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Interview of Bryce DeWitt and Cecile DeWitt-Morette by Kenneth W. Ford on 1995 February 28,
Niels Bohr Library & Archives, American Institute of Physics,
College Park, MD USA,
For multiple citations, "AIP" is the preferred abbreviation for the location.
DeWitt discusses his early exposure to Wheeler's work through the 1939 Bohr-Wheeler paper on fission (studied by Cecile in 1944), and meeting him not long after the end of World War II. Wheeler's visit to the DeWitts at their home in California in the early 1950s. Bryce's Gravity Research Foundation prize and his move to the Glenn L. Martin Company in Baltimore. Their move to the University of North Carolina in Chapel Hill. Summer conferences. Work with Wheeler on quantum gravity. Assessment of Hugh Everett's "many worlds" dissertation and published paper. Wheeler's role as a critic of Bryce's work. Wheeler's recruitment of Cecile to run a series of scientific meetings at Battelle. Wheeler's role in NATO. Wheeler's contributions to the physics department at the University of Texas at Austin.
I'm with Bryce and Cecile Dewitt in Austin, Texas on February 28th, 1995 in their office at the University. If you want to start perhaps with some remarks about his [John Wheeler's] pre-Austin career and an evaluation of his early work in relativity and gravitation, that would be good.
I think the first time I heard the word Wheeler was when I was in Joliot's lab in 1944 and Joliot asked me to read the Bohr and Wheeler paper, which he said was important. Joliot, [who] had never wanted any theorist in his lab, recognized there was some importance there and wanted somebody to read it. And as a matter of fact, I think that was the point at which he decided to hire me as a theorist, which was in his mind to be a house theorist just doing whatever he was telling me to do, and the first job was to read the Bohr and Wheeler paper.
But not having any quantum mechanics of anything, even that paper, which now I think is well written and relativelyCwell it's easy to readCI couldn't make head or tail of it. And that's what started for me the whole process of telling Joliot, "I've got to speak to somebody. I have got to go [somewhere else] to see what's going on." When Joliot got the chance, he sent me to Dublin. Then, I think-but I'm not sure-that I first met Wheeler at the wonderful conference which was held in Cambridge, England. Whether it was '46 or '47 I cannot remember, but that was the first conference in Europe where the people in the U.S. were coming, and it was the first time that lots of colleagues who had not met before the war began to [gather]. It was an incredibly warm exchange time. That could be [where I first met Wheeler], but then I don't have any memory of Wheeler. It would be worth knowing if he was at that conference, because it was a very special conference. I met him afterwards, I believe in Copenhagen, but I don't have anything particularly to contribute. I think at the time he introduced Putnam, I think is his name, to me.
Peter Putnam. And then there was a little bit of a correspondence from Peter Putnam. I don't have my own letters. I still have one of the Putnam letters. I don't know if I have it here, but I have it somewhere. And then I don't know when I met him next.
Well, he probably was in Princeton.
At the Institute in '48, '49, '49-'50.
Yes. Certainly. But I don't know anything in particular which would be useful [from that time].
We didn't see him in all the years that we were abroad. I went to Zurich. We were [I was?] there in '50. We were married in '51. We were in India for nearly a year, and came back, and I got a job at the Livermore [Lab]. That's the first time that I have a distinct memory of Wheeler, although I must have met him, we must have conversed earlier than that, because...
He came to Danville.
He visited us specifically.
At home. And he knew that I was working on the problem of trying to quantize the gravitational field. He asked me all sorts of questions, and I answered the best I could, and the next that I remember from Wheeler reallyCyou interject if you remember anything else.
Well, just a quick thing. When he visited Danville he knew I was, had been [doing] functional integration, Feynman path integrals, and we talked briefly about Feynman path integrals at this point. He wanted to know what I had done.
[Wheeler] was always travelling, always calling people up to meet him at such-and-such a place, he'd have an hour at the airport, we'd go out to the airport and talk physics with him, and he had his notebook and he would write it all down. He probably did that in Danville.
Danville, California, which is about halfway between Livermore and Berkeley. Because Cecile was teaching in Berkeley and I was [at Livermore]. He probably had, could have had, some influence on Teller, [for] Teller was quite generous in allowing me one whole semester off to be at Berkeley to work on something and also a semester off at the Institute for Advanced Study. Then I won the Gravity Research Foundation first prizeC
Cby writing something, essentially giving them hell for such a stupid-the way it had been phrased in those early years. This became known to an industrialist in Winston-Salem, North Carolina, a man named Agnew Bahnson, who wanted to discover an anti-gravity machine. I got two letters almost simultaneously. No, I got a telephone call from Bahnson asking meCI have to backtrack. Why he called me up was, he was a friend of George Rideout, the president of the Gravity Research Foundation, and he'd heard that I'd won first prize, and Rideout says, "There's the man you ought to look for," and then he called up Wheeler, because Wheeler had been at North Carolina I guess. And my name came up again, so he figured that he better call me. But it was just a torrent of words from him, and essentially after half an hour I was not the least bit interested. I was trying to figure out a nice way of saying no, write something up. And I got a letter at that time also from the Glenn L. Martin Company which started out, "It occurred to us a number of years ago that our company had a vital interest in gravity," [laughs] and they wanted to establish a research institute for advanced study that wouldn't be shackled with the preconceived notions of the academic types, and would I come and join that. And then I got a telegram or a letter, was it from the Department at Chapel Hill or from Wheeler himself?
