quantum view, Einstein and Schrödinger  became natural allies. In their later years, each hoped  to find a unified field theory that would fill in the gaps of quantum physics and unite the forces of nature. By extending  general relativity to include all of the natural forces, such a theory would replace matter  with pure geometry—fulfilling the dream of the Pythagoreans, who believed that “all is number.”

Schrödinger  had good reason  to be much indebted  to Einstein. A talk by Einstein in 1913 help spark his interest in pursuing  fundamental questions  in physics. An article Einstein published  in 1925  referenced French physicist Louis de Broglie’s concept  of matter  waves, inspiring Schrödinger  to develop his equation governing  the behavior  of such waves. That  equation earned  Schrödinger  the Nobel  Prize, for which Einstein, among others, had nominated him. Einstein endorsed  his appointment as a professor  at the University of Berlin and as a member of the illustrious  Prussian Academy of Sciences. Einstein warmly  invited Schrödinger  to his summer  home in Caputh and continued to offer guidance  in their  extensive correspondence. The EPR thought experiment, developed  by Einstein and his assistants  Boris Podolsky and Nathan Rosen to illustrate  murky  aspects of quantum entanglement, along with a suggestion  by Einstein about  a quantum paradox involving gunpowder, helped inspire Schrödinger’s cat conundrum. Finally, the ideas developed  by Schrödinger  in his quest for unification were variations of proposals by Einstein. The two theorists  frequently corresponded about  ways to tweak general relativity to make it mathematically flexible enough to encompass  other forces besides gravity.

Portrait of a Fiasco

Dublin’s Institute for Advanced Studies, where Schrödinger was the leading physicist throughout the 1940s and early 1950s, was modeled directly on Princeton’s  Institute  for Advanced  Study, where Einstein had played the same role since the mid-1930s. Irish press reports  often compared the two of them, treating  Schrödinger  as Einstein’s Emerald Isle equivalent.

Schrödinger took every opportunity to mention  his connection with Einstein, going so far as to reveal some of the contents  of their private correspondence when it suited his purpose. For example, in 1943,  after Einstein wrote  personally  to Schrödinger  that  a certain  model for unification  had been the “tomb of his hopes” in the 1920s, Schrödinger exploited  that  statement to make it look like he had succeeded where Einstein had failed. He read the letter publicly to the Royal Irish Academy, bragging that he had “exhumed” Einstein’s hopes through his own calculations. The lecture was reported in the Irish Times, capped by the misleading headline “Einstein  Tribute  to Schroedinger.”

At first Einstein graciously  chose to ignore Schrödinger’s  boasts. However,  the press reaction  to a speech Schrödinger  gave in January 1947  claiming victory in the battle  for a theory  of everything  proved too much. Schrödinger’s  bold statement to the press asserting  that  he had achieved the goal that had eluded Einstein for decades (by developing a theory  that  superseded  general relativity) was flung in Einstein’s face, in hopes of spurring  a reaction.

And react he did. Einstein’s snarky reply reflected his deep displeasure with Schrödinger’s  overreaching assertions.  In his own press release, translated into English by his assistant Ernst Straus, he responded: “Professor  Schroedinger’s latest attempt . . . can . . . be judged only on the basis of its mathematical qualities, but not from the point of view of ‘truth’ and agreement with facts of experience. Even from this point of view, it can see no special advantages—rather the opposite.”

The bickering was reported in newspapers such as the Irish Press, which conveyed Einstein’s admonition that  it is “undesirable . . . to present such preliminary attempts to the public in any form. It is even worse when the impression  is created that one is dealing with definite discoveries concerning  physical reality.”

Humorist Brian O’Nolan, writing in the Irish Times under the nom de plume “Myles na gCopaleen,” savaged Einstein’s response, in essence calling him arrogant and out of touch. “What does Einstein know  of the use and meaning of words?” he wrote. “Very little, I should say. . . . For instance what  does he mean by terms like ‘truth’ and ‘the facts of experience.’ His attempt to meet shrewd  newspaper  readers  on their own ground  is not impressive.”

These two old friends, comrades  in the battle against the orthodox interpretation of quantum mechanics, had never anticipated that they would be battling  in the international press. That was certainly neither Schrödinger  nor Einstein’s intention when they had begun their correspondence  about  unified field theory  some years earlier. However, Schrödinger’s  audacious claims to the Royal Irish Academy proved irresistible  to eager reporters, who often trawled  for stories related  to Einstein.

