by Peter Byrne
The [SIOP] staff is making extensive use of computers, but I believe that their programming could be improved and that the most competent people (such as available in WSEG, for instance,) should become [more] involved.30
As the head of WSEG’s computational efforts, Everett was in a position to generate optimal weapon and target mixes, but it was up to the high command to prioritize targets. In early February, 1961 McNamara was briefed on the new SIOP. He evinced displeasure that the target lists for first and retaliatory strikes were essentially the same—reproducing Wargasm. Military advisors told McNamara that that a more optimal mix of first strike and second strike targets could be generated if more weapons were deployed, which would cost more money, of course, but would also increase the number of possible targets and thereby, flexibility in targeting—or so their circular reasoning went.31
The Marine Corps spoke up. Commandant David Shoup argued that the SIOP’s single list of targets was illogical, not to mention unfair. It called for obliterating the U.S.S.R., Eastern European, and China in one fell swoop, with almost no room for withholding any individual targets. SAC general Thomas Power had told Shoup that the plan was to be executed as a whole, and that leaving any country out would “screw up the plan. Even tiny, Communist Albania, which had disassociated itself from the U.S.S.R., would be wiped out.”32
At Kennedy’s insistence, the original SIOP was revised.33 No doubt, Everett and his colleagues did their best to cost out the risks and benefits of a variety of attack plans, but flexibility was an illusion. In the end, despite the logical foundations of the SIOP, the plan was more about pumping up military budgets than keeping the world safe for democracy—just as Eisenhower had warned.
BOOK 8
TRANSITIONS
27 Behind Closed Doors
I feel very strongly that the stage physics has reached at the present day is not the final stage. It is just one stage in the evolution of our picture of nature, and we should expect this process of evolution to continue in the future, as biological evolution continues into the future…. One can be quite sure that there will be better stages simply because of the difficulties that occur in the physics of today.
P.A.M. Dirac, 1963.1
Attacked by Bohr’s man
After its publication, Everett’s relative states theory appeared to be dead on arrival. The paper was only cited twice in scientific literature before 1962 (it did not take off until 1982).2 However, lack of publicly expressed interest did not mean that it was being ignored. On the contrary, it was causing some of the best minds in physics to debate the measurement problem behind closed doors.
And because Everett’s theory was not dead, he had made a powerful enemy, Leon Rosenfeld, Bohr’s amanuensis. For many years, he campaigned against the relative states theory on the basis that it contradicted Bohr.
The son of a Belgian electrical engineer, Rosenfeld made significant contributions to quantum theory, mostly in collaboration with Bohr. He was timid and kind-hearted—except when defending his mentor, when he became caustic and back-biting. He frequently disparaged theories with which Bohr disagreed as “theological,” as based upon faith, and not upon experimental science.
Wolfgang Pauli affectionately labeled Rosenfeld, “Trotsky × Bohr = Rosenfeld.”3 The Belgian, a Marxist, considered Bohr’s philosophy to be a form of dialectical materialism (although Bohr was unconscious of this deep connection, Rosenfeld asserted). But try as he might, he could not define complementarity:
It must be realized that it is impossible in principle to write a text-book about dialectics, since this would be to fix a mode of thought which is essentially flowing. It is exactly the same with complementarity (which is the modern form of dialectics): you cannot give a ‘definition’ of it, but only understand what it is by re-thinking for yourself the typical cases in which it occurs.4
Rosenfeld rejected the Wigner-von Neumann notion that subjective consciousness is the ultimate reality, holding that, “There is an external world independent of what we think and which is the ultimate origin of all our ideas.”5 But personal loyalty to Bohr appears to have been Rosenfeld’s criterion for interpretive validity. According to historian Anja Skaar Jacobsen,
[Rosenfeld took] up the fight against all disbelievers of complementarity, whether Soviet or Western Marxist physicists or just supporters of the causal program with no Marxist agenda. It was a fight in which he used all possible means, including polemical papers, book reviews, and personal connections. In addition, he served as consultant or referee in matters of epistemology of physics and the like at several well-reputed publishing houses and the influential journal Nature. In this capacity he used his influence effectively, and several books and papers, among them some by Frenkel, Bohm, and de Broglie, were rejected on this account.6
What makes Rosenfeld’s mini-jihad against Everett remarkable is that he viewed himself as a champion of new ideas in physics.
