The Origins Podcast with Lawrence Krauss - Leonard Susskind: Strings, Quarks, Black Holes, and More.

Episode Date: August 7, 2024

I was very happy to finally have the opportunity to have an extended conversation for our podcast with renowned theoretical physicist Lenny Susskind. Lenny has been a friend and colleague for many years. I remember first attending a lecture he gave at a conference when I was an undergraduate and recognizing what a powerful intellect he was, and also how he combined mathematical sophistication within an intuitive framework that reminded me a bit of Richard Feynman. Years later, when I went jogging with him along a beach in California, I also discovered that, he strove for excellence in everything he did, and it nearly killed me to keep up with him. Lenny has been involved over the past 50 years in many of the forefront developments in particle physics, including string theory, the standard model, the matter-antimatter symmetry of the universe, and the mysteries of black hole physics and quantum gravity, to name just a few. It was enlightening to explore his own intellectual development, and also his perspectives on how these major developments in physics fit into our evolving understanding of the universe. Lenny is also an accomplished popularizer of science, something he turned to somewhat late in his career, and I learned something fascinating about what caused him to turn to writing. It was entirely unexpected. I am glad he was motivated, because his semi-popular books following The Theoretical Minimum, covering the essential ideas necessary for someone to have a grasp of modern theoretical physics, are, in my opinion classics. Anyone who is interested in understanding how we got to where we are today, and what the key outstanding questions in theoretical physics are, and where the likely answers may be found, will find our discussion enlightening, and, fascinating. I hope you enjoy this in depth discussion with one of the most accomplished theorists around today, and one of the most enjoyable and thought provoking scientists one might hope to have a conversation with.As always, an ad-free video version of this podcast is also available to paid Critical Mass subscribers. Your subscriptions support the non-profit Origins Project Foundation, which produces the podcast. The audio version is available free on the Critical Mass site and on all podcast sites, and the video version will also be available on the Origins Project YouTube. Get full access to Critical Mass at lawrencekrauss.substack.com/subscribe

Hello and welcome to the Origins Podcast. I'm your host, Lawrence Krause. In this episode, I finally got to have a dialogue with one of my favorite physicists, an old colleague and friend, Lenny Suskind, who has played a key part in many recent developments in theoretical physics and has also written some wonderful popular books and semi-technical texts that I think are extraordinary. Lenny is a fascinating scientist who, who, who who as we talk about began life as a plumber in New York City and moved on to become a theoretical physicist at a time when theoretical physics during the 1960s was changing dramatically.

And he was involved early on in efforts to actually understand and develop what was the original form of string theory. Then he worked on the theory of the strong interaction, trying to understand the nature of quarks and what confines quarks, and then the origin of matter in the universe. And then ultimately to the current controversies which are driving much of theoretical physics involving both the apparent paradox of black hole evaporation, which appears to defy the laws of quantum mechanics in some clear way, and has produced a paradox that a great deal of the community has been trying to solve. And also this remarkable notion of philography, the idea that perhaps our three-dimensional world

really could be codified simply by a two-dimensional surface, just like a hologram, a plate, codifies three-dimensional information. When you look through a hologram, you can see, as you move your head, you can see behind objects. Well, it's become clear in theoretical physics that it's possible that what we mean by dimensions may be to some extent an illusion,

in particular related to black holes, but also to our universe itself, that a universe in four dimensions with one kind of physics could be equivalent to another universe that is three-dimensional with a different definition of physics, but the laws essentially, and what happens would be remarkably the same.

It's a fascinating idea, and Lenny's been at the forefront of that, as he has been many, many ideas in science, and it's been a pleasure to talk to him. He has a down-to-earth way of describing things and, and, an extremely clear viewpoint that I think will elaborate for many people listening to this,

many of these current controversies. At the end of the podcast, we got to talk about his writing. And in fact, behind me, right, if I could point right there, are three of his books called Theoretical Minim, which are great books for young science students who want to basically try and read and understand the basic mathematics and physics that you need to understand to understand sort of modern physics. All in all, it was a great opportunity on, recorded on Lenny's 85th birthday, I believe,

and I was really happy that he took time out to talk to me. I think you'll be entertained and educated by this discussion, and I hope you enjoyed as much as I did. You can watch it ad-free on our Critical Mass Substack site, and the dues for that go to support our nonprofit foundation, the Origins Project Foundation, produces this podcast, or you can watch it on YouTube, and I hope you'll subscribe to our YouTube channel if you watch it there, or listen to it on any standard podcast listening site.

No matter how you listen to it or watch it, I hope you enjoy this podcast with a leading theoretical physicist, my friend Lenny Suskin. Well, Lenny Suskin, thanks so much for coming on the podcast. I want to have you on for so long. It's really nice to see you again. Good to see you, Lars. And I will say that, and it will date this, but happy birthday. Happy Father's Day. Thank you.

Thanks for taking time on this. But I'm not your father. Well, it doesn't matter. All fathers should have a kind of common bond, I think. I guess so. Yes. Oh, and Happy Father's Day to you, too. Thank you.

Thank you very much. As you may know, this is an Origins podcast. So what I like to do is kind of find out how people got to where they are. Well, we then proceed to find out the things they've been doing. And I've known a little bit about you. I mean, I've known the lore about you, but I want to find out more than the lore. I want to find the reality. So I heard about the plumber stuff early on.

So you were up in the South Bronx. And when I look at like... South and East Bronx, Far East Bronx, yeah. Little Italy. Well, it wasn't really. But Italy, mostly Italian and Irish. Interesting. So let me ask you this question.

For some reason, when I look up various problems here, it said brought up in a Jewish family of South Bronx, was your family like Orthodox or anything? No, no. No, no. They were all a bunch of leftist, far-leftist, Communist Party members. Oh, excellent.

Union men. Union men. Your father was a plumber. Am I right? Yes, he was. But plumbing in those days was a different profession than it is now. Still plenty of lead pipe in New York. Yes. Now, there's a noble tradition of plumbers from New York in physics, of course, because our joint friend, Shelley Glasshouse's father was a... That's right. I don't know. He's a little older than you, but I don't know if his father knew your father at all.

I asked him once and he really had no idea. Well, the difference between, one of the difference to him and you is that you actually went to work as a plumber for a little while. Seven or eight years. Seven or eight years. So, okay, we'll get there. Okay, that's what I was wondering. But first, so your father was a plumber. He had no, I assume he had no, did he go beyond high school?

Did he have any? No, he got to the fifth grade. This grade, okay. The family was incredibly poor. His father, as I said, was a leftist in Russia, anti-Zaris. When he came to the United States, I don't know exactly one, maybe 1898 or something like that. He went to work as a house painter. He was a union man, but he was also a gambler and not a good gambler.

Card player. Yeah. His family was incredibly poor. At the age of 12, my father's family got thrown out onto the streets outside the apartment building. and he had to go to work. So the situation was in those days, what was this? It was 1918. In 1918, a poor Jewish boy who had to go to work,

there were really only two options. You could join the gangs. Well, you could be a good boy and go to work, go to work in whatever profession, which generally meant building professions. My father was a good boy. He was a very good boy. He loved his mother.

He loved his sister. I'm not sure exactly how he felt about his father. He went to work as a plumber. But a lot of my upbringing centered around the fact that my family worried that I would do the opposite, that I would get in trouble. Oh, I see. I can see that worry. No, you're okay. I think it was just an over-reaction.

So he was grade five. What about your mother? I don't know anything about your mother. Grade nine. Okay, so where did you get your interest in science? That's an interesting question. I'm not really sure. First of all, to say that my father had a fifth grade education would not be accurate. He and his friends, his buddies who were very similar to him, plumbers, some Jewish, not some Jewish. They were in their own way intellectuals. They would sit around the table in my father's house. My father was the leader. He may have been the oldest. and he had this bunch of friends, and they would sit around and talk about all sorts of things. They were all leftists,

so we'd talk a lot about politics, about history. But science also, the trouble was they didn't have any real way of knowing what was real and what was fake. So sometime around the age of 12, my father's friend, Moisian Durski, Mersh was a real character. Somebody ought to write a book about him. But he gave me this book, Worlds and Collision. Oh, I know the book. Yeah.

Yeah, Velikovsky or something like that. Yeah, yeah. And it was completely fascinating. It was fascinating about how the world got to be the way it was as a consequence of a collision, I think, between Mars and the Earth or something like that. I don't remember. It was very, very fascinating. I remember reading it and talking about it with Mojhe.

I had no idea that this was complete crackpot stuff. How do you tell? Yeah, when you're a kid and someone gives it to you, you know. Sure enough, Mars has cracks on it, or at least. to look that way to some astronomers. And if I remember, I think that was my first real exposure to something that resembled science. But the other thing was, I was good. The only thing I was good at in school, the only thing was math.

I'm not generally considered a very mathematical physicist, but I was very good at mathematics. Did that just happen? Was there any interest in, do you just found the math easy? I mean, your mother had fallen. I found it easy, I found it easy, and I found it satisfying that I could do it better than anybody else. Yeah, yeah, yeah, right. From about the fifth grade through what was called junior high school in New York, I was very good at it, although I was generally considered a very bad student. So you weren't like the other subjects you were telling me.

Oh, it was terrible. It was terrible. And I don't know why it was so bad. I had terrible experiences in English. I write well. I'm a good writer. Yeah, we've written a number, lots of things. You are a good writer. I've been told by good writers that I'm good. But why I was so bad at it? I don't know.

In any case, throughout high school, the only thing I was good was math. I was so bad in the other stuff that it was forbidden to take in physics. Now, that doesn't make any sense, but it was true. When I was ready to go to college, the high school sent a letter to the college saying, this man is not suitable for college. Wow. The only way I got into CCMY, to CCMY in the engineering school

is there was a standardized test. Citywide test, and it was mostly mathematics. It was for engineering school. And I was number one in the city. By way, for listeners CCNY City College in New York, I was going to ask what caused you to go there. And you went there presumably because you couldn't get in anywhere else but given your high school record or you never thought about it.

Yeah, I never tried to get into anywhere else. The plan to go to college, my father had a great idea. He had a brilliant idea. In the New York City tenement buildings, the heating systems were failing. They were old. They were 19th century eating systems. They were failing. And he had the idea that he would go into business replacing the heating systems.

These are giant boilers, coal-fired boilers. He was going to replace them by oil-fired boilers. It was a brilliant idea. It would have made him a load of. the money. The problem is he didn't know anything. He didn't know enough engineering to do it. Now, this wasn't true. He really did know enough. He had enough seat of the pants, understanding of how his heating systems work. But to do it, you had to interact with the engineers and the, so at some point, he got frustrated because he didn't know what a BTU was.

