Peter Byrne is an investigative reporter and science writer based in Northern California.

Show Notes

Peter Byrne is an investigative reporter and science writer based in Northern California. His popular biography, The Many Worlds of Hugh Everett III - Multiple Universes, Mutual Assured Destruction, and the Meltdown of a Nuclear Family (Oxford University Press, 2010) was followed by publication of The Everett Interpretation of Quantum Mechanics, Collected Works 1957-1980, (Princeton University Press, 2012), co-edited with philosopher of science, Jeffrey A. Barrett, of UC Irvine.

Everett's formulation of quantum mechanics, which implies the existence of a quantum multiverse, is favored by a significant (and growing) fraction of working physicists.

Steve and Peter discuss:

0:00 How Peter Byrne came to write a biography of Hugh Everett
18:09 Everett’s personal life and groundbreaking thesis as a catalyst for the book
24:00 Everett and Decoherence
31:25 Reaction of other physicists to Everett’s many worlds theory
40:46 Steve’s take on Everett’s many worlds theory
43:41 Peter on the bifurcation of science and philosophy
49:21 Everett’s post-academic life
52:58 How Hugh Everett is remembered now

Music used with permission from Blade Runner Blues Livestream improvisation by State Azure.

Steve Hsu is Professor of Theoretical Physics and of Computational Mathematics, Science, and Engineering at Michigan State University. Previously, he was Senior Vice President for Research and Innovation at MSU and Director of the Institute of Theoretical Science at the University of Oregon. Hsu is a startup founder (SafeWeb, Genomic Prediction, Othram) and advisor to venture capital and other investment firms. He was educated at Caltech and Berkeley, was a Harvard Junior Fellow, and has held faculty positions at Yale, the University of Oregon, and MSU.

Please send any questions or suggestions to or Steve on Twitter @hsu_steve.

Creators & Guests

Stephen Hsu
Steve Hsu is Professor of Theoretical Physics and of Computational Mathematics, Science, and Engineering at Michigan State University.

What is Manifold?

Steve Hsu is Professor of Theoretical Physics and Computational Mathematics, Science, and Engineering at Michigan State University. Join him for wide-ranging conversations with leading writers, scientists, technologists, academics, entrepreneurs, investors, and more.

Steve Hsu: Welcome to Manifold. My guest today is Peter Byrne. He is the author of The Many Worlds of Hugh Everett the third, a fantastic scientific biography of Hugh Everett, who many of you know as the creator or discoverer of the many world's version of quantum mechanics.

And I've been a fan of Peter's work for a long time. I really enjoyed the biography when it came out, and it is one of my favorite biographies of scientists of all time. I put it up there with the Glick biography of Richard Fineman.

I got into contact with Peter through a very strange series of events, which could only have happened in the internet world. I was watching a video, a YouTube video, of talks at a conference, I think in honor of de Z who we'll get to later. He's a late German theoretical physicist who also worked on topics related to many worlds quantum mechanics. And I heard a talk by Peter and I got so excited by what Peter was saying that I emailed him and I think within an hour we were talking on the phone. So, I'm really happy to have you on the podcast, Peter. Welcome to Manifold.

Peter Byrne: Thanks for having me. It's great.

Steve Hsu: So I have a very deep appreciation for people who put in the work that's required to really create a full picture of another person's life. And I feel that you've accomplished that with Everett. And so I'd like to start just by talking about how you got into this project, how you became aware of Hugh Everett and, just the story of the book and let's just start with that, if that's okay.

Peter Byrne: I'll do my best. Steve. I'm not a physicist. I'm not a mathematician. I'm not a scientist. I'm an investigative reporter and a science writer. I have a master of fine arts in theater directing. I was an English and philosophy major in college, I had no intention of ever writing about physics. But back in the late 1990s, a really good friend of mine, Steve Schenker, who is a renowned strength theorist, got a gig as a professor of physics at Stanford University. I live in the San Francisco Bay Area. And Stanford is a little south of where I am. And he moved up here. And, I wrote a story about him and some of his strength theory friends for the SF Weekly, which was a really cool alt weekly journal that I was on the staff for for a number of years. And, I found that I really liked writing about physics, especially weird physics.

So I was talking to Steve one day, we were in his house down in Palo Alto. I said, You know, I like writing about this stuff, you know, gimme an idea. What can I write about? And so he gets out his laptop and, and does a search engine for Hugh Everett. And up pops a kind of bi short biography of Everett written by a Russian named, Eugene Shaha sos, if I'm pronouncing that correctly.

And, it was a biography that Mr. Eugene wrote from his home in Russia. He lived, not near a big metropolitan area, but he had a scientific publishing business and he had like an old Wang computer or something. And, just from his computer in, in Russia, he started emailing and reaching out to people that he thought would know about Everett, including his, his son Mark, and, and colleagues like, Charles Misner, who's a physicist at Maryland.

And, wrote this, you know, pretty good account of Everett's life and how he came into physics and for his PhD in physics at Princeton and decided to take the shorting equation, the linearity of it seriously, and see what happened. And the result was what he called the relative state theory of quantum mechanics, which later, and we can talk about that, was transmogrified by Bryce Dewitt and others into the mini world's theory of quantum mechanics, which is not actually a label that I think Everett cared very much about.

So, at any rate, I thought, well, this is cool. What I noted from the biography was that Everett, who I knew nothing about, had this rock star son named Mark Everett. And, he had a band called The Eels based in Los Angeles. So I got in touch with Mark and said, I, I wanted to do a story about him, because he had this father that had had a big influence in physics and I wanted to see if it had impacted his music and could we get together.

