Into the Impossible With Brian Keating - Lee Smolin: String Theory is Still Wrong (#152)

Episode Date: May 27, 2021

Lee Smolin is a theoretical physicist who has been since 2001 a founding and senior faculty member at Perimeter Institute for Theoretical Physics. His main contributions have been so far to the quantum theory of gravity, to which he has been a co-inventor and major contributor to two major directions, loop quantum gravity and deformed special relativity. He also contributes to cosmology, through his proposal of cosmological natural selection: a falsifiable mechanism to explain the choice of the laws of physics. He has also contributed to quantum field theory, the foundations of quantum mechanics, theoretical biology, the philosophy of science and economics. He is the author of more than 150 scientific papers and numerous essays and writings for the public on science. Thanks to our sponsors! https://magbreakthrough.com/impossible http://betterhelp.com/impossible Learn more about your ad choices. Visit megaphone.fm/adchoices

Any sufficiently advanced technology is indistinguishable from magic. A legendary figure in my life in physics, in cosmology, in philosophy, in mathematics. And that is Professor Lee Smollin, joining us from the Perimeter Institute, our neighbor to the north. Lee Smollin, how are you today, my friend? I'm very well. Thank you. And thank you very much for the kind words and the invitation. Well, you've been such a huge influence on my life. Since before we met, going back to our mutual friend, Dr. Professor Stefan Alexander, days, and his connecting me to you way back in the early 2000s.

And so he gets an intellectual shout out. So, Lee, you've made fundamental contributions in many different aspects of cosmology, of physics, philosophy. But what I first want to turn to is the influence that you had on me as a younger physicist, as a beginning professor back in 2006 when your really apoccal book called The Trouble with Physics came out. This book influenced me and a whole generation of physicists, both theoreticians and experimentalists like myself. And there are very few books that in physics that are relevant 14, 15, 16, 4 years, 3 years,

two years after they're written, let alone 15 years after. And in this book, which I reread, relistened to recently in preparation for this interview, I noted that you were talking about the stagnation in physics in the previous 25 years. So if I add, I'm not as good at math as you are, but if I add 25 to 15, I get 40. Yes. Wow, I do too. Do you still stand by that, or do you still observe that same stagnation to some extent in physics, at least in theoretical physics. Obviously experimental physics is completely different.

There are certainly areas which are doing very well. There are areas of quantum materials where the theory is really interesting and I think it's still true that we have not made a fundamental discovery experimentally that we explained theoretically or theoretically positive something who was discovered experimentally. fundamentally. And we still don't know the why questions about the standard model, why those, they're now something like 30 parameters including the now that the neutrino has mass, including the masses and the mixing angles of the neutrino. And we have no explanation for what the values of those dimensions are, nor for the strength of the gravitational constant, constant,

nor for the dark energy or the cosmological constant if that's what it is. And I went into physics to understand why the universe was the way it is. And there's lots about that we can get into. The universe is not just some random set of numbers out there. The universe is enormously structured and organized and self-organized and self-overished. and self-organized and that seems to be at least partly due to those constants being in certain narrow windows where there are lots of chemical and nuclear reactions that can take place. So I think I stand by that.

We don't have we have ideas about quantum gravity and we have more ideas than we did 15 years ago. None of them have some of them have some of them make experimental predictions, but none of those predictions have been left out. Always the default, as you would know, we've looked for the Rens Symmetry Breaking at the Kong scale and around the Kong scale using astrophysical experiments, and the evidence is that it's not there. And there's a number of other anomalies that we look for and are not there. So it's a very frustrating period.

And when we look at alternatives to string theory, which has become and still remains a dominant paradigm, I've had conversations with Carla Rovelli, who's become a dear friend. And actually, we are collaborating together. And he is another person. I thank you for putting me in touch with many years ago. And we are collaborating in the first ever audio book version of Galileo, Gale. Galile's dialogue on two chief world systems. Oh, first physicist to work on.

Yeah, it's going to be amazing with another Italian physicist, along with Jim Gates, reading a foreword from Galileo Fabiola Gianate and others. Stay tuned for more information about that. You can get more if you subscribe to my newsletter at briankeating.com. But I want to turn our attention to some surprising developments that I had talking with a string theory proponent, and that was Michi Okaku, who came on my podcast recently in promotion of his new book, The God Equation, which he claims, you know, string theory is responsible for a series of successes,

not stagnations. Even such things like the G-minus-2 anomaly and the LHC Beauty Experiment Anomily, that these things are hints, tantalizing hints, of the efficacy of string theory. And I push back, Lee, you know, I'm only a simple experimentalist, I said. But I said, to my knowledge, and you, Lee, can correct me if I'm wrong. Nobody looked at string theory and said, hmm, let's predict this correction to the to the g minus two from string theory. And he pushed back on me and said, well,