British thermal unit. Yes. So his idea, which is what heating systems were measuring, in those days, still. He said, you've got to go to college, study a little bit of engineering, and then you'll be able to do that side of it. I was going to ask if your parents encouraged you want to. They never wanted, like, my parents wanted my brother to be a lawyer and me to be a doctor, but your parents didn't want that. Did they ever talk to you about that kind of stuff?

Not a lot, but it was just assumed that I was going into my father's business. My father had a very, very, very small business. So it was quite a shock to the family when they discovered I wasn't going to do that. Okay, but I see. So the idea is you're being encouraged to be an engineer so you could make the business, you could bring the business to this massive new money-making scheme of. It would have worked. It would have made a lot of money.

But your father got ill and you actually started working as a plumber when you're 16. So does that mean why you're? I actually started working before that. The reason was not that my father was sick. When I was 14, maybe 13 or 14, I started having to go to work with him. He insisted, and he was a tough, tough character. This was not somebody you told no to. He was a tough, tough character, and he said, you've got to work.

So I came to work with him. And what was the reason? In retrospect, I realized it was to keep me off the streets. Oh, that's smart. It was to keep me off the streets, which didn't work too well, but it was to keep me off the streets on Saturday afternoon. So about the age of 14, I started working with him on Saturday afternoons. And in the summer, the summer I had to work all summer long.

But then at the age of 16, when I was 16, he was 50, his heart started to give out. And he really did need me. So from that time, after school, every day, Saturdays, Sundays, we didn't work. All summer long, all holidays, I was doing. going full-time plumbing. Now, what about when you got to college? Were you doing plumbing then? Absolutely completely. I was married, very young. I had a child when I was in college. I needed the income. My father's needed his business needed me. So yeah, I was working pretty much full-time, easily 40 hours a week. That's one of the virtues, I guess, of having a child young is your great

grandfather. So, okay, so working full-time, essentially full-time while you're going to college, studying engineering, and they didn't, and city college didn't require you to take these sort of English classes or anything like that. As an engineering student, it did not. Oh, okay, excellent. Right. Now, but then you somehow went to the dark side and discovered that you wanted to do physics rather than engineering, which is a reasonable thing to do, of course, but how did that happen?

Well, look, I've told the story so many times. It's a true story. It really happened. It's the only way I can explain it. I took the first genuine genuine engineering course. Oh, no, the first genuine engineering course I took was thermodynamics.

Oh, wow. It was thermodynamics of heat engines, you know, all of the really good... What's up your father wanted you to learn, in fact? The problem was, the problem is I got stuck when it came to entropy. The guy told us that entropy is an

integrating factor. I didn't know what an integrating factor was, but much worse than that, the so-called professor had no idea what entropy was, no idea whatever. And I tried to understand it. This was a mistake. Don't try to understand it. Just do it. I tried to understand it and got completely frustrated. It didn't mean I failed the course. They did well on the course, but I was completely frustrated by it. But then I took another engineering course that was mechanical drawing. Just mechanical drawing, gears. In those days, mechanical engineering,

mechanics and gears and cargs and axles and all that kind of stuff. And you had to draw, you had to make these drawings. Now, in those days, there were no computers. You made a drawing with a piece of paper and a pen. And the pen was in the ink. And the pen was called a ruling pen. If you've ever seen a ruling pen, you know that it has two nibs that stick out and you drop the ink into it and it's held there by capillary attraction.

and then you move the pen. And if you're as unsteady as I am sometimes, you wind up leaving blobs of ink on the paper. This is not allowed. Part of the class was to teach you how to use these pens. So at the end of the class, I had completed one drawing. The rest of the class he completed five drawings. And the professor who ultimately became a friend,

his name was Harold Rothbart. And he came over to me and he said, So again, I'm going to fail you in this class. I can't pass you. I said, Professor Rothbaugh, my father's waiting for me, my kid is waiting for me, my wife is waiting for me, going to go into business. I can't fail a class. He said, no, I'm going to fail you.

And I thought, this guy thinks I'm a real idiot. And then he said to me, he said, you're super smart. You have the mind of a scientist. You need to go into one of the sciences. I will help you. So the first reaction was scientists meant men in white, white gowns or test tubes. So I went to the chemistry department.

Chemistry department says, no, it's too late. You have two years into this. Yeah, if you spend an extra two years, you can become a chemistry major, but you don't have any record of chemistry courses. Next, I went to the math department, and I ran into a guy, a professor whose name was Jesse Douglas. You may not know the name Jesse Douglas, but Jesse Douglas was the first Fields Medalist. Oh, okay. He's the man who solved Plateau's problem, whatever Plato's problem was.

He was completely crazy, although a very good mathematician. And what was he doing in City College? He had been fired from MIT. He had been fired from Princeton. He had been fired from all the great why, because he refused to come to class. He considered the students complete idiots, not worth interacting with, and he wouldn't come to class. He came to City of CCNY, did the same things. but for some unknown reason he took a shine to me, and he started giving me problems.

They were easy problems. They were not hard problems. I would solve the problems, come to him, and he got sufficiently interested in me that he became my protector. But at some point, he had a very similar reaction to what Rothbard had. He said, you know, you solve these problems in a very unusual way. You don't think like a mathematician. You solve the problems, the way. way a physicist would solve the problems. Intuition, some sort of, some sort of pictorial representation you're having your head. I think you should go to the physics department and talk with him. So that's how I got into it. I met a guy called Harry Sudak, who was a lifelong friend

of mine, and he smoked a cigar. He came from the Bronx. I think he came from Washington Heights, which is culturally the Bronx. We started talking, and he told me something I didn't know. He told me that not all physics had been done 200 years ago. A very important thing, yeah. Right. He told me that you could make a living the rest of your life being a physicist, that there are still physicists in the world, and there are still major problems of physics that are understood.

That was completely new to me. I had no idea. It's a really important thing. I just wanted to jump in. I was Dr. Wright in high school. It was Feynman's book, the character of physical law, that the first, I thought, as well, you realize, it's not all done by dead white men 200 years ago, and it suddenly changed everything.

That's an interesting comment, because one of the first books he gave me, I don't know how he got it. I think he got it from Eugene Wigner, who was a friend of us. It was a photocopy of the handwritten notes for Feynman's book, first book. And I started reading that, and a while I was blown away. I was completely blown away. He started teaching me classical mechanics. and he himself was a good physicist,

but he didn't know a lot. He was a CCNY teacher, which meant, you know, they were not, they were PhDs, but they weren't research physicists. Yeah. And then he said,

you've got to learn quantum mechanics. So I got out a couple of books on quantum mechanics. I got Booms book, which was incomprehensible. I could not get a word of it. And he finally said to me, look, I've been buying books, cheap books from Hong Kong.

They're pirated books. Are you against pirated books? I said, no, I'm not against pirated books. I didn't even know what it meant. He said, I'm going to buy you a copy of Dirac's book. I was going to say Dirac's perfect. He got me a copy of Dirac's book. I think I still have it somewhere.

And I started going through it. And again, I was just blown away by it, the logic of it, a clarity of it. So I learned quantum mechanics. I learned a little bit of general relativity, all in, and at that point, you know, I knew. There's no point in going back and with the engineering. I will

never be happy. And how long? Well, first of all, all of this sounds like it was done outside of class. Yeah, it was completely outside of class. I did take some physics classes, which I did well. I got a reason. It was made clear to me that by the physics department that they didn't have much to teach me. Yeah, I was doing very

badly in school. Again, partly as a function of the fact that I was working full time, partly of the fact that I had no interest in anything but the physics and the mathematics. At that point, since I was now a physics major, I did have to take English, I did have to take German, and I did have to take all this stuff, and I was failing everything. The dean would call me in every quarter, it wasn't quarter of a semester, every semester, and tell me, what are we going to do with you?

You failed every course again, but the physics department won't hear of us dropping you out of school. Eventually, the dean together with a couple of the physics department people managed to make contact with some graduate schools and got me into some of the graduate schools without a undergraduate degree. So you never got an undergraduate degree? I did after I was already a professor. Oh, okay, because I read something about you graduated in 1962. Oh, no, I graduated in 19, from CCNY. Yeah. Yeah, no, I finished CCNY in 1962, but I didn't graduate.

Oh, they lie. It says somewhere in your biography you graduated to the degree in physics in 1962. The degree came from 1966 after I already had a PhD. This explains another thing. But before we get there, so now pieces are being to fit together. At some point, you had to tell your father, your parents. Again, the story which I have told more times than is healthy for me. But the story, again, it's true,

once I realized that wasn't going to be an engineer or a plumber, you know, to tell my father. As I said, my father was a very, very tough cut, not tough in the sense of, you know, just an inner core that was immovable. He was not a big man. He had hands that could crush walnuts with one hand. But the rest of his body was not very big or strong.

So I was living in a different section of the bruntlets. strong still when my father was with my wife, with my child. And I said to a Mexican work, I got to go tell my father this is, this is, I was scared of him. He was my hero, but I was also scared of him. And so I got in the car with my wife, with a kid, and drove over to my father's place. He was in the basement cutting pipe, cutting out pipe for the next day's job. Sure. And I went down and I said, Benny, I'm not going to be an engineer.

And he never used foul language. He did not like foul language. It was once in a while, very rarely. But he said to me, what the fuck are you going to be? A ballet dancer? Okay, this was the fifth grade, deep inner city, Bronx character. What the hell are you going to be? What the hell are you going to be a ballet dancer?

I said, no, no, I'm going to be a physicist. And he says, a physicist, you ain't going to work in no drugstore. He didn't know a physicist. He knew pharmacists. Yeah, yeah. I said, no, no, no. And by magical luck, I said the right words. I said, no, no, a physicist like Einstein.

My father was educated enough. He had enough knowledge of the world to know what and who Einstein was. He didn't know what Einstein had done. But, you know, to Jews in New York, Einstein was the golden name. Yeah, it was golden around the... And he just stopped and he thought a minute. I can still picture it. It was a long time ago and still can see it.

He said to me, are you any good at it? And I said, well, of course, you know, it's hard to tell it, but I think I'm probably very, very good at it. He just thought a minute and he said, okay, you're going to be Einstein. I don't remember much after that, but my ex-ex-wife told me what happened. She said she came in with my mother. My mother was crying. She was terrified that the baby was going to starve, that I wasn't going to be able to make a living.

And she started crying to my father, and my father apparently just told her to shut up. He's going to be Einstein. And that was the end of it. It was the end of it. It was the end of it. After that, my father was on board completely. Completely. The whole thing, even doing PhD, which would have been alien to him at the time, the whole idea.

Completely. Yeah, Alien is probably not right. Just didn't know nothing about it. He started to get out some physics books, elementary physics books, and try to learn a little bit, which he did, but it was very hard. You know, he was... Yeah, sure, but that was nice. Nick 60 or how old was he?