And he kind of, hemmed and hawed and he said, well, if you come down here to Los Angeles, we'll meet at the video studio of Jesse Dylan on camera, and you can interview me there because I'm making a video. So music video with Jesse, Jesse being the son of Bob Dylan, actually. And so I did that. I flew down there and met Mark Everett for the first time under the lights in front of a camera. And we hit it off really well. So then I thought, well, I'm gonna, pitch Rolling Stone and see if I could do a story about Mark Everett, the, the rock singer whose got this like kind of cult following, with this father that,is shaking the foundations of, of quantum mechanics, even though he, he died in 1981 and we're talking about 20 some odd years later.

But Rolling Stone said, no, that's interesting. But our readers don't really do physics, so I pitched it to like, you know, Harpers and New York Times and always places. And they're like, no, you know, we like rock musicians, but you know, we're not, our readers are not interested in quantum mechanics. And so out of love, kind of a last ditch desperation and almost as a joke, I pitched it to Scientific American and they got back really quick and they said, yeah, you can write about Everett, but you gotta ditch the rock musician.

Peter Byrne: And I'm like, well, no, it's cool that he's, you know, this guy you know, is dead and his son lives on writing all these sad songs and about his family and stuff like that. And they went along with it more or less. Eventually my editor there, one of them was George Moer, who's no longer there, but he's a very fine editor and he's written many books on physics. And they kind of cultivated me, cultivated me as a writer, which was nice cause I, I wasn't as, you know, really much of a, I wasn't a trained science writer at that time.

And so I wrote this really big feature story for Scientific American. It was published at, on the 50th anniversary of the publication of Everett's famous relative state's formulation of quantum mechanics in a journal. And that was published in 1957. So 50 years later, it was 2007. And I wrote it and there was nice graphics and I was able to access Everett's papers, which had been sitting in his son Mark Everett's basement in Los Feliz, which is part of it is a, a nice suburb of, of Los Angeles near Griffin Park.

Mark has a nice house there. And in his basement, he had just hit about 50 boxes of his father's papers that he had taken from the house in Alexandria, Virginia where their family lived after Everett died in 1981 and his wife Nancy died in the early 1990s. And so Mark just took all the stuff and put it in his basement in Los, in, Los Angeles. There's also a sister that committed suicide, which is the number story we'll probably get into.

And, I started going through these boxes and I realized very quickly that it was pretty astonishing. There was, you know, materials and letters from Norbert Winery and Neils Bore and, you know, all these famous people. We were pantheons in, in the world of physics. And as this was going on, the BBC, I think because of the Scientific American article, decided that they wanted to do a show on Hugh Everett.

But following his son, Mark the Rock singer, as he goes and interviews people about his, late father whose interpretation of quantum mechanics, that there's an infinite number of branching universes of an infinite number of yourselves branching away in them, was ex one of the leading contenders for an interpretation of quantum mechanics and a solution to the so-called measurement problem.

so when the opening scene of the Parallel World's, Parallel Lives, which was created by the BBC and then also shown by Nova and is still sometimes shown by Nova in the United States. The opening scene is being Mark going down into this dark basement in this house with and looking at all these boxes and where to begin, right?

So he left me there and he went gallivanting around the country with this BBC film crew as they interviewed various people, and he sang songs. And it's a really nice, affectionate little film, how they recommend it. Parallel World's, Parallel Lives.

And I sat in a basement with some clip lights, and dust and you know, it was a dirt basement, pulling out these boxes and, and looking through the treatise of, of Everett's life, which was amazing because, I mean, there was like pornography, you know, super eight film pornography. There was, Everett was a little bit of a sexual freak. There were copies of the Marqui, ADEs, Sodo, annotated.

Peter Byrne: And, there was all this correspondence with the giants of quantum mechanics and, and, and the philosophy of science. And so I'm sitting down there and at the same time I'm looking through the papers, I'm, you know, reading up on quantum mechanics and trying to, you know, learn, you know, from shoring there and, and Nebo and the rest of them, you know, what's up with this and why Everett was important.

And I was making some, some progress, when Oxford University decided to have a celebration of the 50th anniversary of the publication of Everett's famous thesis and Simon Saunders at the university is a professor of, philosophy of science, invited me to come and be a speaker at it, because they knew that I had access to Everett's papers.

Now, to digress for a second, I had reached out to the Russian, Eugene Shaz, by email, and he was on their run. I guess he got in trouble with the Russian Mafia at some point, and they burned down his book publishing business. And so he was like Heidi behind anonymous servers and things like that. And his last email to me was, I will give you all my materials, which he sent to me all the, all the interviews and everything he'd done on email. He compressed them and sent them to me, and you can write the book. And that was the last I ever heard of him. I hope he's, Yeah, I hope he's alive. I hope he's listening to this.

And, so I ended up being the person that was holding the access to these archives, because Mark and I got along pretty well. And when I made this presentation at Oxford University, it was like a week-long conference on Everett. And it was all these people like David Wallace and Tim Molin and David Albert always, you know, luminaries in, in the philosophy of science that were making presentations mostly, you know, in favor of Everett's interpretation, but some not. Adrian Kent from Cambridge famously, has arguments against it, which are quite coherent actually.

And, there was a dinner, you know, at Oxford, they served you peasants under glass and things like that. And, and, we ate dinner. David Deutsch was there who wrote the Fabric of Reality, who's a notorious recluse, but he came out for this. He was a big fan of Everett. And he actually shared with me a lot, some of his materials because he communicated with Everett's friends at one point himself. And I made a little talk, about what I had found in the basement. And the thing with Everett was that he was a mathematical prodigy. He grew up in a military family in Alexandria, Virginia, where I am from. So I was attracted to that.

