Is physics discovered or invented?

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25:11All right. And we're back. So Daniel was telling us about how biologists are leading the way in like probably everything and physics physicists are trying to catch up. And so what what kind of work are they doing to try to catch up, Daniel? Well, it's an impossible task to be as cool and as good looking and as suave and as socially well adjusted as biologists. Athletic. But, you know, weak and athletic. Why are you laughing so hard? Oh, sorry. I thought you were joking. I'm going to take that totally seriously.

25:47I'll have you know that we have a physics soccer game here every year and the faculty usually win. Oh, nice. Way to go. Yeah. So following in the footsteps of the wise biologist, we can ask like, well, where are the places where physics could be making assumptions? What are the arguments that suggest physics has to be universal? And what are the arguments against that? And I think one of the most powerful arguments is that physics seems to apply everywhere. We have this universality of physics, which really goes back to Newton. Newton looking at the apple or thinking about gravity and imagining, oh, maybe gravity doesn't just apply here on Earth.

26:22it applies also in the heavens, right? He takes the physics that we deduce, these tiny little apes on this little rock, and applies it to the cosmos. And that's such a huge leap, right? It's incredible to think that the laws of physics we're writing down on pieces of paper, never having left this planet, really, with a very small number of exceptions, very nearby, could apply to things happening across the universe. And that might sound like hubris, right? But it's also totally backed by data. Like we can look at distant galaxies in the telescope and we can see they are following basically the same rules of physics.

26:59We can understand what's happening there back in time and far away. It's funny, hubris was exactly the word that was rolling around in my brain. Way to preempt Kelly's critique. And there's a really fantastic example of this, which is very recent. Maybe people heard about this validation of Hawking's area theorem. Hawking was thinking about black holes and how they come together. And he applied the laws of thermodynamics. Thermodynamics, of course, having its origins in like 18th century dudes in essentially steampunk outfits playing with gas and valves and engines, right? I'm in. Yeah. And they were thinking about heat and energy transfer.

27:35And they figured out some cool stuff. And Hawking said, oh, let's apply this to black holes. And he came up with this theorem about how black holes merge. And because black holes have entropy, when black holes come together, He said, well, the merger of the two black holes have to result in a black hole that's bigger than the sum of the two initial areas, because the area of the black hole is connected to its entropy. And we just saw this happen with this direct validation of Hawking's area theorem. So you have this direct line from like dudes with gas flasks to like black holes a billion light years away.

28:07It really is incredible that the laws of physics we figure out here seem to apply everywhere. And so we have this, you know, Newton's leap to the cosmos. And then Carl Sagan and folks make another leap. Carl Sagan, when asked, do you think that aliens do physics and math the same way we do? He said, quote, yes. And the reason I think that's likely is that they live in the same universe as we. So they must deal with the same laws of physics and chemistry and astronomy as we. So this is Carl Sagan, who, of course, I hesitate to disagree with on anything because smart dude, fantastic science communicator, right?

28:46The best, maybe. But I want to underline that he's making a second leap there, even bigger than Newton's leap to apply the laws of physics across the heavens. He's saying that because the laws of physics that we have to do seem to work everywhere, they must be discovered the same way everywhere or thought of the same way everywhere. And that's really a step beyond, right? I want to separate those two for people because I think a lot of people conflate those two arguments. That just because the laws of physics apply everywhere, our description of the laws of physics apply everywhere, doesn't mean it's the only way to describe them.

29:20So would there ever be a way that you could convince yourself we have found the explanation? Or is it just like a continuous process of testing your theories over and over and over and over again and being willing to get rid of them if they're wrong, but never knowing 100 % for sure if they're totally right until the aliens come? I don't think you could know 100 % for sure if they're right even after the aliens come. I mean, say the aliens show up and, you know, they do physics the same way we have and they follow the same path and they figured out the answers and they're just like, you know, the simplest possible scenario.

29:50They're a thousand years ahead of us. That doesn't mean that it's the only way to do it, right? Even if five different groups of aliens show up and they're all doing quantum field theory, that doesn't mean that it's the only way. Maybe we're all affected by having the same evolutionary history or the same conditions or something. There could always be another way to think about it that we don't know. And so even having the aliens show up, I don't think is conclusive. I think one way to approach this is to think about how close the map matches the territory, right? So this is a question of accuracy.