nobody did that from loop quantum gravity because loop quantum gravity is so simplistic, it doesn't even have fermions in it. And I said, because I'm just a fool. I don't, I didn't know how to answer them, you know, and then we say in Judaism know how to ansel a heretic. So I didn't know how to answer him. How would you have answered him? Michi Okaku, when he says loop quantum gravity, which you are one of its foremost exponents along with Abbas, Abbe Ashtakar, and Carlo and others. But Lee, how should I have answered him? I'm sorry I let you down, but how should I have answered him? No, the way to end there, first of all, loop quantum gravity is a method. It's not, in my understanding, a theory. It's a method of studying systems whose forces are described by gauge fields, and we can talk about

what that means, like the standard model of general relativity. And that method applied to general relativity yields some very interesting descriptions of what the geometry of the world might be on very small scales, that is 10 to minus 30 something of a centimeter. That method can be applied to theories with fermions and there are, and they fermions behave like fermions. So there's no problem including fermions. There's no problem coupling to gauge fields and coupling to the scalar and the fermions of the standard model. There is a very interesting issue around chirality, which I know is a, you know, is a, you know, an issue in cosmology and astronomy with you, but worked on a lot and thought about.

So we have some issues about chirality, which I'm happy to admit. My feeling, and I hope I can say this without sounding egotistical or something, the people you mentioned Abai and Carlo and I are thought of often as the founders of Lupine gravity the inventors but let's break if it's interesting let's break that down yeah

Abai brought into being an approach to general relativity based on seeing the geometry of space and time like a gauge theory. I can tell you what that means in something. It means we care more about measuring how things like fingers or spins move around when you move around space.

That's called the connection. The connection tells things how to mean. And my first role, I guess I have many, but my first role was that there was a whole bunch of beautiful ideas and technology, theoretical technology, that had been developed about QCD, mainly by a Russian school, Sasha Palekar, Gribar, Migdal, and there were also some Americans principally Ken Wilson. and they had a beautiful picture in which,

well, do you know, or do your listeners know, that if you pass magnetic field through a superconductor, it becomes discreet. There's a unit of magnetic flux that that flux line will take on in his organization. And their hypothesis, what was also due to Hover Nielsen and a number of other people, was that in QCD, which is sort of like a complicated version of electromagneticism of three photons,

the electric field flux would be quantized and discrete. And there was a picture of strings made out of that flux holding corks together. And I basically stole that. I mean, it's legitimate. That's what we do in science. all that picture and technology and said, what if instead of QCD I plug in a Binds

theory about seeing gravity and connection with you? And use all those beautiful ideas and tools that I probably call him Ken Wilson. And that was, I got lucky in some sense because where and when

I went to graduate school was immersed in that, those ideas and those technologies. And I was the first to try to apply them to quantum gravity. And I had a picture in my head of loops and areas being quantized and so forth. And that picture, with a lot of input from other people, became quantum gravity. And particularly, Carlos brought a very important picture of how to think of the quantum mechanics of all life. mechanics of all that. But now, but now it's, that was the middle 80s. I don't want to count, but that's a long time ago. I love Lumpuron and Gravity. It's been a family. It's been

an adventure of friends. But it has problems too, and I'm happy to talk about them. I'm not, I would not think of myself as a proponent in the sense of somebody who ignores the issues. I think there are issues. And when I set up a research center perimeter, I used a philosophy, which is part of the book, you want to talk about the trouble with physics, which I gained from the philosopher, Paul Fierrobin, which was to get good people from diverse points. of you and don't privilege one point of view just because I have a legacy with that theory. Get good people who think of quantum gravity from several points of view and have the

conflict, which is what the trouble with physics is about. Right. So there are people in the luploid gravity world who think that I abandoned them, and there people in the rest of the world who think that I'm a Rupon and Favity God, and I'm neither. I really love the way you say that. And, you know, when I think about things, I often wonder, you know, are we putting the gut before the toe or the toe before the gut? And by that, I mean, you know, we don't have a good grand unified theory yet, in my opinion, or my understanding. and yet people want to look for a theory of everything.

First of all, I think a theory of everything, and I think Michio does a disservice, to be honest, by saying that this one-inch-long God equation will describe everything. It'll give you soup and nuts, and it'll give you aliens, it'll give you avatars, traveling at the speed of light, cruising around the galaxy. It will win you a Nobel Prize that Einstein couldn't win, and you know how I feel about the Nobel Prize

as Hey Geographic, you know, kind of idol worship, oninistic idol worship. Nevertheless, it's important to consider what is the importance of a theory of everything. And I want to ask you, are we putting the toe before the gut? Should we, in your opinion, spend more time thinking about how do we unify the theories that we have very strong evidence to believe that are unified? I personally don't believe that we should demand that gravity be unified with quantum mechanics. I hope we can get into that. But what do you think?

Should we focus first on guts before we get to toe? Well, long before that, let's open up, can we open up to the whole universe? Yeah. It seems to me there are two kinds of phenomena. They're loosely speaking, there are phenomena. I mean, we believe, you and I and most of our colleagues, believe some version of the laws are pretty stable and there are fundamental laws, and we're trying to find out what they are, and they're pretty stable. I actually probably disagree with you, or at least with most of our colleagues.

