Hugh Everett III (; November 11, 1930 – July 19, 1982) was an American physicist who first proposed the many-worlds interpretation (MWI) of quantum physics, which he termed his "relative state" formulation.
Discouraged by the scorn of other physicists for MWI, Everett ended his physics career after completing his Ph.D. Afterwards, he developed the use of generalized Lagrange multipliers for operations research and applied this commercially as a defense analyst and a consultant. He was married to Nancy Everett née Gore. They had two children: Elizabeth Everett and Mark Oliver Everett, who became frontman of the musical band Eels.
Early life and education
Born in 1930, Everett was born and raised in the Washington, D.C. area. Everett's parents separated when he was young. Initially raised by his mother (Katherine Lucille Everett née Kennedy), he was raised by his father (Hugh Everett Jr) and stepmother (Sarah Everett née Thrift) from the age of seven.
Everett won a half scholarship to St John's College, a private military high school in Washington DC. From there he moved to the nearby Catholic University of America to study chemical engineering as an undergraduate. While there he read about Dianetics in Astounding Science Fiction. Although he never exhibited any interest in Scientology (as Dianetics became), he did retain a distrust of conventional medicine throughout his life.
During World War II his father was away fighting in Europe as a lieutenant colonel on the general staff. After World War II, Everett's father was stationed in West Germany, and Hugh joined him, during 1949, taking a year out from his undergraduate studies. Father and son were both keen photographers and took hundreds of pictures of West Germany being rebuilt. Reflecting their technical interests, the pictures were "almost devoid of people".
Everett graduated from The Catholic University of America in 1953 in chemical engineering, although he had completed sufficient courses for a mathematics degree as well. Everett then received a National Science Foundation fellowship that allowed him to attend Princeton University for graduate studies. He started his studies at Princeton in the Mathematics Department working on the then-new field of game theory under Albert W. Tucker, but slowly drifted into physics. In 1953 he started taking his first physics courses, notably Introductory Quantum Mechanics with Robert Dicke.
During 1954, he attended Methods of Mathematical Physics with Eugene Wigner, although he remained active with mathematics and presented a paper on military game theory in December. He passed his general examinations in the spring of 1955, thereby gaining his Master's degree, and then started work on his dissertation that would (much) later make him famous. He switched thesis advisors to John Archibald Wheeler some time in 1955, wrote a couple of short papers on quantum theory and completed his long paper, Wave Mechanics Without Probability in April 1956.
In his third year at Princeton Everett moved into an apartment which he shared with three friends he had made during his first year, Hale Trotter, Harvey Arnold and Charles Misner. Arnold later described Everett as follows:
He was smart in a very broad way. I mean, to go from chemical engineering to mathematics to physics and spending most of the time buried in a science fiction book, I mean, this is talent.
It was during this time that he met Nancy Gore, who typed up his Wave Mechanics Without Probability paper. Everett married Nancy Gore, the next year. The long paper was later retitled as The Theory of the Universal Wave Function.
Wheeler himself had traveled to Copenhagen in May, 1956 with the goal of getting a favorable reception for at least part of Everett's work, but in vain. In June 1956 Everett started defense work in the Pentagon's Weapons Systems Evaluation Group, returning briefly to Princeton to defend his thesis after some delay in the spring of 1957. A short article, which was a compromise between Everett and Wheeler about how to present the concept and almost identical to the final version of his thesis, was published in Reviews of Modern Physics Vol 29 #3 454-462, (July 1957), accompanied by an approving review by Wheeler. Everett was not happy with the final form of the article.
Upon graduation in September 1956, Everett was invited to join the Pentagon's newly-forming Weapons Systems Evaluation Group (WSEG), managed by the Institute for Defense Analyses. Between 23–26 October 1956 he attended a weapons orientation course managed by Sandia National Laboratories at Albuquerque, New Mexico to learn about nuclear weapons and became a fan of computer modeling while there. In 1957, he became director of the WSEG's Department of Physical and Mathematical Sciences. After a brief intermission to defend his thesis on quantum theory at Princeton, Everett returned to WSEG and recommenced his research, much of which, but by no means all, remains classified. He worked on various studies of the Minuteman missile project, which was then starting, as well as the influential study The Distribution and Effects of Fallout in Large Nuclear Weapon Campaigns.
During March and April 1959, at Wheeler's request, Everett visited Copenhagen, on vacation with his wife and baby daughter, in order to meet with Niels Bohr, the "father of the Copenhagen interpretation of quantum mechanics". The visit was a complete disaster; Everett was unable to communicate the main idea that the universe is describable, in theory, by an objectively existing universal wave function (which does not "collapse"); this was simply heresy to Bohr and the others at Copenhagen. The conceptual gulf between their positions was too wide to allow any meeting of minds; Léon Rosenfeld, one of Bohr's devotees, talking about Everett's visit, described Everett as being "undescribably [sic] stupid and could not understand the simplest things in quantum mechanics". Everett later described this experience as "hell...doomed from the beginning".