Rosenfeld suggested that… the introduction of a new idea in science will happen only as a result of a veritable fight between the pioneer who made the discovery … and the conservative scientific tradition of the scientific community which he confronts…. If the pioneer is not able to convey his ideas … he remains a forerunner, and it is then necessary to wait…. [If the] time is not ripe for the assimilation of a discovery it will have to be rediscovered at a later stage.7
In the early 1970s, as Everett’s interpretation was gaining credence, Rosenfeld attacked not only the theory, but also the theorist. But long before that, in 1959, he took issue with Everett for daring to question Bohr’s assertion that the quantum world must be explained with purely classical notions. In a letter to a colleague, Saul M. Bergmann, who had inquired about his opinion on Everett’s theory, Rosenfeld observed,
This work suffers from the fundamental misunderstanding which affects all attempts at ‘axiomatizing’ any part of physics. The ‘axiomatizers’ do not realize that every physical theory must necessarily make use of concepts which cannot in principle be further analyzed since they describe the relationship between the physical system which is the object of study and the means of observation by which we study it…. It is clear that in the last resort we must here appeal to common experience as a basis for understanding. To try (as Everett does) to include the experimental arrangement into the theoretical formalism is perfectly hopeless, since this can only shift, but never remove, this essential use of unanalyzed concepts which alone makes the theory intelligible and communicable…. The fact, emphasized by Everett, that it is actually possible to set-up a wave function for the experimental apparatus and a Hamiltonian [the energy of a system] for the interaction between system and apparatus is perfectly trivial, but also terribly treacherous; in fact, it did mislead Everett to the conception that it might be possible to describe apparatus + atomic object as a closed system…. This, however, is an illusion.8
Rosenfeld did not explain how or why Everett’s “perfectly trivial” reasoning was incorrect, excepting that it did not echo Bohr’s reliance on classicality to explain quantum phenomena. But not all physicists went along with Rosenfeld. In October 1962, a select group met privately at Xavier University in Cincinnati, Ohio to discuss the measurement problem among themselves. And shortly after the conference started, they asked Everett to make a presentation.
Everett goes to Xavier
In early 1959, Everett discussed his theory with Xavier University physics professor Boris Podolsky in New York City. Podolsky asked Everett for a copy of his long thesis. Everett said he would send it to him after he returned from “argue[ing] about it with Bohr for a month or so.”9
Two years later, Podolsky invited Everett to speak at the Conference on the Foundations of Quantum Mechanics at Xavier sponsored by the Office of Naval Research and the newly formed National Aeronautics and Space Administration. The meeting was held behind closed doors because, Podolsky explained in his opening remarks, “We want the participants to feel free to express themselves sponta
neously … without things getting out in the newspapers.”10 The conference secretary, F. G. Werner, later reported on some of the discussions (barely mentioning Everett) for Physics Today. But it was not until 2002 that a transcript of the proceedings was released to the public. It is fascinating document, showing an intimate, sometimes angry colloquy between scientific heavyweights. So desperate had these thinkers become about the paradox of measurement, that they were willing to entertain the idea of multiple universes if it provided a possible solution.
Everett despised public speaking, but he could hardly have dreamed up a smarter, more informed group of physicists to address. It was the first of only two known occasions in which Everett explained his theory to a public gathering of his peers.
The stellar panel was composed of Eugene Wigner,11 P.A.M. Dirac,12 Yakir Aharonov,13 Wendell H. Furry,14 Podolsky, and Nathan Rosen.15 Fifteen physicists from various universities and national laboratories were allowed to sit in the room and listen to the discussion, speaking only when specifically asked for their thoughts. It is important to remember that no one except Everett, Wheeler, and a few others had read the original thesis; the group’s prior understanding of Everett’s argument was limited to the edited version published in 1957. This was his chance to expound upon his idea in depth.
The morning of the first day was spent discussing action-at-a-distance, particularly as it related to the contradiction between quantum non-locality and special relativity as posed by EPR.16 Searching for an explanation of EPR, the participants kept returning to the measurement problem with its inexplicable corollary of wave function collapse, and the topic of Everett’s paper arose.
ROSEN:
According to Everett, it is not necessary to worry about the problem of the reduction of the wave packet, because all the different possibilities after measurement are on an equal footing. The various possible results of a measurement correspond to a kind of branching so that if you get one result it means that you are just on one of the branches. But since all of the other branches exist on the same footing, one describes all of the possible measurements as one huge tree. Each time after a given result is found, one simply goes along one of the branches and from this branch one continues into further branching by making another measurement, and so on.
PODOLSKY:
Oh yes, I remember now what it is about–it’s a picture about parallel times, parallel universes, and each time one gets a given result he chooses which one of the universes he belongs to, but the other universes continue to exist.