I think it was from Wheeler himself.
Saying, "Don't say no immediately to this guy." Because Wheeler had been, on a previous visiting committeeCmaybe it was a one-man committee at that time-to the University of North Carolina, and he felt he owed them something and wanted to build up the department. He's an opportunist, a bit like Cecile. Seizing anything, he thought maybe some good could come out of this. So I packed my bags and went off to Baltimore to visit the Glenn L. Martin Company, where I met Lou Witten, the father of Ed Witten—
—who was persuaded to join this thing. Lou was hoping to get me to join it. Then I went down to Chapel Hill, and Bahnson, his original idea was to have it at State University in Raleigh because they had a nuclear reactor. He felt that having [?] a nuclear reactor might be useful for anti-gravity. But in the meantime, the people at Chapel Hill has persuaded me to consider putting this thing in Chapel Hill. And I was assured by the department there that it would be bona fide and it wouldn't be run by Bahnson. Chapel Hill is a beautiful place, and I was wanting to get out of Livermore for an academic position, so we went there, both of us, as visiting research professors. After a few years I was given a regular professorship and Cecile was demoted to a lecturer.
Without being told it was a demotion. "Oh, it will be so much better for you." And that's the part I didn't like, the hypocrisy of letting me believe that it was better. And in the French context, it could have been better, so I took it for granted. Before you go on, I want to say one thing about the gravity prize. Until Bryce, no real physicist wanted to touch it, because it was considered as a total crackpot project. But Bryce could stand up for himself and said, "I don't know ??? the other people have done it."
Well, I didn't want to ???.
Well, you must have been a pathfinder then, because there were subsequently a number of excellent physicists whoC
No. Bryce's things marked a total change of direction of ??? ??? and a total change of perception on the people.
Well, hold on, it wasn't quite as abrupt as you indicate, because it took probably five or six years for the atmosphere to change. The most noteworthy example is when Arnowitt and Deser submitted an essay and won the first prize. They were both at the Institute for Advanced Study, and Oppenheimer called them on the carpet and said, "You've got to give the money back. You've used the Institute for Advanced StudyC[used] the name—inappropriately." They didn't of course, but this was—it took a while for it—
This is not directly related to Wheeler, but you mentioned Lou Witten. Didn't he in fact do some reputable work in relativity?
Oh yes, yes.
Oh sure, sure.
Oh absolutely. No, when I say it changed abruptly, it meant that before Bryce no reputable physicist would have submitted [an] essay, and after Bryce reputable physicists did submit an essay. Now whether it was perceived by everybody including Oppenheimer took a little while, but there was a definite change.
Then we had a—boy!—we had the first of the famous GRGs, GR zeroth.
General Relativity and Gravitation. The zeroth one was in Berne in '55. It was the jubilee of relativity. Then we had this conference in Chapel Hill which was an exceedingly nice conference, primarily because it was by invitation only. Of course Wheeler played an important role in that. Feynman was there. Feynman has said some nasty things about those conferences—I think in some of his writings—but I think his memory failed him, because he was very active, very interested, and very much partook of the discussions at Chapel Hill.
The first one was did you say '55?
The first zeroth one was in Berne, so it's Berne.
In what year?
And ours was in the end of 1956.
I have the report. I think I have the report here.
Early 1950s. In January 1957 or December '56, it was right then.
I believe that Wheeler's first paper in relativity, his geon paper, was in '55. Was it '55? Or it was around that time.
Yes, but he was at the conference and was talking about geons, and I remember Feynman saying, "Geon Wheeler."
Now I have ??? ??? a brochure. I don't know. I mean, that's a good referenceC
??? what Wheeler says in there ???.
Could I stop this just for a moment?
Yeah. [tape off, then back on...]
But that was really a very successful meeting, and I think already by that time we were having the—or it began about that time—the annual going out to Stevens Institute across the river. In the old days when the January meeting of the American Physical Society was at the Hotel New Yorker, there were relativity all-day meetings in Hoboken. Then we had—it was really I think in Bahnson's mind a fund raising scheme, inviting a number of physicists, including Dyson—
No no, down to—some gap in the mountains.
Mountain Gap? No, no. Roaring Gap.
Roaring Gap. ??? office in North Carolina, where there was a nice place. ??? ??? ???—-
To Bahnson. Bahnson had a summer house at Roaring Gap.
That's right. But we all stayed there a couple of days and had these conferences. Lovely setting. And talked about - and not very technical, so that the ??? ??? people would understand. And Wheeler certainly participated in that. Then -
Bryce, does your interest in work in relativity antedate Wheeler's interest?
Yes. Because he didn't become interested-. Yeah, mine started [with] my thesis, probably in 1948. He became interested, according to the stories I've heard him tell, when he decided to [teach] this class. He taught general relativity one year at Princeton, the first time he ever taught it, and he took his class to see Einstein. He saw that there were a lot of unsolved problems here, and he thought it was a very interesting area to work in. And that was around 1955, just before Einstein's death.
Earlier actually. The first course that he taught was '52-'53.
Oh, as early as that. Well, that could explain then why he even came to Danville, he stopped by Danville. Because he was definitely talking about the quantum theory [and] gravity at that time. Yeah, I guess that's right. Then he had this student Everett, Hugh Everett III, who started his thesis work before, probably in the winter of '54-'55, because he wrote the thesis up, but it never became a thesis. Wheeler wouldn't allow it to become a thesis. And in that Urwerk, which I finally got a copy of from Mrs. Everett, he refers to Einstein as if he were alive. So that puts a date on it. ??? ??? ??? His actual thesis was identical with the paper that he had published in the Reviews of Modern Physics. That was an issue devoted to our conference, in fact. A number of the important papers from our conference were published.