30:25And another argument people feel very strongly about is that our human physics must be true, must be real, because it works so darn well, right? It's not just like some fuzzy description of the territory, right? It's like, wow, bang on. And, you know, we talked on this podcast a lot of times about the incredible power of the standard model of particle physics. But, you know, just to highlight it, like we can predict how particles interact and sit down and do pages and pages and pages of calculations and predict some measurement experimentalists will try to do to like 10 decimal places. And then the experimentalists go out and they make these measurements.

31:04And it's like, this is amazing science on both sides. The theoretical calculation takes so much work and careful thought. The experiment to measure something so precisely is really difficult, requires very different skills, but the two numbers agree. And when you have a theory that predicts something to 10 decimal places, boy, you're tempted to make that leap and to say, yeah, this isn't a description. This is a revelation. This is like, we have found the source code of the universe. And I I remember thinking that as like a junior in quantum mechanics at Rice, hearing about these experiments and seeing them compared to the theory and feeling like there's no way this is just a description.

31:43We have really pulled back a veil on nature. Yeah. And that's a very inspiring idea. I love that. But then you look and you're like, oh, wait a minute. But we don't know how to reconcile quantum mechanics and all this other with all the other stuff. And so, like, you know, I have what I want to say there. You want to just generally go, hmm, have you guys really figured it out? Well, I think maybe you all have figured a lot of things out. And truth be told, I'm very impressed by what you all have figured out. But, you know, so you can look at all the things you have figured out, but there's still things that don't fit together the way that you would expect them to, which could mean that there's some other theory out there that would explain all of that stuff that hasn't been found yet, which we were talking to Ethan Siegel about the other day, I think.

32:28Yeah, and that's the incredible puzzle of physics, that quantum mechanics is super duper accurate in scenarios where you can ignore gravity, like particle collisions or interactions, right, because gravity is so weak at the particle level. And also general relativity, a classical theory that ignores quantum mechanics, is super duper accurate in scenarios where you ignore quantum mechanics. So like black hole mergers and gravitational waves and the orbit of Mercury and, you know, ring down of binary pulsars and frame dragging as measured in space with these super duper precise balls that spin in gyroscopes and satellites.

33:03It's amazing how accurate general relativity is also. So you could make the same argument for general relativity. And he's like, wow, this has got to be reality, right? Because it's so correct that every test we've ever done of general relativity has been bang on completely accurate. And it leaves you with the impression like, wow, this is also the truth. But you make the point like you can't have two truths, especially if they disagree with each other. And these two don't agree. They don't agree not only on what's happening out there in the universe, like what's the story? You know, what's reality?

33:36What's really running the machinery? they also don't agree about what is going to happen. They make conflicting predictions about what's inside a black hole or how the universe began or how it's all going to end in frustrating places we can't test. We can't do experiments to reconcile yet. But you're right. And that points to a problem with this argument, right? We have these very precise theories, but all of these theories are what we call effective. None of them, we think, are actually describing the real truth of the universe. We think that all of our theories are describing this process we call emergence.

34:15If you think that there's a real truth out there, that microscopically the universe has something happening, and that our experience somehow bubbles out of that, right? Well, there's this incredible step there, this amazing feature of the universe, that we don't have to know how the universe works at the microscopic level, its fundamental base layer of reality, in order to start doing science at the macroscopic level. Because this magic happens where when you zoom out from the microscopic to the macroscopic, the rules are different and somehow simple, right? Like the universe, imagine it's filled with these tiny buzzing strings or flings or whatever sproings, you know, is at the base layer of reality.

34:59And imagine you have no idea how that works, right? Still, somehow you can zoom out and you can describe how a baseball flies across your backyard with simple mathematics. Why is that possible, right? Why isn't it all just chaos from the bottom up the way like we can't describe hurricanes using simple mathematics because it's a bunch of raindrops and doing all sorts of complicated things. Why doesn't the same thing hold for zooming out from the fundamental layer of reality? We don't know. Is it just too many moving pieces? Like you could maybe predict what, you know, two raindrops are going to do, but not a whole hurricane.