And when he wrote his doctoral thesis in physics under the tutelage of the, the, the very well known, John Wheeler. I'm sure your audience knows the works of John Wheeler. He, as I said, decided to take the shorting equation literally. Now, the shorting equation is a formula which calculates the evolution of quantum states and it's, you know, completely linear.

And when you do, as Everett did, and don't interrupt, its linearity with what is called a wave function collapses, it ends up arguably evolving the universe that you're in into an infinite number of universes, which are almost identical. Maybe they're different. A cat's whisker or maybe there's no life in them, just, you know, an uncountable, infinite number of universes according to Everett.

And so he wrote this, theory, mathematical theory, as his, his doctoral dissertation and Wheeler, who was an accolate of Niels Bohr, who was a student of Niels Bohr in Copenhagen, said, well, this is great Hugh. At first we gotta show it to Bohr and get his permission because it is a little out there.

Peter Byrne: And so eventually Everett ended up meeting with Bohr about a year or so later. but in between there was correspondence and Bohr on a record is not liking Everett's theory through the communicative device of, Leon,was it Rosenthal who was a, his, his personal secretary who, who was very political and, you know, frankly I think that he wanted to shoot down Everett because he didn't want his master, Niels Bohr to be associated with what could be considered to be a crack ball theory.

You know, that there were, you know, multiple universes because people don't normally come to that conclusion. And, Everett eventually did meet with Bohr, but it didn't go anywhere with the conversation. Bohr, you know, smoked his pipe and was notoriously kind of non conversational. And when he did talk, it was in mutters.

He was hard to decipher and his writing is also thought, be hard to decipher, although some might disagree with that. And so Everett walked away from there, after having struggled with Bohr. of other people about the validity of his theory and went into military operations research, which is really what he pretty much was drawn to.

His father was, high ranking military officer and he wanted to make money.

Steve Hsu: Can I. Peter, could I interrupt just a little bit before you? This next stage of Everett's life is super interesting and probably not very well known to most, even to most physicists. They all wonder what happened to Everett after he left academic science. But there's so much in what you've already told us.

I just thought I would intervene on behalf of the audience and just ask you a couple of questions if

Peter Byrne: sure. Please do.

Steve Hsu: So your friend Steve Schenker, whom I know a little bit, but not very well, I'm curious, when he proposed this as a project to you, did he say this guy Everett, did incredible work, which is only now being more broadly appreciated, and his life is kind of obscure, you should go look into it. Is that, is that how he pitched it to you as a project?

Peter Byrne: No, he just said, hey, look at this guy, Hugh Everett. You know, here's this wacky theory about multiple universes, although I don't think Steve thought it was wacky. Steve's a string theorist, and string theorists tend to like Everett's theory, because what it does is it allows the observer to be included in the universal wave function of the universe.

You don't have to stand outside the universe, therefore you, you know, you describe it from within, which fits in very well with string theory and cosmology. But I think Steve was just like, you know, yeah, this is cool. You know, why don't you take us on? And, you know, I took it from there pretty much, you know, he initially helped me out with the, with the kind of learning curve a little bit, and he, he looked at the manuscript, but, but pretty much, the rest was, you know, just me pursuing who was this man and why did he say this and what does it mean?

Steve Hsu: So, you know, the, you were pitching the original article and, and it seemed like you just kept getting deeper and deeper, and at some point you're camp sounds like you're camping out in Mark Everett's basement, digging through boxes of old material, reconstructing someone's life from the, you know, forties and fifties and sixties. What was it that kept drawing you in?

Peter Byrne: Well, the sadness of, of his life. Everett was an alcoholic. He was a sex addict. He died prematurely of a heart attack at the age of 51 back in 1981. A few years later, his daughter, who was also an alcoholic, committed suicide. And then his wife died of lung cancer in 1996. So Mark was the sole survivor, and he wrote entire albums about it and stuff.

But going through this material, there would be things like Liz that was Everett's daughter, deceased daughter. There was a string of white alcoholics, anonymous chips, white representing one day of sobriety, and there were like 30 of them, right? I saw that my heart just left, you know? And next to that would be like, you know, hundreds of pages of Everett's handwritten notes for his thesis, his famous thesis.

And so I read the thesis. I was, you know, studying quantum mechanics. I could. And, what I had learned in England at Oxford was that a lot of these philosophers were saying that Everett's theory was objectively true. That it was a realistic account of the universe. And that the reason that we perceive ourselves as only living in one universe is due to the theory of decoherence, which as your audience knows, is, you know, if there's a quantum superposition,that in a sense the information from which leaks into the environment is shaped by the environment, it has to assume, it ang quantum particles entangle with each other and become, you know, build macroscopic systems.

You know, we could go on and on about that all day long. But the, takeaway was that subsequent to, to Everett's death, those who were upholding his theory justified it on the basis that decoherence could explain the phenomena of why there would be an infinite number of an accountability, infinite number of universes in which you yourself, for example, would take on, millions or billions of, of life trajectories.

And in which, you know, sometimes there was no life at all. And sometimes in which, you know, to the extent that whatever is gonna exist is physically possible. there would be that. and so then I'm looking at, at. dissertation is, his original dissertation, which although I didn't get there in my previous explanation, had been seriously added by Wheeler to please Bohr had been turned from a theory that explained and solved the measurement problem in quantum mechanics into a theory about general relativity, which was useful to Wheeler because he was one of the pioneers of studies of, gravity. Along with Charlie Misner, who was Everett's roommate at Princeton.

Peter Byrne: And, it was useful for him politically to have Everett's theory be used as a justification for, you know, funding more research into, into gravity. And, and, and did that in fact, we would get it published on that basis. But what most people didn't really seem to know, people that were studying Everett in the year subsequent to his death, was that the original long thesis as opposed to the short edited thesis, was a, a concentrated,X of Jesus on the, solving the, the measurement problem, which came out with this kind of weird solution of multiple universes.