One  impetus  for the skirmish  was Schrödinger’s  need to please his host, Irish taoiseach (prime minister)  Éamon  de Valera, who had personally  arranged for his journey to Dublin and appointment to the Institute.  De Valera  took  an active interest  in Schrödinger’s  accomplishments, hoping that he would bring glory to the newly independent Irish republic. As a former math instructor, de Valera was an aficionado of Irish mathematician William Rowan Hamilton. In 1943, he made sure that  the centenary  of one of Hamilton’s discoveries,  a type of numbers  called quaternions, was honored throughout Ireland.  Much of Schrödinger’s  work  made use of Hamilton’s methods.  What  better way to honor  liberated  Ireland  and its leading light, Hamilton, by bringing it newfound fame as the place where Einstein’s relativity was dethroned and replaced with a more comprehensive theory? Schrödinger’s far-reaching  pronouncement matched  his patron’s  hopes perfectly. The Irish Press, owned and controlled by de Valera, made  sure the world  knew that  the land of Hamilton, Yeats, Joyce, and Shaw could also produce a “theory of everything.”

Schrödinger’s approach to science (and indeed to life) was impulsive. Feeling blessed with promising results, he wanted to trumpet them to the world, not realizing until it was too late that he was slighting one of his dearest friends and mentors. He considered his discovery—purportedly a simple mathematical way of encapsulating the entirety of natural law— to be something  like a divine revelation.  Therefore,  he was anxious  to divulge what he saw as a fundamental truth  revealed only to him.

Needless to say, Schrödinger came nowhere  near developing a theory that  explained  everything,  as Einstein correctly  pointed  out. He merely found one of many mathematical variations of general relativity that  technically  made room  for other  forces. However,  until solutions to that  variation could be found  that  matched  physical reality, it was just an abstract exercise rather  than  a genuine description of nature. While there are myriad ways to extend general relativity, none has been found  so far that  matches  how elementary  particles  actually  behave, including their quantum properties.

In the hype department, though, Einstein was hardly  an innocent bystander. Periodically  he had proposed his own unification  models and overstated their importance to the press. For example, in 1929, he announced to great fanfare that he had found a theory that united the forces of nature  and surpassed  general relativity. Given that he hadn’t found  (and wouldn’t  find) physically  realistic solutions  to his equations, his announcement was extremely  premature. Yet he criticized Schrödinger  for essentially doing the same thing.

Schrödinger’s  wife, Anny, later revealed to physicist Peter Freund that  he and Einstein were each contemplating suing the other for plagiarism. Physicist Wolfgang Pauli, who knew both of them well, warned them of the possible consequences  of pursuing  legal remedies. A lawsuit played  out  in the press would  be embarrassing, he advised them. It would quickly degenerate  into a farce, sullying their reputations. Their acrimony  was such that  Schrödinger  once told physicist John Moffat, who was visiting Dublin, “my method  is far superior  to Albert’s! Let me explain to you, Moffat, that Albert is an old fool.”

Freund  speculated  about  the reasons  two aging physicists would seek a theory of everything. “One can answer this question on two levels,” he said. “On  one level it is an act of ultimate  grandiosity. . . . [They] were extremely  successful in physics. As they see their powers waning, they take one final stab at the biggest problem: finding the ultimate  theory, ending physics. . . . On another level, maybe these men are just driven by the same insatiable  curiosity that has stood  them in such good stead in their youth. They want to know the solution  to the puzzle that has preoccupied  them throughout life; they want to have a glimpse of the promised  land in their lifetime.”

Frayed Unity

Many physicists spend their careers focused on very specific questions about  particular aspects of the natural world. They see the trees, not the forest. Einstein and Schrödinger  shared much broader aspirations. Through their readings of philosophy, each was convinced that nature had a grand blueprint. Their youthful  journeys led them to significant discoveries—including Einstein’s theory of relativity and Schrödinger’s wave equation—that revealed part  of the answer. Tantalized by part of the solution,  they hoped to complete their life missions by finding a theory that explained  everything.

However,  as in the case of religious sectarianism, even minor  differences in outlook can lead to major conflicts. Schrödinger jumped the gun because he thought he had miraculously found a clue that Einstein somehow  had  missed. His false epiphany, together  with  the performance pressures  he faced because of his academic position,  generated an impulsive need to come forward before he had gathered  enough proof to confirm his theory.

Their skirmish came at a cost. From that point on, their dream of cosmic unity was tainted  with personal  conflict. They squandered the prospect  of spending  their remaining  years in friendly dialogue, headily discussing possible clockwork  mechanisms  of the universe. Having waited billions of years for a complete explanation of its workings, the cosmos would be patient,  but two great thinkers  had lost their fleeting opportunity.

Excerpted from "Einstein's Dice and Schrödinger's Cat" by Paul Halpern. Published by Basic Books, a member of the Perseus Books Group. Copyright © 2015 by Paul Halpern. Reprinted with permission of the publisher. All rights reserved.

By Paul Halpern

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