Actually I have it here ??? ???
And Wheeler, I asked him many years later why the original article, I mean the original thing, wasn't ever published. Wheeler said, "Because I sat down with Everett and told him what to say," and you know that he wrote a sort of a supporting article to Everett's ideas in this, but then it was all quiet. No one was ever talking about Everett for many years. I had a visit in Chapel Hill from-what's his name? Max Jammer, who was writing a book on the foundations of quantum mechanics, and he had never heard of Everett. And I thought that this was scandalous, because Everett had a brand new idea, it was the first fresh idea in quantum theory in decades, and no one-he was being completely ignored. So I decided to write an article, a popular article, for Physics Today, which really put Everett on the map, and Wheeler promptly disowned Everett. The reason, as far as I can see, was it was too revolutionary an idea, this idea of many worlds. It was anti-Copenhagen; Bohr was one of Wheeler's heroes, and he didn't want to be associated with him. He has denied, he has refused to have anything to do with it in all the years since.
The term "many worlds," was that your term?
Everett in his Urwerk, [which] was titled "The Theory of the Universal Wave Function." In footnotes he refers to splitting, worlds splitting, but I think probably the term was first used as such by me. It was quite clear what Everett meant, what he was talking about.
And that's Wheeler's recollection too. I think he credits you with that term. Oh yes, and Wheeler said Arelative [email protected] was his preferred term.
Here is Everett's paper, and here is Wheeler's assessment of Everett's paper. Do you want copies?
Yes. I'll copy that.
There is something in this—
There is a nice review.
When I first got ???, since I was editor for this issue, and Everett hadn't been at the conference out there, and it had to be submitted to me for my okay. I read it and I was stunned, I was shocked. I wrote him an 11-page letter in answer. When I met him a number of years later, the first thing he did was to wave this paper in the air, taking him to task. And I was objecting essentially that I didn't feel myself split. And so the footnote here says, "In reply to a preprint of this article, some correspondents have raised the question of the transition from possible to actual, arguing that in 'reality'"—in quotes—"there is, as our experience testifies, no such splitting of observer ??? so that only one branch can ever actually exist. Since this point may occur to other readers, the following is offered in explanation. The whole issue of the transition from the possible to actual is taken care of in the theory in a very simple way: There is no such transition, nor is such a transition necessary for the theory to be in accord with our experience.
From the viewpoint of the theory all elements of the superposition, all branches are actual, none any more real than the rest. It is unnecessary to suppose that all but one are somehow destroyed. Since all the separate elements of the superposition individually obey the wave equation with complete indifference to the presence or absence, actuality or not, of any other elements. This total lack of effect of one branch on another also implies that no observer will every be aware of any splitting process. Arguments that the world picture presented by this theory is contradicted by experience, because we are unaware of any branching process, are like the criticism of the Copernican theory that the mobility of the earth as a real physical fact is incompatible with the common sense interpretation of nature because we feel no such motion. In both cases the argument fails and it is shown that the theory itself predicts [?] that our experience will be what it in fact is. In the Copernican case the addition of Newtonian physics was required to be able to show that the earth's inhabitants would be unaware of any motion of the earth." And to me, that was touché, [laughing], I mean that was it. And so—
I'll copy that.
Well, let's see. To get back, well I suppose it was in 1966 or thereabouts, '65 maybe, I had a telephone call from Wheeler. I was still at North Carolina—saying he was going to be en route somewhere and he would be at the Raleigh Durham Airport for a couple of hours, would I come out and talk with him. Then he was very much concerned with his quantum gravity—what is the state function, what are the variables in which the state function of the universe. He got the idea finally that it should be 3-geometries. I had read a paper by Asher Peres not long before, giving a Hamilton-Jacobi formulation of Einstein's theory, using the Hamiltonian constraints that had grown out of Dirac's theory of constraints as applied to gravity. It was a trivial matter to go from the Hamilton-Jacobi viewpoint to a quantum theory viewpoint with a functional differential equation. When we were out at the airport I scribbled his thing down on a piece of paper, [laughs], and Wheeler got all excited about this and started going everywhere talking about this equation, which has become known as the Wheeler-Dewitt equation. There's the birth of it.
Did that result in a joint paper with you and Wheeler?
No, no, it didn't. It was—he referred to it in one of his talks at the Battelle Rencontres in Seattle in '67. I had written [it] up, in the first paper of the trilogy I wrote which didn't get published until '67, although I had submitted it over a year [earlier?]. That was a case of Wheeler interference incidentally, but [also] my negligence ??? ???. It had been sent to him to referee, and I had made it as one single paper. It was a huge thing, and he ??? ???. I was too timid in those days to pound on the table and ask the editor what's happening to that paper, and months went by. Then finally I learned thatCI guess he spoke to you [Cecile] or something—
Yeah. Actually ??? ??? ??? ??? ???.
