Lex Fridman Podcast - #246 – Peter Woit: Theories of Everything and Why String Theory is Not Even Wrong

Episode Date: December 4, 2021

Peter Woit is a theoretical physicist, mathematician, critic of string theory, and author of the popular science blog Not Even Wrong. Please support this podcast by checking out our sponsors: - The Prisoner Wine Company: https://theprisonerwine.com/lex to get 20% off & free shipping - Linode: https://linode.com/lex to get $100 free credit - Sunbasket: https://sunbasket.com/lex and use code LEX to get $35 off - BetterHelp: https://betterhelp.com/lex to get 10% off - SimpliSafe: https://simplisafe.com/lex and use code LEX to get a free security camera EPISODE LINKS: Peter's website: http://www.math.columbia.edu/~woit/ Peter's blog: https://bit.ly/3xCwm9F Not Even Wrong (book): https://amzn.to/3peDzZs Quantum Theory, Groups, and Representations (book): https://amzn.to/316iAjf Love and Math (book): https://amzn.to/3If7B8m The Second Creation (book): https://amzn.to/3rlWzIu PODCAST INFO: Podcast website: https://lexfridman.com/podcast Apple Podcasts: https://apple.co/2lwqZIr Spotify: https://spoti.fi/2nEwCF8 RSS: https://lexfridman.com/feed/podcast/ YouTube Full Episodes: https://youtube.com/lexfridman YouTube Clips: https://youtube.com/lexclips SUPPORT & CONNECT: - Check out the sponsors above, it's the best way to support this podcast - Support on Patreon: https://www.patreon.com/lexfridman - Twitter: https://twitter.com/lexfridman - Instagram: https://www.instagram.com/lexfridman - LinkedIn: https://www.linkedin.com/in/lexfridman - Facebook: https://www.facebook.com/lexfridman - Medium: https://medium.com/@lexfridman OUTLINE: Here's the timestamps for the episode. On some podcast players you should be able to click the timestamp to jump to that time. (00:00) - Introduction (07:22) - Physics vs mathematics (21:51) - Beauty of mathematics (43:42) - String theory (1:12:15) - Theory of everything (1:32:23) - Twistor theory and spinors (1:48:50) - Nobel Prize likelihood for theory of everything (1:52:36) - Simulating physics (1:56:07) - Sci-Fi, aliens and space (2:05:19) - Responsibility of scientists

The following is a conversation with Peter Wight, a theoretical physicist the Columbia, outspoken critical strength theory, and the author of the popular physics and mathematics blog called Not Even Wrong. If you want to support this podcast, the best way is to check out the following sponsors in the description. First, is Prisoner Wine, my wine of choice. Second, is Linode, my wine of choice. Second is linode, linux virtual machines. Third is sunbasket, healthy meal delivery service.

Fourth is better help, an online therapy service. And fifth is simply safe, the home security company I use. So the choice is wine, linux, food, mental health, or physical security, choose wise and my friends. And now onto the full ad reads. As always, no ads in the middle. I try to make these interesting, but if you skip them, please still check out our sponsors. I enjoy their stuff. Maybe you will too. This show is brought to you by Prisoner Wine, my wine of choice. Beautiful artwork on the

bottle, delicious taste, especially their prisoner Cabernet Sauignon paired with a nice steak. That is happiness for me. Prisoner wine, steak and a good friend. I actually just want to thanksgiving dinner a couple of days ago with Mr. Michael Malice and I brought prisoner wine. So we enjoy some delicious turkey over some nice wine. I can't tell you how much I love prisoner wine. This is not just an advertisement. I really hope to keep sponsoring because I would sing it praises whether they were sponsoring it or not, to be honest. Go to theprisonerwine.com slash Lex for 20% off

plus shipping included on your first purchase. We can toast to the holidays together with the same wine. for 20% off plus shipping included on your first purchase. We can toast to the holidays together with the same wine. If you go to theprisonerwine.com slash lex, we shall toast to victory and to happiness. That's theprisonerwine.com slash lex offers valid. On first time online orders only for US residents of legal drinking age through the

end of December 2021. Other exclusions may apply, please enjoy wine responsibly. This episode is also brought to you by Linode, Linux Virtual Machines. It's an awesome compute infrastructure that lets you develop, deploy, and scale what applications you build faster and easier. This is both for small personal projects and huge systems. I like to do a bit of both. Lower cost than AWS, but more importantly, to me, is the simplicity, quality of customer

service with real humans, 24.7365. I can't say enough about the importance of compute infrastructure to the success of any kind of computational based effort. Again, small scale or large scale. I guess the best compute infrastructure is invisible in that it's super easy to use, it's reliable, whenever issues come up, you can always resolve those issues quickly. All of those things are essential for great computer infrastructure and when everything's working great, it's just life is amazing.

Anyway, if it runs on Linux, it runs on Linux. Visit linode.com slashlex and click on the Create Free Account button to get started with $100 in free credit. This show is also brought to you by Sun Basket Meal Delivery Service. Its restaurant quality food, packaged up, delivered to your home and ready to heat and eat. Many times in my life, many of the happiest moments in my life have to do with friends over a meal, like conversations with good friends over a meal. To be honest, it has less to do with the meal and more with the friends, but you should have the meal. So I think Sunbask is one of the easiest ways to have that meal. It's healthy, there's a variety, it's fun, just like the kind of meals they have in both healthiness and deliciousness and the variety of it is something I never make by myself.

So it's really nice to have that help from Sun Basket. They deliver it very easily, it's affordable. Right now, Sun Basket is offering $90 off your first four deliveries, including free shipping on the first box. When you go to sunbasket.com slash Lex and enter code Lex. That's sunbasket.com slash Lex. Enter code Lex. This episode is also brought to you by BetterHelp spelled H-E-L-P-H-L-P. Like the thing you'll be spelling in the sand on a deserted island, after many days of talking to a volleyball.

Speaking of talking, I'm a big believer in talk therapy and the power of that. Better help help you figure out what you need and match it with the lessons professional therapist in under 48 hours. They help you with the talk therapy. They make it easy, private, affordable. It's available anywhere walled wide You can be wearing your pajamas. You can talk a video and audio

You can schedule however you want. I mean they make it super easy And I think it should be part of the toolkit you use to fortify the walls of the castle that is your mind within me there's a love for psychiatry and especially sort of talk therapy, sort of delving into the human mind, exploring it through rigorous conversation. Check them out, betterhelp.com slash Lex, that's betterhelp.com slash Lex. This shows Ausserbrought to you by SimplySafe, a home security company designed to be simple and effective. They just launched their new wireless outdoor security camera.

It has an ultra wide 140 degree field of view 1080p HD resolution with an 8x zoom. It has a built-in spotlight with color night vision. It was named the best home security system of 2021 by U.S. News and World Report. I have several layers of both physical and cyber protection, keeping yourself safe, keeping yourself secure in all of those kinds of ways, provides a kind of freedom because when you have security, you have the freedom to act. So you should definitely use the best tools for the job in terms of security. Simply safe is best on several dimensions.

Very importantly, it's very simple to set up. So take advantage of SimplySafe's holiday sale and get 40% off your new home security system by visiting simplysafe.com slash Lex. Again, that simplesafe spelled S-I-M-P-L-I-S-A-F-E.com slash Lex. Hurry up since the 40% off deal ends soon. This is the Lex Friedman podcast, and here is my conversation with Peter White. You're both a physicist and a mathematician. So let me ask, what is the difference between physics and mathematics? Well, there's kind of a conventional understanding of a subject that they're two, you know, quite different things, so that mathematics is about, you know, making rigorous statements

about these abstract, abstract things, things of mathematics and proving them rigorously and physics is about, doing experiments and testing various models. But I think the more interesting thing is that the, there's a wide variety of what people do is mathematics, what they do is physics, and there's a significant overlap. And that I think is actually the much, very, very interesting area.

And if you go back kind of far enough to in, in history and look at figures like Newton or something, I mean, there, at that point, you can't really tell, you know, it was Newton a physicist or a mathematician, yeah. Mathematicians will tell you it was a mathematician, the physicist will tell you it was a physicist. But he will say he's a philosopher. Yeah, that's interesting. But anyway, there was kind of no such distinction, then it's more of a modern thing. But anyway, I think these days there's a very interesting space in between the two. So in the story of the 20th century and the early 21st century, what is the overlap between mathematics and physics, would you say? Well, I think it's actually become very, very complicated.

I think it's really interesting to see a lot of what my colleagues in the math department are doing. They, most of what they're doing, they're doing all sorts of different things, but most of them have some kind of overlap with physics or other. So I mean, I'm personally interested in one particular aspect of this overlap, which I think has a lot to do with the most fundamental ideas about physics and about mathematics. But there's just, you kind of see this really everywhere at this point. Which particular overlap are you looking at Goop theory?

Yeah, so the, at least, the way it seems to me that if you look at physics and look at the our most successful laws of fundamental physics, they're really, you know, they have a certain kind of mathematical structure. It's based upon certain kind of mathematical objects and geometry connections and curvature, the spinners, the derogatory equation, and that these, this very deep mathematics provides kind of a unifying set of ways of thinking that allow you to make a unified theory of physics. But the interesting thing is that if you go to mathematics and look at what's been going on in mathematics, the last 50-100 years, and even especially recently, there's a, 50-100 years, and even especially recently, there's a, similarly, some kind of unifying ideas which bring together different areas of mathematics, which have been especially

powerful in number theory recently, and there's a book, for instance, by Edward Frankel about love and math. And yeah, that book's great. I recommend it highly. It's partially accessible. But it has a nice audio book that I listened to while running an exceptionally long distance like across the San Francisco bridge. And there's something magic about the way he writes about it, but some of the group theory

in there is a little bit difficult. It's a problem with any of these things to really say what's going on and make accessible is very hard. In this book and elsewhere, I think it takes the attitude that kinds of mathematics he's interested in and he's talking about are provide a grand unified theory of mathematics. They bring together geometry and number theory and representation theory, a lot of different ideas in a really unexpected way. But I think to me the most fascinating is if you look at the kind of grand unified theory of mathematics he's talking about and you look at the physicists kind of

ideas about unification, it's more or less the same mathematical objects are appearing in both. So it's this, I think there's a really, we're seeing a really strong indication that, you know, the deepest ideas that we're discovering about physics and some of the deepest ideas that mathematicians are learning about are really, are, you know, intimately connected. Is there something like, if I was five years old and you were trying to explain this to me? Is there a way to try to sneak up to what this unified world of mathematics looks like. You said number theory, you said geometry, words like topology. What does this universe begin to look like? Are these, what should we imagine in our mind? Is it a three-dimensional surface? And we're trying to say something about it. is it triangles and squares and cubes?

Like, what are we supposed to imagine our minds? Is this natural number? What's a good thing to try to, for people that don't know any of these tools, except maybe some basic calculus and geometry from high school, that they should keep in their minds as to the unified world of mathematics, that also allows us to explore the unified world of physics. I mean, what I find kind of remarkable about this is the way in which we've discovered these ideas,

but they're actually quite alien to our everyday understanding. We grow up in this three spatial dimensional world and we have intimate understanding of certain kinds of geometry and certain kinds of things, but um these things that we've discovered in both math and physics are that they're not at all close in have any obvious connection to kind of human everyday experience that they're really quite different and I can say say that some of my initial fascination with this when I was young and started to learn about it was actually exactly this kind of arcane nature of these things.

It was a little bit like being told while there are these kind of semi-mystical experience that you can acquire by a long study and whatever except that it was actually true, and there's actually evidence that this actually works. So I'm a little bit worried of trying to give people that kind of thing, because I think it's mostly misleading. But one thing to say is that geometry is a large part of it.

And maybe one interesting thing to say about more recent, some of the most recent ideas is that when we think about the geometry of our space and time, it's kind of three-spatial and one time dimension, it's a physics in some sense about something that's kind of four-dimensional in a way. And a really interesting thing about some of the recent developments in number theory have been to realize that these ideas that we were looking at naturally fit into a context where your theory is kind of four-dimensional. So geometry is a big part of this and we know a lot

and feel a lot about two or three-dimensional geometry. So wait a minute. So we can at least rely on the four dimensions of space and time and say they can get pretty far by working in those four dimensions. I thought you were going to scare me that we're going to have to go to many, many, many, many more dimensions in that. My point of view, which goes against a lot of the ideas about unification, is that, no, this is really everything we do we know about really is about four dimensions that and that you can actually understand a lot of these structures that we've been seeing in fundamental physics and in

in number theory, just in terms of four dimensions that it's kind of it's in some sense I would claim has been a really, has been kind of a mistake that physicists have made and for decades and decades to try to go to higher dimensions, to formulate a theory and higher dimensions, and then you're stuck with the problem, how do you get rid of all these extra dimensions that you've created?