ROSEN:
I just have some recollection of the paper. It’s not a question of mathematics, it seems to me, but rather a question of interpretation. The mathematics involved is very simple, you expand a wave function as a linear combination of the [possible states] of the observed quantity…. The usual belief is that when the measurement is over, one of these terms is singled out and the others are thrown away. That is what is referred to as reduction of the wave packet. The other point of view, that of Everett, is to keep all of the terms.
AHARONOV:
There seems to be a problem here. It raises the question is time reversible? If you look on the process of branching you see that it has a definitely preferred direction of time. You never experience any collection of past branching connected together with one observer in the present.
Aharonov was concerned that as, in physics, action is theoretically reversible, Everett would have to explain the apparent irreversibility of his branching model. A phone call was made to the Pentagon. Everett agreed to fly to Cincinnati for the next day’s session.17
That evening, Wigner presented a talk, “The Concept of Observation in Quantum Mechanics.” He distanced himself from Bohr, saying that it is not possible nor desirable for physics to reduce the study of quantum nature to measuring collisions between particles:
WIGNER:
Fundamentally it is not enough because the world is constantly in a collision with us, and there is a constant interaction between matter. Unless we make it the purpose of physics to describe only certain carefully made experiments, but not more than that, we can’t get along entirely with just the collision matrix. It is not true that everything is only a collision. The world continues. For instance, a gas constantly exerts a pressure on the wall. There are many similar examples which show that it is not really possible to reduce everything to a collision.18
Wigner then distanced himself from Everett, too, declaring that unless physics gives up the superposition principle, “The fact is quantum mechanics does not permit objective reality.”19 Everett was persuaded otherwise: his branching universes emerged from cascades of collisions between superposed objects in an objectively real quantum environment.
The next morning, with Everett in the room, Rosen began the discussion, “I would like to think that the world has an objective reality independent of whether there are people present to observe it or not.” He acknowledged Everett’s presence and characterized his view of the measurement problem.20
ROSEN:
He does not accept the reduction of the wave packet…. He does not want to distinguish between the actual result as obtained in a given case and the other possible results which might have been obtained, so that even after the measurement he has the series of terms, instead of one term. He thinks of the wave function as changing only in accordance with the Schrödinger equation, in a continuous way, without the possibility of this sudden change in the wave function, which we call the reduction of the wave packet. My own feeling is that such a point of view is tenable and consistent, but should be interpreted as referring not to what one observer finds but what many observers carrying out the same sort of measurement on the same sort of system would find.
Rosen was attracted to keeping intact the logical consistency of the Schrödinger equation, but he was not ready to accept branching universes.
EVERETT:
I think you said it essentially correctly. My position is simply that I think you can make a tenable theory out of allowing the superpositions to continue forever, even for a single observer.
From the floor, Abner Shimony said that Everett’s theory suggested two possibilities regarding consciousness. One was that “Ordinary human awareness is associated with one of these branches and not with the others.”21 The other possibility, said Shimony, was that a separate awareness is associated with each branch.
Rosen asked Everett to briefly describe his theory.
EVERETT:
Well, the picture that I have is something like this: Imagine an observer making a sequence of results of observations on a number of, let’s say, originally identical object systems. At the end of this sequence there is a large superposition of states, each element of which contains the observer as having recorded a particular definite sequence of results of observation. I identify a single element as what we think of as an experience, but still hold that it is tenable to assert that all of the elements simultaneously coexist.
In any single element of the final superposition after all these measurements, you have a state which describes the observer as having observed a quite definite and apparently random sequence of events. Of course, it’s a different sequence of events in each element of the superposition. In fact, if one takes a very large series of experiments, in a certain sense one can assert that for almost all of the elements of the final superposition the frequencies of the results of measurements will be in accord with what one predicts from the ordinary picture of quantum mechanics. That is very briefly it.
PODOLSKY:
Somehow or other we have here the parallel times or parallel worlds that science fiction likes to talk about so much.
EVERETT:
Yes, it’s a consequence of the superposition principle that each separate element of the superposition will obey the same laws independent of the presence or absence of one another. Hence, why insist on having a certain selection of one of the elements as being real and all of the others somehow mysteri
ously vanishing?
FURRY:
This means that each of us, you see, exists on a great many sheets or versions and it’s only on this one right here that you have any particular remembrance of the past. In some other ones we perhaps didn’t come to Cincinnati.
EVERETT:
We simply do away with the reduction of the wave packet.
PODOLSKY:
It’s certainly consistent as far as we have heard it.
EVERETT:
All of the consistency of ordinary physics is preserved by the correlation structure of this state.
PODOLSKY:
It looks like we would have a non-denumerable infinity of worlds.
EVERETT:
Yes.
PODOLSKY:
Each proceeding with its own set of choices that have been made.