And what the people subsequently Everett were saying was that the decoherence phenomena could explain why there would be multiple universes and, and why, we only perceive ourselves as living in one. And, I'm looking at Everett's stuff and I'm thinking, Well, gosh, it looks kind of too, to me, I'm a lay person. What do I know? But it looks to me like he knew about decoherence, this thing they call decoherence. I mean, he called it quantum correlation. He didn't call it decoherence. That was the term that was later invented by Oz, I think. And, and, Zurek and others. And, so what I did was I made, like I went to, Kinko's and I spent hundreds of dollars making copies of Everett's handwritten original thesis before it was published because it had more material in it than was ever published, and I sent it to.

Peter Byrne: Simon Saunders at Oxford and Vick, Zurek at Los Alamos and Jeffrey Barrett at UC, Irvine, and I think one other person, you know, that was, ever,or, and a decoherence specialist.

Steve Hsu: Peter, what year was this?

Peter Byrne: Oh, this was like 2006, I think, or no, no, by this time it's, it started in 2006.

The anniversary of Everett's publication was 2007, which is when the Scientific American article came out. And after the conference in England, which was in 2007, was when I really started to dig into the stuff because Mark let me take it up to my office in Petaluma. I couldn't sit there in that dirty basement, you know, doing this. Finally he trusted me enough that I just got a truck. And pulled it all up here into my office, most of which now is, was donated later by Mark to the American Institute of Physics in Maryland and, and is in the archives there. But I was asking, I was asking these, these guys, would you guys look at this?

That looks to me like Everett and,invented or, or, or recognized the phenomena of decoherence before anybody else. This is an amazing story. I, so, so already in 2006 ish, before the 50th anniversary, you are, were already in touch with the researchers who worked on decoherence like Zurek and others, and you had noticed that Everett had really anticipated them, which is, which is what I believe as well.

Steve Hsu: And that's actually how you and I got in touch a few weeks ago. I came to the same conclusion when I finally got ahold of Everett's thesis and read it, and I thought, why is this guy not getting any credit from the decoherence folks for really anticipating almost everything that they said? But anyway, sorry.

So, so yes. I didn't realize that this was the case. Go on, go on with your story.

Peter Byrne: So I asked these guys, Will you look at Everett's work here? Because I could follow the equations. And tell me if he, Adam, braided the phenomenon of decoherence and if he used that to explain, you know, the Mini World Series. It was already a deadline by that time, and they all said no, but, oh, the other person I sent it to, of course, was Dieter Zeh at the University of Heidelberg.

But Zeh was a little bit different. Zeh, who died a couple of years ago, 2018, I guess, in 1970 a paper, which is widely considered to be the first paper revealing the phenomenon of decoherence. There were papers, around the same time by Wojciech Zurek, looking at it from a slightly different angle.

But both, Zeh and, and and Zurek are, are kind of known as the fathers of decoherence theory and, So I was asking Zeh in particular, since he knew a lot about the origins of the theory of decoherence to look at Everett's stuff and tell me if, if he thought that Everett was actually aware of this phenomena.

Peter Byrne: And a book came out, as well in the last year, because Zeh passed away in I think 2018 and Clause Keifer, who is his, of his closest students. and Springer commissioned a book about Zeh's work. And Zurek is there and, and many others. And, they asked me to write a chapter about my experience with Zeh, which I did.

And you can find that book. It's called the Life of Dieter Zeh, I think. And,

Steve Hsu: I have a copy of this. I have a copy. I'll put a link in the show notes.

Peter Byrne: Yeah, it's a good book, you know, Because this debate, you know, is still hot and heavy, it still keeps going on. But Zeh and I, I never met the man, in person. We had email correspondence for about 10 years, starting in 2006 or so. And, he was a teacher to me. He taught me a lot about quantum mechanics, from afar. And he was also like, I would run sections. I also, I forgot to mention, Oxford University Press commissioned me to write a biography, the biography that you mentioned of Hugh Everett. So, in 2008 I started writing that and I got a grant to do it from the Foundational Questions Institute, which was very nice, so I could concentrate on it full time.

And I spent a lot of time emailing back and forth between, you know, various physicists and myself, like Zurek and, and Barrett and Saunders and, David Wallace and numbers that are experts in this. And especially, Zeh. And as the story that I wrote for, for the book Honorings, A Recounts, I kept pushing this notion that Everett, that Everett had foreshadowed, at the very least the concept of coherence.

That, actually I thought that he was, he was consciously using entanglement, as an explanation of how the universe has the universal superposition, split into, or it could be conceived to be splitting into, multiple, trajectories of, of, of macroscopic reality. And I won't go into the whole story, but over time, Zeh started to agree with my theory, and ultimately he validated it and said, yes, I believe that Everett did actually know what decoherence was, although he didn't call it that, and that he used it when he fashioned the, the mathematics of his theory.

Steve Hsu: And that was a pretty big thing. I, I thought, you know, especially for Zeh because he took a great deal of pride in being the pioneer of decoherence and, when he, you know, acknowledged that Everett came before him, it was with tremendous scientific humility and integrity, I thought. I, I think you're properly giving Dere credit for being intellectually honest, because obviously the thing he was most famous for, it would've been difficult for him to admit he had been anticipated. I guess almost 20 years, or 15-plus years by Everett. I had conversations also by email for many years with Dieter Zeh about physics.

And he even used to come on my blog and comment and at one point I think there was a conversation going on where it was him and me and then some readers of my blog in a comment thread. And I think I explained to one of the readers that decoherence was the mechanism by which Everett's different branches lost contact with each other and Zeh approved of my, he agreed with me.