However, whilst in Copenhagen, in his hotel, he started work on a new idea to use generalized Lagrange multipliers for mathematical optimization. Everett's theorem, published in 1963, relates the Lagrangian bidual to the primal problem.
In 1962 Everett accepted an invitation to present the relative-state formulation (as it was still called) at a conference on the foundations of quantum mechanics held at Xavier University in Cincinnati. In his exposition Everett presented his derivation of probability and also stated explicitly that observers in all branches of the wavefunction were equally "real." He also agreed with an observation from the floor that the number of branches of the universal wavefunction was an uncountable infinity.
In August 1964, Everett and several WSEG colleagues started Lambda Corp. to apply military modeling solutions to various civilian problems. During the early 1970s, defense budgets were curtailed and most money went to operational duties in the Vietnam War, resulting in Lambda eventually being absorbed by the General Research Corp.
In 1973 Everett left Lambda to establish DBS Corporation in Arlington, Virginia, a computer consulting company. Much of their work seems to have concerned statistical analysis. He seems to have enjoyed programming, and spent the rest of his life working at DBS. He also established Monowave Corporation with several DBS and family friends.
In 1970 Bryce DeWitt wrote an article for Physics Today on Everett's relative-state theory, which evoked a number of letters from physicists. These letters, and DeWitt's responses to the technical objections raised, were also published. Meanwhile DeWitt, who had corresponded with Everett on the many-worlds / relative state interpretation when originally published in 1957, started editing an anthology on the many-worlds interpretation of quantum mechanics. In addition to the original articles by Everett and Wheeler, the anthology was dominated by the inclusion of Everett's 1956 paper The Theory of the Universal Wavefunction, which had never been published before. The book was published late in 1973, sold out completely, and it was not long before an article on Everett's work appeared in the science fiction magazine, Analog.
In 1977, Everett was invited to give a talk at a conference Wheeler had organised at Wheeler's new location at the University of Texas at Austin. As with the Copenhagen visit, Everett vacationed from his defense work and traveled with his family. Everett met DeWitt there for the first and only time. Everett's talk was quite well received and influenced a number of physicists in the audience, including Wheeler’s graduate student, David Deutsch, who later promoted the many-worlds interpretation to a wider audience. Everett, who "never wavered in his belief in his many-worlds theory", enjoyed the presentation; it was the first time for years he had talked about his quantum work in public. Wheeler started the process of returning Everett to a physics career by establishing a new research institute in California, but nothing came of this proposal. Wheeler, although happy to introduce Everett's ideas to a wider audience, was not happy to have his own name associated with Everett's ideas. Eventually, after Everett's death, he formally renounced the theory.
Death and legacy
At the age of 51, Everett, who believed in quantum immortality, died suddenly of a heart attack at home in his bed on the night of July 18–19, 1982. Everett's obesity, frequent chain-smoking and alcohol drinking almost certainly contributed to this, although he seemed healthy at the time. A committed atheist, he had asked that his remains be disposed of in the trash after his death. His wife kept his ashes in an urn for a few years, before complying with his wishes. About Hugh's death his son, Mark Oliver Everett, later said:
I think about how angry I was that my dad didn't take better care of himself. How he never went to a doctor, let himself become grossly overweight, smoked three packs a day, drank like a fish and never exercised. But then I think about how his colleague mentioned that, days before dying, my dad had said he lived a good life and that he was satisfied. I realize that there is a certain value in my father's way of life. He ate, smoked and drank as he pleased, and one day he just suddenly and quickly died. Given some of the other choices I'd witnessed, it turns out that enjoying yourself and then dying quickly is not such a hard way to go.
Of the companies Everett initiated, only Monowave Corporation still exists (in Seattle as of March 2015) and is still managed by co-founder Elaine Tsiang (who had studied physics under Bryce DeWitt at the University of North Carolina at Chapel Hill).
Everett's daughter, Elizabeth, committed suicide in 1996 (saying in her suicide note that she wished her ashes to be thrown out with the garbage so that she might "end up in the correct parallel universe to meet up w[ith] Daddy"), and in 1998, his wife, Nancy, died of cancer. Everett's son, Mark Oliver Everett, who found Everett dead, is also known as "E" and is the main singer and songwriter for the band Eels. The Eels album Electro-Shock Blues, which was written during this time period, is representative of these deaths. Mark explored his father's work in the hour-long BBC television documentary Parallel Worlds, Parallel Lives. The program was edited and shown on the Public Broadcasting Service's Nova series in the USA during October 2008.