I think those laws are changeable, and I think they do change, and I think they have changed, and I think that because that's the only way we're going to explain the question of why they have the form that they have. So I'm on the lookout for principles by which the laws can change. that is I'm no longer hopeful that there's going to be some magic formula that's going to tell us what the values of all those elements are I think it evolved that way because there are consequences for the natural world, for the physical world

which we can come to thinking about it that way you have to invoke functional explanation a functional explanation is an explanation of something where you use some consequences of what it does in the world. So there are 20

to the thousand different kinds of proteins, roughly. That's 20 different amino acids in a thousand places. It's a typical protein. That's a whole lot more than the kinds of proteins that exist

on the biosphere that are coded for in the DNA or the RNA of the various creatures, which are like them. A million. So any protein that exists is lucky because most of the other alternative proteins don't exist. And why did it get lucky? It got lucky because, for example, my code for hemoglobin, which is a fundamental way to move oxygen around within a creature, and which there's a lot of, along with various variants and so forth. So if you ask, why does hemoglobin exist? Sure, you've got to be able to analyze and see the laws of electromagnetism and so forth,

acting inside that crazy, wound up, folded up thing. But it's also, there's also functional explanations, and both of them have got to work. So I don't, so I, and I think that's going to apply to everything. And I also don't take the mathematics as dogma, as religion, if I can use that. I was at one time, but I am no longer looking for that mathematical object, which has all the truth of that nature, to somehow transcend our existence and give our life meaning. I think we give life meaning through friendship and families and what we believe in and who we love. and the universe kind of does, is doing the same thing.

So I'm not, many of our colleagues are looking for something transcendent when they want to know what the law is, what the standard model, you know, what the two unified theory is. I would love to see some explanation of the structure of the standard model. I've been attending a, we have weird conferences, of course, of the human. know, some promises are every week, or some or every month. So there's a conference about an idea that used to get you kicked out of the archive, but it turns out to be solid enough that there are a lot of interesting people doing it, which is that the standard model has something to do with the number system of Octonians. And that would be cool.

But I certainly like some explanation. Where does the SU3 course S.S.U.2 come from? where does the three generations come from? We all want some kind of answer to that. And my, I'm willing, I'm in fact eager to have a functional kind of example. For example, this might come up later. If you want the universe to reproduce itself through black holes, which is an idea that I had,

you want the upper mass limit of neutron stars, to be as low as possible so that as many supernovas lead to black holes as opposed to neutron stars. And from that, you can get a prediction that the heaviest stable neutron star can't be more than two solar masses. And the reason is some complicated thing about the strange core, if I won't bore you it unless you really, really want. But the thing is that recently there's better and better evidence. that there are some neutron stars up in 20, I'm sorry, two solar mass at 2.2 and so forth.

And if those hold up, then my theory or my hypothesis is falsified. And I will proudly say so. For the moments that matter, choose Kyrad Naturals. infused with aloe vera and vitamin E. Kyrad natural's bandages protect your unexpected scrapes, cuts, and burns, while also moisturizing your skin. Find deeper relief with natural ingredients you can trust to start the healing. When life surprises call for the best, choose Kiraad, a deeper level of care.

Shop the full collection on Amazon or visitkirad.com to learn more. Yeah, you talk about that a lot in the book. You talk about, you know, different gamma-a-ber, signatures that could be falsified as of 2006. You have other tests that could be, you describe them as very exciting variation in the fine structure constant. You point out as very exciting. And I know that you have extreme integrity in all ways, not only personally, but because I know you personally, but also because publicly you've talked about how this has gone away, that there's no, you've stated that you kind of abandoned that that hope and you admit that it was a hope back in the

early part of the of the you know of the 2000s that these fine structure constant could be revelatory of new physics but now it's ruled out and you accept that and you move on I wonder you know when I first started hearing about you from my from my best friend Stefan you know I always thought that you know when I first learned about you it was like what Stephen Hawking reputedly said about Yaakov Zeldovich, when he met him, he thought that Zeldovich was like Burbaki, like a collective, a set of people. And I thought that about Smolin. I thought Smolin was like Satoshi Nakamura or whoever that guy is who supposedly or collective came up with Bitcoin or blockchain. I want to ask you, you put out three or four papers recently, and some of them

with Stefan, some of them solo papers, this voluminous effort. I think you're writing a paper right now. I'd like to see your hands lead because you put your hands up. So I know that you're not typing out of paper as we're having this lovely interview. But I want to ask you, what would a theory of everything look like? Would it be the semi-classical Wheeler-Dewitt equation that would be fundamental? Would it be the Schrodinger equation if gravity is fundamental? Some say the Schrodinger equation. If gravity is emergent, some say it's the latter.

Your recent paper is so fascinating. You have one called the quantum mechanics of the present written with Clea Verde, I think is how you. Clelia. And the other one, the symbiotic emergence of space and the quantum. That one is a solo paper. Let's talk about that first, Lee, please. What does it mean that for space to become emergent?