Late 50s, I can't remember. It's interesting. My father was, it's hard to say, but it was a brilliant, brilliant plumber. He had the capacity of diagnosing plumbing problems that was extraordinary. So I always thought that maybe some of whatever technical abilities I have came from my father. But then much more recently, after my father died, after I was remarried, my mother used to come to visit.

And I had some experiences with her. I knew that she was very, very good at arithmetic and bookkeeping. That was her profession. I was going to say she worked. She worked outside of business. No, only when I was very young. Okay. Even before she was married, I knew she was considered really impacted.

But it never occurred to me. She was not an intellectual, not at all. And it never occurred to me that she might have these abilities. But then one day, two things happened. There was my kids had come to, my kids were there, my wife was there, and a well-known physicist had been visiting. It was an experimental physicist. I won't mention this man.

And we were talking, and he asked me, well, my kid's good at this. And I said, I don't know, let's try some things out. And so I said to my kids, supposing you have a cube and has a certain volume, they knew what that meant. I figured my mother has no idea what it meant. And I said, supposing you double the size of a cube, double the length of the equivalent of each side, how much does the volume go out? And my kids were young.

My kids who were young, didn't get it right. my mother instantly said eight. Wow. Where the hell did that come from? She completely visualized it. Yeah. And so on that it was eight. And then later that night, we got in the car with this physicist in my car, and I had a helium balloon in the car.

And I said to them, when I accelerate the car, which way is the helium balloon going to go? Wonderful. The physicist got it wrong. Oh, yeah. Really? My kids all got it wrong. My mother said it's going to go forward. Wow.

And I said, why? And she said, because the air is going to push it backwards. I was flabbergasted. And I started to think, and I started to realize that in many occasions, my mother really had shown a certain intuitive concept for things that I really had never thought up before that show. So I suspect some of whatever talent I'm not. might have been in the

mathematical ability. Well, that's when I was asking about your mother earlier. I was trying to see if she ever talked to you, but she didn't talk to you, but obviously her genes did in some ways. Well, well, something. So I don't know how much your talent comes from genes, how much it comes, but I'm a believer in genes.

Well, they exist, that's for sure. Yeah, but I was kind of flabbergasted. That's wonderful to learn that. You know, it's a shame, of course, you never you never the opportunity to use it, but that's really interesting to learn. But I was going to ask you, In terms of plumbing, do you think your experience as being a plumber? I mean, in picturing the mechanics of how works affected the way you think about physics at all?

No. No? No. No, I was not a good plumber for one. I thought it was brilliant. I was not. Okay. No, I don't think so.

And in fact, I would say the opposite. Whatever abilities I have picturing things and so forth did not help with plumbing. By the way, when I told him I want to be a physicist, my uncle said, you want to do give physics? I don't know if you know what, like it's like enemus and stuff. He thought maybe. Okay. Yeah, so he didn't quite understand it. But this explains then why.

I was trying to figure why you went, you did your PhD where? Cornell. So you got to do it. So you must have to get it. I mean, you went from CCNY to Cornell, which is something. So your professors must have given you. Two of the professors there, I was very close to one of the, then was his fellow, Harry Sudak.

He took me down, oh, it had an interesting experience. He was a friend of Wignor's. He had worked in Oak Ridge with Wigner on whatever it is they used to do in Oak Ridge. Yeah. I won't marry it because then I'll have to put you in jail. He knew Wigner quite well. He decided to take me down to Princeton and see if we'd get me into Princeton. Wigner was away, so he made arrangements for me to meet John Wheeler.

So I went down to meet John Wheeler. My mother had me dress up. But anyway, I went down there, and I saw this guy who, the only thing I can say about him is he looked like a conservative. He looked like a Republican. Yes, he was. But I was brought up to not like such people. Oh, I see. So my first reaction to him is, it wasn't for political reasons.

He just seemed like a very conservative. of height-laced guy. But he sat me down and started to talk about physics with me. And before a half an hour, I was just completely enchanted by him, completely. He was telling me about

quantum mechanics. He was telling me about gravity. He was telling me about it from bit and wormholes and things. And I completely revised, I realized the guy was maybe he was a conservative politically. But he had it.

But he was in the best possible sense, a wild man when it came to physics. Absolutely. In the best possible sense. And my reaction was, boy, I want to be a student of Wheeler. But they accept me. So Cornell did, through a professor of mine by the name of Arthur Bierman, who was a close friend of J. O'Rea. J. O'Rea was a professor of experimental physics at Cornell.

They just accepted me flat out, no question asked. Oh, that's nice. I had one more, I had one of the offers from Columbia. I didn't go to Columbia for one reason. I knew that if I stayed in New York, I would have to do plumbing. My father would call me in the middle of the night. And if I got out of New York, it was the end of plumbing for me. Okay, I was wondering why you wanted to get out of New York,

but that's a very practical reason. Well, that's fascinating. Well, you know, I was trying to think where the Cornell experience, I knew, I now remember you to go to Cornell, but it was interesting because you wouldn't remember this. I know, I vividly remember the first time I saw you. I was an undergraduate, but I was a very good student. My professors, there was an organization. It was like of northern upstate New York, and then there were some universities in Canada,

and they would have this meeting every year. And you remember that anyway, and I remember, they took me. Syracuse? Syracuse. Yeah. And also, where was Marshall? Rochester, maybe? Rochester.

Yeah. I think those were the origins of the Rochester meetings. Yeah, maybe they were. I can't remember anything, but they would let me come down with them. And I remember. Where were you? You were in? I went to school in Canada, Carlton University.

Yeah, I know. Where? In Ottawa, Carleton University. And my professors all had gone to Cornell, by the way. Anyway, so they would let me go. And I didn't understand much. but I remember hearing you when I was then, I would go listen. And you got your PhD pretty quickly, H.

Cornell. Very quickly. In three years, yeah. Why? Well, I guess I would have thought that given your background, which I figured must have been sporadic if you were learning for your professors, that it might have taken you longer to your PhD, but. No, by that time I knew a lot of physics.

I had really learned by myself, but I learned the right way. I knew more than most of the incoming graduate students. I spent orange summer I was working as but on Sundays I remember I would go to the beach

and Rockaway and Rockaway and I would carry a pair of paper with me and learn to calculate finding diagrams

when I was undergraduate so I went to work way is a good place to calculate five in diagrams

isn't it yeah they're completely accidental I know I know I know but I grew up

Rockway yeah yeah I'll go there for the summers because it was too hot in New York

Yeah, yeah. So I had learned quite a lot by that point. I think I know the answer is. It's probably the same reason I did it, but you already knew you sort of kind of wanted to do particle physics or at least what, it wasn't, yeah, at that point, which, you know, and what were your reasons? Well, I wanted to do theoretical physics.

Theoretical physics and the fundamental stuff. Yeah. I knew that I probably would not make a good experimental physicist. I like the idea of it. I like the idea of going into the lab and tinkering things, But when I actually tried it, I did not have good rapport with the apparatus, let's say. I couldn't get the oscilloscope to oscillate. I couldn't get the, I could see nothing through a microscope.

So you did have to make labs as an undergraduate at Citigod? I didn't. I didn't, but still, as an undergraduate, as an engineering student, I remember in one of the classes, engineering class, the class was called Strength of Materials. and one of the experiments we did was crush concrete and measure the strength of concrete. That it was okay at. I wasn't good in electronics.

I was very good in mechanical things. It was not good. I couldn't get the electronics things to work, but it doesn't matter. I knew that my interests were largely theoretical and mathematical. Yeah, since you had an apt to in mathematics, in my case, I ended up doing a degree in math as well as in physics, for the precise reason, because if you did that, you didn't have to do it. take the lab, the lab's. So that was a way to get out of a senior lab. But then I'm intrigued by why you went from there to Yeshiva. And I must have been, I never went to Berkeley first for a year. He was Berkeley first for how long? With an intercept, just for one year. One year. The reason was

not because I went there for one year because at the end of the year, I had an offer from from David Finkelstein to go to Belfa graduate school. That's interesting. So you were in Berkeley 66-ish or something like that? 65-66, yeah. An interesting time of you, were you influenced by with the Jeff was sort of Jeff Chu and that, yeah. Yeah, I was influenced but in the opposite direction.

I went there because there was all this activity going on in hydron physics and I can understand it. When I got there, I was not enamored by this S-Matrix. I did not like that way of doing physics. The other two people who were

there were Weinberg in Glashow. And I spoke some to Weinberg, some to Glashow, and I realized that the S-Matrix way of doing things was not what I wanted to do. And they convinced it. That's interesting. I didn't realize, yeah, they were both there for a little while. Interesting. Okay. They were both associate professors, I think. So now I want to, I want to sort of move into physics. Because your career in physics is, well, it's very wide and encompassing. But you started, because the interesting questions at the time you were becoming a physicist really seemed to be about the strong interaction. For me, they were about the strong interactions. For all of the business, I know they see at that period, they seem to be the strong interaction.

Well, of course, it turned out that the weak interactions were pretty damn interesting, too. Yeah, I know, I know, but what drove people at the time was because they were, they're all the new particles, all the new stringly interacting particles. It seemed so strange and so different than everything else. I went back and read your paper on the structure of hadrons implied by. duality from 1969. I thought I'd go back and look at it. There were a lot of phenomenal logical approaches, and for the listeners, that phenomenological basically means taking the data and building some cluge that worked, but it wasn't fundamental. But there were phenomenal approaches to dealing with this strange theory, the strongest force in nature, and someone

had come up with a very nice way of understanding of Venetiano, and you would, in that paper, you showed that you could think of it as what we would now call a string theory. Right. That's exactly right. I was certainly not the only one, but it became fairly clear that these things we were calling hadrons. We can spell it out. Protons, neutrons, and all their various relatives, mesons, things to which today we think of as composite quark systems. At that time, quarks were already being talked about, but only talked about. It was pretty obvious to me that hadrons were some sort of composite structures, which could

spin about their axis, which could vibrate and so forth. And that was experimental data. That was good experimental data. That you could take a proton and spin it up and make a thing called the delta three halves out of it, or you could cause it to vibrate. Unlike electrons, electrons are really point particles. It doesn't make any sense to cause them to vibrate internally. So I had been thinking about how to represent them as composites of whatever.

Of whatever. What was going on? I had some ideas, but the turning point, the pivotal event was a friend of Yakira Haranov, who I was very close to. We had worked on quantum mechanics together. Now I'm on particle physics. And Yakir's friend whose name was Hector Rubenstein. You probably know the name. You probably remember him.