35:35And you can predict throwing a ball because that's, there's a limited number of things acting on that. But the more complicated it gets, the more we're like, ah. Yeah, exactly. Sometimes simplicity emerges, right? And sometimes it doesn't. And when it doesn't, the reason is chaos. Like you have two raindrops, you can maybe describe it, You have 10 to the 20 raindrops. There's too many interactions. And the outcome is very sensitive to how those raindrops started, the direction they were going. And no simplicity emerges. It just gets more and more complicated as you add raindrops. But sometimes simplicity does emerge.

36:09You have 10 to the 26 particles moving across your backyard. They pull together and they follow a simple parabola. Hurricanes don't follow simple parabolas. And so because we don't understand why it ever happens, right, and why it doesn't always happen, that tells us that we're not sure if it's a part of the universe. Like, is the fact that we can attack the questions of the universe and make some progress at some levels without knowing what's going on underneath and we can make chicken soup without knowing quantum gravity. Is that because that's just how the universe is? Simplicity emerges and we'll figure that out why that is at some point.

36:46Or is it part of our minds? Is it the way that we understand and filter the universe? Is it some selection we're making that we're like, we're going to choose this thing to focus on, ask questions and do science. I'm going to choose that thing. Is it an interplay between our brains and the universe? Or is it only part of the universe? And that's the kind of question we could answer if we had alien brains, right? Which worked differently. And maybe they saw different things emerging, or maybe they saw the same. We just don't know where the line is between the human and the universe. Alternative idea.

37:20We put a ton of money into trying to make bats, which echolocate, and bees, which see in more colors. We try to make all of them have advanced intelligence and then see what they come up with. Because now we'll have different ways of looking at the world. And we've discovered that biology needs more money. For physics sake. Oh, I see. Right. Yes. Okay. In the end, it's all just a scheme. Yeah. Nice, for big biology. I'm schemey. Okay, so is the idea here then that like if we could dig down and understand everything at exactly the base level and then we could scale up and understand the hurricane, would that make us feel like we had discovered something?

37:58Or would we still just be inventing because we just managed to describe what happened instead of necessarily knowing why? Yeah, great question. And that's the temptation. And, you know, I'm a particle physicist. That's my goal. It's like, I want to drill all the way down to the base layer of reality and find out what are the bits there? Because philosophically, that feels like that's a moment of possible revelation. You force the universe to tell you, okay, I'm naked now. Here are all my basic components. Now you've seen the reality of how things work. Everything else, how things come together and make baseballs and marching bands and whatever, that's more complex science.

38:33That's basically chemistry. But the fundamental physics is about the fundamental things in the universe. So yeah, if we drilled all the way down to those, wouldn't we have those in common with aliens? Couldn't we avoid all these questions of like, what's emergent and why? Well, the problem with that is we don't know if there is a fundamental layer. You know, I think about our theories as sort of like a tower. We have this tower of effective theories at different scales, like zoom all the way out. We have like theories about how galaxies work. Zoom a little bit in, you have theories about how planets form.

39:06Zoom a little bit more in, you have like classical physics of the everyday. Zoom even more, you have chemistry. Zoom even more, you have physics. Zoom even more, you have particle physics. You could keep zooming, and at every level we have a theory. Do we know that there is a foundational truth, like a base layer to reality? We haven't found it, right? We just got to get to the Planck scale. Well, we definitely got to keep going. But the problem is, number one, we have no guarantee that there is a fundamental layer. And I hear this all the time. Planck scale is the pixel of reality. And Elon Musk likes to say it.

39:40And it's sort of out there in the popular science world that we somehow know that the Planck scale is the layer, the finest grain we have of reality. And that's just fundamentally a misunderstanding. The Planck scale is the point where we can no longer ignore gravity when we do our quantum mechanical calculations because things are so hot and so dense. and we can no longer ignore quantum mechanics when we do our gravity calculations because things are so small and the particles are now relevant. And so it's just the point beyond which we can no longer calculate. It's sort of like an intellectual horizon, right?

40:16We don't know anything about what's below the Planck scale. I remember the Planck scale is not even like a solid estimate of these things. It's just like, let's take a bunch of constants and mush them together until we get a distance. That's not like a reliable way to estimate things. It's what you do when you have no idea how to answer a question on a test. You're like, I'm just going to guess the units and see what numbers I can push together to get the right units. Maybe this is close. I hope it's within a factor of 100 or 1 ,000. So the Planck scale is no guarantee that the universe has a fundamental layer.