Because we only ever see anything important. The kind of thing leads us astray, you think? So creating all these extra dimensions just to give yourself extra degrees of freedom. Yeah. I mean, isn't that the process of mathematics is to create all these trajectories for yourself, but eventually you have to end up at a final place. But it's okay to create abstract objects on your path to proving something. Yeah, certainly.

But from that position, it's a point of view. I mean, the kind of, that position is also a very different than physicists. And we like to develop very general theories. We like to, if we have an idea, we want to see what's the greatest generality, and we like to develop very general theories. If we have an idea, we want to see what's the greatest generality, and what you can talk about it. From the point of view of most of the ways geometry is formulated by mathematicians, it really works in any dimension.

We can do one, two, three, four, any number. There's no particular, for most of geometry there's no particular special thing but for. But anyway, but with physicists have been trying to do over the years, is try to understand these fundamental theories in a geometrical way. And it's very tempting to kind of just start bringing in extra dimensions and using them to explain the structure. But typically, this attempt kind of founders because you just don't know. You end up not being able to explain why we only see four. Anyway, it is nice in the space of physics that like you feel like I've from

Oslo's theorem, that's much easier to prove that there's no solution for n equals 3, then it is for the general case. And so I guess that's the nice benefit of being a physicist is you don't have to worry about the general case because we live in a universe with n equals 4 in this case. Yeah, the physicists are very interested in saying something about specific examples. And I find that interesting. Even when I'm trying to do things in mathematics and I'm trying to even teach in courses and to mathematics students, I find that I'm teaching them in a different way than most mathematicians because I'm very often very focused on examples on what's kind of the crucial example that shows how this powerful new mathematical technique how it works and why you would want to

do it. And I'm less interested in kind of proving a precise theorem about exactly when it's going to work and when it's not going to work. Do you usually think about really simple examples, like both for teaching and when you try to solve a difficult problem? Do you construct the simplest possible examples that captures the fundamentals of the problem and try to solve it? Yeah, exactly. That's often a really fruitful way to, if you've got some idea, to just kind of try to boil it down to what's the simplest situation

in which this kind of thing is gonna happen and then try to really understand that and that is almost always a really good way to get insight into it. Do you work with paper and pen or like for example, for me, coming from the programming side, if I look at a model, if I look at some kind of mathematical

object, I like to mess around with it sort of numerically. I just visualize different parts of it, visualize however I can. Most of the work is like when you're on that work, for example, because you try to play with a simple, possible example and just to build up intuition by, you know, any kind of object has a bunch of variables in it. You start to mess around with them in different ways and visualize in different ways to start to build intuition. Or do you go to Einstein route and just imagine like everything inside your mind and

sort of build like thought experiments and then work purely on paper and pen. Well, the problem with this kind of stuff that I'm interested in is you rarely can kind of. It's really something that is really kind of or even the simplest example. You know, it can is you can kind of see what's going on by looking at something happening at three dimensions. There's there's generally this, the structures involved are um. dimensions. There's generally this, the structures involved are either they're more abstract or if you try to kind of embed them in some kind of space and where you could manipulate them in some kind of geometrical way, it's going to be a much higher dimensional space. So even simple examples, the embedding them into three dimensional space, you're losing

a lot. Yeah. But to capture what you're trying to understand about them, you have to go to four or more dimensions. So it starts to get to be hard. You can train yourself to try to as much as to kind of think about things in your mind. I often use pad and paper. And often, if my office office is the blackboard, and you are kind of drawing things, but they're really more abstract representations of how things are supposed to fit together, and they're not really, unfortunately, not just really living in three dimensions where you can

understand. Are we supposed to be sad or excited by the fact that our human minds can't fully comprehend the kind of mathematics you're talking about? I mean, what do we make of that? I mean, to me, that makes me quite sad. It makes me, it makes it seem like there's a giant mystery out there that will never truly get to experience directly. It is kind of sad, you know, how difficult this is. I mean, or I would put it a different way that, you know, most questions that people have about this kind of thing, you know, you couldn't, you can give them a really true

answer and really understand it, but the problem is, is one more of, of time. It's like, yes, you know, I could explain to you how this works, but you have to be willing to sit down with me and, you know repeat to leave for hours and days and weeks. It's just going to take that long for your mind to really wrap itself around what's going on. That does make things inaccessible, which is sad. It's just part of life that we all have a limited amount of time and we have to decide what we're going to spend our time doing.

Speaking of a limited amount of time, we only have a few hours, maybe a few days together here on this podcast. Let me ask you the question of amongst many of the ideas that you work on in mathematics and physics, which is the most beautiful idea, or one of the most beautiful ideas, maybe a surprising idea. And once again, unfortunately, the way life works, we only have a limited time together, try to convey such an idea. Okay. Well, actually, let me just tell you something,

which I've tempted to kind of start trying to explain what I think is the most powerful idea that brings together math and physics ideas about groups and representations and how it fits quantum mechanics. But in some sense I wrote a whole textbook about that and I don't think we really have time to get very far into it. Well, can I actually, on a small tangent, you did write a paper towards a grant, you know, if I theory mathematics and physics. Maybe you could step there first. What is the key idea in that paper? Well, I think we've kind of gone over that. I think that the key idea is what we were talking about earlier

that just kind of a claim that if you look and see what's the, have been successful ideas in innovation in physics and over the last 50 years or so. And what's been happening in mathematics and the kind of thing that Frankl's book is about, that these are very much the same kind of mathematics. And so it's kind of an argument that there really is, you shouldn't be looking to unify just math or just fundamental physics, but taking inspiration for looking for new ideas

and fundamental physics, that they are going to be in the same direction of getting deeper into mathematics and looking for more inspiration and mathematics from the successful ideas about fundamental physics. Could you put words to sort of the disciplines we're trying to unify? You said number theory. We literally talking about all the major fields of mathematics. So it's like the number theory geometry, so the differential geometry topology. Yeah.

So the, I mean, one name for this, that this is acquired in mathematics is the so-called Langlands program. And so this started out in mathematics. It's that, you know, Robert Langlands kind of realized that a lot of what people were doing and that was starting to be really successful in number theory in the 60s and so that this actually was, anyway, that this could be a thawnav in terms of these ideas about symmetry in groups and representations, and in a way that was also close

to some ideas about geometry. And then more later on in the 80s and 90s, there was something called geometric langlands that people realize that you could take what people have been doing in number theory in langlands. And just forget about the number theory and ask, what is this telling you about geometry and you get a whole some new insights into certain kinds of

geometry that way. So it's, anyway, that's kind of the name for this area is Langlands and geometric Langlands. And just recently in the last few months there's been a really major paper that appeared by Peter Schultza and Laurel Farg, where they made some serious advance and try to understand a very much kind of a local problem of what happens in number theory, near a certain prime number. And they turn this into a problem of exactly the kind of geometric this into a problem of exactly the kind of geometric langling people had been doing these kind of pure geometry problem and they found by generalizing the mathematics,

they could actually reformulate it in that way. And it worked perfectly well. Well, one of the things that makes me sad is, I'm a pretty knowledgeable person. And then what is it? At least I'm in the neighborhood, like theoretical computer science, right? And it's still way out of my reach.

And so many people talk about like Langlands, for example, is one of the most brilliant people in mathematics and just really admire his work. And I can't, it's like almost I can't hear the music that he composed and it makes me sad. Yeah. Well, I mean, I think unfortunately it's not just you, it's I think even most mathematicians have no really don't actually understand what this is about.

I mean, the group of people who really understand all these ideas and so for instance, a paper of Shulton Farg that I was talking about, the number of people who really actually understand how that works is anyway, I'm on very, very small. So I think even if you talk to mathematicians and physicists, even they will often feel that there's this really interesting sounding stuff going on, which I should be able to understand it's kind of in my own field, I have a PhD PhD in but it still seems pretty clearly far beyond me right now. Well, if you can step into the back to the question of beauty, is there an idea that maybe is a little bit smaller that you find beautiful in this pace of mathematics of physics? There's an idea that I kind of went, got a physics PhD, and spent a lot of time learning about mathematics.

And I guess it was embarrassing, and I hadn't really actually understand this very simple idea until I kind of learned it when I actually started teaching math classes, which is maybe that there's a simple way to explain kind of fundamental away in which algebra and geometry are connected. So you normally think of geometry is about these spaces and these points. And you think of algebra is this very abstract thing about these abstract objects that satisfy certain kinds of relations.

You can multiply them and add them and do stuff. But it's completely abstract. It is nothing geometric about it, but the kind of really fun and light idea that unifies algebra and geometry is to realize, is to think, whenever anybody gives you what you call an algebra, some abstract thing of things that you can multiply and add, that you should ask yourself, is that algebra the space of functions on some geometry? So one of the most surprising examples of this,

for instance, is a standard kind of thing that seems to have nothing to do with geometry is the the integers. So you can multiply them and add them. It's an algebra. But it has seems to have nothing to do with geometry. But what you can, it turns it, but if you ask yourself this question and ask, you know, is our integers, can you think, if somebody gives you an integer, can you think of it as a function on some space, on some geometry? And it turns out that yes, you can, and the space is the space of prime numbers. And it turns out that yes you can and the space is the space of prime numbers. And so what you do is you just if somebody gives you an integer, you can make a function on the prime numbers by just, you know, at each prime number taking that, that integer

modulo, that prime. So if, as you say, I don't know, if you give it 10, you know, 10, and you ask, what is its value at 2? Well, it's, it's 5 times 2, so mod 2 is 0, so it has 0, 1. What is its value at 3? Well, it's 9 plus 1, so it's 1 mod 3. So it's 0 at 2, it's 1 at 3, and you can kind of keep going. And so this is really kind of a truly fundamental idea. It's at the basis of what's called algebraic geometry and it just links these two parts of mathematics

that look completely different. And it's just an incredibly powerful idea and so much of mathematics emerges from this kind of simple relation. So you're talking about mapping from one discrete space to another. So for a second, I thought perhaps mapping like a continuous space to a discrete space, like functions over a continuous space.

Because yeah, well, you mean you can take, if somebody gives you a space, you can ask, you can say, well, let's, let's, and this is also, this is part of the same idea, the part of the same idea is that if you try and do geometry and somebody tells you, here's, and this is also, this is part of the same idea. The part of the same idea is that if you try and do geometry and somebody tells you, here's a space, that what you should do is you should wait, so say, wait a minute, maybe I should be trying to solve this using algebra. And so if I do that, the way to start is,

you give me the space, I start to think about the functions on the space, okay? So for each point in the space, I associate a number. I can take different kinds of functions and different kinds of values, but basically functions on a space. So what this insight is telling you is that if you're a Geometer, often the way to work is to change your problem into algebra by changing your space, stop thinking about your space and the points in it and think about the functions on it. And if you're in algebraists and you've got these abstract algebraic gadgets that you're

multiplying and adding, say, wait a minute, are those gadgets, can I think of them in some way as a function on a space? What would that space be? What kind of functions would they be? And that going back and forth really brings these two completely different looking areas of mathematics together. Do you have particular examples where it allowed to prove some difficult things by jumping from one to the other?

Is that something that's a part of modern mathematics or such jumps are made? Oh, yes. This is kind of all the time. A lot much of modern number theory is kind of based on this idea. But when you start doing this, you start to realize that you need what simple things, simple things on one side of the algebraist start to require you to think about the other side about geometry in a new way.