He had simply held it up. And the only thing he said [was], "How can we get Bryce to split this up?" but he had never spoken to me about that. And so that was an easy thing. I just split it into three, and then published it, and one of the important things, in the second paper of the series, was the Feynman rules for all orders in non-Abelian gauge theories. So although it was submitted over a year before, it didn't see print until two weeks before Fadeev and Popov presented their streamlined version of that. Of course the whole thing became known as Fadeev-Popov. Oh, I should have had sense enough to write that up as a Physical Review letter as soon as I had it worked out ??? ??? I should have ??? ???. But you know, in those days—
Say that phrase again, so I get it straight, about two loops. What was that?
Two-loop, you know, in the loop expansion for quantum field theory. Feynman already as early as the Warsaw conference, ???, which was one of these GRG conferences, had worked out the rules for one loop. He was the discoverer of the fictitious quanta known as ghosts, which are known as Fadeev-Popov ghosts, although they really should be known as Feynman ghosts. He's the one that put a name to them [?]. He was unable to do it for two loops. In '64 that was one of the semesters I was off. ??? '64 I was ??? Chapel Hill, I discovered the rules of two loops ??? work it out. And then in writing this paper I noted that the rules for two loops could actually be gotten in the functional integral, and I checked the functional integral to see whether it was invariant, and it was, so there was the rules to all orders. And I knew this already in '65. I ??? ??? ??? written and submitted in '66, and it didn't get published until '67. All right.
Okay. There [are] two things [to this] discussion, one of which concerns his trilogy, and one [concerns] a totally different aspect of our relationship with Wheeler, which has to do with his involvement in the Ford Foundation and what became afterwards the Scientific Division of NATO. So let me briefly comment about the trilogy, and then we'll have to start a whole new chapter about the NATO business.
Wheeler came to me once and said that the enormous paper from Bryce, AI don't know what to do, it's too long." And I said, "Well, [tell him to make it into] three papers," and eventually suggested that to Bryce Going to a separate issue, which is Wheeler's role in the creation of the NATO Scientific Division: I have very precise documents which I will pull out for you. So what I am saying now it's time to be corrected once in term of data, etc., once I give you the documents. But basically the sequence of events is the same thing. Senator Henry Jackson—
—from Washington, was asked what can we do to strengthen the NATO Alliance? Jackson appoints a— Jackson appoints a committee, Wheeler becomes a chairman of that committee, and they prepare a report. The conclusion was what became the NATO Scientific Division. One of the interesting facts about the NATO Scientific Division is that it is somewhat independent of the other [divisions] in the sense that a country can belong to the Scientific Division without belonging to the political and economic and military division. For instance when France pulled out of NATO, France stayed in the NATO Scientific Division. And I must say, that report was extremely well thought through. At that time I got quite involved with Wheeler, because the report was suggesting three activities. One was summer school on the pattern of the Les Houches summer school which I had founded in 1951C
That was written by Norman Ramsey. [Ed: At the request of Bryce and Cecile, a portion of the discussion is skipped at this point.]
Then a fellowship for postdoc mobility between the various countries in the NATO Alliance, and then a research project which needed the collaboration of more than one country of the NATO Alliance. I am not sure [about] the Jackson people, but anyway, the sequence of events is that the committee chaired by Wheeler wanted action right away. So they talked to the Ford Foundation, who said they could put things into place right away until the NATO things could be put into place. So the first year for those projects was funded by the Ford Foundation, which started a number of feature of that plan which were extremely good. Like, the Ford Foundation said, we=ll offer money for the Les Houches school right away, because we had been part of the picture right at the beginning. I'll have to find out the name of the—I can find the name of the person at the Ford Foundation who was running it. He said, "I will not give money to a university or to an agency in which there would be a heavy bureaucracy with lots of constraints. I will only give it if you can use the money freely and very, very ??? at the minimum to cover that." That gave me an opportunity to have a separate account. It's a complicated story, but anyway, it was great. It was not administratively correct, but it was great. And it all worked out eventually. I'll tell you right away the name of that Ford guy. Shephard Stone. Then the following year—
Say that again, Shephard Stone?
Was that two words? Shephard Stone.
Shephard was his first name, and Stone was his last. And then in '59 the Scientific Division of NATO was in place, and the first—what was his title then? But anyway the boss. The first person there who was responsible was Ramsey, the next one was Seitz, the next one was Nierenberg. They ran it extremely well. I remember the first letter I got from Ramsey. First of all, he gave me the document he had written which became the initial document in which actually said on the first line, "summer school like the Les Houches summer school," and I have a copy of that document. Then there was another letter which said, "I don't want a financial report. All I want is a scientific report," and give me money that I can spend freely. I'll do things.
Of course it doesn't operate that way anymore.
No no. After those three great—who ???, well not secretary general or director, but anyway—
Director of the Scientific Division.
Yes. Well, I can find. I mean, I have it in these letters, you know, ??? ???. It became a much more bureaucratic enterprise in which the persons in charge are more interested in making statistics of the number of people who have been there, etc., etc. But it was started in absolutely wonderful fashion, and in this little document, which is about Les Houches up to '66, in which the official report of the people who had given money to Les Houches or had this school in one way or another, but in light of sort of background I have put the name, because those agency are fine, but they work, only the person that does the work is great, and opposite the Ford Foundation you see Shephard Stone, but opposite the first line, Le Cxxx, you see Henry Jackson and John Wheeler, and then below around the inside Steven Berry, and then the others afterwards.
John lectured twice, didn't he, ??? ???? It was '63—
I'll tell you. I could find that—
And in '73, the black hole year [?] and the relativity group ??? ???—
I have the list of lectures. I could tell you that right away.
Well, he certainly lectured there at least one time.