At the time, he was at Weitzman Institute. Yakir was an Israeli. Hector came to visit us, or to visit Yarkier, and he was incredibly excited. This young physicist at Weitzman Institute by the name of Veneziano and invented a solution to the bootstrap problem, as it was called. Bootstrap problem was the problem of the Hadron S-Matrix or whatever that means. And I didn't know what he was talking about. He jumped up and down, and he ran back and forth,

and he finally wrote a formula on the blackboard, which made him. nothing to yark here. It had two gamma functions in the numerator and one gamma function in the denominator. Very famous formula today, at least among the small group of physicists who know what it means, the Venetiano formula. And I looked at it and I said, that's it? That's very simple. I must be able to figure out what that means.

I knew what a gamma function was. It was a good mathematician. And I knew that gamma functions had sequences of poles. Those poles would represent excited, rotational, vibrating states of whatever it was they were describing. I looked at it and I said, my God, the thing is a harmonic oscillator. It's a harmonic oscillator, for God's sakes. It's got equally spaced levels. I had also worked on what's today called light comb quantization.

It may have bent at the part of it. And so I knew how to think about the Hamiltonian version of it. I said, this thing is a harmonic oscillator, and I went home, and I probably spent a good month fiddling around, and did some problems of scattering things off harmonic oscillators. You know, you take a spring, you attach it to the ceiling, you put an electron on the end of the spring, and then you scatter a photon off it. I got things which look awfully much like the Venetiano amplitude, but not quite. I wrote a paper that was called the harmonic oscillator analogy for the Venetiano formula. it had the basis of those ideas. And while I was writing it, I suddenly realized that to get it to come out right,

to really look like the Venezuelanianal amplitude, did not have to be a spring, but it had to be what we would now call a string. A string is just a lot of little harmonic oscillators connected together to form a chain. So I wrote that in as a comment, comment added in proof that the right structure seems to be a, I don't think I called it a string. I think I called it a rubber band or harmonic continuum or something.

I thought I was the only one in the world who knew that. I was sort of flying, thinking, my God, I'm the only human being in the world who knows this. It turned out that there was one more human being who knew it. You probably know who it was. Nambu. Yeah, Nambu. And then, yeah, certainly Nambu first.

Yeah, Nambu knew a lot. In some sense, when I found out that Nambu knew it, I was let down. I was disappointed. On the other hand, to be in the same league with the great bamboo. Wow. Yeah, that's great. He's a great, great, great science. Yeah. Yeah.

You know, when I look at your paper from 69, you talk about strings already in there, and you also, by the way, talk about forks. We've sort of jumped ahead, but really what I'm, and this is, that's really fascinating. But the idea, what people don't realize, and well, some people do, but is that, you know, string theory grew out of this fascination, well, this fascination and puzzlement about the nature of a strong interaction. It wasn't something to explain gravity or anything like that. Your interest, like many of the good theorists at that time, was in the strong,

trying to understand the strong interaction. And that's what caused you to get interested in this whole idea, trying to explain these, you know, I would say, Benet's the San, I guess I would say it's a phenomenal, it's a picture that gives you the right answer for some things, but it's really here. not fundamental. Well, it was just a product of two gamma functions over a third gamma. Incidentally, that was one hell of a brilliant insight of his. Oh, sure. He did not get the string idea, but it's an incredibly simple formula he wrote down. That's great that we're getting into physics, but I do have this question for you.

I think you told me, so David Finkelstein, I was wondering why he went to Shiva, which I'd never heard of. It wasn't a trajectory that a lot of people took. Let me put it that way. And so was it because it was a graduate school or was it? So I would not have gone to the Yeshiva College to teach rabbis. First of all, I had known David a little bit before that, and I knew how brilliant I thought he was. Then, David Finkelstein is not a household name among physicists, but among some subclass of physicists who knew about him, he was considered very wonderful. Yeah, he's a sharp mark man. Well, you know, I won't tell you what he did, but...

I think I know. Anyway, many beautiful and important things. Yeah, yeah, yeah. But for reasons that you are sort of suggesting, I was not at all clear that I wanted to go to this place. I said, who was there? And he started listing the people who were there, whose names I knew. And I realized this was a very, very serious institute for theoretical physics. Aharonov.

who I sort of worshiped as a master of quantum mechanics. Arnold Joel Lieberwitz, whose work I knew in statistical mechanics, just Elliot Leib, Elliot Leib, was a professor there at the time. And then they had made an offer to Dyson, who accepted the offer at Sevecly, but then went back to the institute. He didn't want to live in New York. Dyson was supposed to come in. Deraq used to spend a lot of time there.

There was a famous astrophysicist by the name of Al Cameron. Sure, I knew Al Cameron. Who was there. And I realized, wait a minute, this is a serious, serious place, as it was, as it truly was. Was there an attraction to go back to New York, too, or no? No. Only insofar as I was beginning to think about getting a job. And, you know, I wanted to get my career started.

I wanted to get my family. I had a family. I wanted to get my two kids by that time. And I wanted to get settled and done. Was the fact that it was kind of a faculty position attractive, when I finished my position at Harbor, you know, as junior fellow, I had a lot of offers and they were like five-year positions as to that. But I had a family and a young child, or at least I had a wife and himself.

And I took a faculty offer at that time at Yale because I didn't want to sort of move around and have the kind of, you know, army experience. wanted to settle down. Was that, was that, was that was the fact that the back? Yeah, yeah, yeah, I didn't yeah, yeah, absolutely. That plus the fact, I had only taught once. I had taught at Berkeley, I had this, I was a post-doc, I had an NSF fellow, I didn't have to do anything. But I asked them, could I teach choir mechanics? Would it be okay if I thought, I would have to try out my hand in teaching? I loved it. It was an undergraduate teaching. I really, really like teaching. I recognized something, which has been something in the rest of my life, that the only way I ever learned

new things is by teaching them. The idea of being at a place and not teaching was not terribly attracted to me. But this is a graduate school. Did you ever teach you graduates or no? Not there, no, only when I came to Stanford a little bit. Now to get back, if I try and picture, I'm sort of trying to picture your career as I've sort of looked through, you know, as I said, I've known you, but the history of what you've done. And it was a strong interactions, and it was, which initially got you, you know, into thinking in terms of what would now be called string theory, which was one of the key ways of thinking about the strong interaction, which sort of ended with the development of asymptotic freedom,

with the discovery that good old one built theory could. I don't think that's correct. Half the question is what happens at very high energy. That's asymptotic freedom. The other half of the question is what happens at very long distance. That's called confinement. They're not the thing. Strings and the idea of flux tubes and my experiences with lattice gauge theory and that sort of thing.

Well, I want to get to lattice gauge theory. I mean, because as I look from strings you move to lattice gauge theory, I guess what I wanted to say to be more clear, and I think you'll maybe you'll agree with me on this one, but it's good if you don't, is that part of the confusion of the 1960s and going to string theory, are going to bootstrap, it was the belief that somehow quantum field theory was not going to work.

At least what Ascentra Freedom changed was the realization that a quantum field theory of the strong interaction was the right picture. Now, whether the tools of conventional quantum field theory would be useful, a different thing. But at least it changed the perspective that you didn't have to give up this notion of quantum. I do agree with you, but I would say

it wasn't the whole story. I would say the secret. change happened before that. It happened as a consequence of the deep inelastic scatterings. At Slack. And just so they know, these were experiments that somehow showed when you, when you looked in the proton, there were fundamental objects and they didn't seem to be interacting with each other. Not strongly. Not strongly. And that was a big job. But it did indicate that there was some substructure there. The substructure was point like in the hands of Feynman, and Burekane became clear that there was this substructure.

substructure of point-like things, which, if anything, were more like electrons than like protons and neutrons. Yeah, and of course, that was the key, Jane. And I think what I first heard of you were talking about, when the first talk I heard from me was probably a lettuce gauge theories, which I didn't understand at the time. So you were still focused in trying to understand how to understand the strong interaction and indeed how to understand this other remarkable feature that we don't seek works, that they're confined.

And we still don't have a fundamental understanding. We have a numerical understanding, but... Well, I think we have better than that. We have a clear picture. And the picture from all directions comes to the idea that when quarks separates strings form between them. That was the link. The lattice gauge theory told you that when you separate two quarks,

string-like objects, which look like the same kinds of strings that we had been exploring earlier, form between them. Is that what caught you in the stress? I was going to say, why the, how did you make the transition from doing this kind of S-matrix duality, string-like approach to strong directions, to think about something very concrete, lattice case here, which is, by the way, saying we'll make space discrete, and we'll put particles and fields on these discrete points, and it will allow us to do calculations we might not be able to do, and also ultimately later on, numerically do things that we could do

otherwise. But what would cause you to make that transition? Kenneth W. Wilson. Okay. Okay. Ken had invented a version of lattice gauge theory. When I first spoke to him, he actually had some wrong ideas about what the confinement was saying. He thought there was a phase transition of a certain kind that can't exist there.

But he showed me this picture that what I'm now called Wilson. and loops are filled in in the area between them, this area law, whatever the area law was. I looked at it and I said, Ken, you're talking about strings. He said, strings? I said, yes.

What you're telling me is that the lattice gauge theory is telling you that when you separate quarks, strings form between them. He went back and looked at some papers on strings. I have been visiting Cornell. I've been visiting Cornell. This was long after I passed through. He wasn't, professor. Was he there? Was he there,

when you were a student? Yeah, he was there. He was there, and he was doing his work on Lavis Cage Theory, and he got very excited. He started to learn a little bit about stream theory, and he said, yes, you're right, that's the picture. These long, thread-like things are forming between the quarks. And I went home and said, I would like to think of this, not from his Euclidean path integral formulation, but I would like to formulate a standard quantum mechanical, what we would call Hamiltonian theory, which I did with John Koget, and that made it extremely clear that what was happening was that it was closely related to the picture that hadrons are strings.

I thought you might have just thought of it as a new tool. I mean, Latestatechia, and your version of Lattiscus theory is so essential way of understanding, which we now use in, as I say, a lot of miracle simulations, Well, let me go back a step. I had already gotten interested in gauge theories. This was the question that arose, the paradox, which was arose, because up until the early 70s, it was assumed that every quantum field has a particle associated with it. Every elementary particle has a quantum field, and they're in one-to-one correspondence. Here were these things called quarks, and it was getting pretty clear. Quarks were the right idea. 19, you know, my early 70s, but there were no particle-like real things in the laboratory. This was a violation of this one-to-one correspondence between fields, quark fields, and particles. I saw it as a bit of a paradox. I began to realize that this could happen in gauge theories. So, John Kogan and I wrote a whole series of papers on what is called a Schwinge model,

one plus one dimensional electrodynamics in which we showed this phenomenon of confinement happens. So I was already on the wagon not my drinking habits, but I was already on the gauge theory

wagon. I recognized that what was happening in this one plus one dimensional theory is that the strings were forming between the charged particles and it was just about at that time when we had finished writing always one plus one dimensional pictures that I came into contact with Ken.