You have to kind of get a more sophisticated idea about geometry. If you start thinking about the functions on a space, you may need a more sophisticated algebra. But in some sense, I mean much or most of modern number theory is based upon this move to geometry. And there's also a lot of geometry and topology is also based upon change. If you want to understand the topology of something, you look at the functions, you do deramen called homology and you get the topology. Anyway. Well, let me ask you then the ridiculous question. You said that this idea is beautiful. Can you formalize the definition of the word beautiful and why is this beautiful? the word beautiful and why is this beautiful? Like, first, why is this beautiful? And second, what is beautiful? Well, and I think there are many different things you can find beautiful for different reasons. I mean, I think in this context, the notion of beauty, I think really is

just kind of an idea as beautiful if it's packages a huge amount of power and information into something very simple. In some sense, you can almost try and measure it in the sense of what are the implications of this idea, what not trivial things as it tell you versus how simply can you express the idea? So the level of compression, what is it correlates with beauty? That's what that's wanting one aspect of it. So you can start to tell that an idea is becoming uglier and uglier as you start having to.

It doesn't quite do what you want, so you throw in something else to the idea and you keep doing that until you get what you want. But that's how you know you're doing something ugly or nugglier when you have to keep adding and more into what was originally a fairly simple idea and making it more and more complicated to get what you want. Okay, so let's put some philosophical words on the table and try to make some sense of them. One word is beauty, another one is simplicity, as you mentioned, and another one is truth.

So do you have a sense if I give you two theories? One is simpler, one is more likely to be true to capture deeply the fabric of reality? The simple one or the more complicated one? Yeah, I think all of our evidence, what we see in the history of the subject is the simpler one. Often it's a surprise, it's simpler in a surprising way. But yeah, that we just don't, we just, anyway, the kind of best theories have been coming up with

our ultimately, we're not properly understood, relatively simple and much, much simpler than they would expect them to be. Do you have a good explanation why that is? Is it just because humans want it to be that way? Or we just like ultra biased, then we just kind of convince ourselves that simple is better because we find simplicity beautiful. Or is there something about at the our actual universe that at the core is simple? My own belief is that there is something about a universe that is that simple and I was trying to say that there is some kind of fundamental thing about math, physics, and physics, and all this picture, which is

in some sense simple. It's true that our minds have certain, our very limited and can certainly do certain things and not others. So it's in principle possible that there's some great insight, there are a lot of insights into the way the world works, which is aren't accessible to us because that's not the way our minds work. We don't. And that what we're seeing, this kind of simplicity, is just because that's all we ever have any hope of seeing.

But so there is a brilliant physicist by the name of Sabine Hassan Fowler, who both agrees and disagrees with you. I suppose agrees that the final answer will be simple. Yeah. But simplicity and beauty leads us astray in the local pockets of scientific progress. Do you do you agree with her disagreement. Do you agree with her disagreement? Do you disagree with her agreement?

And agree with the agreement? Yes, I thought it was really fascinating reading her book. And anyway, I was finding disagreeing with a lot. But then at the end, when she says, yes, when we find, when we actually figure this out, it will be simple. And okay, so it's how we agree in the end. It does beauty lead us astray, which is the core thesis of our work in that book.

I actually, I guess I do disagree with her on that so much. I don't think, and especially, and I actually feel strongly disagree with her about sometimes the way she'll refer to math. So the problem is, you know, physicists and people in general just refer to a math, and they're often, they're often meaning not what I would call math, which is the interesting ideas of math, but just some complicated calculation. And so I guess my thing about it is more that it's very, the

problem we're talking about simplicity and using simplicity as a guide is that it's very easy to fool yourself. And it's very easy to decide to fall in love with an idea. You have an idea, you think, oh, this is great, and you fall in love with it. And it's like any kind of love of say, it's very easy to believe that, you know, you're the object of your affection is much more beautiful than the others might think and they really are.

And that's very, very easy to do. So if you say, I'm just gonna pursue ideas about beauty and mathematics and this, it's extremely easy to just fool yourself, I think. And I think that's a lot of what the story she was thinking of about where people have gone astray that I think it's I would argue that it's more people. It's not that there was some simple, powerful, wonderful idea which they'd found and it turned out not to be useful, but it was more that they kind of fooled themselves that this was actually a better idea than it really was, and that it was simpler and more beautiful than it really was, is a lot of the story.

I think it's not that simplicity would be leaves us astray, it's just people, our people, and they fall in love with whatever idea they have. And then they weave narratives around that idea, or they present in a situation that emphasizes the simplicity and the beauty. Yeah, that's part of it. But the thing about physics that you have is that you know what really can tell it. If you can do an experiment and check and see if nature is really doing what your idea expects that you do in principle have a way of really testing it.

And it's certainly true that if you thought you had a simple idea and that doesn't work and you got to do an experiment and what actually does work is maybe some more complicated version of it that can certainly happen and That that that that that can be true. I think her emphasis is more that I don't really disagree with is that people should be concentrating on When they're trying to develop better theories on More on self-consistency not so much on beauty, but is this idea beautiful, but is there something about theory which is not quite consistent and use that as a guide that there's something wrong there which needs fixing? And so I think that part of her argument,

I think I was, we're on the same page, you bet. What is consistency and inconsistency? What exactly do you have examples in mind? Well, it can be just simple inconsistency between theory and an experiment that if you, so we have this great fundamental theory, but there are some things we see out there which don't seem to fit in it, like dark energy and dark matter, for instance.

But if there's something which you can't test experimentally, I think she would argue and I would agree that, for instance, if you're trying to think about gravity and how are you gonna have a quantum theory of gravity, you should kind of be, you know, test any of your ideas with kind of, kind of a thought experiment, you know, is does this actually give a consistent picture

of what's going to happen of what happens in this particular situation or not? So this is a good example. You've written about this. Since quantum gravitational effects are really small, super small, arguably unobservably small, should we have hope to arrive at a theory of quantum gravity somehow? What are the different ways we can get there? You've mentioned that you're not as interested in that

effort because basically, yes, you cannot have a waste to scientific validity given the tools of today. Yeah, I've actually, you know, I've over the years, certainly spent a lot of time learning about gravity, about temps to quantize it, but it hasn't been that much in the past, the focus of what I've been thinking about. But I mean, my feeling was always, you know, as I think, speaking of what I agree, that the, you know, one way you can pursue this, if you can't do experiments, is just search for

consistency. It can be remarkably hard to come up with a completely consistent model of this, in a way that brings together a quantum mechanics and general relativity. That's I think kind of been the traditional way that people who pursued quantum gravity have often pursued, you know, we have the best route to finding a consistent theory of quantum gravity. String theorists will tell you this, other people will tell you it's kind of what people argue about. But the problem with all of that is that you end up, the danger is that you end up with that that everybody could be successful. Everybody, everybody's

program for how to find a theory of kind of gravity, you know, ends up with something that is consistent. And so in some sense, you could argue this is what happened to the string theorist. They, um, they solved their problem of finding a consistent theory of quantum gravity, and they ended up, but they found 10 to the string theorist. They solve their problem of finding a consistent theory of quantum gravity, but they found 10 to the 500 solutions. So, you know, if you believe that everything that they would like to be true is true, well, okay, you've got a theory, but it ends up being kind of useless because it's just one of an infinite, essentially infinite number of things which you have no way to experimentally distinguish.

So this is just a depressing situation. But I do think that there is a, so again, I think pursuing ideas about what, more about beauty and how can you integrate and unify these issues about gravity with other things we know about physics. And can you find a theory where they were these fit together in a way that makes sense and hopefully predict something that's much more promising?

Well, it makes sense and hopefully, I mean, we'll sneak up onto this question a bunch of times because you kind of said a few slightly contradictory things, which is like it's nice to have a theory that's consistent, but then if the theory is consistent, it doesn't necessarily mean anything. So like, it's not enough, it's not enough. It's not enough, and that's the problem. So it's like it keeps coming back to, okay, there should be some experimental validation.

So, okay, let's talk a little bit about strength theory. You've been a bit of an outspoken critic of strength theory. Maybe one question first to ask is what is strength theory? And beyond that, why is it wrong? Or rather, the title of your blog says not even wrong. or rather, the title of your blog says not even wrong. Okay. One interesting thing about the current theta string theory, I think it's actually very, very difficult at this point to say what string theory means. If people say they're a string theorist,

what they mean and what they're doing is kind of hard to pin down the meaning of the term. But the initial meeting, I think, goes back to, there was kind of a series of developments starting in 1984 in which people felt that they had found a unified theory of a sort of a sort of standard model of all the standard, well-known kind of particle interactions and gravity and it all fit together in a quantum theory,

and that you could do this in a very specific way by, instead of thinking about, having a quantum theory of particles moving around in space time, think about a quantum theory of kind of one-dimensional loops moving around in space time, so-called strings. And so, instead of one degree of freedom, these have an infinite, never-graded freedom. It's a much more complicated theory,

but you can imagine, okay, we're gonna quantize this theory of loops moving around in space time. And what they found is that you could do this and you could fairly, relatively straightforwardly make sense of, such a quantum theory, but only if space and time together were 10 dimensional. And so then you had this problem,

again, the problem I refer to at the beginning of, okay, now, once you make that move, you've got to get rid of six dimensions. And so the hope was that you could get rid of the six dimensions by making them very small, and that consistency of the theory would require these six dimensions satisfy a very specific condition called being a Klaabi al manifold, and that we knew very, very few examples of this. So what got a lot of people very excited back in 84, 85 was the hope that you could just

take this 10-dimensional string theory and find one of a limited number of possible ways of getting rid of six dimensions by making them small and then you would end up with an effective four-dimensional theory which looked like the real world. This was the hope. So then there's then a very long story about what happened to that hope over the years. I mean There's then a very long story about what happened to that hope over the years. I mean, I would argue in part of the point of the book, and its title was that, you know, this ultimately was a failure that you ended up, that this idea just didn't, they're ended up being just too many ways of doing this, and you didn't know how to do this consistently. It was kind of not even wrong in the sense that

you could never could pin it down well enough to actually get a real falsifiable prediction out of it that would tell you it was wrong, but it was kind of in the realm of ideas which initially look good, but the more you look at them, they just don't work out the way you want and they don't actually end up carrying the power or the that you originally had this vision of. And yes, the book title is not even wrong, your blog, your excellent blog title is not even wrong. Okay, but there's never less been a lot of excitement about string theory through the

decades as you mentioned, what are the different flavors of ideas that came, like they branched out, you mentioned 10 dimensions, you mentioned loops with infinite degrees of freedom, what are the interesting ideas to you that kind of emerged from this world? Well, yeah, I mean, the problem in talking about the whole subject and part of the reason I wrote the book is that, yeah, it it gets very very complicated.

I mean, there's a huge amount, you know, a lot of people got very interested in this, a lot of people worked on it. And in some sense, I think what happened is exactly because the idea didn't really work, that this caused people to, you know, instead of focusing on this one idea and digging in and working on that, they just kind of kept trying new things. And so people, I think, ended up wandering around in a very, very rich space of ideas about mathematics and physics and discovering, you know, all sorts of really interesting things. It's just the problem is there tended to be an inverse relationship between how interesting and beautiful and fruitful this new idea that they were trying to pursue was and how much it looked like the real world. So there's a lot of beautiful mathematics came out of it.

I think one of the most spectacular is what the physicist called two-dimensional conformal field theory. And so these are basically quantum field theories and kind of think of it as one space and one time dimension, which have just this huge amount of symmetry and a huge amount of structure which is some totally fantastic mathematics behind it. And again, and some of that mathematics is exactly also what appears in the Langlands program. So a lot of the first interaction between math

and physics around the language program has been around these two dimensional conformal field theories. Is there something you could say about what the major problems are with strength theory? So like besides that there is no experimental validation, you've already had a big hole in string theory that has been its perturbative definition. Perhaps that's one can you explain what that means? Well, maybe to begin with, I think the simplest thing to say is the initial idea really was that, okay, we have this, instead of what's great is we have this thing that only works, it's very structured and has to work in a certain way for it to make

sense. But then you ended up in 10 space time dimensions. And so to get back to physics, you had to get rid of five of the dimensions, six of the dimensions. And the bottom line, I would say in some sense, is very simple. And so to get back to physics, you had to get rid of five of the dimensions, six of the mentions. And the bottom line, I would say in some sense, is very simple, that what people just discovered is just there's kind of no, particularly a nice way of doing this. There's an infinite number of ways of doing it, and you can get whatever you want depending on how you do it.