In '63 certainly, =73. I would have to pull out another document. So maybe I should give you—what should I give you? Maybe that document of Ramsey. Then Wheeler became quite knowledgeable about what was going on at Les Houches, and later on after the ??? ???, when he wanted to involve the Battelle Memorial Institute in similar activities, he actually invited me to Princeton. I remember having breakfast and he was asking me whether I would do something similar for the Battelle Institute. I was a little bit reluctant because Les Houches was really taking a lot of my time in administration and you can do just so much. To do more would have really interfered with any other research or ??? ??? administrative duties I wanted to do. But then I remember Janette Wheeler saying, "You may not be aware of it, but in Wheeler's words 'that was a hard sell'!" And I don't know, I eventually accepted because Wheeler said, assured me, I wouldn't have any of the Les Houches problem with the, you know, the planning and this and that, that Battelle would give me all the support I wanted, and jokingly I said, "Including cocktail in the afternoon?" and he said, "Yes." My argument was that in that relaxed time and with a little bit of, you know, ??? up things, people communicate better, etc., so we ??? ??? ???.
Well, it was a good meeting.
[Yes], it was a good meeting. So that was Battelle Rencontres meeting, that was the first one. So I only organized—
Cecile gave the name to it.
Yeah. I was looking for a name, and I said in French I would have called it the Rencontres, and he said, "Okay, let's go for it." So I called it Rencontres, and now you said it with an English, with an American accent.
Well, you would say re-con-tres for something. But anyway, and it ran for a few years ??? ??? ???, until there was an audit of the will of Mr. Battelle to really stay much more in the more limited sense of the wording of the wills, and an activity like that was felt to be not clearly inside the will. That was important for Battelle to keep its tax status, ??? ??? ???. So they lasted just so many years. My involvement, and I think Wheeler's involvement afterwards, was much more limited to a sort of advisory role of who should run the meeting and which subject it should be. But then he had also asked me, I had also said okay, but we need a purpose, not just do it because other places would do it, and at that time I was, I felt that the need of communication between mathematicians and physicists was very much needed, and there had been a glorious time where physicists were talking to mathematicians and vice versa.
I mean, I'm talking about of the days of ???. And then they had split, and I felt there was a need to go back together, so it was decided there would be for ??? between physicists and mathematicians. That's why I simply said they were ???. And I've actually here a nice letter ??? ??? of Feynman to Wheeler, but since I was doing the work of the organization it essentially was put in my file. We had invited Feynman to a meeting because I felt that functional integration was one of these areas where mathematics and physics should communicate. I think it was Wheeler who called up or contacted Feynman, I don't know. But anyway, the answer is a letter from Feynman to Wheeler essentially saying, "Dear John, I couldn't care less what mathematicians have to say. Sincerely, Feynman." So if you want to, I could also show you that letter. This is a separate issue, and chronologically out of place. Richard Matzner had obtained some cross sections for the scattering of gravitational waves by a black hole and they were displaying some oscillation.
He showed them to Wheeler, and Wheeler said, "I believe this is glory scattering and also orbiting scattering at other angles," which he, Wheeler, had computed with Kenneth Ford some years ago. [Ed: 1959] Matzner was thinking that was a very intriguing idea, that this computation is done entirely on the computer, and there was no way of really saying for sure this is orbiting or this is glory. So I told Matzner that I could compute it analytically, and by computing analytically I would see whether they were glory and orbiting. And ??? ??? ??? say okay, I'll do that for you. Well, I could do it on first principles through functional integration, but it took me three to four years because there were problem within problem within problem which had to be solved—how you do functional integration when there are conservation laws, how you do functional integration with the critical point of the ??? ??? ???, i.e., caustics, etc. But eventually, with some of my graduate students, I completed the glory scattering and indeed they were matching absolutely with two hands on top of each other with a ??? result. Of course Matzner had to run his result at a different energy than I was. I had to do some approximations, but they were matching completely, so it was very satisfactory.
And it certainly brought to our attention much more precisely the Wheeler paper that we knew about but had not really worked out, and that was a great time. And then the orbiting ??? ??? and the matching was good, but not quite so good because the approximation had to do analytically work on ??? ??? ???. But certainly well enough to say it was orbiting. Moving on to the Austin years, one of the good contributions of John Wheeler was his interest in attracting good graduate students to the university and having one- or two-day meeting of the applicants for graduate school, the ones we mostly wanted to have, bring them here and I think [have] an interesting and challenging meeting for them so that they would be interested in coming here. That certainly was a very valuable contribution.
Well, the idea was potentially [great, but] as you know, we never got a single graduate student [as a result of these meetings].
You actually paid the transportation of potential graduate students from other parts of the country?
Actually you're right for the following years. I'm not sure that the first one or two years when Wheeler was really involved in the—
Are you allowed to check with Griffy on that? Because he has all those statistics, and according to Griffy it didn't pan out.
It didn't pan out later on. I think it—Okay. Bryce and I have a different memory. I totally agree with Bryce. I totally agree with Bryce that we tried it later, and it didn't serve any purpose.
Well, one thing that he did bring [to us] was David Deutsch, and Philip Candelas.
And Claudio Teitelboim.
Yes. And I believe he was teaching an interesting course for nonscience major which is always a difficult thing, which was called Great Ideas, Great People, Great ???, something like that. And I think that was ???.
I have some sort of memory, but then that must be false, that he was involved in the eclipse expedition.