What does that even mean? What it means is that the organization of space, of things moving in space, is not fundamental. It's real for sure. Of course, we see it. But it's not fundamental. And what I mean is that I'm looking, like many of our colleagues, for a formulation of theory that is a story about the world and how it's made,

that will explain the mysteries of quantum mechanics. So I'm a little ambitious for better or worse. to explain the mysteries of quantum mechanics and resolve those issues like the measurement problem. I want that same structure to explain general relativity, so to be the quantum theory of gravity, although the fundamental theory that it's coming from is neither quantum mechanics nor gravity. And after a lot of thinking and talking, here I've been in. influenced by a number of people. It's always important.

I mean, we never do these things alone. So Fotini Marco Pulo was the first person who said to me, space does not exist so time can. Space is not in the fundamental list of things that are there all the way down, but time is. For example, space time is in some fundamental way a different thing than matter. And if space time is an environment, if space-time is an emergent concept,

then it's not really clear what you would mean by unification. Surely it would not be the unification of matter with gravity. It might be a way to get gravity out of matter. That would be a different sort of, I guess you could think of it as a unification scenario, but it's a bit different than what people are considering now. I see. And Roberto Mangibar, Hunger, who is a Brazilian philosopher,

was interested in the same kind of thing. and we wrote it was hard, but we wrote a very interesting book together. That book is called The Single Universe. And the basic idea of that theory, that theory is now called the causal theory of views. And the basic idea of that theory comes from Leibniz, the philosopher. And it's going to sound a little weird. It's that the universe is composed of partial views of itself. What I mean is that at every event, and this is a theory of events and the causes between events.

There might be two events here, which in some sense are the cause of a third event, which is a cause of the fourth event. And each event has a past, has the things that led up to causing it. and I call that the view. That's far from my mind. And I take the set of all the views from all the events in the universe to be what the universe is. And then I apply laws to those. And the main idea there came from work in common with Julian Barber,

a long time ago, which is to measure the complexity of some complex system, whether it's a city or an economy, or a piece of quantum space and time, by making the views from different events or different situations in it be as diverse as possible. And you can write down a numerical measure of that, and that we take as the quantity that gets, extremized to give you the equations of motion. Physics is often organized in such a way that physics and quantity that gets extremized or minimized, that's called an action. And so the theory has an action which is related to what we call the

variety. Now, the one last thing I have to say about how this goes together is that If you don't have space, you don't have distances between things, you don't have functions, you don't have fields, you don't have derivatives. So how are you going to write down dynamics? All the things that will go into are writing down some law of a field or a particle involved distances or derivatives or fields. And so we don't have any of that, but what we can do is compare the views. We can ask, you look around where you are, I look around where I am, and that there's a mathematical language to record that view, and then they can be compared. And so the whole dynamics that I develop is based on those comparisons.

So that's the basic idea. Then what happens in that paper with unfortunately too many technicality. and so forth, is I derive quantum mechanics from those ideas. Interesting. Now, you mentioned Julian Barboor. He's an upcoming guest on The Into the Impossible podcast, and I asked him to ask a question of you, and he responded, and then I will ask you to ask him a question

that I will convey through me to him. So his question to you, if you're willing to play this game of time traveling. questions. This is a very inefficient way to use the internet, Lee. I hope you appreciate how time inefficient this is to talk about time in this way. But anyway, Lee, Julian asked you, with warm regards he sends to you, if time is fundamentally, what is it like? What are its attributes? Very good. So what we say, and this is in the work we did with Marina Cortez, developing a prior structure to the theory that was describing. What we say is that the business of time,

so I'm not going to define, I'm going to duck it, but I'm going to say that the business or the work of time is to continually make new events which make up. So what I want to say, what time is like is what we experience. That is, we experience the momentary present and the passage of those moments when new things happen and new things happen. And that's the business and the mechanism of time to keep choosing what new things get made and what they, and therefore that chooses what their past looked like. I talked to Frank Wilczek about time.

And his basic thesis, you know, is that, you know, time and entropy are somehow fundamentally linked. Carlo feels this way as well that the Clausius equation of, you know, delta S is greater than or equal to zero. Entropy is, you know, and that things change. And that Frank then supplements that equation with the fact that a clock measures something that is changing. And time is what we call the change in something. So it's sort of a totology, but it's almost the best that we can do. So clocks measure time, and time is what measure, you know, clocks measure changing time, and time is what clocks measure. And so, but, you know, to my opinion, there, because, you know, microscopic physics is reversible, except at the moment of quantum measurement, it may be just like with the twin paradox, and you know, I have twins and I get to do experiments on twins all the time, something I share with a lot of physicist, David Kaiser, Sabina Hosenfelder,

Peter Diamandes. We all have twins. Some of us have boy-girl twins, and that makes it even more fun. But anyway, you know, the kind of the classic twin paradox, which you talk about in your book on Einstein, an unfinished revolution at some level, the question is, you know, if two twins set out, one sets out at close to speed of light, turns around after a rocket voyage and comes back to Earth, the other twin seems to have aged a lot on earth, even though they seem to be moving at relativistic speeds, each one experiences the other one moving relativistically, but it's the one that undergoes the acceleration when he or she turns back and comes back. So at that moment, that instantaneous moment, it's almost as if all the acceleration of time takes place. And I wonder, is that not possible

on the microscale? In other words, yes, the microscopic laws of physics are immutable, their time irreversible, until you do a measurement, and then that measurement, that's where all the time, you know, directionality of time takes place. Here's how I've been thinking about it lately, which is, some of which comes from that last book, Einstein's Unfinished Revolution, and some of it is recent work with another collaborator, which is Cleo Verde.