So you end up the whole program of starting at 10 dimensions and getting to four, just kind of collapses out of a lack of any way to kind of get to where you want because you can get anything. There'd be the hope around that problem has always been that the standard formulation that we have of string theory, which is you can go in by the name perturbative, but it's kind of, there's a standard way we know of given a classical theory of constructing a quantum theory and working with it, which is this the so-called perturbation theory, that we know how to do, and that by itself just doesn't give you any hint as to what to do about the Sixth dimensions. So actual perturb with the string theory by itself really only works in 10 dimensions.

So you have to start making some kinds of assumptions about how I'm going to go beyond this formulation that we really understand of string theory and get rid of these Sixth dimensions. So kind of the simplest one was the the clobbyale postulate, but when that didn't really work out, people have tried more and more different things. And the hope has always been that the solution, this problem would be that you would find a deeper and better understanding of what string theory is, that would actually go beyond this perturbative expansion, which would generalize this. And that once you had that, it would solve this problem of, it would pick out what to do with this extension.

How difficult is this problem? So if I could restate the problem, it seems like there's a very consistent physical world operating in four dimensions. And how do you map a consistent physical world in 10 dimensions to a consistent physical world in four dimensions? And how difficult is this problem? Is that something you can even answer? Just in terms of physics intuition, in terms of mathematics,

mapping from 10 to 4 dimensions. Well, basically, yeah, I mean, you have to get rid of the six of the dimensions. So so there's, I mean, there's kind of two ways of doing it. One is what we call compactification. You say that there really are 10 dimensions, but for whatever reason, six of them are really, are so, so small, we can't see them. So you basically start out with 10 dimensions, and what we call, you know, make, make six of them not go out to infinity, but just kind of a finite extent, and then make that size

go down so small as that observable. But that's a, that's a math trick. So, can you also help me build an intuition about how rich and interesting the world and those six dimensions is? So compactification seems to imply that. Well, it's not very interesting. Well, no, but the problem is that what you learn if you start doing mathematics and looking at geometry and topology and more and more dimensions is that, I mean, asking the question like,

what are all possible six-dimensional spaces? It's just a, it's kind of an unanswerable question. It's just, I mean, it's even kind of technically undecidable in some way. There are just too many things you can do with all these. If you start trying to make one dimensional spaces, it's like, well, you've got a line, you can make a circle, you can make graphs, you can kind of see what you can do. But as you go to higher and higher dimensions, there are just so many ways you can put things together and get something of that dimensionality.

us together and get something of that dimensionality. Unless you have some very, very strong principle, which is going to pick out some very specific ones of these six-dimensional spaces, and there are just too many of them, and you can get anything you want. So, if you have ten dimensions, the kind of things that happen, say that's actually the way, that's actually the fabric of our reality's tend to mesions. There's a limited set of behaviors of objects, I don't know, even know what the right terminology to use, that can occur within those dimensions, like in reality. Yeah. And so, like, what I'm getting at is, is like is there some consistent constraints? So if you have some constraints that mapped the reality then you can start saying like

Dimension number seven is kind of boring All the excitement happens in the spatial dimensions one two three and time is also kind of boring And like it's someone more exciting others, or we can use our metric of beauty. Some dimensions are more beautiful than others. Once you have an actual understanding of what actually happens in those dimensions in our physical world, as opposed to sort of all the possible things that could happen. In some sense, just the basic fact is you need to get rid of them. We don't see them. So you need to somehow explain them. The main thing you're trying to do is to explain why we're not seeing them.

And so you have to come up with some theory of these extra dimensions and how they're going to behave. String theory gives you some ideas about how to do that. But the bottom line is where you're trying to go with this whole theory you're creating is to just make all of its effects essentially unobservable. So it's not a really, it's an inherently kind of dubious and worries something that you're trying to do there. Why are you just adding and all this stuff and then trying to explain why we don't see it? I mean, it's just this maybe a dumb question, but it's, is this an obvious thing to state

that those six dimensions that are unobservable or anything beyond four dimensions is unobservable? Or do you leave a little door open to saying the current tools of physics and obviously our brains aren't unable to observe them. But we may need to come up with methodologies for observing it. So as opposed to collapsing your mathematical theory into four dimensions, leaving the door open a little bit to maybe we need to come up with tools that actually allow us to directly measure those dimensions. Yeah, so I mean, you can certainly ask, you know, assume that we've got model, look at models with more dimensions and ask, you know,

what would the observable effects? How would we know this? And you go out and do experiments. So for instance, you have a like gravitationally, you have an inverse square law of forces. Okay, if you had more dimensions, that inverse square law would change something else. So you can go and start measuring the inverse square law and say, okay, inverse square law is working, but maybe if I get, get, it turns out to be actually kind of very, very hard measure gravitational effects, and even kind of, you know, somewhat macroscopic distances, because they're so small. So you can start looking at the inverse square lawns, start trying to measure it at shorter and shorter distances and see if there were extra dimensions at those distance scales, you would start to see the inverse square law fail. And so people look for that. Again, you don't see it. But you can, I mean, there's

all sorts of experiments of this kind. You can imagine which test for effects of extra mentions at different distance scales, but none of them, they all just don't work. Nothing yet. But you can say, oh, but it's just much, much smaller. You can say that. Which, by the way, makes LIGO. And the detection of gravitational waves, quite an incredible project.

Ed Witten is often barred up as one of the most brilliant mathematicians of physicists ever. What do you make of him in his work on string theory? Well, I think he is a truly remarkable figure. I've had the pleasure of meeting him first when he was a postdoc. And I mean, he's just completely amazing, mathematician and physicist. And he's quite a bit smarter than just about any of the rest

of us, and also more hardworking. And it's a kind of frightening combination to see how much he's been able to do. And, but I would actually argue that, his greatest work, the things that he's done that have been of just his mind-blowing significance of giving us, I mean, he's completely revolutionized some areas of mathematics.

He's totally revolutionized the way we understand the relations between mathematics and physics. And most of those, his greatest work, is stuff that doesn't have, has little or nothing to do with string theory. I mean, for instance, he, you know, he, so he was actually one of the fields, the very strange thing about him in some sense is that he, he doesn't have a Nobel Prize. So there, there's a very large number of people who are nowhere near as smart as he is and don't work anywhere near as hard who have Nobel prizes.

I think he just had the misfortune of coming into the field at a time when things had gotten much, much, much tougher and nobody really had no matter how smart he was. It was very hard to come up with a new idea that was going to work physically and get you a about prize. But he got a field's medal for certain work he did in mathematics. That's just completely unheard of. For mathematicians to give a field's medal to someone outside their field in physics, it really wouldn't know before he came around.

I don't think anybody would have thought that was even conceivable. So you see things, he came into the field of theoretical physics at a time when, and still to today, is you can't get a Nobel Prize for purely theoretical work. A specific problem of trying to do better than the standard model is just this insanely successful thing and it kind of came together in 1973 pretty much. And all of the people who were involved in that coming together, many of them ended up with no-bought rises for that. But if you look, post 1973 pretty much, it's a little bit more there's some

Edge cases if you like but the if you look post 1973 at what people have done to try to do better than the standard model And to get a better you know, I there it really hasn't it's been too hard a problem It hasn't worked the theory's too good and so it's not that other people went out there and did and did it and Not him and that they got no more prizes for doing it. It's like no one really, the kind of thing he's been trying to do with string theory is not, no one has been able to do since 1973. Is there something you can say about the standard model? So the four laws of physics that seems to work very well and yet people are striving to do more talking about unification and so on. Why?

What's wrong? What's broken about the standard model? Why does it need to be improved? I mean, the thing that gets you most attention is gravity that we have trouble. So you want to, you want to, in some sense, integrate, integrate what we know about the gravitational force with it and have a unified quantum field theory that has gravitational interactions also. So that's the big problem everybody talks about. I mean, but it's also true that if you look at the standard model, it has

these very, very deep, beautiful ideas, but there's certain aspects of it that are very... Let's just say that they're not beautiful. They're not... To make the thing work, you have to throw in lots and lots of extra parameters at various points. A lot of this has to do with the so-called... The so-called Higgs mechanism in the Higgs field. If you look at the theory, everything is, if you forget about the Higgs field and what it needs to do, the rest of the theory is very, very constrained and has very, very few free parameters, really a very small number. There's very small number of parameters and a few integers, which tell you what the theory is. To make this work as a theory, the real world, you need a Higgs field and you need to do something.

And once you introduce that Higgs field, all sorts of parameters make it apparent. So now when we've got 20 or 30 or whatever parameters that are going to tell you what all the masses of things are and what's going to happen. So you've gone from a very tightly constrained thing with a couple parameters to this thing which the minute you put it in, you had to add all these extra parameters to make things work. And so that, it may be one argument as well, that's just the way the world is. And the fact that you don't find that aesthetically pleasing is just your problem. Maybe we live in a multiverse and those numbers are just different than every universe.

But you know, another reasonable conjecture is just that, well, this is just telling us that there's something we don't understand about what's going on in a deeper way, which would explain those numbers. And there's some kind of deeper idea about where the Higgs field comes from and what's going on, which we haven't figured out yet, and that's what we should look for. But to stick on strength theory a little bit longer, could you play devil's advocate and try to argue for strength theory? Why it is something that deserves the effort that it got and still can like if you think of it as a flame

still should be a little flame that keeps burning. Well, I think the the most positive argument for it is all the you know all sorts of new ideas about mathematics and about parts of physics really emerge from it. So it was very a fruitful source of ideas. And I think this is actually one argument, you'll definitely, which I kind of agree with, you'll hear from Whitten and from other strength theorists, and you know, this is this is just such a fruitful and inspiring idea, and it's led to so many other different things coming out of it that there must be something right about this. And that's, you know, okay, that anyway, I think that's probably the strongest thing that they've got. But you don't think there's aspects to it that could be neighboring to a theory that

does unify everything. To a theory of everything. It may not be exactly the theory, but sticking on it longer might get us closer to the theory of everything. Well, the problem that now really is that you really don't know what it is now. You've never, nobody has ever kind of come up with this non-perturbed theory. So, it's become more and more frustrating and an odd activity to try to argue with a string theorist about string theory because it's become less and less well defined what it is. And it's become actually more and more kind of a, whether you have this weird phenomenon

of people calling themselves string theorists when they've never actually worked on any theory where there are any strings anywhere. So what has actually happened kind of sociologically is that you started out with this fairly well-defined proposal and then I would argue because that didn't work, people branched out in all sorts of directions doing all sorts of things. It became farther and farther removed from that. And for sociological reasons, the ones who kind of started out or now or were trained by the people who worked on that have now become this string theorist. And but it's becoming almost more kind of a tribal denominator than a, um, well, it's very hard to know what you're arguing about when you're arguing that string theory these days.

Well, to push back on that a little bit, I mean, string theory, it's just a term, right? It doesn't like, you could, like, this is the way language evolves. Is it could start to represent something more than just the theory that involves strings? It could represent the, uh, the effort to unify the laws of physics, right? And at high dimensions with these super tiny objects, or something like that, we can sort of put string theory aside.

So for example, neural networks in the space machine learning, there was a time when they were extremely popular, they became much, much less popular to a point where if you mentioned, you're not going to be respected at conferences. And then once again, you know, that works became all the rage about 10, 15 years ago. And as it goes up and down, and a lot of people would argue that using terminology like machine learning and deep learning is often misused, over-general. Everything that works is deep learning, everything that doesn't, isn't something like that. That's just the way, again, we're back to sociological things, but I guess what I'm trying

to get at is if we leave the sociological mess aside Do we throw out the the baby with the bath water? Is there some Besides the side effects of nice ideas from the Ed Wittens of the world is there some core truths there that we should stick by and in in the full there that we should stick by. And in the full, beautiful, massive space that we call strength theory, that people call strength theory. You're right. It is kind of a common problem that, you know,

how what you call some field changes and evolves in interesting ways as the field changes. But I guess what I would argue is the initial understanding of string theory that was quite specific, we're talking about a specific idea, 10 dimensional super strings, compactified as it's dimensions. To my mind, the really bad thing that's happened to the subject is that it's hard to get people to admit, at least publicly, that that was a failure, that this really didn't work. And so the fact of what people do is people stop doing that and they start doing more interesting

things, but they keep talking to the public about string theory and referring back to that idea and using that as kind of the starting point and is kind of the place where the whole tribe starts and everything has comes from. So the problem with this is that having as your initial name and what everything points back to something which really didn't work out, it kind of makes everybody, it makes everything, you created this potentially very, very interesting field

and interesting things happening, but, you know, people in graduate school take courses on strength theory and everything kind of, and this is what you tell the public in which you continually pointing back, so you're continually pointing back to this idea which never worked out as your guiding inspiration. And it really kind of deforms the whole your whole way of your hopes of making progress. That's to me, I think the kind of worst thing has happened in this field.