And I, I think he, I, I have to go back and now look at the timestamps and, and try to understand whether my conversation was about, this was before, after yours, but, I'm convinced, I think, you and I had this conversation when we first spoke on the phone a few weeks ago. I rushed after hearing your talk. I think there's a, there's an online YouTube version of a talk you've given based on your chapter, the contribution to that book in memory of Dieter Zeh. I saw that, and I rushed to my bookshelf to get my copy of the average thesis, and I convinced myself relatively quickly that he certainly knew what quantum entanglement was. He didn't use that term. He used the quantum correlations, but he meant quantum entanglement, and he definitely knew more or less what decoherence was, I think.

Here's a funny thing. I was, before we got on today, I, I just fired up Wikipedia, with decoherence, just to see what they were saying about it. And towards the end of it, it says, here's a sentence. decoherence was then used by Hugh Everett in 1957 to form the core of his many world's interpretation and the references to his long thesis.

Peter Byrne: I didn't dig into the edits to see who put it there, but that wasn't there the last time I looked at it. So somebody has come along and, and made that

Steve Hsu: It wasn't me.

Peter Byrne: I was, I was wondering, it wasn't me. So, you know,

Steve Hsu: It wasn't me. But it's, it's amazing that you and I went on almost exactly the same intellectual journey, which is to, to read Everett's thesis and then to realize that there was this more quote, modern thing, which by the way, the, the word, the, the topic of decoherence is completely accepted by physicists now. And this phenomenon is really important for quantum computing.

So quantum people who build quantum computers are fighting for coherence all the time in order to make their quantum computers behave as they would like them to behave. Now, the interesting thing is if you go into a department and you start over coffee or tea, and you start talking to the physicists there and say, oh, I'm a big devote of Everett's interpretation and, relative states and many worlds, you know, half the people will, or maybe a third of the people will like what you're saying, but a third or a half will just tune out immediately and think you're nuts and go away. Whereas if you start saying almost the same things, but you just insert the word decoherence in your sentences instead, never mention Everett. Never mention many worlds. Just say decoherence. Then they'll all look at you respectfully

And it's a very weird sociological situation. which kind of shows that scientists are a little bit oblivious about their, the extent to which sociological and and cultural factors, can influence their scientific thinking.

Peter Byrne: Well, decoherence is a physical phenomena, so anybody that's doing experiments or that is theorizing, you know, about quantum mechanics is, is going to see it. That's the question of, you know, analyzing it and formalizing it, you know, I mean, way before ever people were talking about entanglement, which is, you know, maybe not exactly the same thing, but, you know, it's, it's on that path.

You know, Dieter was penalized in his scientific career for being such an advocate of not just decoherence, which, like you say, people were increasingly accepting of because it is physically provable. But for advocating Everett's many world's theory.

Peter Byrne: Now, just to digress for a second, I've long argued that Everett was not pleased when Bryce Dewitt called his theory, schizophrenia with a vengeance and, and labeled it the Mini World's theory.

Everett called it the relative state Theory of quantum mechanics for a reason, because what he was looking at was, pure wave mechanics. He wanted to, to do away with the, what he thought was the ridiculousness of the wave collapsed postulate, which is, postulate, you know, it's not provable in that, you know, a sense. It's, simply, a philosophical way, I think of trying to explain, or or to white wash to push under the rug a phenomenon, which we can't explain. But however, Everett did come up with a mathematical, physical explanation, which people also would like to put under the rug. And so Zeh, throughout his life, he would submit papers that dealt with relative states and multiple universe implications to journals.

And they would edit it out, or they would refuse it, or, or they would talk to him about why he was so insistent in the kind of language that he used. Could he please dumb it down? And at the very end of his life, Zeh shared with me, he had written a really marvelous paper about, particle, wave particle duality.

Point being that he didn't think there was such a thing as particles actually just wave packets, I believe. and he was having trouble getting in accepted anywhere. And he shared with me, that a prominent editor of a journal had said that he would never, ever publish anything about the mini world theory of quantum mechanics.

Peter Byrne: And so I was writing my book at that time. This was 2009, 2008. And so I called up that editor of that journal, who I will not say who it was at this point. And I said, hey, you know, Dieter told me that you said that you on just principle would never ever publish anything about the relative state, interpretation of quantum mechanics or many world theories.

And he goes, how dare Dieter Zeh tell you that. And I'm like, well, he did. You know, because Dieter was a rebel, right? And then he goes, you're not gonna publish that, are you? And I'm like, no, I'm not gonna publish it because it isn't really that relevant at the moment. But I can't promise that I will never publish you know that. And obviously I did in the article about Dieter.

But then when my book came out, this editor who had an aversion to Everett's work assigned Adrian Kent as the reviewer, I think presuming that Adrian would completely trash it, right? . But Adrian is very full of integrity and smarts himself. And even though he is not an inheritor of Everett's interpretation, he loved the book and he wrote great things about it.

Peter Byrne: It was a glowing review, you know, it cracked me up. but that is, you know, an interesting bifurcation in the universe of, you know, of science, isn't it? That decoherence, which in a way kind of spurred, I mean the, the phenomena was there. It kind of spurred Everett in a sense, to, to come up with his theory because that phenomenon was there, you know?

And now that phenomena is taken, as, true, whereas the accompanying philosophical interpretation, and I, I know of no other, interpretation of quantum mechanics that deals with decoherence in the same way, is, is, is, causes, philosophical jitters still. And frankly, it, you know, it causes jitters to me too.

Peter Byrne: I don't really want to think that every time I crossed the street, an infinite number of me got squashed by a concrete truck. Do you?