I very knew Ken. He explained this picture from the lattice gauge theory, which just, you know, it meshed completely with the earlier pictures, strings forming between quarks. Was this before Electro, before, was before Ascendotic Freedom or after? No, it was at exactly the same time. I remember exactly when it happened. I was visiting CERN. Sidney Coleman was at Cern

and Sydney was a friend of mine Sydney didn't like me very much but never mind and Ken Wilson was there and okay this was a meeting of three people this was 1973

I sympathized that freedom had just barely come out and he told me about it and he of all people had the right idea of what it meant that it would hopefully someday explain how confinement and freedom can coexist.

Ken was there. I talked to him separately. I don't believe we all three of us interacted. Ken told me about lattice gauge theory. And bang, the whole thing was just coming together. Oh, okay. So this was 1973, the early, the beginnings of ascentanic freedom, or at least the beginnings of the fact that people knew about it. Of course, it was at least a year old that a tuft had also discovered it. And of course, Ken Wilson also was one of the fathers of renormalization group. So he also understood very deeply the meaning of the asymptotic freedom. Absolutely, if anyone wanted. I think the interaction with those two people, Sydney on the one side, Ken Wilson on the other, just made it clear what was going on.

String long flux tubes forming between quirks. Yeah, and we should say for again listeners of paper, Ken Wilson, one than all, Prize for trying to exactly understand how physics theories evolve the scale and use these examples to try and to formalize and quantify what he was doing. And Cindy Coleman, who, while he didn't win a Nobel Prize, while I was at Harvard, was probably the smartest person there. Okay, so you're still focusing on this on QC, on strong interactions, strong interactions. Did you ever do any work on the weak interaction, by the way? Yes. It ultimately, failed, the work was called Technicolor.

The field moved so, so, you know, it was the heyday in the mid-1970s were, before that we didn't have any, we knew one, we had one quantum field theory that worked, well, electronics, and by the end of the 70s, we had, we understood three of the four forces of nature, all by the same kind of theories, and there was a lot of interest in that, and your career, of course, as all good theorists, followed that kind of evolving. It seemed to me, and again, I'm just looking at this from a distance, that your background thinking about the strong interaction clearly influenced you because the big question with the other theory, this electroweat theory, is that, well, we now call it the Higgs particle and that there

would be something that would basically have, the symmetries of nature would change. There'd be a background field throughout all nature. But you gave a potential solution, which really is a harborder of exactly what had happened in strong interactions. So why don't you talk about your thinking about technical and the weak interaction? Okay. So by that time I was already, at least I was at Slack, and it was about the time when I became a Stanford professor. The fact that I hadn't worked in weak interaction didn't mean I wasn't interested. Of course.

I absolutely got interested in Higgs phenomena or when I'm in Weinberg's theory and so forth. Probably as a consequence of my knowledge of strongly direction physics, I realized something. something that apparently nobody else would really realize. If there was no Higgs sector, then we would say, okay, electrons don't get mass, no masses for particles because it's the Higgs particle. It's not true. There's chiral symmetry breaking in the strong interactions, which leads to a symmetry breaking which parallels the same symmetry breaking coming from the Higgs phenomenon. What is true is that that would be enough to give masses to the quarks, leptons, the usual story, except a thousand times too small. A thousand times too small because the scale of strong interactions, the scale of pyons, the scale of chiral symmetry breaking is a thousand times smaller, weaker.

Let me ask you a question. Just to give people a sense, I've talked before, that when a symmetry of nature, breaks like that when suddenly there's something that, and that's the simplest thing to think of as a background field, particles propagating in that field can appear to be able to get a mass. And sort of in carosymmetry, it's kind of like that. But when you say that chiosymmetry breaking happens in the strong interaction, gives it forks masses, but you'd say it would feed into the leptons as well? It would feed into the leptons in exactly the same way as it was to the Higgs story.

Leptons are electrons and muons and things like that. Yeah. So it was sufficient to break the symmetry in exactly the right pattern, except a thousand times too weak, which meant that the electron, the forks, their masses would be a thousand times too small. So I remember sitting in my office at Slack, and I said, hey, wait a minute, all we have to do is create a new sector, which is very much like the ordinary strong interactions, let it break sidecarry. symmetry in exactly the same pattern, except at a thousand times higher energy scale. I ran out of my office.

I ran over to Burekane, and I told him, I said, by that point, I instantly understood how everything would work. And he got very excited. He said, that's got to be right. That's got to be the way it works. I don't know if people know who Burekane was, but Burekine was another character who was one of the great physicists of a generation, half a generation. of me sort of. Yeah, yeah.

BJ, we call him. And not only did we have learned field theory through his book, but I got to know him well. Yeah, and he, yeah, he had seminal, many seminal ideas, but. It was a giant, not only in physical stature, he was close to 17 feet tall, but yeah, he was an intellectual, right? And, yeah, and, yeah, in so many ways, unsung. And in a way, he kind of liked that, and I talked about that later.

Sydney had also been visiting Slack. He got excited about it. It smells. It smells right. It smells right. It's the physics that we exactly know and just a new sector. And then you solve all these problems. So it's one of these things where you think nature would do it, but it didn't.

And I often talk about that to people. They don't understand, especially since some people talk about things like elegance and theories. The wonderful thing about physics is you can have an idea that's beautiful. And that is certainly a beautiful idea. But if nature doesn't, you know, if nature doesn't do it, you just show it out. And it's the great liberation that science offers people is to take an idea that they find so beautiful that it has to be true and be willing to say, it's not. I was probably the first person to let it go. I knew it wasn't working.

Oh, really? Oh, yes. I knew it wasn't working. I knew that they were having a very hard time coming to groups with a quark mass matrix. And, you know, at some point, I just said to Savas, who was my collaborator and all of that, I said, this isn't working. This is just not working. We're making a terribly complicated story by now.

It's not working. We need to think of something else. Yeah, it was started simple, and you had to have epicycles and epicycles. That's right. It was an epicyclicic theory. A very simple starting point. Yeah. Planets move around the sun in circles.

beautiful and simple, and then it gets more and more and more complicated. Some might say that in string theory, but we'll get to it. But I want to fall, because the interesting thing is, as I looked at your career, I mean, obviously, like good theorists, it follows the major developments in the field in interesting ways, and it's taken you in interesting directions that I guess I never would have imagined when I'm 30 years ago. So technical art was a way to try and understand, use the what you knew about the strong interactions to understand this puzzle of the weak interaction.

But at that same time, there was the heyday. that you had these three forces in nature that we understood. And we understood, in the mid-1970s, this remarkable result discovered a bunch of different ways that the strong interaction gets weaker, the electromagnet gets stronger. And if you go to some extremely small energy scale, it looked like all the forces might unify,

and that was... Extremely large energy scale. Extremely large. Sorry, small distance scale, large energy scale, thank you. Extremely large, 16 orders of magnitude, at the time, 15 or is magnate higher than the mass of the proton. Astronomical, but physicists with their chutzpah, having just had the success of discovering three or the four forces in nature and how they work, were unabashed.

And then it offered the possibility of solving a problem, which I think many people beforehand didn't even think about. But it was the first example where particle physics, fundamental physics might explain something about the large-scale structure of the universe and where people realize they're very small and they're very big come together. And of course, as you know, a lot of my career has been and spent in that area. But I didn't know, I should have,

that you also got involved in this question of bariogenesis, Barry synthesis. Oh, yes. Oh, yes. Let me just say what it is. I mean, people again have heard it because I've talked about it in various contexts, but the idea is that we live in a universe which has matter and essentially no antimatter,

and any reasonable universe you would think would have equal amounts since they're the same mass and largely the same properties. And how could you start with a sensible universe that might have equal amounts of matter and antimatter and end up in a universe that would just have matter? That's this problem that goes by the technical name of sort of burial genesis now. And that was a big mystery and, you know, still is to some extent. But again, the leading theorist realized maybe there's the hope of actually addressing that. If we really have a theory that that has all the characteristics required to generate

matter from no you know an asymmetry in nature and and and uh there there were certain requirements which were known in 19 early as 1967 by saccharov it was incredibly exciting that you might answer this fundamental question about why nature was the way so that got you interested on well i think we answered insofar as it can be answered that president w we don't know no physics to be quantitative about it yes sacharov was there first but nobody in the west knew anything about the Ackero of your paper project. This wasn't exist at all. Bob Wagoner came to me and asked me,

do I have any ideas about why B. Barion in balance? Now, at that time, I knew very little about cosmology. So I had to learn some cosmology to even talk to him. Yeah, sure. A lot of physics. He's a master cosmologist, of course. Yeah, he was, Wagner was, yeah, and I'm sorry, really. Really one of the smartest.

Yeah. Yeah. So I started to talk to Savas, partly Savas, probably by myself, probably with Bob, and I turned the question around in my head. Why should it be that there should be no? Why should the barion imbalance not be there? Okay, so what are the conditions for which there will or won't be a barriac of balance? That's right.

You rediscovered those conditions, didn't you? Yeah, yeah, okay. The first reaction was that you need to have a violation of barion conservation. If the universe in the very beginning, possibly because of inflation, started out with a very, very small imbalance between varions and antipotons, negligible, let's say, how could you possibly get something which had more barions and anti-barions? it would require a variant number to not be concerned. To go from zero to not zero requires it to be not concerned. Well, by that time, I already knew that there were all sorts of important theories

called Grand Unified theories, SU5, and all that stuff, which had Barion violation. And I still believe in that stuff, incidentally. Me too. The SU.5 idea, I think, is probably at some level correct. You say SU5 itself, that specific model? Well, no, I mean. The Grand Unified stuff.

Yes, but with SU5 as a subgroup. Okay. With SU5 as a subgroup, yeah, I think something's right about. It's probably too technical over the audience. That's another question. That's another. I already knew that people were very definitely entertaining the idea that barion number is not concerned that the proton would decay over very long periods of time.

So, okay, that's not a problem. The other problem is the second problem is the problem of, symmetry between plus jar, between electrons, between particles and antiparticles. But again, I already knew that empirically that symmetry is broken. It's called CP violation. I knew that there were phenomena reactions, particle physics reactions involving k-mazons, which were not symmetric under particles and anti-particles. So that argument went away saying that there's no reason that It can't be an imbalance. And the final one, which I understood fairly early,

was that if the universe is in thermal equilibrium, as a consequence of CPT invariance, it would have to have equal number of particles or antiparticles. But the universe is not in thermal equilibrium. And the early universe was expanding very rapidly and far out of that. So I just realized that there was absolutely no argument saying that that in the end of the day, after all this goes on, even if it started absolutely symmetric, that it would end up at symmetric.