Okay, sure. So there's a lack of transparency, sort of authenticity about communicating the things that failed in the past. And so you don't have a clear picture of like firm ground that you're standing on. Again, those are sociological things. And I, there's a bunch of questions I want to ask you. So one, what's your intuition about why the original idea failed? So what can you say about why the original idea failed. So what can you say about why you're pretty sure it has failed? You know, and the initial idea was, as I tried to explain it, it was quite seductive

and that you could see why, when the others got excited by it, it was, you know, at the time it looked like there are only a few as possible, Cobby as that would work. And it looked like, okay only a few possible Coby-As that would work. It looked like, okay, we just have to understand this very specific model in these very specific six-dimensional spaces, and we're going to get everything. So it was a very subjective idea. But as people learn more and more about it, they just kind of realize that they're just more and more things you can do with these extensions and you can't and this

This is just not going to work. Meaning like it's I mean, what was the failure? Mode here is as you could just have an infinite number of possibilities You could do so it's you can come up with any theory you want. You can fit quantum mechanics. You can explain gravity. You can explain anything you want with it. Right.

Is that the basic failure mode? Yeah. So it's a failure mode of kind of this idea ended up being essentially empty. That it just doesn't end up not telling you anything because it's consistent with just about anything. So, I mean, there's a complete, if you try and talk with string theorists about this now, I mean, there's an argument, there's a long argument over this about whether, you know, oh no, no, no, maybe there's still our constraints coming out of this idea or not.

Or maybe we live in a multiverse and everything is true anyway. So there are various ways you can kind of, the string theory is I've kind of react to this kind of argument that I'm making. I try to hold on to it. What about experimental evaluation? Is that a fair standard to hold before a theory of everything that's trying to unify quantum mechanics and gravity. Yeah, I mean, ultimately, to be really convinced that, you know, that on some new idea about your vacation really works, you need some kind of, you need to look at the real world and see

that this is telling you something, something true about it. I mean, either telling you that if you do some experiment and go out and do it, you'll get some unexpected result and that's the kind of gold standard or it may be just that like all those numbers that are we don't know how to explain, it will show you how to calculate them. I mean, you can be various kinds of experimental validation but that's

certainly ideally what you're looking for. How tough is this, do you think? Four theory of everything. I just drink theory. So for something that unifies gravity and quantum mechanics, so the very big and the very small, is this, let me ask you one way, is it a physics problem, a math problem, or an engineering problem? My guess is that it's a combination of a physics and a math problem that you really need. It's not really engineering. It's not like there's some kind of well-defined thing you can write down and we just don't have enough computer power to do the calculation. That's not the kind of problem it is at all.

But the question is, what mathematical tools you need to properly formulate the problem is unclear. So one reasonable conjecture is the way the reason that we haven't had any success yet is just that we're missing either or missing certain physical ideas or we're missing certain mathematical tools, which are some combination of them which would Which we need to kind of properly formulate the problem and see and see that it

It has a solution that looks like the real world. But those you need I guess you don't but there's a sense that you need both gravity like all the laws of physics to be operating on the same level. So it's a, it feels like you need an object like a black hole or something like that in order to make predictions about. Otherwise, you're always making predictions about this joint phenomena.

Or can you do that as long as the theory is consistent and doesn't have special cases for each of the phenomena? Well, your theory should, I mean, if your theory is going to include gravity, our current understanding of gravity is that you should have, there should be black hole states in it, you should be able to describe black holes in this theory. And just one aspect that people have concentrated a lot on is just this kind of questions about if your theory includes black holes like it's supposed to and it includes quantum mechanics, then there's certain kind of paradoxes which come up. So that's been a huge focus of quantum gravity work.

Work has been just those paradoxes. So stepping outside of string theory, can you just say first at a high level, what is a theory of everything? What is a theory of everything seek to accomplish? Well, I mean, this is very much a kind of reductionist point of view in the sense that so it's not a theory. This is not going to explain to you, you know, anything. It doesn't relate. This kind of theory, this kind of theory of everything we're talking about doesn't say anything interesting particularly about like macroscopic objects

about what the weather is going to be tomorrow or you know things are happening at this scale. But just what we've discovered is that as you look at the universe that kind of, you know, if you kind of start breaking it apart into, a new end up with some fairly simple pieces, Quanta, if you like, and which are interacting in some fairly simple way. What we mean by theory of everything is a theory that describes all the correct objects you need to describe what's happening in the world and describes how they're interacting with each other at a most fundamental level. How you get from that theory to describing some macroscopic, incredibly

complicated thing is there that becomes, again, more of an engineering problem and you may need machine learning or you made a lot of very different things to do it. Why don't you even think it's just engineering, it's also science. One thing that I find kind of interesting talking to physicists is a little bit, there's a little bit of hubris. Some of those brilliant people I know are physicists, both philosophy and just in terms of mathematics in terms of understanding the world. But there's a kind of either hubris or what would I call it? Like a confidence that if we have a theory of everything, we will understand everything.

This is the deepest thing to understand. I would say, and the rest is details. That's the old Rutherford thing. To me, this is like a cake or something. There's layers to this thing, and each one has a theory of everything. At every level, from biology, how life originates, that itself, like complex systems. That in itself is this gigantic thing that requires a theory of everything. And then there is, in the space of humans, psychology, like intelligence, collective intelligence,

the way it emerges among species, that feels like a complex system that requires its own theory of everything. On top of that is things like in the computing space, artificial intelligence systems, like that feels like an user theory of everything, and it's almost like once we solve, once we come up with the theory of everything, it explains the basic laws of physics that give us the universe, even stuff that's super complex, like how the universe might be able to originate, even explaining something that you're not a big fan of, like multiverses, or stuff that we don't have in evidence of yet. Still, we won't be able to have a strong explanation of why food tastes delicious.

Oh, yeah. I agree completely. I mean, there is something kind of completely wrong with this terminology of theory or everything. It's not. It's really in some sense, it's not, it's really in some sense, right bad term, right? You're bristic and bad terminology because it's not. This is explaining, this is a purely kind of reduction at this point of you that you're trying to understand certain, a certain very specific kind of things, which, you know, in principle, other things, you know, emerge from, but to actually understand how anything emerges from this is it can't be understood in terms of this underlying fund wealth area is going to be hopeless in

terms of kind of telling you what about this various emergent behavior. And as you go to different levels of explanation, you're going to need to develop different, completely different ideas, completely different ways of thinking. I guess there's a famous kind of Phil Anderson's slogan is that, you know, more is different. And so it's just, it's just, you know, even once you understand how what a couple of things, if you have a collection of stuff and you understand perfectly well, how each thing is interacting with it. With the others, what the whole thing is going to do is just a completely different problem and it's just not.

And you need completely different ways of thinking about it. What do you think about this? I get to ask you at a few different attempts at a theory of everything, especially recently. So I've been for many years a big fan of cellular top of complex systems and obviously, because of that, a fan of Stephen Wolfram's work in that space. But he's recently been talking about a theory of everything through his physics project, essentially.

What do you think about this kind of discrete theory of everything, like from simple rules and simple objects and the hypergraphs emerges all of our reality, where time and space are emergent. Basically everything we see around us is emergent. Yeah, I have to say, unfortunately, I have kind of pretty much zero sympathy for that. I mean, I don't, I spent a little time looking at it and I just don't see, it doesn't seem to me to get anywhere.

And it really is, just really, really doesn't agree at all with what I'm seeing, this kind of unification of math and physics that I'm kind of talking about around certain kinds of very deep ideas about geometry and stuff. If you want to believe that your things are really coming out of cellular to autumnative at the most fun level, you have to believe that everything that I've seen my whole career and as beautiful, powerful ideas, that's all just kind of a mirage, which just kind of randomly is emerging from these more basic, very, very simple, minded things.

And I have to give me some serious evidence for that, and I'm saying nothing. So Marage, you don't think there could be a consistency where things that quantum mechanics could emerge from much, much, much smaller discrete computational types of systems. I think from the point of view of certain mathematical point of view, quantum mechanics is already mathematically as simple as it gets. It really is a story about really the fundamental objects that you work with, and when you write down a quantum theory are in some form point of view, precisely the fundamental objects at the deepest levels of mathematics that you're working with, they're exactly the same. So, and cellular automata are something completely different which don't fit into these structures.

And so, I just don't see why. Anyway, I don't see it as a promising thing to do. And then just looking at it and saying, does this go anywhere? Does this solve any problem that I've ever, that I didn't, does this solve any problem of any kind? I just don't see it. Yeah, to me, cellular, autominal and these hypergraphs, I'm not sure solving a problem is even the standard to apply here at this moment.

To me, the fascinating thing is that the question it asks have no good answers. So there's not good math explaining, forget the physics physics of it math explaining the behavior of complex systems. And that to me is both exciting and paralyzing like we're at that very early days of understanding you know how complicated and fascinating things emerge from simple rules. Yeah, you know, I agree. I think that is a truly great problem. And depending where it goes, it may be, you know, it may start to develop some kind of connections to the things that I've kind of found more fruitful and hard to know, just I think a lot of that area, I kind of strongly feel, I best not say too much about it because I just, I don't know

too much about it. And I mean, again, we're back to this original problem that, you know, your time in life is limited. You have to figure out what you're going to spend your time thinking about. And that's something I just never seen enough to convince me to spend more time thinking about. What also timing, it's not just that our time is limited, but the timing of the kind of things you think about there, there's some aspect that our time is limited, but the timing of the kind of things you think about. There is some aspect to cellular atomic, these kinds of objects that it feels like or very many years away from having big breakthroughs on. And so it's like, you have to pick the problems that are solvable today.

In fact, my intuition, again, not perhaps biased, is it feels like the kind of systems that complex systems that cellular automata are would not be solved by human brains. It feels like, well, like, it feels like something post-human-nose software, or like, significantly enhanced humans, meaning like using computational tools, very powerful computational tools to crack these problems open. That's if our approach to science, our ability to understand science, our ability to understand physics

will become more and more computational, or there'll be a whole field that's computational nature, which currently is not the case of currently. Computation is the thing that sort of assists us in understanding science the way we've been doing it all along. But if there's a whole new, I mean, that will from new kind of science, right? It's a little bit dramatic, but, you know, this, if computers could do science on their own, computational systems, perhaps that's the way they would do the science. They would try to understand the cellular automata, and that feels like we're decades away. So perhaps you'll crack open some interesting facets of this physics problem, but it's

very far away. So timing is everything. That's perfectly possible. Well, let me ask you then in the space of geometry, I don't know how well you know Eric Weinstein. I'm quite well here. What are your thoughts about his geometric community and the space of ideas that he's playing with in his proposal for

theory of everything. Well, I think that he has, he, fundamentally has, I think, the same problems that everybody has had trying to do this. And, you know, they're various, they're really version of the same problem that you try to, um, you try to get unity by putting everything into some bigger structure. So he has some other ones that are not so conventional that he's trying to work with. But he has the same problem that even if he can get a lot farther in terms of having a really well-defined, well-understood, clear picture of these large, these things he is working with, they're really large geometrical structures, the many dimensions, many kinds. And I just don't see, anyway, he's going to have the same problem, the string there is have. How do you get back down to the structures of the standard model and how you, yeah, so I just, anyway, it's the same, and there's another interesting example of some little kind of thing is Garrett Luzy's

theory of everything. Again, it's a little bit more specific than Eric's, he's working with this E8, but again, I think all these things found are at the same point that you don't You know, you create this unity, but then you have no You don't actually have a good idea how you're gonna get back to the actual To the objects we're seeing how are you gonna you create these big symmetries? How are you gonna break them and and because because we don't see those symmetries in the real world. So ultimately, there would need to be a simple process for collapsing it to four dimensions. You'd have to explain it well.