- ^ abLemaréchal (2001, pp. 125–126): Lemaréchal, Claude (2001). "Lagrangian relaxation". In Michael Jünger and Denis Naddef. Computational combinatorial optimization: Papers from the Spring School held in Schloß Dagstuhl, May 15–19, 2000. Lecture Notes in Computer Science. 2241. Berlin: Springer-Verlag. pp. 112–156. doi:10.1007/3-540-45586-8_4. ISBN 3-540-42877-1. MR 1900016.
- ^Everett (1963): Everett, Hugh, III (1963). "Generalized Lagrange multiplier method for solving problems of optimum allocation of resources". Operations Research. 11 (3): 399–417. doi:10.1287/opre.11.3.39. JSTOR 168028. MR 0152360. Archived from the original on 2011-07-24.
- ^Everett (1957): H. Everett (1957). "Recursive games". In Melvin Dresher, Albert William Tucker, Philip Wolfe. Contributions to the Theory of Games, Volume 3. Annals of Mathematics Studies. Princeton University Press. pp. 67–78. ISBN 978-0-691-07936-3. MR 0091863. (Reprinted in Harold W. Kuhn, ed. Classics in Game Theory, Princeton University Press, 1997. ).
- ^"The Many Worlds of Hugh Everett" by Peter Byrne, from Scientific American, December 2007
- ^ abcdefghijPeter Byrne (2010). The Many Worlds of Hugh Everett III: Multiple Universes, Mutual Assured Destruction, and the Meltdown of a Nuclear Family. Oxford University Press. p. 29. ISBN 978-0-19-955227-6.
- ^Fabio Freitas, Os estados relativos de Hugh Everett III: uma análise histórica e conceitual. Programa de Pós-Graducação em Ensino, Filosofia e História das Ciências. 2007 "Archived copy"(PDF). Archived from the original(PDF) on 2008-12-18. Retrieved 2008-12-18.
- ^ abcMark Oliver Everett, Things the Grandchildren Should Know, ISBN 978-0-316-02787-8
- ^Eugene Shikhovtsev, Biographical Sketch of Hugh Everett, III, Eugene Shikhovtsev's Biography of Everett, maintained byMax Tegmark
- ^Olival Freire, Jr.: Science and exile: David Bohm, the hot times of the Cold War, and his struggle for a new interpretation of quantum mechanics
- ^Olival Freire Jr.: Science and exile: David Bohm, the Cold War, and a new interpretation of quantum mechanics"Archived copy"(PDF). Archived from the original(PDF) on 2012-03-26. Retrieved 2011-08-07.
- ^Hugh Everett III and George E.Pugh, "The Distribution and Effects of Fallout in Large Nuclear-Weapon Campaigns", in Biological and Environment Effects of Nuclear War, Hearings Before the Special Sub-Committee on Radiation of the Joint Congressional Committee on Atomic Energy, June 22–26, 1959, Washington, D.C., U.S. Government Printing Office, 1959.
- ^Cf. Dr. Linus Pauling Nobel Peace Prize 1962 lecture (and reprinted in Peace by Frederick W. Haberman, Irwin Abrams, Tore Frängsmyr, Nobelstiftelsen, Nobelstiftelsen (Stockholm), published by World Scientific, 1997 ISBN 981-02-3416-3), delivered on December 11, 1963, in which he mentioned the work by Pugh and Everett regarding the risks of nuclear profliferation and even quoted them from 1959. Pauling said: "This is a small nuclear attack made with use of about one percent of the existing weapons. A major nuclear war might well see a total of 30,000 megatons, one-tenth of the estimated stockpiles, delivered and exploded over the populated regions of the United States, the Soviet Union, and the other major European countries. The studies of Hugh Everett and George E. Pugh , of the Weapons Systems Evaluation Division, Institute of Defense Analysis, Washington, D.C., reported in the 1959 Hearings before the Special Subcommittee on Radiation, permit us to make an estimate of the casualties of such a war. This estimate is that sixty days after the day on which the war was waged, 720 million of the 800 million people in these countries would be dead, sixty million would be alive but severely injured, and there would be twenty million other survivors. The fate of the living is suggested by the following statement by Everett and Pugh: 'Finally, it must be pointed out that the total casualties at sixty days may not be indicative of the ultimate casualties. Such delayed effects as the disorganization of society, disruption of communications, extinction of livestock, genetic damage, and the slow development of radiation poisoning from the ingestion of radioactive materials may significantly increase the ultimate toll.' ..."
- ^ abcdefgOsnaghi, Stefano; Freitas, Fabio; Olival Freire, Jr (2009). "The Origin of the Everettian Heresy"(PDF). Studies in History and Philosophy of Modern Physics. 40 (2): 97–123. Bibcode:2009SHPMP..40...97O. doi:10.1016/j.shpsb.2008.10.002.