Steve Hsu: One. One way I characterize the situation right now is that because of its practical importance and the fact that it manifests itself directly and experiments decoherence itself is well understood by a fair number of physicists, but most of those people, they do something which I call stopping short.

I dunno if you remember Seinfeld. But, they stop short. They're, they're willing to follow the decoherence equations only so far, but if they push them a little further, they'll see, they start to uncomfortably imply that many worlds are correct and they don't wanna go that far. So they sort of stop themselves at a certain point and they just refuse to go further.

But, you know, more and more people are creeping further along, saying, and coming to the point where, well, this Everett interpretation seems to be entirely self consistent and, and consistent with what we see in our laboratories. So, for me, I would, I would say it's a strange time in physics and I think 20, 30 years from now, the fraction of physicists who accept Everett's ideas much more strongly, will, will, will become much greater.

Peter Byrne: It also depends on, you know, how it's presented. And Wikipedia has gotten, I noticed recently, because I hadn't looked at it for years, has gotten better at it. But there was a notion that was promoted by the duet, that it was the universe that splits. And so people were thinking, well, how could energy be conserved if, you know, the universe is splitting into copies of itself and, and you know, Dieter actually had this, this kind of formulation of, a giant light speed zipper, you know, unfolding the splitting of the universe, But that's not really how Everett viewed it. Everett, following some comments that Einstein had made in, in his last, public talk to students at Princeton, right before he died, Everett was in attendance. And, Einstein says something about, you know, does the universe care about the fate of a mouse or something like that? And Everett wrote that it's not, you know, in so many words, it's, it's not the universe that splits, it's the mouse that splits. It's the observer that splits. It's not the whole universe that splits.

It's the observer. Because if there's a giant universal superposition, right? Then you've got these subjectively, decoherent trajectories that include certain macroscopic observers, entities such as ourselves, which are just a collection of atomic particles anyway, right? In this, you know, vastly unfolding royaling turmoil of linearly,disaggregating,microscopic systems, you know.

And that makes a lot more sense to me to talk about the observer splitting, which is very, very firmly what Everett was talking about than, you know, the, the kind of. More science fiction type of approach that Dewitt took. Dewitt did that. And, and he admitted it, that he did it to popularize the notion because Dewitt was also interested in a theory of quantum gravity.

Peter Byrne: And to do that, he had to get rid of the wave function collapse. So he had to be, including the observer in the whole universe, you know. But he, I think, did not carefully follow what Everett was saying there. He, he was, politicizing it, in an opposite to the way that, that,Rosenfeld Bohr's secretary, was, was,politicizing it.

And subsequently, it happened during Everett's lifetime. It was, I think 1974 when,was it, Physics Today I think had a cover where dewitt exposed the many worlds theory to, to a popular audience, you know, that propelled it. in, into the realm of, of public consciousness and, and also I think probably into, you know, students that were physicists that were learning at the time.

Peter Byrne: I think Steve Schenker mentioned, you know, he learned about it in college and, and, and he thought it was pretty cool.

Steve Hsu: Say the same way for me. I think those papers that were in, maybe in Physics Today by, I think they might have been by Dewitt, and then there were some by Zurek about decoherence. All that happened, roughly when I was an undergraduate, and had a big impact on me. I didn't fully understand what was in there, but I understood there were problems with the conventional interpretation of quantum mechanics and, and those articles really were a turning point in the consciousness of the field.

Peter Byrne: Yeah. Well, let me turn around and ask you a question. I mean, you came across my video because there was a conference at Oxford that was looking into Everett's theory from the point of view of, 2021, which is when it took place, you know, many years after the, the conference that Simon Saunders organized back in 2007.

And, you know, I went to it and many of the same people were there rehashing the same arguments about Everett. I mean, it is almost, you know, people have taken, they've dug in these positions that I guess they can hold for decades, around it pro and con, you know. But my feeling about it is, You know, since I don't have any career stake in, you know, from a scientific point of view, more fluid, you know, but I'm wondering from your point of view, do you think that there's some dogmatism now involved by people that are espousing the Everettian, interpretation.

Steve Hsu: Well at, at the risk of getting myself into trouble, I gotta answer your question. But I have to give a little background, which is that I'm not a philosopher and I'm not someone who primarily works on quantum foundations. So those are two subcategories of either philosophers or physicists. I'm a practicing particle physicist and cosmologist. And there are loads of people like me who are interested in quantum foundations, interested in Everett, and how the measurement problem actually is resolved. And we need it because if we want to study cosmology, we need to actually, we can't have an observer. We, I mean, we can't, we can't have an observer outside the system.

We have to deal with the system as a whole, a closed, isolated thing. So there are many of us, I could name names of some of the most famous physicists, you know, Galman, Swinger, Fineman Weinberg, Hawking,

Hardell. Who have thought through quantum mechanics on their own and come to largely similar conclusions as Everett and Deter Zeh.

Steve Hsu: To us, when we dip our toes into this very small subfield, which is a handful of philosophers and physicists who are a hundred percent focused on quantum foundations, yes, it does seem some, sometimes these people are ossified and, frozen at their positions. you know, there are some younger people like David Wallace who are involved in this, that you just have to remember, that's a very small sub community who does this kind of thing full time. Whereas there's a much larger group of physicists who are, say, primarily working on string theory or black holes or cosmology or, you know, Higgs bosons who are interested in this topic and, and, and think about it when they have free time, but it's not their main research focus.

In that community, I see movement toward more and more acceptance of, of, Everettian ideas over time.