Yeah, and I forget in his case, but it's not just four dimensions. It's also these structures you see in the standard model. There's a certain very small dimensional groups of symmetry. It's called U1, SU2, and SU3. The problem with, and this has been the problem since the beginning, almost immediately after 1973, about a year later or two years later, people started talking about grand unified theories. So you take the U1, the SU2, and the SU3, and you put them in together into this

bigger structure called the SU5 or SO10. But then you're stuck with this problem, that wait a minute, how, why does the world not look? Why do I not see these SU5 symmetries in the world? I only see these. And so, and I think, you know, those, the kind of thing that Eric and also in Garrett and lots of people who try to do, they all kind of found her in that same, in that same way that they don't have, they don't have a good answer to that. Are there lessons, ideas to be learned from theories like that, from Gary Leasey's from Erics? I don't know, depends. I have to confess, I haven't looked that closely at Erics. I mean, he'd explained to this to me personally a few times, and I've looked a bit at his paper, but it's um,

again, we're back to the problem of a limited amount of time in life. Yeah, I mean, is this an issue in effect, right? Why don't more physicists look at it? There. I mean, I'm in this position that somehow, you know, I've, I've, people write me emails for whatever reason. And I work in the space of AI, and so there's a lot of people, perhaps AI is even way more accessible in physics,

in a certain sense. So a lot of people write to me with different theories about they have for how to create general intelligence. And it's again, a little bit of an excuse I say to myself, like, well, I only have a limited amount of time, so that's why I'm not investigating it. But I wonder if there's ideas out there that are still powerful, they're still fascinating, and that I'm missing because I'm dismissing them because they're outside of the sort of the usual process of academic research.

Yeah, well, I mean, the same thing in pretty much every day in my email, Because they're outside of the sort of the usual process of academic research. Yeah, well, I mean, the same thing pretty much every day in my email. There's somebody's got a theory of everything about why all of what physicists are doing. Perhaps the most disturbing thing I should say about my being a critic of string theory is that when you realize who your fans are, that they're every day, I hear from somebody, he says, oh, well, since you don't like string theory, you must, of course, agree with me that this is the right way to think about everything. Oh, no, oh, no. And, you know, most of these are, you know, you quickly can see this is, person doesn't

know very much and doesn't know what they're doing. You know, but there's a whole continuum to people who are quite serious, physicists and mathematicians who are making a fairly serious attempt to try to do something and like Lekker and Herak. And then your problem is, you know, you spent, you do want to try to spend more time looking at it and try to figure out what they're really doing. And that at some point you just realized, wait a minute wait a minute, for me to really, really understand exactly what's going on here would just take time. I just don't have.

Yeah, it takes a long time. Which is the nice thing about AI is unlike the kind of physics we're talking about. If your idea is good, that should quite naturally lead to you being able to build a system that's intelligent. So you don't need to get approval from somebody that's saying, you have a good idea here. You can just utilize that idea and engineer a system like naturally leads to engineering. With physics here, if you have a perfect theory that explains everything that still doesn't obviously lead one to to scientific experiments that can validate that theory and to like trinkets you can build

and sell. Very. At a store for $5. Yeah. I can't make money out of it. So that makes it much more challenging. Well let me also ask you about something that you found, especially recently appealing, which is Roger Penerosa's

Twister Theory. What is it? What kind of questions might it allow us to answer? What will the answers look like? It's only in the last couple of years that I really, really kind of come to really, I think, to appreciate it and to see how to really, what I believe to see how to really do something with it. And I've gotten very excited about that the last year or two.

I mean, one way of saying one idea of Twister theory is that what it's a different way of thinking about what space and time are and about what points and space and time are. But which is very interesting that it only really works to four dimensions. So four dimensions behaves very, very specially unlike other dimensions. And in four dimensions, there is a way of thinking about space and time geometry where, as well as just thinking

about points and space and time. You can also think about different objects, these all called twisters. And then when you do that, you end up with a really interesting insight that you can formulate a theory. You can formulate a very standard theory that we formulate in terms of points of space and time. And you can reformulate in this Twister language. And in this Twister language, it's the fundamental objects are actually are more kind of the, are actually spheres

in some sense kind of the light cone. So maybe one way to say it, which actually, I think is really, is quite amazing. If you ask yourself, what do we know about the world? We have this idea that the world out there is all these different points. That's kind of a derived quantity. What really don't know about the world is when you open our eyes, what do you see? You see a sphere. What you're looking at is you're looking, a sphere is worth a light rays coming into your, into your eyes. And what Penrose says is that, well, what, what a point in space time is, is that sphere,

that sphere of all the light rays coming in. And, and he says, and you should formulate your, um, instead of thinking about points, you should think about the space of those spheres, if you like. And formulate the degrees of freedom as physics, as living of those fears, if you like, and formulate the degrees of freedom as physics, as living on those fears, living on, so you're kind of living on, your degrees of freedom, or living on light, Ray, is not on points. And it's a very different way of thinking about, um, about physics. And you know, he, and others working with him, develop a, you them develop a beautiful mathematical form of capitalism and a way to go back from forth between some aspects of our standard way we write these things down

and work in the so-called Twister space. And they, certain things worked out very well, but they ended up, I think kind of stuck by the 80s or 90s, that weren't, it's a little bit like string theory that they, by using these ideas about twisters, they could develop them in different directions and find all sorts of other interesting things, but they were getting, they weren't finding any way of doing that that brought them back to kind of new insights into physics. And my own, I mean, what's kind of gotten me excited, really, is what I think I have an idea about that, I think,

does actually work that goes more in that direction. And I can go on about that endlessly or talk a little bit about it, but that's the, I think that that's the one kind of easy to explain inside about Twister Theory. There are some more technical ones. I should, I mean, I think it's also very convincing what it tells you about spinners, for instance, but that's a more technical. Well, first, let's like linger on the spheres and the

light goes, you're saying twist or theory allows you to make that the fundamental object with which you're operating. Yeah. How that, I mean,, first of all, philosophically, that's weird and beautiful. Maybe because it maps, it feels like it moves us so much closer to the way human brain's perceived reality. So it's almost like our perception is like the content of our perception is the fundamental object of reality. That's very appealing. Is it mathematically powerful?

Is there something you can say a little bit more about what the heck that even means for because it's much easier to think about mathematically like a point in space time. What does it mean to be operating on the light cone? It uses a kind of mathematics that's relative, you know, what was kind of goes back to the 19th century among mathematicians, it's not. Anyway, it's a bit of a long story, but one problem is that you have to start, it's crucial that you think in terms of complex numbers, and not just real numbers. And this, for most people, that makes it harder to, for mathematicians, that's fine.

We love doing that, but for most people, that makes it harder to think about. I think perhaps the most, the way that there is something you can say very specifically about it, you know, in terms of spinners, which I don't know if you want to, I think perhaps the most the way that there is something you can say very specifically about it You know in terms of spinners, which I don't know if you want to I think it's a point. Yeah, so maybe what are spinners? Let's start with spinner because I think that if we can introduce that that I can By the way Twister spelled in O and spinner is spelled in O as well. Yes, okay So in case you want to Google it and look it up, there's very nice Wikipedia pages. As a starting point, I don't know what is a good starting point for Twitter.

Well, when you say about penrose, I mean, penrose is actually a very good writer and also very good draftsman. He's our drafts. He, the extent this is visualizable, he actually has done some very nice drawings. So, I mean, almost any kind of expository thing you can find him writing is a very good place to start. He's a remarkable person. But the, so, spinners or something that independently came out of mathematics and out of physics, and to say where they came out of physics, I mean, what people realized when they started looking at elementary particles like electrons

or whatever, there seemed to be, there seemed to be some kind of doubling of the degrees of freedom going on. If you counted what was there in some sense in the way you would expect it, and when you started doing quantum mechanics, it started looking at elementary particles, there were seem to be two degrees of freedom they're not one.

And one way of seeing it was that if you put your electron in a strong, magnetic field and ask what was the energy of it, instead of it having one energy, it would have two energies. There would be two energy levels. And as you increase, maybe at a field, splitting what it increased.

So physicists kind of realized that, wait a minute. So we thought when we were doing it, first started doing quantum mechanics, that the way to describe particles was in terms of wave functions and these wave functions were complex to complex values. Well, if we actually look at particles, that that's not right. They're pairs of complex numbers, pairs of complex numbers. So, you know, why, so one of the kind of fundamental, from the physics point of view, the fundamental question is, why are all our kind of fundamental particles described by pairs of complex numbers? Just weird. And then, but if you go, and then you can ask, you know, well, what happens if you like take an electron and rotate it? So how, how do things do things move in this pair of complex numbers?

Well, now, if you go back to mathematics, what had been understood in mathematics some years earlier, or not that many years earlier, was that if you ask very, very generally, think about geometry of three dimensions, and ask, and if you think about things that are happening in three dimensions, in the standard way, everything, the standard way of doing geometry, everything is about vectors. So if you take it any math class, as you probably see vectors at some point, there's triplets of numbers, tell you what a direction is or how far you're going in three-dimensional space. And most of all, everything we teach in most standard courses in mathematics is about vectors and things you build out of vectors.

So you express everything about geometry in terms of vectors or how they're changing or how you put two of them together and get planes and whatever. But what I've been realized, right on, is that if you ask very, very generally, what are the things that you can consistently think about rotating? So you ask a technical question, what are the representations of the rotation group? Well, you find that one answer is they're vectors and everything you build out of vectors. But then people found, but wait a minute, there's also these other things, which you can't build out of vectors, but what you can consistently rotate.

And they're described by pairs of complex numbers, by two complex numbers. And they're the spinners also. And to make a lot, and to make, and you can think of spinners in some sense as more fundamental than vectors, because you can build vectors out of spinners. You can take two spinners and make a vector. But you can't, if you only have vectors, you can't get spinners.

So there are in some sense, there's some kind of level of lower level of geometry beyond what we thought it was, which was kind of spinner geometry. And this is something which even to this day when we teach graduate courses in geometry, we mostly don't talk about this because it's a bit hard to do correctly. If you start with your whole setup as in terms of vectors, getting, describing things in terms of spinners is a whole different ballgame. terms of spinners is a whole different ball game. But anyway, it was just this amazing fact that this kind of more fundamental piece of geometry spinners and what we were actually

seeing if you look at electron are one and the same. So it's a kind of a mind-blowing thing, but it's very uncatter intuitive. What What is some weird properties of spinners that are counterintuitive? There are some things that they do for instance, if you rotate a spinner around 360 degrees, it doesn't come back towards, it becomes minus what it was. So the way rotations work, there's a kind of a funny sign you have to keep track of in some sense. So they're kind of too valued in another weird way. But the fundamental problem is that it's just not, if you're used to visualizing vectors, there's nothing you can do visualizing in terms of vectors that will ever give you a spinner,

it just does not get to have a work. As you were saying that I was visualizing a vector walking along a mull be a strip, and it ends up being upside down. But you're saying that doesn't really capture. So what really captures it, the problem is that it's really the simplest way to describe it is in terms of two complex numbers. And your problem with two complex numbers is that's four real numbers. So your spinner kind of lies in a four dimensional space. So you, that makes it hard to visualize. And it's crucial that it's not just any four dimensions. It's just that it's actually complex numbers. You're really going to use the fact that these are to complex numbers. So it is very hard to visualize. But to get back to what I think is mind blowing about twisters is that

another way of saying this idea about talking about spheres, another way of saying the fundamental idea of twister theory is, in some sense, the fundamental idea of twister theory is that a point is a two complex dimensional space so that every and that it lives inside the space that it lies inside is twister space. So in the simplest case, it's two or two space is four dimensional and a point in space time is a two complex dimensional subspace of the four complex dimensions. And as you move around in space time, you're just moving your planes or just moving around. And that, but then the plane, four dimensional space, it's a plane complex.

Complex, so it's two complex dimensions in four complex. But then to me, the mind-blowing thing about this is this then kind of todologically answers the question, is what is a spinner? Well, a spinner is a point. I mean, the space of spinners at a point is the point. In Twister Theory, the points are the complex two planes. And you want me to, and you're asking what a spinner is, well, a spinner, the space of spinners is that two-plane. So it's, you know, just your whole definition of what a pointed space time was, just told you what a spinner was. It's the same thing.