It wasn't [Wheeler], I guess, because it was Bob Dicke, it was really Bob Dicke from Princeton. And Peebles was here. Didn't he visit us? At any rate, I had taught a course in astronomy while I was in Chapel Hill, and I [had an] astronomy book that I was using, this tabular list of all the eclipses that would take place this century—solar total eclipses of the sun. One of the ones reaching theoretical maximum was going to occur in West Africa, well all across the Sahara, in '73. I arrived here in '72 and went to Harlan Smith, the chairman of the Astronomy Department, also the Director of the McDonald Observatory, saying, "Are you sending up anybody for this eclipse?" I didn't know that eclipse chasing was rather looked down upon by astronomers by that time and was strictly for amateurs, and I said, "Well, this is a long eclipse"—Anyway, no attempt had been made to do the light deflection experiment for 20 years, because it had been usually rather unsatisfactory after working with ??? and the statistics were never very good, the perversity of the elements. But there were a number of developments in technology [in the intervening] years and we consulted with Bob Dicke and I think Jim Peebles. Particularly Dicke felt that yes, there were lots you could do now that weren't possible then. So Harlan reluctantly, but then later enthusiastically, decided let's go for this thing. But since we were ??? involved in that, I guess ??? ??? ??? talk about. When he [Wheeler?] did come, well we were certainly responsible. Tom Griffy I guess was chairman at that time.
I don't know whether I approached Tom or Tom approached me, and we [contacted] Wheeler, since he was going to be forced to retire. I'm very hazy on the point of why he actually came here. Obviously my being here and the relativity center being here had something to do with it, and I guess the university was willing to give him very good terms and set up his own center with funds so that he could have postdocs. Anyway, it was very successful. And one of the very first things he did when he arrived was actually to invite and pay for Everett to come. And that was my first meeting with Everett. I hadn't seen this guy at all. I knew about his work, but I'd never met him, and that was a very enjoyable occasion to me, and I'm sorry that it couldn't have been repeated on other occasions, but Everett smoked and drank himself to death, and so he died young. I think it was probably not more than a year, year and a half later that he was dead.
He had worked for the National Security Agency, and then he quit, and but actually continued to work for them, but at a higher rate as a consultant. He was just doing the same work, but he set up his own company. Everett always took the attitude—and I got this from Charlie Misner as well—that he was not really strongly committed to this. It seemed to him that this was the logical way to look at quantum mechanics, and if physicists aren't interested, well, he couldn't care less. It was no concern to him. He wasn't trying to publicize himself. I was the one who did that. I felt that he deserved a much better, wider recognition, and I don't think he would be known to this day if I hadn't done something about it, or ??? ???. In any case, as soon as you start talking about quantum gravity, gravity is important only on a grand scale. Quantum gravity is certainly going to be important in the early moments of the universe, then you are driven to the notion of a wave function for the universe, and how do you interpret a thing like that when there's no observer outside? The Everett point of view was the only way of doing this.
Okay. It turns out that I've lost the document of theC [Balance of interview is with Bryce only.]
Continuing with Bryce Dewitt on February 28th. I'd like to phrase the question this way. If you were writing a biography of Wheeler instead of him writing his autobiography, what are the achievements that would you pick out for emphasis that you think are most significant in his career, at least within the latter part of his career that you're familiar with.
Well, my reply would of course be colored by my interests. He certainly posed early the questionCor, as he put it, the issue—of the final state, where general relativity and the quantum theory would get together in a fiery marriage. I always remember Pauli's remark on that subject. Let's see: "Let not therefore man unite what God hath put asunder." He was applying it I think more to unified field theories than to quantum theory and gravity. But certainly Wheeler recognized it as an exceedingly fundamental and important problem, and he probably as much as anybody, made it acceptable in physics circles. It didn't really become acceptable until strings were invented.
Then everybody got on the bandwagon. But Wheeler had the courage to see that there was a very deep and important problem there. Well Feynman also saw it, and I think Wheeler bequeathed fundamental ways of looking, broad ways of looking at physics to his students. In the same way—not in the same way, but with sort of somewhat the same effect that Schwinger had on his students. Schwinger did it through his lectures. I think Wheeler must have done it through his one-on-one interaction with his students, leading them to important things to read or study, dealing with problems that were worth looking at. He was very fertile in picking up problems, good problems within the framework of general relativity. And you know, that's not easy to do. As I said before, he had an engineering approach. That's the way I always phrased it to myself, an engineering approach to general relativity. Suppose you wanted to build a gadget to do something with gravity, how would you go about it? Can you extract energy from gravitational waves? How can you produce them? Are there ways of getting energy out of gravitating systems, unique ways? How do you express the basic laws in terms that are a little bit more usable than just writing down Einstein's equations?
Well, ask another question.
Well, sort of a related question: Are there any areas of your own research that have been influenced by Wheeler?
Well, obviously my work on the canonical approach to quantum gravity was influenced by Wheeler. In fact the whole paper, the first paper of my trilogy, which is on the canonical theory, was in response to persistent nagging or questioning from Wheeler. He would ask, "What is the domain space? What is the nature of this space?" So I looked at that, and I saw that it was a metric space, and it has rather nice mathematical properties, the space of 3-geometries, or just taking the space of 3-by-3 symmetric matrices, signature minus plus plus plus at one point. That's a very interesting space. It turns out that it's the product of the line with a certain symmetric space. I learned that it was a symmetric space from Sigurd Helgason at MIT.