- ^Aldhous, Peter (2007-11-24). "Parallel lives can never touch". New Scientist (2631). Retrieved 2007-11-21. .
- ^Gardner, Martin (July 2003). "Multiverses and Blackberries". Are Universes Thicker Than Blackberries?. New York: W. W. Norton & Company. ISBN 0-393-05742-9.
- ^See Keith Lynch's recollections in Eugene Shikhovtsev's Biography of Everett 
- ^Things the Grandchildren Should Know, ISBN 978-0-316-02787-8, pg 235
- ^Last night's TV: Parallel Worlds, Parallel Lives, Nancy Banks-Smith, Guardian blog, 27 November 2007.
- ^Parallel Worlds, Parallel Lives BBC Four documentary about Eels founder Mark Everett and his fatherArchived 2008-02-14 at the Wayback Machine., Band Weblogs, 16 November 2007.
- ^"Parallel Worlds, Parallel Lives", BBC Press Release
- ^"Parallel Worlds, Parallel Lives", BBC iPlayer
- ^Parallel Worlds, Parallel Lives", PBSNova TV program, October 2008.
- ^Healy, Pat, "‘Nova’ came for his soul: Eels front man on the healing power of a science doc about his dad"Archived 2011-07-15 at the Wayback Machine., Metro newspaper, October 21, 2008.
- ^Hugh Everett: New film tackles "many worlds" theory of quantum mechanics 60 second science, Scientific American blog, by Jordan Lite and George Musser
- Hugh Everett (1957). "'Relative state' formulation of quantum mechanics". Reviews of Modern Physics. 29 (3): 454–462. Bibcode:1957RvMP...29..454E. doi:10.1103/RevModPhys.29.454. Lay summary – Stanford Encyclopedia of Philosophy. 
- Hugh Everett (1955) "The Theory of the Universal Wavefunction", Manuscript, pp 3–140 of Bryce DeWitt, R. Neill Graham, eds, The Many-Worlds Interpretation of Quantum Mechanics, Princeton Series in Physics, Princeton University Press (1973), ISBN 0-691-08131-X The original and most comprehensive paper on many-worlds. Investigates and recasts the foundations of quantum theory in information theoretic terms, before moving on to consider the nature of interactions, observation, entropy, irreversible processes, classical objects etc.
- John A. Wheeler (1957). "Assessment of Everett's "Relative State Formulation of Quantum Theory". Reviews of Modern Physics. 29 (3): 463–465. Bibcode:1957RvMP...29..463W. doi:10.1103/RevModPhys.29.463.
- Stefano Osnaghi, Fabio Freitas, Olival Freire Jr, The Origin of the Everettian Heresy, Studies in History and Philosophy of Modern Physics 40(2009)97–123. A study of the painful three-way relationship between Hugh Everett, John A Wheeler and Niels Bohr and how this affected the early development of the many-worlds theory.
Operations research references
- H. Everett (1957). "Recursive games". In Melvin Dresher, Albert William Tucker, Philip Wolfe. Contributions to the Theory of Games, Volume 3. Annals of Mathematics Studies. Princeton University Press. pp. 67–78. ISBN 978-0-691-07936-3. MR 0091863. (Reprinted in Harold W. Kuhn, ed. Classics in Game Theory, Princeton University Press, 1997. ).
- Hugh Everett, III; Pugh, George E (1959). "The Distribution and Effects of Fallout in Large Nuclear-Weapon Campaigns". Operations Research. 7 (2): 226–248. doi:10.1287/opre.7.2.226.
- Everett, Hugh, III (1963). "Generalized Lagrange multiplier method for solving problems of optimum allocation of resources". Operations Research. 11 (3): 399–417. doi:10.1287/opre.11.3.39. JSTOR 168028. MR 0152360. Archived from the original on 2011-07-24.
- The Many Worlds of Hugh Everett III: Multiple Universes, Mutual Assured Destruction, and the Meltdown of a Nuclear Family by Peter Byrne, ISBN 978-0-19-955227-6, Nature review
- Eugene Shikhovtsev's Biography of Everett
- John Archibald Wheeler, Geons, Black Holes & Quantum Foam, ISBN 0-393-31991-1. pp 268–270
- Interview: Parallel lives can never touch, Mark Oliver Everett talking to Peter Aldhous, New Scientist, 24 November 2007.
- Are we closer to a 'theory of everything'?Susan Watts interview with Stephen Hawking and Mark Oliver Everett, Wednesday, 8 September 2010
- Mark Oliver Everett, Things the Grandchildren Should Know, ISBN 978-0-316-02787-8
Editor's Note: This story was originally printed in the December 2007 issue of Scientific American and is being reposted from our archive in light of a new documentary on PBS, Parallel Worlds, Parallel Lives.