Yeah, well, we're trying to project that into a three-dimensional space and trying to intuit. Yeah, I can't. Yeah, so the intuition becomes very difficult, but, but from, if you don't, you're not using Twister Theory, you have to go through a certain fairly complicated rigmarole to even describe spinners to describe electrons. Whereas using Twister Theory, it's just completely total logical. They're just what you want to describe the electron is fundamentally the way you're describing the point in space

time already, it's just there. So, do you have a hope, you mentioned that you've been, you found an appealing recently, is it just because of certain aspects of its mathematical beauty or do you actually have a hope that this might lead to a theory of everything? Yeah, I mean, it certainly do have such a hope, because I think the thing which I've done which I don't think, as far as I can tell, no one had really looked at from this point of view before, has to do with it this question of how do you treat time in your quantum theory?

And so there's another long story about how we do quantum theories and about how we treat time in quantum theories, which is a long story. But the short version of it is that what people have found when you're trying right down a quantum theory, that it's often a good idea to take your time coordinate, whatever you're using to your time coordinate, and multiply it by the square root of minus one and make it purely imaginary. And so all these formulas which you have in your standard theory, if you do that to those, I mean, those formulas have some very strange behavior and they're kind of singular. If you ask even some simple questions, you have to take very delicate singular limits

in order to get the correct answer. And you have to take them from the right direction, otherwise it doesn't work. Whereas if you just put a factor of scroll to minus one wherever you see the time coordinate, you end up with much simpler formulas which are much better behaved mathematically. And what I hadn't really appreciated until fairly recently is also how dramatically that changes the whole structure of the theory. You end up with a consistent way of talking about these quantum theories, but it has very some very different flavor and very different aspects that I hadn't really

appreciated. And in particular, the way symmetry is act on it is not at all what I originally had expected. And so that's the new thing that I think gives you something is to do this move, which people often think of as just kind of a mathematical trick that you're doing to make some formulas work out nicely, but to take that mathematical trick as really fundamental and turns out in Twister theory allows you to simultaneously talk about your usual time and the time times the square root of minus one. They both fit very nicely into Twister theory. You end up with some structures which look a lot like the standard model. Let me ask you about some Nobel prizes. Do you think

there was a bet between Michoacaku and somebody else about St.orkin. And John Horkin, about, by the way, maybe discover a cool website, longbets.com or dot org. Better, yeah, yeah. It's cool. It's cool that you can make a bet with people and then check in 20 years later. It's, I really love it. There's a lot of interesting bets on there.

I would love to participate, but it's interesting to see, you know, Tom flies. And you make a bet about what's going to happen in 20 years. You don't realize 20 years, he goes like this. Yeah. And then, and then you get to face, and you get to wonder like, what was that person? What was I thinking that person 20 years ago? It was almost like a different person. What was I thinking back then to think that is interesting.

But so let me ask you this, on record. 20 years from now or some number of years from now, do you think there will be a Nobel Prize given for something directly connected to a first broadly theory of everything? And second, of course, one of the possibilities, one of them, strength theory. Um, strength theory is definitely not that things have gone.

Yeah. So if you were giving financial advice, you would say not to bet on that. No, you're not. And even I actually suspect if you're asked strength theory is that question, you're these as you're, you're not going to get fewer of them saying, I mean, if you'd asked them that question 20 years ago, again, when Taco was making this a bit, whatever, I think some of them would have taken you up on it. But, um, and certainly back in 1984, a bunch of them would have said, oh, sure, yeah.

But now, like, I get the impression that they've, even they realize that things are not looking good for that particular idea. Again, it depends what you mean by string theory, whether maybe the term will evolve to mean something else, which will work out. But I don't think that's not going to like it to work out. Whether something else, I mean, I still think it's relatively unlikely that you'll have any really successful theory of everything. And the main problem is just the, it's become so difficult to do experiments at higher energy that we've really lost this ability to kind of get unexpected input from experiment.

And you can, while it's maybe hard to figure out what people's thinking is going to be 20 years from now, looking at, you know, energy particle, energy colliders and their technology, it's actually pretty easy to make a pretty accurate guess what it's going to look, what, except what you're going to be doing 20 years from now. And I think actually, I would actually claim that it's pretty clear where you're going to be 20 years from now. And what it's going to be is you're going to have the LHC, you're going to have a lot more data, an order of magnitude or more data from the LHC, but at the same energy, you're

not going to see a higher energy accelerator operating successfully in the next 20 years. And like maybe machine learning or great sort of data science methodologies that process accelerator operating successfully in the in the next 20 years and like maybe machine learning or great sort of data science methodologies that process that data will not reveal any major like shifts in our understanding of the underlying physics you think. I don't think so I mean I think that that that feel that my understanding is that they they're starting to make a great use of those techniques, but it seems to look like it will help them solve certain technical problems and be able to do things somewhat better, but not completely change the way they're looking at things. What do you think about the potential quantum computers simulating quantum mechanical systems

and through that sneak up through simulation, sneak up to a deep understanding of the fundamental physics. The problem there is that's promising more for this for Phil Anderson's problem that you know if you want to there's lots and lots of you know you take you start putting together lots and lots of things and we think we know they're pair by pair interactions, but what this thing is going to do, we don't have any good calculation techniques. You know, quantum computers may very well give you those, and so they may, what we think of is kind of strong coupling behavior, we have no good way to calculate. Even though we can write down the theory, we don't know how to calculate anything with any accuracy in it. The quantum computer may solve that problem, but the problem is that I don't think that they're going to solve the problem, that they help you with the problem of not having

the knowing with the right underlying theory. As somebody who likes experimental validation, let me ask you the perhaps ridiculous sounding, but I don't think it's actually ridiculous question of do you think we'll live in a simulation? Do you find that thought experiment at all useful or interesting? Not really, not really.

I don't, it just doesn't, and anyway, to me, it doesn't actually lead any kind of interesting lead anywhere interesting. And yeah, to me, so maybe I'll throw a wrench into your thing. To me, it's super interesting from an engineering perspective. So if you look at virtual reality systems, the actual question is how much computation and how difficult is it to construct a world that, like, there are several levels here. One is you won't know the different, our human perception systems, and maybe even the tools of physics won't know the difference between the simulated world and the real world.

That's sort of more of a physics question. The most interesting question to me has more to do with why food tastes delicious, which is create how difficult and how much computation is required to construct a simulation where you kind of know it's a simulation at first, but you want to stay there anyway. And over time, you don't even remember. Yeah. Well, yeah, anyway, I agree. These are kind of fascinating questions. And they may be very, very relevant to our future as a species, but, um, yeah, they're just very far from anything. I, both so from physics perspective, it's not useful to you to think taking a computational perspective to our universe, thinking of as an information processing system, and then to give it as

doing computation, and then you think about the resources required to do that kind of computation, and all that kind of stuff. You can just look at the basic physics and who cares what the computer is running on us. Yeah, it just, I mean, the kinds of it, I mean, I'm willing to agree that you can get into interesting kinds of questions going down that road, but they're just so different from anything from what I found interesting. And I just, again, I just have to kind of go back to life is too short. And I'm very glad other people are thinking about this, but I just don't see anything I can do with it.

What about space itself? So I have to ask you about aliens. Again, something since you emphasize evidence, do you think there is, how many, do you think there are and how many intelligent alien civilizations are out there? I have no idea why I've certainly as far as I know, unless the government's covering it up or something, we haven't heard from, we don't have any evidence for such things yet, but there's that there seems to be no, there's no particular obstruction why there shouldn't be. So, I mean, do you, you work on some fundamental questions about the physics of reality when you look up to the stars? Do you think about what there's somebody looking back at us? I guess you know, actually I originally got interested in physics. I actually started out as a

kid interested astronomy exactly that and a telescope and whatever that and certainly read a lot of science fiction and thought about that. I find over the years I find myself kind of less, anyway, less and less interested in that just because I don't, I don't really know what to do with them. I'm also going to kind of at some point kind of stop reading science fiction with that much kind of feeling at the derges too. But the actual science I was kind of learning about was perfectly kind of weird and fascinating and unusual enough, but better than any of the stuff that Isaac Asimov, so why should I? And you can mess with the science much more than the distant science fiction.

The one that exists in our imagination or the one that exists out there among the stars. Well, you mentioned science fiction. You've written quite a few book reviews. I've got to ask you about some books, perhaps, if you don't mind. Is there one or two books that you would recommend to others and maybe if you can, what ideas you choose from them. Either negative recommendations or possible recommendations.

Well, do not read this book for sure. Well, I must say, I mean, unfortunately, yeah, you can go to my website and there's a, you can click on book reviews and you can see I've written a lot of, I mean, you can tell from my views about string theory, I've written a lot of, I mean, as you can tell from my views about string theory, I'm not a fan of a lot of the kind of popular books about, oh, isn't string theory great and about, yes, I'm not a fan of a lot of things of that kind. Can I ask you a good question on this, a small tangent? Are you a fan, can you explore the pros and cons of the Gist drink theory, sort of science communication, sort of cosmos style, communication of concepts to people that are outside of physics,

outside of mathematics, outside of even the sciences, and helping people to sort of dream and fill them with awe about the full range of mysteries in our universe. That's a complicated issue. I think I certainly go back and go back to what inspired me and maybe to connect it a little bit to this question about books. I mean, certainly one, some books that I remember reading when I was a kid were about the early history of quantum mechanics, like Heisenberg's books that he wrote about, you know, kind of looking back

at telling the story of what happened when he developed quantum mechanics. It's just kind of a totally fascinating romantic, great story. And those were very inspirational to me. And I would think maybe other people might also find them. But the, and that's almost like the human story of the development of the ideas. Yeah, the human story, but also how, they have these very, very weird ideas that didn't seem to make sense, they're how they were struggling with them

and how they actually, anyway. It's, I think it's the period of physics beginning, 1905, with the planet, an Einstein, and ending up with the war when these things get used to make passively destructive weapons. It's just the truly amazing. So many new ideas. Let me turn it on top of a tangent, on top of a tangent, ask, if we didn't have Einstein. So how does science progress? Is it the lone geniuses? Or is it some kind of weird network of ideas swimming in the air and just kind of the geniuses pop up to catch them and others would anyway without Einstein would we have special relativity, general relativity? I mean, it's an interesting case to case, I mean, special relativity, I think we would have had, I mean, there are other people, anyway, you could even argue that it was already there

in some form, but I think special relativity would have had without Einstein fairly quickly. General relativity, that was much, much harder thing to do and required a much more effort and much more sophisticated. I think he would have had sooner or later, but it would have taken quite a bit longer. Other things that took a bunch of years to validate scientifically the general relativity. But even for Einstein, from the point where he had kind of a general idea of what he was trying to do to the point where he actually had a well-defined theory that you could actually compare to the real world, that was, you know, I don't forget the number of the order magnitude, 10 years of very serious work, and if he hadn't been around to do that, it would have taken a while before anyone else got around to it. On the other hand, there are things like

with quantum mechanics, you have a high-senberg and Schrodinger came up with two, which ultimately equivalent, but two different approaches to it within months of each other. And so if heisenberg had been there, you already would have had Schrodinger or whatever, and if neither have and been there, you already would have had shrewdigger or whatever. And if neither of them had been there, I would have been somebody else a few months later. So there are times when the, you know, just the, a lot often is the combination of the right ideas are in place and the right experimental data isn't placed to point in the right direction and it's just waiting for somebody's going to find it. Maybe, maybe to go back to your, to your aliens, I guess the one thing I often wonder about aliens is,

would they have the same fundamental physics ideas as we have in mathematics? Would they, you know, how much is this really intrinsic to our minds? If you start out with a different kind of mind, would you end up with a different ideas of what fundamental physics is or what the structure mathematics is. So this is why, if I was, you know, I like video games, the way I would do it as a curious being, so first experiment I'd like to do is run Earth over many thousands of times and see if our particular, you know what, I wouldn't do the full evolution. I started homo sapiens first and then see the evolution of homo sapiens,

millions of times and see how the ideas of science would evolve. Like, would you get like, how would physics evolve? How would math evolve? I would particularly just be curious about the notation they come up with. Every once in a while, I would like throw miracles at them to like, to mess with them and stuff. And then I would also like to run earth from the very beginning to see if evolution will produce different kinds of brains that will then produce different kinds of mathematics and physics. And then finally, I would probably millions of times run the universe over to see what kind of What kind of environments and what kind of life would be created to then lead to intelligent life to then lead to

Theories of mathematics and physics and it's the C the full range and like sort of like Darwin kind of mark. Okay, it took them What is it? Several hundred million years to come up with calculus. I would just like keep noting how long it can get an average and see which ideas are difficult, which are not. And then conclusively sort of figure out if it's more collective intelligence or singular intelligence that's responsible for shifts and for big phase shifts and break-throughs and science. If I was playing a video game and ran this, I got a chance to run this whole thing. But we're talking about books.