Peter Byrne: Well at, at the risk of getting myself in trouble now, you know, when I,found myself ensconced in this kind of academic philosophy of science community that was focused on Everett and very welcoming to me and very nice to me, over a long period of time, you know, I began to, you know, see, and hear from physicists. Well, we don't like philosophers. And then a lot of philosophers were like, yeah, I was a physicist, but I couldn't stand their arrogance, so I became a philosopher, you know. And of course, you know, Con was both a physicist and a philosopher. I mean, physics and philosophy were the same for hundreds of years, you know, post so-called enlightenment and all that.

And I'm very disappointed, you know, to see that the academy has bifurcated, you know, and created such a boundary between the study of physics and, and the study of, of the philosophy of the interpretation of it because how can you study or do experiments in quantum mechanics and not be a philosopher at the end of the day, you know?

That's why I'm personally drawn to it. Karen Barad, who wrote this great book, 10 years called Meeting the Universe Halfway, where she took Bohr's writings and, and made sense out of them to me for the first time. And she's not in the academy. She's an accomplished physicist herself and the philosopher at the University of California Santa Cruz. And she's got this huge following on YouTube because she's a great, or she's a, they actually, speaker. And you know what her writing did for me, especially that meeting the Universe halfway was, it corrected something that I had gotten wrong in my book aboutEverett and Bohr. I basically went along with this whole notion that Bohr was so scientifically sclerotic that he was incapable of appreciating Everett's theory and that he was immensely unjust in his rejection of it.

Barad is very much a Bohr scholar, and very open-minded about it,after reading her analysis of Bohr's approach to what she calls a gentle realism, where the observer is included in the unfolding of reality and cannot stand outside of it, which is what Everett was saying, I'm beginning to see that Bohr and Everett probably had a lot in common in regard to this. And for whatever reason, probably political, probably because of this Rosenfeld character, probably because of Wheeler who was also very devious, they were not able to collaborate on, on the same wavelength as it were.

But I think my book actually misrepresents Bohr in a way because I fell into this, this trope that was, presented by one of Bohr's anti biographers called Marabella. You know, basically painting him as some kind of satanic figure. I think Bohr was much more subtle. I, he was obviously a great scientist and I think he was a great philosopher. I mean, ARDS convinced me that he was a great philosopher also. Although he was definitely obscure as heck.

Peter Byrne: But nonetheless, he wasn't the kind of guy. He had international, you know, governments listening to him that were gonna go around saying, Oh yeah, I think there's like an infinite number of me saying different things, different universes.

Steve Hsu: Well, I, I, I think it's hard to know exactly what Bohr thought because his writings are, as you said, very obscure and hard to interpret. There are readings of Bohr, which would make him seem, the Copenhagen interpretation seem much more, accepting aspects of Everett. I would, I definitely say that.

Peter Byrne: Well, let's, you know, be clear though, because I think there's a common misunderstanding about the Copenhagen interpretation. The Heisenberg version of it is, and the Von Numan version of it includes wave function collapse. The Bohr version of it does not. Bohr very definitively, was not the least bit interested in that postulate and did not consider, although he would say things like, we can't know what goes on inside the quantum realm, which is, you know, in some ways, is true enough. He was not an advocate of wave function collapse. And I, I think a lot of people,fail to appreciate that historical fact.

Steve Hsu: Yeah, so I think you're right about this. So, people like von Neumann, who was a mathematician are very clear, so he postulates collapse and obviously that is just a hundred percent inconsistent with Everett's picture. Bohr's writings are a little bit harder to interpret, so it's possible he also doesn't necessarily require collapse, right?


Peter Byrne: No, he doesn't. I mean, really, no, I mean, I, you know, I don't, I'm not like, read, I don't read Bohr's, you know, German and, and, and Danish language writings and stuff. Although I certainly read his English translations. It takes some, some study to follow along with him, but it's there, you know. It's there to be seen, and that's why I keep pushing Karen Barad. Now my friends in, you know, academia in philosophy science are like Karen Barad. Oh, isn't she some feminist at UC Santa Cruz? And I'm like, what? Why don't you read her? You know, I mean, she's got important things to say and in fact, she's in the, like the Department of Feminism and consciousness raising or something like that because the, standard academic, philosophical departments don't, don't want somebody with the, the kind of, feminist oriented, post humanist, let's not put humans at the center of everything, non-representational kind of way of looking at the universe, which is, you know, not to say that her or anybody else is denying objective reality. They're saying that when we experience objective reality, it's because we're included in the de coherent phenomena that is going on around us.

Steve Hsu: So, Peter, I, when we spoke on the phone, I promise you I would look into Barad and I, I went so far as to look her up, on the internet, but I haven't read any of her serious writing, so I, I haven't, fulfilled my promise to you.

But let me turn to, since we're, we're running a little bit low on time, where it, almost at an hour, I wanted to go back to, Everett's work at the Pentagon in the Cold War. What he did after he sort of left physics. And also the sad aspects of his family life and how he eventually passed.

Peter Byrne: Well, after the, the world of physics didn't want to deal with the ramifications of his theory, he did what I think he wanted to do all along, which is to make money and, and be around military type of power things because his father, you know, had trained him in that way. And so he got a job with the weapons systems evaluation group at the Pentagon, which is a top secret operations research cabal of brilliant scientists, brilliant young scientists, that were examining, for example, the fallout effects of nuclear war.

Everett very famously, actually, along with, George Pugh, who was his colleague at, at WSEG at the Pentagon, did a formidable study of the, effects of fallout, on even a limited nuclear war, showing that it would pretty much exterminate life on Earth, which, Linus Pauling, when he got the Nobel Peace Prize for his anti-nuclear, his disarmament work in 1962, I think it was, actually referenced both Everett and Pugh in his speech saying, thanks to the Everett and Pugh, we now know that fallout would make, life unsustainable.