Hugh Everett III was a brilliant mathematician, an iconoclastic quantum theorist and, later, a successful defense contractor with access to the nation’s most sensitive military secrets. He introduced a new conception of reality to physics and influenced the course of world history at a time when nuclear Armageddon loomed large. To science-fiction aficionados, he remains a folk hero: the man who invented a quantum theory of multiple universes. To his children, he was someone else again: an emotionally unavailable father; “a lump of furniture sitting at the dining room table,” cigarette in hand. He was also a chain-smoking alcoholic who died prematurely.
At least that is how his history played out in our fork of the universe. If the many-worlds theory that Everett developed when he was a student at Princeton University in the mid-1950s is correct, his life took many other turns in an unfathomable number of branching universes.
Everett’s revolutionary analysis broke apart a theoretical logjam in interpreting the how of quantum mechanics. Although the many-worlds idea is by no means universally accepted even today, his methods in devising the theory presaged the concept of quantum decoherence— a modern explanation of why the probabilistic weirdness of quantum mechanics resolves itself into the concrete world of our experience.
Everett’s work is well known in physics and philosophical circles, but the tale of its discovery and of the rest of his life is known by relatively few. Archival research by Russian historian Eugene Shikhovtsev, myself and others and interviews I conducted with the late scientist’s colleagues and friends, as well as with his rock-musician son, unveil the story of a radiant intelligence extinguished all too soon by personal demons.
Everett’s scientific journey began one night in 1954, he recounted two decades later, “after a slosh or two of sherry.” He and his Princeton classmate Charles Misner and a visitor named Aage Petersen (then an assistant to Niels Bohr) were thinking up “ridiculous things about the implications of quantum mechanics.” During this session Everett had the basic idea behind the many-worlds theory, and in the weeks that followed he began developing it into a dissertation.
The core of the idea was to interpret what the equations of quantum mechanics represent in the real world by having the mathematics of the theory itself show the way instead of by appending interpretational hypotheses to the math. In this way, the young man challenged the physics establishment of the day to reconsider its foundational notion of what constitutes physical reality.
In pursuing this endeavor, Everett boldly tackled the notorious measurement problem in quantum mechanics, which had bedeviled physicists since the 1920s. In a nutshell, the problem arises from a contradiction between how elementary particles (such as electrons and photons) interact at the microscopic, quantum level of reality and what happens when the particles are measured from the macroscopic, classical level. In the quantum world, an elementary particle, or a collection of such particles, can exist in a superposition of two or more possible states of being. An electron, for example, can be in a superposition of different locations, velocities and orientations of its spin. Yet anytime scientists measure one of these properties with precision, they see a definite result—just one of the elements of the superposition, not a combination of them. Nor do we ever see macroscopic objects in superpositions. The measurement problem boils down to this question: How and why does the unique world of our experience emerge from the multiplicities of alternatives available in the superposed quantum world?
Physicists use mathematical entities called wave functions to represent quantum states. A wave function can be thought of as a list of all the possible configurations of a superposed quantum system, along with numbers that give the probability of each configuration’s being the one, seemingly selected at random, that we will detect if we measure the system. The wave function treats each element of the superposition as equally real, if not necessarily equally probable from our point of view.
The Schrödinger equation delineates how a quantum system’s wave function will change through time, an evolution that it predicts will be smooth and deterministic (that is, with no randomness). But that elegant mathematics seems to contradict what happens when humans observe a quantum system, such as an electron, with a scientific instrument (which itself may be regarded as a quantum-mechanical system). For at the moment of measurement, the wave function describing the superposition of alternatives appears to collapse into one member of the superposition, thereby interrupting the smooth evolution of the wave function and introducing discontinuity. A single measurement outcome emerges, banishing all the other possibilities from classically described reality. Which alternative is produced at the moment of measurement appears to be arbitrary; its selection does not evolve logically from the information- packed wave function of the electron before measurement. Nor does the mathematics of collapse emerge from the seamless flow of the Schrödinger equation. In fact, collapse has to be added as a postulate, as an additional process that seems to violate the equation.
Many of the founders of quantum mechanics, notably Bohr, Werner Heisenberg and John von Neumann, agreed on an interpretation of quantum mechanics—known as the Copenhagen interpretation— to deal with the measurement problem. This model of reality postulates that the mechanics of the quantum world reduce to, and only find meaning in terms of, classically observable phenomena—not the reverse.
This approach privileges the external observer, placing that observer in a classical realm that is distinct from the quantum realm of the object observed. Though unable to explain the nature of the boundary between the quantum and classical realms, the Copenhagenists nonetheless used quantum mechanics with great technical success. Entire generations of physicists were taught that the equations of quantum mechanics work only in one part of reality, the microscopic, while ceasing to be relevant in another, the macroscopic. It is all that most physicists ever need.