And it was basically her idea. So she came to me and she said, so I think I worry about the distinction between the past, the present, and the future. And so my friend Carlo and lots of people believe that there is no objective distinction between the past, present, and the future. And I do. I think that the time is now, now is real. And that that matters to stating the laws of physics. And the question is, certainly the present is real, but is the past, is the future?

And how does this relate to quantum mechanics? So Clele's idea, which turned out when we looked into it, to have quite a legacy, which I'll come to, is that the future realm is indefinite. And everything that from quantum physics is indefinite, that is a part of a superposition, could go this way, could go this way, is part of the future. That is the way function,

the quantum state is a description of the future. And what the present is, is the resolution of indefiniteness and ambiguities to definitenesses because the past is always only definite. And I was really interested in that and shook up by that. And then I started to ask some friends. And it turns out that Heisenberg said this quite precisely. It's not, it's hard to find.

But Heisenberg said this in Schroeder and Freeman Dyson quite at length in one quote you can find, which of course we put in the paper. So that's, and this is a new idea, so it could be wrong, but I'm kind of, I find it very interesting, this idea that what the present is, is the resolution of indefinitenesses and ambiguities. And so let's think about that for it. Yeah, I wonder if, you know, some of the most interesting things in physics come about because of anomalies. And those anomalies are really the things that make you sit up and notice. As you know, I'm a pilot. And, you know, an anomaly in the cockpit is a flashing red light, you know, and you ignore that at your peril.

And I think, you know, those are some of the greatest gifts that physicists have. And one of the greatest gifts that we got was in the 1950s when we noticed the parody and chirality of nature. was not a perfectly obeyed symmetry. But we do think, you know, correct me if I'm wrong, that the combination of discrete symmetries, charge, parity, and time reversal is respected. But I wonder, this is work you did with Joao Magesio and others on chiral gravitational waves in 2008

that had some, you know, startling predictions. But I remember one line in particular that Stefan really drove home to me was that you make the claim that if the laws of, physics are unified, and if the electroweak sector, you know, violates parity, as we know it does, then if gravity becomes unified with the electrowe weak sector, then it's almost unavoidable, that gravity will have some chirrality. And I guess this is characterized by this Imeritsy parameter, etc. Can you say more, as your thinking on that evolve? That was one of the most, you know, kind of, you know, earth-shattering bombshells that I ever heard, because it meant that in my field,

we might see bigger chiral anomalies in the cosmic micro rate background that might illuminate physics beyond the standard model indicative of Lorentz invariance violation, which is more startling to me than inflation. Yeah, me too. I think, I don't know if I have anything new to say. I'm very grateful for your interest in other observers who has taken these things seriously enough to look for them. But let me, here's something which is, which fascinates me.

General relativity, and I'm not assuming that our listeners, your listeners, are experts in physics, but general relativity has a reputation of being difficult, partly because the Einstein equation is really complicated. And it's a function of this thing, the metric that measures distances, but you've got the inverse of the metric and the determinant of the metric and the square root of the metric and the square root of the determinant of the metric.

And it's a mess to compute with, and it's sure a mess to make quantum mechanical. So what Abai used, turned out, we didn't, he didn't know that, we didn't know that at the time, but a Polish physicist who was a refugee to Mexico named Plobansky had discovered something wonderful, which is that you can look at the Einstein equations from a kind of different point of view, which is Cairo, that is where you only focus on how the left-hands and neutrinos react to a gravitational way. and not the right-termine and neutrinos. And if you do that, you get equations which are just quadratic equations, period.

There's no determinants, there's no square roots, there's no inverse, it's just quadratic equations. And if something were simpler than that, it would be linear, and then there are linear or linear equations we can solve. So it's as simple as it can get while still being non-trivial. and loop quantum gravity the reason why all those ideas worked is because

Abai rediscovered Flandsky's formulation so now, so that makes me wonder does nature know about this and so for example Roger Penrose's great construction I mean he's done so many great things

but the grave, in my opinion, is Twister theory. It just found a lot of use in particle physics and string theory and quantum gravity, but of its own is a very radical idea. And twister theory has this chirality built into it. The left-handed gravitational waves are described in a way that's different than the right-handed gravitational way. Interesting. So that is an earlier, yes, and you do speak about that in the book, And also, Roger's been a guest four times on the show as well. And his 90th birthday is coming up.