Spell that for me.
Helgason, either one s or two; I think it's one s. Sigurd, I think. It has a relevance. It turns out that this space itself is 6-dimensional, but it too has a Lorentzian signature. It's very intimately connected with the fact that the Hamiltonian constraint canonical theory has time built into it. Time is not something that you paint on space-time as a coordinate; it's a dynamical thing. I guess his questions forced me to think deeply about some of those issues. For me—and I was influenced in this also by Everett. Everett took the quantum theory the way it was and didn't impose anything on it from the outside. No classical realm. Does the theory produce its own interpretation? If so, how? And he, in my view he's the only one who's answered properly in the affirmative that it provides its own interpretation. What about general relativity? Does it provide its own interpretation? The answer is ultimately yes.
Everything you need to know. It's an extremely parsimonious theory. It doesn't give you anything more than the bare bones. If you want to talk about time, you have to put a clock in; if you want to talk about space and measure space then you've got to put in measuring rods or an elastic medium of some kind. And everything's fine. I made an analysis for Lou Witten, a book that he invited a number of us to write. I don't think Wheeler contributed to that volume. I'm not sure. I know Arnowitt, Deser, and Misner did. I was at that time reading the old Bohr-Rosenfeld paper on the measurability of the electromagnetic field, the consistency of that with the quantum theory, and I asked myself the question, "Can I do the same for gravity?" This raised immediately the issue of, "How do you build an observable?" The only thing that a theory like general relativity will admit as physical observables are invariants, and this means diffeomorphism invariants, because that's the gauge group of general relativity. And if you just had pure gravitational field, it's extremely difficult to build useful diffeomorphism invariant quantities. As soon as you put in physical objects, no problem. So I had to work out the theory of the gravitational field interacting with an elastic medium carrying a field of clocks. And then just turn the crank so to speak, get the commutation relations for these invariant quantities and see how you could push through the whole measurability program that Bohr and Rosenfeld had done.
Well, you mentioned the final state as in one sort of central thing that one might talk about and write about it in Wheeler's book. My question was whether any additional sort of critical ideas or critical papers that you think of might be worth using as focal points in the Wheeler book.
Well another one is spacetime foam. The whole idea of fluctuating topology. I've seen younger physicists in writing papers on this subject give the credit for that to Hawking, and that's ridiculous. It antedated Hawking by many years, by I would say almost, well at least 15 years. That was a novel idea. I think that's entirely—
That grew out of the wormhole concept?
Yes. The fact that general relativity allowed for variant [?] topologists. To this date nobody has developed a proper description of fluctuating topology. I don't think it's possible as long as you stay solely within the framework of general relativity, because the theory assumes a priori that you have a certain manifold, and there's a metric on the manifold. It has no way of coping within its own framework, coping with changing topology. Wheeler felt that—that didn't worry him. Details like that certainly didn't worry him. But as I say, he had an engineering approach. I don't know whether he ever gave a student that problem. How would you make this concept meaningful in a dynamic or causal way? [I don=t] remember any paper or any student working on this issue.
He just left the question there for people to do with as they felt appropriate. I think in some ways Hawking has abused this idea more than anyone else, because so often with Hawking a hypothesis masquerades as a theorem. He says, "We must sum over all topologies in doing a path integral." Why must we? Who says so? The only person who says so is Hawking. You should be forced to do this; the theory should somehow force you to do that. And well that goes back to Wheeler wanting to see what the theory forces you to do, and it certainly forces you to do something crucial when you get into the Planck domain, there's no doubt about it. There's nothing to prevent a black hole collapsing right down to the ultimate singularity. We know that our present description of quantum gravity has to break down at that point, and at the present we don't have anything better than string theory to deal with it. Even string theory doesn't deal with it very well.
Bryce, do you have any comments or any perspective on the work of Wheeler's later years more focused on fundamentals of quantum theory and measurement theory?
Well, they all left me sort of unimpressed. I guess largely because he had this golden opportunity of doing something with Everett, and he just let it lapse. You have people like Jim Hartle now working with Murray Gell-Mann on decoherence and decoherent history's approach, ??? ??? his approach to the quantum theory, and particularly the quantum theory of the total wave function. And it's curious that even those people who are so much in the stream of Everett's ideas waffle when you ask them, "Well, are all these consistent histories real? Are they there?" And it's as if they either don't want to upset Wheeler because they were a student of Wheeler—like Wheeler didn't want to upset Bohr because he admired Bohr so much. Some of the most vitriolic comments directed at people who questioned the Copenhagen Doctrine were given by Rosenfeld. He's written some papers that have taken the young people who were wanting to probe a little more deeply to task. Certainly Rosenfeld wasn't the person that was keeping Wheeler back from embracing Everett. I never did—I've asked Wheeler why he doesn't accept Everett more, but I've never gotten a satisfactory answer from him.
I think he told me something interesting, which was that Everett's committee, not Wheeler specifically, but other people in the department, found his thesis, or what you call the Urwerk, incomprehensible, so Wheeler undertook the writing of this [supporting] paper that appeared in RMP as a way of explaining the meaning of Everett's work.
The funny thing is, you have to read the Reviews of Modern Physics article very carefully, as I did, to see what's really there. Whereas in the Urwerk it's quite well spelled out, to me. Have you seen the book that I edited, Princeton University Press, on the Many Universes or Many Worlds?
I haven't [seen] it.