Universal Wave Function
In stark contrast, Everett addressed the measurement problem by merging the microscopic and macroscopic worlds. He made the observer an integral part of the system observed, introducing a universal wave function that links observers and objects as parts of a single quantum system. He described the macroscopic world quantum mechanically and thought of large objects as existing in quantum superpositions as well. Breaking with Bohr and Heisenberg, he dispensed with the need for the discontinuity of a wave-function collapse.
Everett’s radical new idea was to ask, What if the continuous evolution of a wave function is not interrupted by acts of measurement? What if the Schrödinger equation always applies and applies to everything—objects and observers alike? What if no elements of superpositions are ever banished from reality? What would such a world appear like to us?
Everett saw that under those assumptions, the wave function of an observer would, in effect, bifurcate at each interaction of the observer with a superposed object. The universal wave function would contain branches for every alternative making up the object’s superposition. Each branch has its own copy of the observer, a copy that perceived one of those alternatives as the outcome. According to a fundamental mathematical property of the Schrödinger equation, once formed, the branches do not influence one another. Thus, each branch embarks on a different future, independently of the others.
Consider a person measuring a particle that is in a superposition of two states, such as an electron in a superposition of location A and location B. In one branch, the person perceives that the electron is at A. In a nearly identical branch, a copy of the person perceives that the same electron is at B. Each copy of the person perceives herself or himself as being one of a kind and sees chance as cooking up one reality from a menu of physical possibilities, even though, in the full reality, every alternative on the menu happens.
Explaining how we would perceive such a universe requires putting an observer into the picture. But the branching process happens regardless of whether a human being is present. In general, at each interaction between physical systems the total wave function of the combined systems would tend to bifurcate in this way. Today’s understanding of how the branches become independent and each turn out looking like the classical reality we are accustomed to is known as decoherence theory. It is an accepted part of standard modern quantum theory, although not everyone agrees with the Everettian interpretation that all the branches represent realities that exist.
Everett was not the first physicist to criticize the Copenhagen collapse postulate as inadequate. But he broke new ground by deriving a mathematically consistent theory of a universal wave function from the equations of quantum mechanics itself. The existence of multiple universes emerged as a consequence of his theory, not a predicate. In a footnote in his thesis, Everett wrote: “From the viewpoint of the theory, all elements of a superposition (all ‘branches’) are ‘actual,’ none any more ‘real’ than the rest.”
The draft containing all these ideas provoked a remarkable behind-the-scenes struggle, uncovered about five years ago in archival research by Olival Freire, Jr., a historian of science at the Federal University of Bahia in Brazil. In the spring of 1956 Everett’s academic adviser at Princeton, John Archibald Wheeler, took the draft dissertation to Copenhagen to convince the Royal Danish Academy of Sciences and Letters to publish it. He wrote to Everett that he had “three long and strong discussions about it” with Bohr and Petersen. Wheeler also shared his student’s work with several other physicists at Bohr’s Institute for Theoretical Physics, including Alexander W. Stern.
Wheeler’s letter to Everett reported: “Your beautiful wave function formalism of course remains unshaken; but all of us feel that the real issue is the words that are to be attached to the quantities of the formalism.” For one thing, Wheeler was troubled by Everett’s use of “splitting” humans and cannonballs as scientific metaphors. His letter revealed the Copenhagen-ists’ discomfort over the meaning of Everett’s work. Stern dismissed Everett’s theory as “theology,” and Wheeler himself was reluctant to challenge Bohr. In a long, politic letter to Stern, he explicated and excused Everett’s theory as an extension, not a refutation, of the prevailing interpretation of quantum mechanics:
I think I may say that this very fine and able and independently thinking young man has gradually come to accept the present approach to the measurement problem as correct and self-consistent, despite a few traces that remain in the present thesis draft of a past dubious attitude. So, to avoid any possible misunderstanding, let me say that Everett’s thesis is not meant to question the present approach to the measurement problem, but to accept it and generalize it. [Emphasis in original.]
Everett would have completely disagreed with Wheeler’s description of his opinion of the Copenhagen interpretation. For example, a year later, when responding to criticisms from Bryce S. DeWitt, editor of the journal Reviews of Modern Physics, he wrote:
The Copenhagen Interpretation is hopelessly incomplete because of its a priori reliance on classical physics ... as well as a philosophic monstrosity with a “reality” concept for the macroscopic world and denial of the same for the microcosm.
While Wheeler was off in Europe arguing his case, Everett was in danger of losing his student draft deferment. To avoid going to boot camp, he decided to take a research job at the Pentagon. He moved to the Washington, D.C., area and never came back to theoretical physics.