And I'm delighted to be asked to speak on behalf of that, of that wonderful, okay. And that'll be something to celebrate in August, I believe, is his 90th birthday. It's quite amazing. And thinking about his late-grade colleague, Stephen Hawking, who passed away three years ago, it's hard to believe. this notion that, you know, he kind of died without having unified, you know, quantum mechanics with gravity. I've been having this provocative statement, Lee, and at the risk of insulting my mentor, you know, Lee Smolin and friend, I don't know that gravity has to be unified with quantum mechanics.

I mean, after all, there are only two situations to my knowledge at which the quantization of gravity, the failure of gravity to play nice with quantum mechanics. economics becomes important. And that's near a singularity in a black hole and near the origin of the universe, if indeed it began with a singularity, which Sir Roger, as you know, does not believe it did. And Paul Steinhart does not believe it did. Neil Tarok, your colleague, does not believe it did. And so there's one very questionable scenario that could get ticked off that we don't have to worry about quantum gravity in that scenario. And a black hole's, you know, once beyond below the event horizon, as you know, better than almost anybody else, we cannot observe the details, you know,

what happens in the singularity inside the event horizon, stays inside the event horizon. So why do we care? I mean, would there be any signature of quantum gravity outside the event horizon? And that would be the only, or are there other scenarios in addition to physics beyond the event horizon that is relevant to the mandate that we must quantize gravity? Very good. So I'm going to give you another reason. I mean, I'm very interested in the idea of quantum gravity. I don't think there's an open and shut case that we shouldn't contact it. But here's something I've been fascinated by since graduate school days. And I'll tell the background, in graduate school days, I got interested in Einstein. I was always interested in Einstein. And I had a friend who once. I had a friend who, was a historian of physics, Amelia Rochelle Cohn. And she made a proposal to me.

She said, why don't we read all of Einstein's papers from the beginning, at least the first 10 years or so. And very few of them were in English except the three or four classics. Why don't we start with his very first paper, which was on thermodynamics and life, and read with her translating and read forward. And so we did that. And there was a thing that was very apparent as we did that, which is that he was enormously interested in the consequences of applying thermodynamic ideas to life.

And therefore, he was very interested in the situation, which is called the ultra-vada catastrophe, where if you make a box with conductors, and you must actually know how to do this. And you put some light, you have a little hole and you put some light in and you close the hole, the light bounces around. It doesn't interact with itself,

doesn't interact with the walls where the conductors are, and it thermalizes itself. It bounces and bounces and bounces and thermalize itself. And then you open a little hole and you put a spectrograph there, and it comes out the black body spectrum. And that was really interesting, Freinstein, because the black body spectrum,

without even having the form of the spectrum, although he did actually, of course, this was after Planck, so he knew Planck's guess. And it was obvious that classical physics couldn't explain the fall off at the high frequency. the E to the minus H bar omega over temperature, basically.

And this was a reason why you had to quantize electromagnetism was to prevent that spectrum from just going out unstably to infinity. And so we read that in several different versions, And I thought, I wonder if you could make gravity waves, do that. That is, if you can make gravity waves, put them in a box, and force them into a catastrophe, which you had to save by saying there were gravitons. And then the H-bar-or-or-le-may-be was the energy applied to gravity as well, to gravitational waves as well.

And you know what? You can't do it. You can't make the analog of conducting waves which reflect and keep confined gravitational waves. You can show. And I managed, I'm not that good at this kind of stuff, but I managed a derivation of the efficiency of reflection of gravitational waves. off a wall made out of any material. And as long as the speed of sound of that material is less than the speed of life, and the thing is not a black hole and the energy,

the positivity of energy conditions are met, then you can show that the efficiency is bounded way, way, way away from one. And the gravitational wave just saunter is outside the box. Never is forced to come to equilibrium. And you can even build on that and show that in the history of the universe, a gravitational wave will never come to equilibrium. That is, at any time since the Big Bang in a Big Bang picture, the mean-free time of gravitational waves is longer than the cosmic time.

And you can show an inequality like this. So I think that's an interesting bit of physics that supports you. Interesting. And if you look out at kind of other tests that one could devise, it's natural to kind of look at, you know, look for tests that could potentially be crisp or decisive test as there's a word for this, in Latin, critical tests that could.

not, the theory could not survive otherwise but to pass this test. The bending of light by massive objects, the Eddington experiment is often cited as such an example, even though many experimentalists doubt that it was really truly feasible in the technology back in 1919 to truly verify the level of precision that Einstein achieved. But nevertheless, we won't get into that. People can read your book and Jim Gates' books and other books about Einstein, of which there are many. but I want to turn to the other aspect, which kind of fascinates me and also dismays me about string theory, but about, you know, kind of all theories of everything. And our mutual friend Max Tagmark has written about these.