I made some quantitative arguments about it, quantum mechanical models and so forth, where you could see, given the three conditions, barion violation, CP violation, and out of thermal equilibrium, it would inevitably wind up with an imbalance. And we wrote those papers, papers. papers were good papers. Later, a couple of, I can't remember, there was two Russians came to me, and they said, we're writing a book about Sakharov. I knew Sanharov's name, but not through physics, through politics. They said, would you be willing to write for this book a chapter on Sakharov's work on Barrio Genesis? I said, well, sorry, I don't want anything about Sakharov's

work. It gave me the paper, and my mouth fell open. Yeah, it had to be so. Absolutely. In 1967, he had all the right ideas. So, in fact, I wrote it and I circulated it, and that's how Sachero's work got to be known in the West. That's how people knew about it. Okay, I was wondering about that. For the audience, that's an amazing thing, is that at the time Sackerov wrote this, by the way,

essentially, even though one had been sort of been discovered, essentially none of the ingredients that were required were a part of physics. It was fascinating, but it was all completely expected. It's interesting how a decade later, all three of those things, as you just pointed out, the requirements that the universe could create a universe of matter instead of matter and antimatter had all entered the physics lore. It's really a remarkable historical accident in a way. I think what you're saying is morally true, but just as a matter of historical fact, which I think the CP violation had been discovered several months.

or, no, a year, at least a year. A full year before. I didn't know if Sakharov was, you know, given the way the Soviet sector. No, Sakharov did know. But I find it very impressive that Sakharov, just knowing that CP was violated, then moved ahead with all of this. Yeah, it's really amazing. And then, but it is fascinating for people who wonder how one did you get things like that,

something from nothing in a version of that. When you think about it from a fundamental perspective, we have all the ingredients. we haven't got the model, but no one's surprised anymore. It's just a matter of finding the details. I'm going to give maybe a biased historical development here, and I want you to correct me as I know you will, any. Well, there was a great Hutzpub, the grand unified theories. It looked like everything was going to come together.

We'd have a theory of all the forces, nature, but gravity. It was only gravity left over to do, and that would just take a little time, and everything would be fine by the 1980s, and we'd all be happy. go home. But that didn't happen. But what did happen was that, was that physicists for the first time honestly began to extrapolate and with a solid theory of the standard model felt that we could, in all seriousness, quantitative as well as qualitative seriousness, could begin to think about scales that were astronomically smaller in size or higher energy than anything we can see. then this fundamental problem, which it's always been there, but had been ignored because the scale is so

remote, which is a scale where gravity and quantum mechanics might come together. And there was a small group of people, and I don't think you were one of them. Maybe you were, so you'll tell me if you were in the wilderness. John Schwartz, there were a bunch of people in the wilderness thinking about resurrecting this idea Because what it was recognized, and it was, I don't, actually, you can tell me when it was first recognized, but a theory of strings naturally gives you a force that looks like gravity, and that maybe it would be a theory of quantum gravity. And, of course, there were several mathematical developments in 1984, I think, that made the world, a large fraction of the physics world decide that this was potentially the theory of quote, unquote, everything. But where were you in the, how did you, I'll tell you,

I'll tell you. Yeah. Okay, I just wanted to get the background for people. Okay. The fact that string theory as defined rigorously, certain mathematics, the fact that it had a spin-two massless particle in it, I knew.

I'm not sure if I was the first to realize it or not. I knew it. But I considered it a nuisance. I did not consider it a virtue. The Hadron spectrum does not contain massless. spin to. I truly missed the boat on hatch. Well, so did everyone. I mean, it took many years. Everyone was focused on the smogging direction, not gravity. The one who first said, look, this could be gravity. And not only did he just say it because it was a mass

to spend particle, he identified the gauge symmetry. He identified, was a physicist by the name, a Japanese physicist named Yonea. Tamiaki Yonaya. He wrote a wonderful paper, just pointing out that string theory had the symmetries of a gravitational theory, the ward identities we call them and all that stuff, and pointed out that if you lifted the scale from one GEV to 10th to the 19th GEV, you suddenly have a theory of gravity. At the same time, I think it may have been just slightly later, the wonderful physicists, John Schwartz,

and Joel Scherck, both who were incredibly brilliant scientists, had the same idea, I think possibly a little bit more from the supersymmetry perspective, but I'm not sure. They understood the same thing. They were much more in the center of the culture of Western physics, and everybody jumped. Yeah, but it was a development, I think, it was more than just knowing it was a near gravity.

It was suddenly discovering that these things that seem to plague these infinities that seem to plague things went away. That's when everyone jumped on the way. Absolutely. Look, after the fact, I know that you apply, we're going to talk about applying ideas from Spring Theory to Black holes and allography and all the rest, which you played a central role in.

I kind of felt like you came into it from the outside. But I'm wrong. Absolutely true. My interest in gravity, I understood, okay, the Custaria has gravitons in it. But, you know, I was still interested in Lovacay. I was still interested in other things. And the things you can measure in the real world.

No, it wasn't that so much. What has always driven me is clashes of principle. Okay. When two things, both of which you have very strong reason to believe, disagree with each other, court confinement was an example. Every particle has a field. Every field has a particle. It's not working that way.

I've always been driven by conflict of principle. I understood that about myself a long time ago. The existence of gravity was troubling and so forth, but I regarded it as a major inconsistency or conflict of principle in physics. The conflict of principle that really drove me to a gravity was Hawkins. Was Hawking's paradox about information being lost in black holes? Why don't you explain?

I've done it many times for people, so why don't you? Yeah, okay. it's not hard to say in a coherent way. I'm sure you said it in a coherent correct way. First was Beckinstein, who recognized that black holes have a thermal quantity, a thermal aspect to them.

They're warm objects. They're not cold. In other words, they have entropy. Famous entropy. Hawking did not believe that. And eventually had to do his own argument about it. Did some calculations involving quantum fields in the presence of a black hole and discovered, yes,

not only are they warm bodies having a temperature and entropy, but like any warm body, they will eventually evaporate away their energy. That would mean in the context of black holes that they just evaporate, get smaller and smaller and smaller, and eventually just go pop and disappear as a consequence of the thermal energy that they have.

But then a couple of years later, he came to a conclusion that that undermines the basic validity of the principles of quantum mechanics. Why? Because that which goes into the black hole and can't get out, because nothing can ever get out of a black hole, it's prevented from getting out of a black hole by the properties of the horizon, will tell you that information, information means distinctions,

distinctions between things which might have fallen behind the horizon. What might have fallen behind the horizon might have been an election, or it might have been a muon or it might have been an electron with spin up or a electron with spin down or whatever. Those distinctions will be destroyed when the black hole evaporates. There will be nothing left to encode those distinctions. So what it says is that information or distinctions are erased by black hole evaporation. this may not sound like so much of a big deal to the people, but it is a huge big deal from the point of view

of the basic principles of quantum mechanics, also classical mechanics, incidentally, but quantum mechanics, especially. Quantum mechanics says that nothing is ever erased. It cannot be erased. It's called the principle of unitarity. And it is so deeply ingrained in quantum mechanics that if Hawking was wrong,

right, this would have been a major, major shock to the structure of the laws of physics as well. In fact, that that's a beautiful description of this paradox, which was known, you know, from the 1970s. And as you point out, it's interesting that you say you're driven by these conflicts, but of course physics has been largely too. I mean, Einstein, you know, these fundamental complex that led to relativity, led to quantum mechanics, and now this paradox between two fundamental pillars, general relativity, one of the beautiful theories of the 20th century, and quantum mechanics, the other amazing theory that's one of the century, if Hawking's right, they don't work together. And that's profoundly, and from a fundamental perspective,

it's profoundly important. Let me at least step back and say, from a fundamental perspective, it's incredibly important. From a practical perspective, as you point out, it's, it doesn't really matter for almost anything, except for the beginning of the universe in black holes, probably, but if you really want to understand the fundamental physics of the universe, that's the central question. Demi, would you disagree with me? Well, I have a feeling that if Hoking had been right, it would work its way into physics and you would find it reappearing possibly and miserable things, but that's beside them. I've always been enchanted by a remark of Faraday's.

Faraday was asked, what's all this electricity and stuff good for? And he said, well, he really didn't know, but he was sure the British government would tax it. Meaning to say, that which is fundamental at one time will turn up. Okay. Okay, good. You really think you're eventually going to be taxed by quantum gravity? That'll be interesting question. There were many great hopes of string theory in the 1980s when it looked like it was going to solve all the problems.

One was it would produce a consistent theory of quantum gravity. Therefore, it should, if it was a consistent theory of quantum gravity, it should solve this paradox. It also should explain the properties of the world like why we have this very small cost. It hasn't done that. Some people, and I think you're one of them, think it solves, it does resolve the Hawking paradox. I don't disagree with that, but I don't think so much that it resolves the Hawking paradox, is it that it tells you there must be a resolution of it. String theory, and in particular in its form that's sometimes called ABS-C-F-T now,

but it's a version that's a particular version of string theory, makes it clear that there are at least some constructions in which gravity and quantum mechanics can coexist with pretty good mathematical rigor, and that there's something wrong with the argument that Hawking made, because in this context, we know that these two things do fit together, So it's kind of an existence proof that there must be a resolution, that there must be a resolution of this problem in which both of them can coexist together.

I would say that is one of the main, what should we call it, triumphs or of string theory. Outreduced a context in which those who had followed that line of reasoning would have to be totally certain that there was a resolution of it, place. That's a completely different question of whether string theory is the theory of elementary particles and self-force. It's quite a different, and I have very strong feelings about that. To some extent, it's a matter of words. What do we mean by string theory? There is a very precise mathematical theory. That theory has won a number of mathematicians' fields medals. It's very precise. It's very accurate.

and it's rigorous. I'll call that string theory with a capital S. It's super symmetric. It fails when you try to make it not super symmetric. It has exactly zero cosmological constant. It has a number of features which are different than what the real world has. So I can tell you, with absolute certainty, string theory with a capital S is not the theory.

of what you call the real world. I can tell you that 100% back. Now the question is, is there a theory which is sort of string theory inspired? String theory with a small S, which may be bigger, which boundaries may lie outside string theory level. We don't know.

We don't know how to generalize it. We don't know how to push those boundaries away so that there might be things which are not super symmetric, which don't have the zero cosmological constant, we don't know, and we don't know if string theory will help us find those things. When I said I have very strong feelings,

my strong feelings are exactly that, that capital S string theory is definitely not the theory of the real world, and we are still uncertain about whether whatever it is, whether it can be generalized, boundaries, push, string-inspired,

theories we don't know. And I think that's the bottom line now. Well, we agree. This is really neat because I thought we might disagree. We agree 100%. I agree 100% of what you said. And that's my feeling. Some people think I'm kind of anti-string theory. I've never been anti-stream theory. I've just been anti-staffirm. It's a mathematical structure. You can't be anti-mathematical structure. You can't be anti-math categorical structure. But being an anti-Pathagoras is theorem. It's well-motivated and it may have at its heart something that inspires an understanding that's important. But we don't know yet. People will say, oh, all you have to do is spontaneously break supersymmetry, blah, blah, blah.