During the next year, however, he communicated long-distance with Wheeler as he reluctantly whittled down his thesis to a quarter of its original length. In April 1957 Everett’s thesis committee accepted the abridged version—without the “splits.” Three months later Reviews of Modern Physics published the shortened version, entitled “‘Relative State’ Formulation of Quantum Mechanics.” In the same issue, a companion paper by Wheeler lauded his student’s discovery.
When the paper appeared in print, it slipped into instant obscurity. Wheeler gradually distanced himself from association with Everett’s theory, but he kept in touch with the theorist, encouraging him, in vain, to do more work in quantum mechanics. In an interview last year, Wheeler, then 95, commented that “[Everett] was disappointed, perhaps bitter, at the nonreaction to his theory. How I wish that I had kept up the sessions with Everett. The questions that he brought up were important.”
Nuclear Military Strategies
Princeton awarded Everett his doctorate nearly a year after he had begun his first project for the Pentagon: calculating potential mortality rates from radioactive fallout in a nuclear war. He soon headed the mathematics division in the Pentagon’s nearly invisible but extremely influential Weapons Systems Evaluation Group (WSEG). Everett advised high-level officials in the Eisenhower and Kennedy administrations on the best methods for selecting hydrogen bomb targets and structuring the nuclear triad of bombers, submarines and missiles for optimal punch in a nuclear strike.
In 1960 he helped write WSEG No. 50, a catalytic report that remains classified to this day. According to Everett’s friend and WSEG colleague George E. Pugh, as well as historians, WSEG No. 50 rationalized and promoted military strategies that were operative for decades, including the concept of Mutually Assured Destruction. WSEG provided nuclear warfare policymakers with enough scary information about the global effects of radioactive fallout that many became convinced of the merit of waging a perpetual standoff—as opposed to, as some powerful people were advocating, launching preemptive first strikes on the Soviet Union, China and other communist countries.
One final chapter in the struggle over Everett’s theory also played out in this period. In the spring of 1959 Bohr granted Everett an interview in Copenhagen. They met several times during a six-week period but to little effect: Bohr did not shift his position, and Everett did not reenter quantum physics research. The excursion was not a complete failure, though. One afternoon, while drinking beer at the Hotel Østerport, Everett wrote out on hotel stationery an important refinement of the other mathematical tour de force for which he is renowned, the generalized Lagrange multiplier method, also known as the Everett algorithm. The method simplifies searches for optimum solutions to complex logistical problems—ranging from the deployment of nuclear weapons to just-in-time industrial production schedules to the routing of buses for maximizing the desegregation of school districts.
In 1964 Everett, Pugh and several other WSEG colleagues founded a private defense company, Lambda Corporation. Among other activities, it designed mathematical models of anti-ballistic missile systems and computerized nuclear war games that, according to Pugh, were used by the military for years. Everett became enamored of inventing applications for Bayes’ theorem, a mathematical method of correlating the probabilities of future events with past experience. In 1971 Everett built a prototype Bayesian machine, a computer program that learns from experience and simplifies decision making by deducing probable outcomes, much like the human faculty of common sense. Under contract to the Pentagon, Lambda used the Bayesian method to invent techniques for tracking trajectories of incoming ballistic missiles.
In 1973 Everett left Lambda and started a data-processing company, DBS, with Lambda colleague Donald Reisler. DBS researched weapons applications but specialized in analyzing the socioeconomic effects of government affirmative action programs. When they first met, Reis-ler recalls, Everett “sheepishly” asked whether he had ever read his 1957 paper. “I thought for an instant and replied, ‘Oh, my God, you are that Everett, the crazy one who wrote that insane paper,’” Reisler says. “I had read it in graduate school and chuckled, rejected it out of hand.” The two became close friends but agreed not to talk about multiple universes again.
Despite all these successes, Everett’s life was blighted in many ways. He had a reputation for drinking, and friends say the problem seemed only to grow with time. According to Reisler, his partner usually enjoyed a three-martini lunch, sleeping it off in his office—although he still managed to be productive.
Yet his hedonism did not reflect a relaxed, playful attitude toward life. “He was not a sympathetic person,” Reisler says. “He brought a cold, brutal logic to the study of things. Civil-rights entitlements made no sense to him.”
John Y. Barry, a former colleague of Everett’s at WSEG, also questioned his ethics. In the mid-1970s Barry convinced his employers at J. P. Morgan to hire Everett to develop a Bayesian method of predicting movement in the stock market. By several accounts, Everett succeeded— and then refused to turn the product over to J. P. Morgan. “He used us,” Barry recalls. “[He was] a brilliant, innovative, slippery, untrustworthy, probably alcoholic individual.”