So Everett produced that.He was a brilliant computational scientist. He was one of the first people to come up with the concept of, relational databases. He was never very good at making money. He would associate with people, they would form companies together. They would go off and make millions of dollars. And, by the end of his life, he was, he was broke. And, one of the reasons was because he had a terrible alcoholism. he, was a bit of philanderer, and

Steve Hsu: And even a swinger, right? This guy was even like, little more than just a philander, right?

Peter Byrne: Yeah, he was a sex addict, you know. Although we didn't have that term back in the seventies and eighties.

But, yeah, he had lots of flings and affairs and he used prostitutes and,they had like, you know, weird swinger parties at their house and stuff like that. At any rate, he also loved French food, and I got his autopsy report as. His heart was, you know, clogged like a brick by the end.

And he smoked. He, you know, smoked two or three packs a day. And, so he was in ill health, which causes demise at an early age.

But, you know,he wrote on legal pads, yellow legal pads a lot. And in the Mark's basement in one of the boxes I came across, this very plain of, scrolling that he had done towards the end of his life where he was broke and didn't know where he was gonna get the money to, you know, keep paying his bills.

Peter Byrne: And he was thinking about various types of computation that he could do. And,he was writing to himself about,what did he call it? I can't remember the exact word. Oh, it's Mr. Snidely Whiplash. You know, I don't know if you remember Snidely Whiplash, but he was a cartoon character that stole people's stuff, right? And he was talking about making some kind of Snidely Whiplash, you know, we would call it an app now that could go and, and figure out ways to steal people's money and stuff, you know, I mean, it was terrible. And, you know, either he was gonna get sober, which he didn't, or he was gonna die, you know? And what we lost with Hugh was a brilliant mathematical mind, a brilliant physicist.

He was kind of a rotten person, to tell you the truth. Even his best friends didn't like him that much. His son, you know, loved him, but also was continually disappointed in him. And, you know, one of the nice things about this is that, you know, Mark Everett and I, have a bit of a relationship and, he goes on tour with his band The Eels every couple years, and he always gives me a VIP ticket and we go backstage and chat for a while and stuff.

But there was something really nice that happened in 2019, which I wanted to relate to your listeners. Uh, it was completely out of, of some other universe, and it occurred in this one. The Royal Theater of Sweden in Stockholm, Sweden,commissioned a musical version of my biography of Hugh Everett.

It was written by and directed by Lar Olson, who is a very famous director there. It had the leading singers and actresses in Sweden in it. And in 2019, right before Covid, they flew me and my family over for opening night. And I walked into this theater, Stephen, and looked at a set and it was a wall of cardboard boxes, 35 feet tall.

It was the boxes from the basement man. And then there was a band and there was, you know, this kind of, Kurt Vile type music. And there were probably 20 songs. And the whole thing was about Everett's life and, you know, he was there, there were two versions of his wife Nancy, and they met, because they can cross universes. And so they try to figure out how to deal with Hugh in each of their universes. And the set would revolve around and we see the different Highs and the different universes. And then Mark was like a little boy in, in the play and he's, he's upstairs beating on his drum, you know. And, they literally put footnotes from the book about quantum mechanics and, and the Cold War to music.

The Swedes have got something going on. First of all, they speak English, which is nice, although the play was in Swedish. But I could follow up pretty well because I wrote the book. But they're interested in quantum mechanics. I mean, I gave a talk one night and there were several hundred people in the audience. I mean, they care about quantum mechanics and, and philosophy and, and literature in Sweden for some reason. They're a literate crowd of people.

you know what a wonderful tribute that was to my mind, you know, to Hugh Everett that his, his sad family, is almost tragic, you know, family, occurrences, which there's only this one survivor, his son Mark, you know? And you know, and then there's this theory that, that that is still, you know, pulling at, at the, the scientific heartstrings of, of the world, that there could be a, a play that was so compassionate about him and, and so accurate in what it portrayed. And, you know, that was, it was one of the most amazing experiences of my life.

I mean, they called me up on stage, you know, for a bow at the end, you know, opening night. They gave me roses and stuff. But it was for you, you know, It was for you.

Steve Hsu: And, and I think appropriately for you too, because, none of that would've been possible if you hadn't done the work to write what I, again, what I wanna say again is one of my favorite biographies of a great scientist.

Peter Byrne: Well, that's, that's nice to hear because, people should keep reading it, you know? It's not hard to read and it's got some interesting science in it, along with a lot of tales. A lot of tales.

Steve Hsu: Yeah. In a way it's as a story because he was such an unusual character and, and the topic of his science was so fundamental and also weird. It really is one of the best scientific stories of all time.

Peter Byrne: Yeah. And, you know, frankly, the condition that this universe is in right now, I wouldn't mind being able to step into a, a slightly more sane one, would you?

Steve Hsu: Yeah. Well, there's another Peter, maybe that's, living an even better life than you are.

Peter Byrne: Oh, that would be hard. My life is great. My life is great, you know, But, the rest of the world seems to be going down the tubes.

Steve Hsu: Yep. Well, Peter, I, I want to thank you for coming on this podcast. I've really enjoyed this conversation and I'll just tantalize my listeners in case there's an actual movie producer or billionaire who wants to fund this project. I believe Mark has a full script for a biopic of Hugh Everett. And so I hope someone will fund that and make it into a great motion picture.

Peter Byrne: That would be great. There are screenplays ready to roll.

Steve Hsu: Yep. Thanks a lot, Peter.

Just a quick addendum to my conversation with Peter Byrne. I mistakenly said, Mark, when I referred to the screenplay that Peter and a professional screenwriter had produced for a potential movie treatment of Hugh Everett's life. Just wanted to correct that. If there are any movie producers or billionaires out there that want to create a movie version of this incredible story, please contact Peter Byrne. Thank you, bye.