Before I distract the score. Yeah, go back, books. Yeah, so that's one thing I recommend is the books about the original people, especially Heisenberg about how that happened. There's also a very, very good kind of history of what happened during this 20th century in physics. Up to the time of the standard model in 1973 it's called the the second creation by pop creason and man that's one of the best ones I know that's but the one thing that I can say is that so that book I think forget when it was late 80s 90s

the problem is that there just hasn't been much that's actually worked out since then so most of the books that are kind of trying to tell you about all the glorious things that have happened since 1973 are, they're mostly telling you about how glorious things are, which actually don't really work. And it's really, the argument people sometimes make in favor of these books is, well, oh, they're really great because you want to do something that will get kids excited. And so they're getting excited about things. Something that's not really quite working. It doesn't really matter

on anything. It's get them excited. The other argument is, wait a minute, if you're getting people excited about ideas that are wrong, you're actually kind of discrediting the whole scientific enterprise in a not really good way. So there's just problems in my own. I general feeling about expository stuff is yeah, to the extent you can do it kind of honestly and well that's great. There are a lot of people doing that now. But to the extent that you're just trying to get people excited and enthusiastic by kind of telling them stuff which isn't really true, you really shouldn't be doing that. You obviously have a much better intuition about physics.

I don't do, in the space of AI, for example, you could use certain kinds of language, like calling things intelligent, that could rub people the wrong way, but I never had a problem with that kind of thing, saying that a program can learn its way without any human supervision as alpha zero does to play chess to me that um may not be intelligence but it sure that that's how it seems like

a few steps down the path towards intelligence and like, I think that's a very peculiar property of systems that can be engineered. So even if the idea is fuzzy, even if you're not really sure what intelligence is, or like if you don't have a deep fundamental understanding or even a model of what intelligence is, if you build a system that sure as high as impressive and showing some of the signs of what previously thought impossible for a non-intelligent system, then that's impressive and that's inspiring and that's okay to celebrate in physics because you're not engineering anything you're just not swimming in the space directly when you do the theoretical physics, that it could be more dangerous, you could be out too far away from shore. Yeah, well the problem, I think physics,

is it, I think it's actually hard for people even to believe or really understand how, that this particular kind of physics has gotten itself into a really unusual and strange and historically unusual state, which is not really, I mean, I spent half my life among mathematicians and having a physicist. And, you know, mathematics is kind of doing fine. People are making progress and it has all the usual problems, but also so you could have a, but you do, I just, I don't know. I've never seen anything at all happening in mathematics, like what's happened in the specific area in physics.

It's just the kind of sociology of the way this field works banging up against this harder problem without anything from experiment to help it. It's really, it's led to some really kind of problematic things. And those, so it's one thing to kind of oversimplify or to slightly misrepresent, to try to explain things in a way that's not quite right, but it's another thing to start promoting to people as the successes, ideas, which really completely

failed. And so, I mean, I'm kind of a very, very specific, if you have people, I won't name any name, as for instance, coming on certain podcasts like yours telling the world, you know, this is a huge success and this is really wonderful and it's just not true. And this is, this is really problematic and it carries a serious danger of, you know, once, when people realize that this is what's going on, you know, the, you know, the loss of credibility of science is a real, real problem for our society. And you don't want, you don't want people to have an all too good reason to think that what they're being, what they're being told by kind of the best institutions in our country and our

authorities is not true. It's not true. It's a problem. That's obviously characteristic of not just physics. It's sociology. And it's obviously in the space of politics, it's the history of politics is you sell ideas to people, even when you don't have any proof that those ideas actually work,

you speak as if they've worked, and that that seems to be the case throughout history. And just like you said, it's human beings running up against a really hard problem. I'm not sure if this is like a particular trajectory through the progress of physics that we're dealing with now, or it's just a natural progress of science. You run up against a really difficult stage of a field. And different people that behave differently in the face of that. Some sell books and tell narratives that are beautiful and so on. They're not necessarily grounded

in solutions that have proven themselves. Others put their head down quietly, keep doing the work, others sort of pivot to different fields. And that's kind of like, yeah, ants scattering. And then you have, feels like machine learning, which is, there's a few folks mostly scattered away from machine learning in the 90s in the winter of AI, AI winter, as they call it. But a few people get up their head down and now they're called the fathers of deep learning. And they didn't think of it that way. And in fact, if there's another eye winter, they'll just probably keep working on it anyway, sort of like a loyal ants to a particular area. So it's interesting, but you're sort of saying that we should be careful over hyping things that have not proven themselves because people will lose trust

in the scientific process. But unfortunately, there's been other ways in which people have lost trust in the scientific process. That ultimately has to do actually with all the same kind of behavior as your highlighting, which is not being honest and transparent about the flaws of mistakes of the past. Yeah, that's always a problem. This particular field is kind of almost, it's always a strange one. I think in the sense that there's a lot of public fascination with it, that it seems to speak to kind of our deepest questions about, you know,

what is this physical reality where do we come from and what and he's kind of deep issues? So there's there is this unusual fascination with it mathematics. This versus very different nobody's that interest in mathematics Nobody really kind of expects to learn really great Deep things about the world from mathematics that much. They don't ask mathematicians that so so it's a very unusual It's draws this kind of unusual amount of attention and it really is historically and in a really unusual state It's kind of it's gotten itself way kind of down a Down a blind alley and in a way which It's hard to find other historical parallels.

But to push back a little bit, there's power to inspiring people. And if I just empirically look, physicists are really good at combining science and philosophy and communicating it. There's something about physics often that forces you to build a strong intuition about the way reality works. Right?

And that allows you to think through sort of and communicate about all kinds of questions. Like if you see physicists, it's always fascinating to take on problems that have nothing to do with their particular discipline. They think in interesting ways and they're able to communicate their thinking in interesting ways.

And so in some sense, they have a responsibility not just to do science, but to inspire, and not responsibility, but the opportunity and thereby, I would say, a little bit of a responsibility. Yeah, yeah, and sometimes, but I don't know, anyway, it's hard to say because because different um, there's many, many people doing this kind of thing with different degrees of

of success and whatever. I guess one thing them but I mean, my what's kind of front and center for me is kind of a more parochial interest. It's just kind of what, what damage do you do to the subject itself, ignoring, okay, miss, miss representing, what a high school students think about string theory, and not that it doesn't add much, but what the smartest undergraduates or the smartest graduate students in the world think about it,

and what paths you're leading them down, and what story you're telling them, and what textbooks you're making them read, and what they're hearing, and so a lot of what's motivated me is more to try to speak to this kind of specific population of people to make sure that, look, people, it doesn't matter so much what the average person on the street thinks about string theory, but what the best students at Columbia, Harvard, Princeton, whatever who really want to change work in this field and want to work that way. What they know about it, what they think about it, and that they not be going to the field

being misled and believing that a certain story, this is where this is all going, this is what I got to do, is that's important to me. Well in general, for graduate students, for people who seek to be experts in the field, diversity of ideas is really powerful, and is getting into this local pocket of ideas that people hold on to for several decades is not good, no matter what the idea. I would say no matter if the idea is right or wrong because there's no such thing as right in the long term. Like it's right for now until somebody builds on something makes bigger on top of it. It might end up being right but being a tiny subset of a much bigger thing. So you always should question sort of the ways of the past. So how to kind of achieve that kind of diversity of thought and within kind of the sociology of

how we organize scientific research is, I know this is one thing and I think it's very interesting that it's to be in a Hassan Felters very, it's interesting things to say about it. And I think also at least Smollin in his book, which is also about that. Very much an agreement with them that there's, anyway, there's a really kind of important questions about how research in this field is organized and how people, what can you do to kind of get more diversity of thought and get more to and get people, you know, what can you do to kind of get more diversity of thought and get more and get people thinking about a wider range of ideas. At the bottom, I think humility always helps.

Well, the problem is that it's also a combination of humility to know when you're wrong and also, but also you have to have a certain serious lack of humility to believe when you're wrong and also, but also you have to have a certain serious lack of humility to believe that you're going to make progress on some of these problems. I think you have to have both modes, which between them when needed. Let me ask you a question. You're probably not going to want to answer because you're focused on the mathematics of things and mathematics can't answer the why questions, but let me ask you anyway. Do you think there's meaning to this whole thing? What do you think is the meaning of life? Why are we here? I don't know. Yeah, I was thinking about this. So the

and it did occur to me. What what what interesting thing about that question is that you don't, you know, so I have this life in mathematics and this life in physics. And I see some of my physicist colleagues, you know, kind of seem to be, people are often asking them, what's the meaning of life? And they're writing books about the meaning of life and teaching courses about the meaning of life. But I realize that no one ever asked my mathematician, Kully.

No one ever asked mathematicians. Yeah, that's funny. So, yeah. Yeah. Everybody just kind of seems okay, well, you people are studying about that, I see whatever you're doing, it's maybe very interesting,

but it's clearly not going to tell you anything useful about the meaning of my life. And I'm afraid a lot of my point of view is that if people realize how little difference there was between what the mathematicians are doing and what a lot of these theoretical physicists are doing, they might understand that it's a bit misguided to look for deep insight into the meaning of life from many theoretical physicists. It's not a, you know, they're people and they may have interesting

things to say about this. You're right. They have, they know a lot about physical reality and about, about, in some sense, about metaphysics, about what is real of this kind. But you're also, to my mind, I think you're also making a bit of a mistake that you're looking to, I'm very, very aware that I've led a very pleasant and fairly privileged existence, and with fairly, without many challenges of different kinds, and a certain kind. And I'm really not in no way the kind of person that a lot of people who are looking for, try to understand, in some of the meaning of life, in the sense of the challenges that they're facing in life, I

can't really, I'm really the wrong person for you to be asking about this. Well, if struggle is somehow a thing that's core to meaning, perhaps mathematicians are just quietly the ones who are most equipped to answer that question. If in fact, the creation or at least experiencing beauty is at the core of the meaning of life because it seems like mathematics is the methodology, but which you can most purely explore beautiful things. Right? Yeah. So in some sense, maybe we should talk to mathematicians more. Yeah, maybe, but unfortunately, I think people do have a somewhat correct perception that what these people are doing every day, whatever, is pretty far removed from anything.

Yeah, from what's kind of close to what I do every day and what my typical concerns are. So you may learn something very interesting by talking to mathematicians, but it's probably not going to be, you're probably not going to get what you're hoping. So when you put the pen and paper down, you're not thinking about physics and you're not thinking about mathematics and you just get to breathe in the air and look around you and realize that you're going to die one day. You know, do you think about that? Your ideas will live on, but you, the human.

Not especially much. It's certainly been getting older. I'm now 64 years old. You start to realize, well, there's probably less ahead than there was behind. And so you start to, that starts to become, you know, what do I think about that? Maybe I should actually get serious about getting some things done, which I, which I may not have, which I may, otherwise not have time to do, which I didn't see. And this didn't seem to be a problem when I was younger,

but that's the main, I think the main way in which that thought occurred. probably when I was younger, but that's the main, I think the main way in which that thought occurred. But it doesn't, you know, the stoics have been on this, meditating on mortality helps you more intensely appreciate the beauty when you do experience it. Oh my God, I suppose that's true, but it's not, yeah, it's not, not something I've spent a lot of time trying, but yeah. Day to day, you just enjoy the positive mathematics. Just enjoy our life in general. Life is a perfectly pleasant life and enjoy it.

Often think, wow, this is, things are, I'm really enjoying this. Things are going well. Yeah, life is pretty amazing. I think you and I are pretty lucky. We get to live on this nice little earth. Yeah. Well, a nice little comfortable climate. We'll get to have this nice little podcast conversation. Thank you so much for spending your valuable time with me today and having this conversation.

Thank you. Glad to have you. Thank you. Thanks for listening to this conversation with Peter White. To support this podcast, please check out our sponsors in the description. And now, let me leave you some words from Richard Feynman. The first principle is that you must not fool yourself. And you are the easiest person to fool.

Thank you for listening and hope to see you next time. you