Everett was egocentric. “Hugh liked to espouse a form of extreme solipsism,” says Elaine Tsiang, a former employee at DBS. “Although he took pains to distance his [many-worlds] theory from any theory of mind or consciousness, obviously we all owed our existence relative to the world he had brought into being.”
And he barely knew his children, Elizabeth and Mark.
As Everett pursued his entrepreneurial career, the world of physics was starting to take a hard look at his once ignored theory. DeWitt swung around 180 degrees and became its most devoted champion. In 1967 he wrote an article presenting the Wheeler-DeWitt equation: a universal wave function that a theory of quantum gravity should satisfy. He credited Everett for having demonstrated the need for such an approach. DeWitt and his graduate student Neill Graham then edited a book of physics papers, The Many-Worlds Interpretation of Quantum Mechanics, which featured the unamputated version of Everett’s dissertation. The epigram “many worlds” stuck fast, popularized in the science-fiction magazine Analog in 1976.
Not everybody agrees, however, that the Copenhagen interpretation needs to give way. Cornell University physicist N. David Mermin maintains that the Everett interpretation treats the wave function as part of the objectively real world, whereas he sees it as merely a mathematical tool. “A wave function is a human construction,” Mer-min says. “Its purpose is to enable us to make sense of our macroscopic observations. My point of view is exactly the opposite of the many-worlds interpretation. Quantum mechanics is a device for enabling us to make our observations coherent, and to say that we are inside of quantum mechanics and that quantum mechanics must apply to our perceptions is inconsistent.”
But many working physicists say that Everett’s theory should be taken seriously.
“When I heard about Everett’s interpretation in the late 1970s,” says Stephen Shenker, a theoretical physicist at Stanford University, “I thought it was kind of crazy. Now most of the people I know that think about string theory and quantum cosmology think about something along an Everett-style interpretation. And because of recent developments in quantum computation, these questions are no longer academic.”
One of the pioneers of decoherence, Wojciech H. Zurek, a fellow at Los Alamos National Laboratory, comments that “Everett’s accomplishment was to insist that quantum theory should be universal, that there should not be a division of the universe into something which is a priori classical and something which is a priori quantum. He gave us all a ticket to use quantum theory the way we use it now to describe measurement as a whole.”
String theorist Juan Maldacena of the Institute for Advanced Study in Princeton, N.J., reflects a common attitude among his colleagues: “When I think about the Everett theory quantum mechanically, it is the most reasonable thing to believe. In everyday life, I do not believe it.”
In 1977 DeWitt and Wheeler invited Everett, who hated public speaking, to make a presentation on his interpretation at the University of Texas at Austin. He wore a rumpled black suit and chain-smoked throughout the seminar. David Deutsch, now at the University of Oxford and a founder of the field of quantum computation (itself inspired by Everett’s theory), was there. “Everett was before his time,” Deutsch says in summing up Everett’s contribution. “He represents the refusal to relinquish objective explanation. A great deal of harm was done to progress in both physics and philosophy by the abdication of the original purpose of those fields: to explain the world. We got irretrievably bogged down in formalisms, and things were regarded as progress which are not explanatory, and the vacuum was filled by mysticism and religion and every kind of rubbish. Everett is important because he stood out against it.”
After the Texas visit, Wheeler tried to hook Everett up with the Institute for Theoretical Physics in Santa Barbara, Calif. Everett reportedly was interested, but nothing came of the plan.
Totality of Experience
Everett died in bed on July 19, 1982. He was just 51. His son, Mark, then a teenager, remembers finding his father’s lifeless body that morning. Feeling the cold body, Mark realized he had no memory of ever touching his dad before. “I did not know how to feel about the fact that my father just died,” he told me. “I didn’t really have any relationship with him.”
Not long afterward, Mark moved to Los Angeles. He became a successful songwriter and the lead singer for a popular rock band, Eels. Many of his songs express the sadness he experienced as the son of a depressed, alcoholic, emotionally detached man. It was not until years after his father’s death that Mark learned of Everett’s career and accomplishments.
Mark’s sister, Elizabeth, made the first of many suicide attempts in June 1982, only a month before Everett died. Mark discovered her unconscious on the bathroom floor and got her to the hospital just in time. When he returned home later that night, he recalled, his father “looked up from his newspaper and said, ‘I didn’t know she was that sad.’” In 1996 Elizabeth killed herself with an overdose of sleeping pills, leaving a note in her purse saying she was going to join her father in another universe.
In a 2005 song, “Things the Grandchildren Should Know,” Mark wrote: “I never really understood/ what it must have been like for him/living inside his head.” His solipsistically inclined father would have understood that dilemma. “Once we have granted that any physical theory is essentially only a model for the world of experience,” Everett concluded in the unedited version of his dissertation, “we must renounce all hope of finding anything like the correct theory ... simply because the totality of experience is never accessible to us.”