Well, it's been 25, 30, 40 years by now that nobody's figured out how to do that. Yeah, exactly. Well, let me see if the other – okay, so I'm going to put all these together. Before I do that, let me say. Let me make very clear that the existence of string theory where the capital S has been a very, very valuable. in this context of demonstrating that quantum mechanics and gravity can coexist. There's not been a failure on that. It has, whether it's been a failure in producing a theory of elementary particles,

and just remains to be seen, but with a capital S, it is not the right theory. Okay, no, you're right, and we should not misstate this. So we're in agreement there. Now, I want to see if we agree on the other thing, which I thought we would disagree about. I would say one reads, especially in the popular literature and also in the physics literature, sometimes the same people. Many people claim they've solved explicitly the Hawking Paradox, and one reads this all the time. And I guess my attitude is that because string theory gives in principle the statement that one,

that it's possible to resolve it, that the two theories can be. consistent, there's hope, and there are lots of interesting ideas, but we still do not know specifically how to resolve the Hawking paradox. That's my statement, and I would have thought you would disagree, but maybe you don't. What I would say is I don't think the last word about what has been said, but there has been a lot of very, very fascinating progress that's been made through the connections with quantum information theory, complexity theory, entanglement theory, and these are highly technical things. There was a very, very beautiful construction by Jeff Pennington,

which I think goes a long way toward removing the tension between the quantum aspects. They were motivated to some extent by string theory and then by the SCFT, but they stand alone. They stand alone as quantum mechanical constructions. the existence of things like quantum teleportation. Quantum teleportation is a magical thing which seems to take things through wormholes. It's a real thing.

All these things, I think, have contributed to a conviction that the problem can be solved, parts of it are solved, and the main outlines of the solution, I think, are known. There are lots of interesting ideas having to do with quantum mechanics and entanglement and affect the horizon. And there are a lot of things being thrown at it,

but I guess I'm a less more dubious about whether the statement you just made of the main ingredients or the main... Well, you know, there's a difference between us. Difference between us is I have a proprietary interest in this. A lot of the ideas are mine. Yeah, of course. And that's why I'm bringing them up

because a lot of the ideas of yours you played a key role in so many aspects of this. So I want to ask you then, And if you think the key, the general picture is, the framework is there, describe it. So that'll be useful. I want to hear what do you think is the likely general framework of the solution of a black hole paradox? It's not that I can't do that.

It's that I can't do that in five minutes on the, here's the thing. Let me just tell you, Lettie, I want to get to two key areas that you've played a key role in that I know, and there are many key areas you play to be rolling. But one is that, uh, that, uh, I'm not. this idea of holography, and the other is the idea of the landscape, which we'll eventually get to. In this context of the Hawking paradox, the holographic principle is absolutely key. What it says in a highly unintuitive way is that all of the degrees of freedom of a system or contained within a region of space are located at the boundary of the region of space.

That's highly unintuitive. We usually think of, you're sitting in a room, I can see the walls, I can see your bookcases, the boundaries of your room are the walls, you're sitting somewhere in the interior. Your degrees of freedom are not on the walls of the room. Your degrees of freedom are somewhere in the middle of the room. What the holographic principle says is that that's absolutely misleading. When you push things to the ultimate limit of Planckian physics,

there is no more information in that room than can be encoded. on the walls of the room in tiny, tiny, tiny, plunky and pixels. All right, so that tells you from the beginning, from the get-go. Let me step back for a second, just for the period. And the reason it's called holographic, and maybe you were going to say this, but the reason it's called holographic is that in physics, and everyone's looked at a hologram, which is a plate, a two-dimensional plate, but when you look through it, you see the three-dimensional universe,

and you can look around people, and it's a plate, a two-dimensional plate that it includes. Three-dimensional information being encoded, in a highly non-linear way in the two-dimensional, what you call a piece of film, two-dimensional piece of film. In many cases, that two-dimensional piece of film surrounds the region that it's encoding. Early holograms are like that.

And so that's a direct example of the ability of two-dimensional systems at a boundary to encode details of what's going on. All right, so that already told you that this idea that information falls into a black hole that can't get out, it can't be right, because the right picture is the black hole and everything else is encoded on the boundary of space far from the black hole. That idea that all of the dynamics, the information in some sense takes place on the boundary of region of space is called the holographic principle. It's due to myself. It hoofed them myself. And I must say that when we first put this forward,

I think a lot of people thought we have really lost their marbles. Yeah. We lost our marbles. That they went to two good physicists, too bad. Yeah, but a tuft is so ethereal that people kind of figured maybe he had, but you never see that way. Okay. But one of the people who got pretty convinced very quickly

was Witten. Witten thought instantly, almost instantly, he asked me to come to Princeton and talk about it, which he did. And he was on board with the sake of the beginning.

He understood why it was important, how it worked, as he always does. I cannot remember if Juan Malasina was in the audience or not when I spoke. Probably not,

because, but the whole thing didn't really get legs, as they say, until Juan found a very, very concrete example. Yeah, I want to stop you here because I find this fascinating. You and

and Tufth had come up and talked about, and it's not too surprising when you think about, you know, the, the, the, the, the, something called the horizon of a black hole. Lots of strange things happen at the surface. You're standing in infinity. It looks like time stops there. So it's not too surprising to think somehow all of the information is encoded on the surface. And I think that's what motivated Tuf and, and, and you as well, fascinating. So this idea that, that things would be embedded in one dimension less came from that very physical thinking and then from a totally different perspective coming from string theory while meldasena a decade later maybe i think maybe no no no no no oh sorry 1993 uh yes more than a decade yes see okay i'm maybe more than a decade but anyway it was

certainly a totally well later discovered an amazing property related to string theories that showed that physics fought one way, the world could be described by physics on, described in with one theory in a certain number of dimensions and with a very different kind of theory, exactly the same physics in a world with one less dimension. Literally, and so may you, you can expand on that. Yeah, let me just, let me just correct your, your history a little bit. Okay. The holographic principle went back to something between 1993 and 1994.

Yeah. Juan's paper was 1998, so it was five years. Oh, five years. Okay, it seemed like in a decade. But anyway, but it came from a totally... Came from a different place, yeah, absolutely. I would suspect it wasn't motivated by that black hole thing. It looked like it was completely motivated by mathematical properties of these things called conformal field theories.

And D brains, D brains. Joe Coltrinsies D brain. Yeah, and properties of one of the things that string theory metastasize into called M theory and brains. And so that's, you know, very technical, mathematical stuff. And he had this amazing insight, which was a speculation. It looked like, it looked like for certain very specific theories, very specific theories, you can show that the world could be described two equivalent ways with different numbers of dimensions. And so dimensions and one less than another, which is, of course, another way of thinking of a hologram.

Let's see. One is, of course, has very great talent as a theoretical, physicist, intuition, intuitive talent, but he also much more than me has an ability to be precise, quantitatively, and mathematical. So his construction was so precise, so mathematically sophisticated that it caught on instantly. People recognize, yes, it has to be right. People make sounds about it. As the whole holographic idea was much less, yeah, yeah, touchy feel. Yeah, it was intuitive. I mean, you can read the papers. It's that. But it's a good thing I like, actually.

Yeah, well, no, I think the arguments were solid. The arguments were solid, but ones were far more technically precise, rigorous. I think that what your point you're going to make then is if all the information in the world can be encoded on a boundary that's one less dimension than the actual volume, then in principle, that's the solution of the hockey paradox, essentially. In principle, that's a, I will say that's part of a solution, yes, yes. It is an essential part. And so that's the idea, but how exactly is yet to be determined? Would you agree with that?

Yes, I would agree with that. It's still a bit mysterious and counterintuitive for sure. There are mathematical examples, N-equal source who being those, blah, blah, blah, blah, blah, and this so-called S-YK theory where these things actually occur and where you can trace them through. But nevertheless, they are still rather mysterious. Well, they're more than that.

I'm looking at you. I'm looking at you sitting in your room. And I'm saying, you're in the middle of the room. You're not on the walls of the room. But it's not to your... Rarely. But at the same time, it also reminds me to something you said earlier,

the small ass versus the big S. The case is where one knows, knows one can use this, one can use this mathematical construction, are very specific cases, which we know are not the case of the world in which we live. I think that's a person. And so that's a significant problem. And it motivates you, but they clearly don't describe the world in which we live. That's correct. But on the other hand, there are enough to tell you that when anybody comes to you and tells you, I have a proof that information will be destroyed in black holes, you're permitted them to say, no, you don't have a proof because I have a

counter example. I wanted to give people the sense of where we're at, because they hear all the time in the media about black holes and arises and firewalls and all this stuff. And, you know, they're fascinating ideas and they're being applied. And lots of smart people are thinking about it. And there's lots of wonderful developments at the forefront of thinking about information and quantum mechanics and stream theory. And it is fascinating. And make it taxed. It may get taxed as a consequence of quantum computer technology. Okay, maybe that's the way. I was wondering where you'd see it detect.

Because some of these ideas, you're right, are extremely relevant to quantum computers, and some people would claim, and I think you actually are one. There was a lot of hype about a quantum computing calculation that claimed to do something that I'm not sure with. Oh, oh, those calculations, you're talking about the experiment.

Yeah, the quantum computing experiments It's an equally important formable. It's not a very good experiment. The experiment was an attempt to carry out a protocol that was invented by several people, and myself included, but the protocol is a great protocol. The experimental implementation of it left more than a little bit to be desired. It got a lot of hype. But anyway, and I'm always, I told you, what I'm always against is just hype, not the idea of surprise.

Well, that got much too much hype, yeah. And so, I mean, my problem with string theory was in idea where it was the hype, that it was immediately going to be a theory of everything. It was a fascinating idea, but it wasn't that it wasn't what it, you know, whatever. Yeah. That's all. People get excited. I know, I know.

It's enthusiastic. They get optimistic. Absolutely. We're going to get to this near the end in a few minutes, in fact, because I don't want to get a little. But you, like me, you write books and some of them in popular books as well as beautiful textbooks or semi-popular book. By the way, we'll get there.

Do you see these few books here? Those are theoretical minimum. Yeah, they're right there. Yeah, they're your books. My eyes are so good, I can actually read what's written on the wall. Yeah, yeah, that's right. Anyway, as you know, I've spent a lot of my life in sort of the public communication science. And I think what I worry about is we owe it to the public, I think, to be careful in what we say.