It has the Urwerk. That's the very first thing in it, and then it has the Everett paper and Wheeler's assessment, [which are] followed by something by Cooper and van Vechten, a student of his, and something by Neil Graham [?], and a paper by me. (I ran a lecture course at Varenna.) And I guess it also has my Physics Today article.
The Urwerk, if you want to judge for yourself, I think the Urwerk. Of course in 1955 it would have been a strange idea. I had this student, Graham, who came to me wanting to do a thesis on the foundations of quantum mechanics, and I said oh, no way. You do that when you're an old man and you can't do anything better. But he persisted. He kept very persistent, you know, and it was at that time that I'd had that visit from Max Jammer and I felt that something should be done for Everett, and I said, "All right, you can do your damn thesis on that subject, but you're going to wish you hadn't, because you are going to have to read every paper—it's going to be more like a thesis in the history department. You are going to have to read every paper that was ever written on the subject of the foundations of quantum mechanics, make a card catalog, cross file all the ideas, and then while you're at it have a look at Everett." ??? And I had a share in some of this, and I must say reading the old literature, including Bohr's, in fact sometimes especially Bohr's, it's exceedingly dull and boring, and the same old ideas are thrown up over and over again, with a new twist, trying to rehash old things, and there are a few articles that stand out like beacons: One is Heisenberg's first paper when he was explaining the intuitive content of quantum mechanics and the ??? ???; the next was a paper by Neville Mott on the wave mechanics of alpha wave tracks. Why is it that if a wave function of the alpha rays come oozing spherically out of a nucleus, what you see is not something spherical but tracks, and it's a beautiful paper, and it has already in it the germ of much later developments by Gell-Mann and Hartle.
Then Everett himself, that paper just stands out like something fresh, and enabling you to—it's an enabling paper in the sense that it enables you to ask questions that would not have occurred to you before, like the consistency of—the fact that you don't feel yourself split. Why? Can you show that? And where is the, what is it that really makes the dividing line between the classical realm and the quantum realm? This are also issues that Gell-Mann and Hartle are addressing. Now to me, those are the great things that stand out. And Wheeler was certainly responsible for one, albeit maybe indirectly. In fact, I don't really know how Everett chose his topic. I think he had been talking a lot about problems like this with Charlie Misner. They were both graduate students together and graduates of [Notre Dame?] and they really had a lot of discussions, and that may be what led Everett to decide to do a thesis on that. You've talked to Charlie I'm sure.
Yes, I have. Charlie and Kip Thorne.
Did Charlie discuss the Everett episode?
[He might] talk about it. It would be interesting to get his point of view on Wheeler's objection of Everett.
Well, let me ask you just a kind of more general question about Wheeler as a faculty colleague here. How do you assess his impact on The University of Texas and what good he did and what style or benefit he brought?
He certainly was friends with the top people in the administration, and they listened to what he had to say and I think basically he had very good relations with the administration—with a few exceptions, which had nothing to do with Wheeler. He was given money by the university for postdoc students. I can't point to any particular episode, because I never paid much attention to the administrative side of things. Tom Griffy would be more likely to have known of things like that. He was always fond of referring to the Santa Rita, the whole story of the wealth of The University of Texas. It was 40 acres in downtown Austin that was given to the university in the State Constitution back in—when was it? '83 or ???, something like that, previous century and quite a bit of land in the Hill Country immediately west of Austin, a lot of land. Well that Hill Country land became more and more valuable, and so finally the Texas Legislature took it away from the university and gave them a lot of worthless land way the hell out in West Texas. Oil was promptly discovered on the West Texas land, and they couldn't play the same trick twice. [laughs]
And that area was called Santa Rita?
No, that was the name of the rig, the actual well where they first struck oil.
Oh, I see.
And they have the actual rig is on campus. It's on 19th Street there. He always used to ??? ???, liked to talk about the Texas style. He did enjoy his stay in Texas. And we had very interesting people. I had spent, in fact, I spent the academic year of '75-'76 at Oxford as a visiting fellow at All Soul's College, and I got well acquainted with David Deutsch, who was a fervent adherent of Everett. He was a student of Philip Candelas, or actually I think was a student of Dennis Sciama, but Sciama had Candelas as a student and Candelas was really looking after Deutsch. The two of them wrote an important paper together on the stress tensor in accelerating frames. And as soon as Wheeler got here, he asked me did I know any people that we should try to get. And I said, yeah, there's a couple over there in Oxford, it would be great if we could get them here, and they were Candelas and Deutsch. So he promptly arranged for them to come, and they were here, well Deutsch was here for at least two years ??? ???, and he and I interacted very strongly, and Candelas stayed on in the department.
And still is here?
Though I understand he's at Princeton at this moment.
Well, I think we could wrap this up. Let me look for any anecdotes that you might have, any personal reminiscences or anything of the kind? It might help to enliven the story.
I don't have any anecdotes as such. I have mental pictures of Wheeler, for example at High Island he had a group of us there for two or three days in the summer just to discuss gravity, and students of his had invited me. I remember him going swimming vigorously every day, right there down by the docks. He no longer does that.
Yes, in the frigid water. He tells stories about firing his cannon from the lawn there across to the opposite shore. He actually put a ball in the thing. I think it really fired something. He was always intrigued by explosions. Oh, one nice thing that he and Janette did was have visitors sign the napkins when they were at their house, and so they have embroidered the signatures of many, many famous people.
You've never seen those?
No, I didn't know about that.