And that's really the multiverse. And this is quite disturbing in some ways, especially, not the least of which are the, you know, the multi-multiverses that Max speaks about, you know, the kind of four levels of multiverses that can exist, including a multiverse in which, you know, laws of nature can vary from string vacuum to string vacuum. And this is part of the fight I had with Michi Okaku. Of course, you know, he was a gentleman, even if I wasn't. But the argument was, you know, I said to him, you know, you say it's not fair to test string theory, because I have to tell you which of the 10 to the 500th or more vacua we live in. And he said, that's just like

solving Newton's equations. How many solutions are there in a Newton's equation? I said, there's an infinite number of solutions to Newton's equation. How many solutions to Maxwell's equation? There's an infinite number. What do you need to solve them? He asked me. I said, boundary conditions, initial conditions. But I said the situation seems hopeless in string theory.

And even more hopeless maybe than Max, Tegmark would admit. And I think I've discovered a fifth level of the multiverse Lee, if you'll indulge me, and forgive me. Because as I think rabbi used to say, the Nobel Prize should go to someone who doesn't discover a new particle back in the 30s. But in this case, I think the Nobel Prize should go to someone who doesn't discover a new multiverse. I'm worried that there could be a type of multiverse where not only the laws of physics change, but the laws of logic change. In other words, why should it be that modus Tolens holds in some universe where, or two plus two equals four in another universe? And he claims, no, no, no, that was a foolish question. But if, you know, if there are 10 to the 500 different laws of physics, why should they're not?

be 10 to the 500 different laws of mathematics. So, first of all, of course, there are different, I don't know how many there are, but there are different versions of set theory and logic and mathematics depending on how you answer questions like the continuum

hypothesis and the exclusive middle. And there's a whole bunch of different logics in different worlds of mathematics. And I find that fascinating. Since I'm not a Platonist, I don't have to believe that they're real,

and any of them are real. But they're structures by which we reason, and what you say is interesting. And I don't know if it's worrying, but it's interesting. It's interesting. I could come back to that because I would think a lot about mathematics, and I worry about it, especially since the final play in this.

Right. So I do want to talk about this third paper that you wrote, co-author with Stefan and six other authors, Geron Lanier. Geron Lanier, can you say something about him? He's an interesting character. He's, his affiliation is listed as Microsoft Reuters. research in Redmond, Washington. I once met him in Berkeley, California. Can you say something about Geron? I know he's a friend of yours and Stefan's, but he's an interesting character.

Is he not? He's a very interesting person, and I feel very lucky to have him as a friend. We're very good friends. Jaron is speaking about autodidactics Jaron is almost entirely self-educated he went to a few schools

a few times he is wonderfully imaginative wonderfully he's really quick he's a great communicator he's a great writer

He's one of the few people I think of as in this class of people who are endlessly original and have endlessly important things to say. And he does have a lot that's very important to say, whether it's about thinking about artificial intelligence or the role in the economy of the Internet companies. And so lots and lots of other things besides we were talking anything yesterday. about a whole lot of these things. So this paper. Yeah, yeah, go ahead.

So here's how that paper came to be. So first of all, I have been interested, as we mentioned, in the idea that the laws of physics could change for a long time. And there was cosmological natural selection, if we discussed. I had another approach or had another approach called the principle of precedence. And Jaron is interested in that idea. And over several, maybe it's even many years, Jaron and Stefan are also friends, and they're both musicians.

One thing, Jaron plays an incredible variety of musical instruments from all over the world. And there are so many stories to tell that I'll skip doing that. I'll keep doing that now. Well, there's one, let me just bracket this. There's the time Jaron took Stefan and I to meet Ornette Cohneman. And let me just use the- Can you speak a little closer to the microphone? Who would you mean?

There's the time that Jaron took Stefan and I to meet Ornette Coleman. Oh, that's right. Which stands out in my, is one of the very fortunate experiences I've had. Sharon has Sharon is among other things a computer scientist so we didn't even get to that he's credited with inventing virtual reality

he is and his position in Microsoft I don't really understand it but it seems to allow him complete freedom to do whatever he wants and think about whatever he wants but he's also involved in projects there

and so anyway, over years he and Stefan and I talked about a variety of different ideas and I don't know where the key idea in the paper comes from. I try to think of it. The key idea in the paper is that we can talk about the laws of nature learning and learning the laws and finding its way around those vacuilla that you're worried about to one that somehow benefits the universe best

and this sounds crazy and what we're going to argue is the following there's a lot in that paper that's an 80-page paper about what learning is because we had to do it because we couldn't find you anywhere but let me skip that and say that people are interested in these machine learning algorithms.

And let's just give me that what they do is to learn. They learn facial recognition, they learn pattern recognition, they learn bunch of other things. And let's not get into the epistemology of what it means to say that one of those machines or algorithms learn something. You just give it to me that they learn. and I'm going to take your favorite candidate for the laws of nature

as long as there of the form of something like general relativity and something like age fields and permeants and scanners and we're going to map that theory into the learning machines and machine learning algorithms and we discovered that map I don't remember why we were looking for it. But at some point it was clear that there was a map. And the map uses a technical result, which I knew,

which has to do with a class of models called matrix models. That's just the technicality that was used. So we have demonstrated that result. And then we have thought of, about what devices you could make that could be mapped to the laws of nature to investigate this idea. There were seven people on the paper. Everyone was essential. And they range from a senior Microsoft computer scientist who was kind of of bringing in all of the knowledge about machine learning. Will Cunningham, who's a very talented young theoretical physicist who unfortunately

would learn and losing at the moment to the world of startups. And it was a lot of fun. It was really hard. I haven't worked on anything. You work in collaborations all the time. all the time. Yeah. And for me, it was kind of a new experience to work in a collaboration that large. And it really did work and it came together, but it took a year. That's a full year of meeting together three times a week.