And I understand we get excited and it's fine for physicists to get excited with each other. We have to be careful of what we say we can do because if we don't, it'll come down and bite us in the bottom. Well, yeah, yeah. I completely agree with that. But on the other hand, there is a tension between that and the importance of keeping excited and letting the public know why we're excited. So there's a tension there. Let's talk about the last tension because, and you invented the term and at least for one of the people

and the key ideas, and I don't know the history enough to know. I heard it from a variety source. But a bog of string theory has been turned into a virtue in a sense. that strength theory we people thought string theory would give this unique theory that and in fact it's exactly the opposite it gives not just theories it gives worlds and physics it's not an infant number but you know such a large number that it's probably infinite and and you might say well there there goes there goes physics because it's no predictive value and anything else but what it's led to and i think you were the first person to popularize it but i don't know

I read the paper on the landscape. He certainly coined the word, noting that, well, maybe this bug is actually a feature because there's certain properties of our world that seem very inexplicable, and one of which is near and dear to my heart, since I guess I was one of the first people that was there, was a cosmological constant. And it's an absurdly weird value that none of our fundamental theories no one has any idea how to get that kind of number. But it could just be an accident.

If there is a lens, if there's a string landscape, that means it can be, it means it's the opposite of what you and I, what drove you and I into physics. Both you and I, I'm sure, got into physics the same reason. We wanted to discover the theory of the world. We wanted to discover why the world had to be the way it is, right? Yeah, I think that's fair.

And what we now discover is, well, and the world's can be many, different ways, and it just happens to be the way it is, if this is true. And why do you, why do you elaborate? I'm talking... Well, the only thing I would say about what you just said is evidently, as a matter of empirical fact, the world is much, much, much, much bigger than the portion we can see. To say, the world is a particular way. You're talking about a little bit of it. Exactly. It's a my own picture. The universe, we used to call universe something very different. What these ideas of a landscape

require, they require, I think. So there are three things that I think push you in that direction. The first is this fact that inflation theory tells you that the world is much bigger than the portion of it. Yeah, I want to get, I want to contrast the string

landscape and inflation because I let me tell you where I'm coming from and then you'll be when people ask me about the multiverse, my response and is what I happen to the world true. Inflation generically predicts a multiverse. So I view the multiverse inflation is incredibly well motivated from physics that we more or less can understand. The string theory

landscape is another version of a multiverse, and it might be true, but I guess I hold it as less directly motivated. Do you agree with that? The fact that there are many little subuniversers out there, That does seem rather well motivated from inflation. Whether or not they all have the same properties, that's a separate issue. They might all just, if there was only one solution of the equations, whatever the equations are, they might be string theory, they may not be string theory, the with a capital T, equations, if there's only one solution that allows only one kind of universe, then all of these little sub-regions will have to be the same rules, the same empirical rules, same

particle content and so forth. If on the other hand, the equations, whatever they are, have multiple solutions, 10 different solutions, 100 different solutions, which means 10 different possibilities for the particle spectrum, 10 different possibilities for the cosmological constant, then I think there would be every reason to believe that these different cells of sub-universes can be, can and will be different than one another. Absolutely.

The question comes down to whether the equations have multiple solutions and if so how many. If the number is huge, then fine-tuning becomes a new issue. If the number of solutions are so large that there will always be some solutions which have the properties that you're looking for, then we're in this funny situation. It's hard to be predictive from it. But on the other hand, the rules will tell you there are a lot of structures out there, only some of which make sense as possible habitable worlds where we collect. If that's really the case, I think we have no choice but to say our original hopes and dreams for a unique solution, which is misguided. they may reoccur on a bigger scale, on a bigger scale of the equations,

but we have to expect that the world that we live in may be just contingent, may just be a contingent property of a particular environment. It turns physics and environmental science. In a sense, yeah. In a sense, in a sense. Now, let me ask you this question in it. So this is the, just for the audience again, that it's often called the anthropic argument, which is the contingency argument you gave is that the certain properties of our world may just be

our artifact of the fact that they allowed us to be here to measure them, that if they'd been different, we wouldn't be here to measure them. It's not an intent. Does the design, you wrote a beautiful book, I think, or at least an article, a book, I'm arguing in another deal with mythology design. It doesn't. But it just means that, you know, it's, as I often say, it's like of an intent. intelligent fish would ask the question, why is the world made of water? Because if it wasn't, they wouldn't be asked the question. It's a fascinating question. It's an open question. I think, I know, I think most of many people are on the same side of this, but I want to just check. One of the fundamental problems of particle physics is this weird thing called the cosmological

constant of why this energy of empty space is the value it is. If you were going to guess, do you think the resolution of that problem will be anthropic, namely an accident of nature, or that we'll have a fundamental theory that will explain why it is what it is. What's your guess? I don't know another answer. I simply don't have another answer. This is a possible answer. It seems to me logically coherent.

It seems well motivated that the equations push you in that direction. And I simply don't have another available answer at all. So I would have to say, given all the available answers, which one is most likely? right. There's only one. Yeah, it's the only one available answer. You know, and I agree with you completely. But historically, I will put in perspective, at least, there have been a number of times in physics when anomalous and weird quantities showed up, and arguments like this, an anthropic

argument made with the states of certain nuclear states and why there were, why carbon is producing stars. And there were no reasonable answer. So people assumed it was anthropic. what's interesting is the minute a reasonable answer comes up, then the anthropic argument goes out. And so this could be another example. We're at a point where we don't know. Yeah, look, I mean, what you're saying is the thing that worries me about this.

There are historical examples where extremely compelling visions just turned out to be wrong. Any number of them, but ether is one of them. How can the world possibly have electromagnetic signals propagating through it unless there's some substance that it to propagate through? It was so compelling that everybody would have to believe it. It was wrong. Technicolor was so compelling. I was going to say technical color is another example. I would argue, I think, yeah, I had many ideas that I thought was so compelling nature.

However, I would say after a good number of years, 20, 25 years, however long it is, nobody has been able to produce a better explanation of all. we see in this one. So it has to be considered the leading candidate, I think, just because they don't know what this. Yeah, and let me say, I would go, let me ask you if you agree with this. I think everything I know about physics at a fundamental scale from inflation and even string theory, but it leads me to think that there is a multiverse, that the multiverse is the most likely, that there is, that it's highly unlikely that our universe that we call our universe is unique. that's different than saying the solution of this weird problem will come from that. So you would agree with me that if your guess is that it's highly likely that we live in a multiverse.

It's hard to imagine we don't. Yeah, I do think that's right. Yeah, yeah. And just for the people who, because I'm often solved and involved these kind of debates, some people think we physicists involved in a multiverse, you know, because we didn't like God or something. and this is our version. What I want to point is that we were drag kicking and screaming the multiverse. I mean, a lot of us would like the world not to have a multiverse

and have a unique laws of nature. And it's, well, I think we can agree there. We're not wearing a little bit of it. Look, it came once again from a conflict of principles, from things which we deeply want to believe, but which are inconsistent with each other. And something has to give. In this case, the speculation is that what has to give is the uniqueness of the solution of the equations. And the uniqueness of our universe.

And that is a, that, you know, that's, I mean, it has a noble tradition because we, it's the ultimate version of the Copernicum principle. And, you know, that we're not the center of our solar system, we're out the center of the galaxy is nothing. And now we now think our universe may be nothing special. That's fine. For me, I find it in light, I find it energizing and fascinating, it makes the accident of my existence even more precious and the accident of the fact that I can have a conversation with you even more valuable. Before we end it, I want to, and I want to spend the last two minutes. You've written popular things and I've written, I happen to love the theory. I just think it's a, those are, are really, Lenny, I, I read them. And of course,

even when I understand the stuff, I find it has illuminated for me my thinking. Well, that's high praise, Lawrence. That's high praise indeed. Thank you so much. Sure, no, it's great. So what made you decide to do it? I was going to tell you something which is kind of ridiculous. All of my life, I have been under the impression that I'm terrible at writing. This centered back to my experience as a young student in school where my English teachers, all day, was terrible. I didn't believe it. I suspected that I had some talent

at it. So at some point, I just said to my wife, you know, I want to try. I want to try to write. The first books I wrote of the popular books. Yeah. The Black Hole War and the Cosmic White. I said, I want to try. I want to see if I do have any talent at all. I suspect

I do. I had written a number of magazine articles for Scientific American articles that were well-received, people like that. And I'm going to try, I'll write a couple of chapters of a book. I wrote a couple of chapters of the landscape book. He gave him to a friend of my wife who had been a professor of literature in University of Washington, a friend Malcolm Griffiths. And he read it and said, you know, you are a good writer.

You write well, but you have no concept of what it means to write a whole book. Books have to hold together. chapters have to lead from one to another and so forth, and you're just chaotic. That was enough. He didn't have to tell me anymore. I looked at it, and I said, yes. And I got very intrigued

by the problem of how you put a book together. You put a book together and get it to cohere. And so, to some extent, it really was just a curiosity of whether I had the capacity to do it. It was fun. I got completely absorbed in it.

They're absorbed in it. Most of my friends who wrote books about physics said they were so sick of it after two weeks that they just went away for it to be finished. I would wake up in the morning ready to start. And then we'd go through to 5, 6 o'clock in the evening. My wife wouldn't see me all the time. I'm just completely absorbed in it. Wonderful.

So I found writing very energizing. Yeah, no, well, obviously, I can't say, you know, I've written 12 books. Well, you've done a lot of writing. I don't know how much you enjoyed it. Well, there are days when I don't. And it's very, when you really have a hard time, I've always wondered in the end whether the most useful thing I would have ever done is my science or my writing. And I'm not to me to decide.

And I don't really care. That's right. Exactly. I don't really care. It's something, yeah, it's both two things and I value them both. I'm glad you've written. And as I say, I think the theoretical minimum is a brilliant idea. And it's a beautiful, you know, it's a beautiful set of.

books that are semi-technical, but they're great. Anyway, I just think they're great. Thank you for this. I, you know, I wanted a trip through your life is a trip through modern physics in many ways, and I enjoy talking to you so much. In fact, I'll tell you something, one of my sadnesses in life, there was a while, long time and I wanted to move to Stanford, and one of my life, I thought, if I could just spend every day talking physics with Lenny, my life would be better.

So I'm glad we got to spend. Yeah, that was fun. That was fun that it was. Yeah. Thank you. I think the people, I found it fun. I think people are fun and thank you for taking the time on your birthday. And Father's Day to spend with me.

And I'm glad you enjoyed it. And it'll be a great, I think it'll be a great record for people. So thank you very much. Hi, it's Lawrence again. As the Origins podcast continues to reach millions of people around the world, I just wanted to say thank you. It's because of your support, whether you listen or watch, that we're able to help enrich the perspective of listeners

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