That's great. And you don't know what's in the cutting room floor. There's a whole bunch of stuff on the company. Yeah, I believe it. Yeah, so I'll try to get Geron and Stefan on the podcast at some point, too. Stefan's been on three or four times already, but I've never had Geron on. I'm going to have Nathan Mirvald on, who was director of research at Microsoft for a while and is kind of an autodidact.

And maybe that'll segue to my final question for this interview. I hope you'll give us the opportunity to talk more about physics and in the intervening month or so before we can talk again about maybe cosmology talk. We'll do a dedicated cosmology talk next time. You'll probably write 10 other papers. three books, but I do want to talk just once about you are, you know, I see you as an autodidact, you've written papers in economics, you've written papers in, as you say, set theory and physics and cosmology, you've written six books to date. And speaking of learning, as we just

did with, you know, computer learning, do you think you can teach creativity, Lee? Can you teach someone to be imaginative, to be creative. Is there a nature, nurture thing? You just have to be born with it. That's a very good question, and I don't know. I certainly believed that it was teachable most of my life, and I would hope that that's true, because being created is a great thing,

and I would hope that every year. everybody, whatever, however the life was organized, had access to that, and it doesn't mean that you're good at it. I mean, I'm not good, I'm not a good musician. I got, unlike Stefan, he is a good musician.

I was Aaron, I got good enough to play with the people who were really good. And then it was like, okay, that's not, that's not my genre, but I still have a few guitars and still play them sometimes. and I'm working with two people now that are unusual people to be working with

and they're endlessly creative and smart and I don't know where it comes from I you know Jaron, Stefan Fahlia so many people I've been fortunate enough to know, have their own ideas about everything.

They look at the world, the same world I look at, they read the same stuff, and they come up with stuff just, it's like turning on a faucet, stuff is worth thinking about and worth listening to. And I don't know where that comes from. there are certainly claims that you can't teach it but but I'm going to I'm going to take a left turn on you

here's what I think is changeable and I hope I don't sound like I don't know when it's so moralistic something like and people are going to look like He said that. But let me try it.

I think character matters enormously. And being in this crisis that we've been, I see it every day. And I think that the ability to see clearly what's going on around you, and take responsibility for it and think about it, the ability to follow your own compass, to not care is fine and put it what other people think.

I think and I have a friend I've learned a lot from St. Clair's Sandman who is a sculptor. He's a great sculptor. And so I'm going to leave it with a kind of quote of St. Clair's.

St. Clair used to tell me that that you get sort of into your 20s for free. And if you're going to go on

and become useful and really make a contribution with what you do, it really starts to matter what your character is and how much you're willing to be on the edge and take risks and

question yourself. And by 50 and 60, it really really shows, it really starts to show. He was probably 40-something. I'm about 10 years younger than him. And then I'll say something else.

You don't have to keep this in the tape or not. No, that's great. But this is, I'm saying this to you from him anyway. Unlike you, we had children late. and had to be, and talked about it and thought about it. And he had his daughter a few years before we had time. And he said to me, you have no idea what you're giving to the world

by having a child. You're unmerdering somebody. And you're giving this to the much higher degree than I am, but I am certainly fully involved, and it is a great thing to do. You know, it's wonderful that you say that, Lee. And actually, I was going to close with this to give us some time between our next conversation. But I did want to say that I once heard, you know, Sam Harris talking about, you know, the impossibility of, you know, teleportation and, you know, time travel.

It's kind of this fantasy that human beings have. And I said, no, that's actually a lie. I didn't say it to him because, you know, he won't pick up the phone when I call. on. But anyway, I said, actually, there is such a thing as teleportation. It's just you can't teleport yourself. You teleport your values. You teleport your ethics. You teleport your character into the future. And it's called children. And it doesn't even have to be your biological children, Lee. It's your ideological children. And I count myself, and I don't blame you, but I count myself as kind of one of your ideological children. So, you know, I have a great, you know, friend,

her name is Melanie Notkin. She's known as the savvy auntie. She can't have children. She didn't have children, whatever. She has influenced thousands of millions of people, even though she didn't have biological children. So I am blessed to have biological children. But even if someone is not, you can act like a parent.

You can communicate and thereby doing teleport yourself into the future. And what else is there, Lee? That's time travel. And you've done that for me and you've done that for millions of people. I just want to thank you so much, Lee, for being such a great human being and being an influence on me

even long before you knew me. And again, you don't get any of the blame for anything bad I do with your good influence. Whoa, Brian, that's, thank you. I have no words. Thank you for that. Well, Lee, thank you so much for going into The Impossible.

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