40:50And if you talk to philosophers, they think it's just as likely that the universe is what they call gunky, right? That everything is made of something smaller. Nothing is made of itself. and immediately you're like, what? Come on. How could that possibly be? But actually, if you think about it, it's the more natural explanation. Everything we've ever seen has been made of something else. So why would we expect there to be something which is just made of itself? It feels sort of like the cause that needs no cause. It's a bizarre philosophical construct, and we assume it's natural even though we've never seen it in the universe.

41:30So this is the kind of stuff where you really got to ask yourself, hmm, why do I accept this explanation and not that other explanation when I have no evidence and not even really great arguments for it? Wait, so you're saying that we might be just digging down and down and down and down ad infinitum? Yeah. It could be that it goes on forever, right? That it's just smaller and smaller and smaller down infinitely, right? An infinite tower of effective theories, an infinite tower of emergent phenomena. And so we can't shortcut this question by saying, we're just going to zoom down to the fundamentals and talk to the aliens about the sprawings or the springs or the schmings or whatever is down there at the fundamental layer, because we don't know that there is a fundamental layer.

42:12Do you think they'll stop giving out Nobel Prizes eventually if it turns out there's just like infinite fundamental layers? And they're like, you know, Kelly found the 20th one. Daniel found the 25th. Hooray. Oh, in this scenario, you're a particle physicist who's discovered some fundamental layer of reality? Love that. Welcome aboard. I'm a biologist, man. I can do anything. Thanks. After you win the Olympics, right? And I'm going to hang this Nobel next to my Olympic gold medal. Wow. Wait, has there ever been anybody who won an Olympic medal and a Nobel Prize? Hmm. Oh, Philip Noel Baker is the only person who has won both an Olympic medal and a Nobel Prize.

42:52Amazing. It was for a race in the 1920 Summer Olympics. I mean, things were easier then. That's an incredible achievement. Congrats, dude. I think he's passed away. Yeah, so it could be that particle physics is just a big grift for infinite Nobel Prizes. Yes, that's the answer to your question. Oh, great. You forced me to reveal that on air. Thank you. Amazing. Amazing. Well, yeah. Good. My work here is done. All right. On the next episode. No. So now imagine, right, we have this tower of effective theories that we use to describe science. We have chemistry, we have physics, we have particle physics, we have subatomic particle physics.

43:33And the question then is like, well, if there's no firmament in which to ground these things, and we don't know why these things seem to emerge to allow us to explain them, why they're not just like totally intractable, then do we know if aliens would or wouldn't find the same tower of effective theories? Like, you know, the skeptic in you might say, well, look, you know, planets are obviously a thing. Aliens are going to think about planets, you know, orbiting stars. Like, let's not get ahead of ourselves and get too deep in the philosophy that we imagine that, like, aliens don't observe planets and come up with Kepler's laws, right?

44:08That's a, I think that's like an intuitive argument people might make to feel like aliens are going to see the same stuff as we. But they're probably going to call it Zorblacks' laws or something, you know? Yeah, exactly. Exactly. And that might be, right? And I don't want to say that that's impossible, but I do want to open your mind maybe a little bit to the possibility that they wouldn't see planets. Think about why we think about planets and does it actually make sense to think about planets? Because in reality, the solar system is a big spectrum of stuff. You know, you have the sun and then you've got a bunch of other little blobs and those blobs go all the way from Jupiter down to dust specks.

44:45And humans, we like to categorize things, right? We like to say this is A and this is B. And historically, we saw a few different kinds of things. And so we started making boxes. But also we've seen over time that those boxes don't really make sense, that our categories of stuff are sort of arbitrary dotted lines that we draw around things. And not just randomly, we draw those arbitrary dotted lines in a way to make ourselves more important. this whole concept of planets that we argued with phil metzger about it recently on the podcast does it even make sense to have this category it's obvious to me because this category has become so baroque you know they have to add so many qualifiers it has to have cleared its path it has to be gravitationally round they're reverse engineering this category because we like it we want there to be a special category of things that seem important and that are relevant to us But if you're going to take like a hard, objective scientific eye to the solar system, you might never come up with this special category of planets.

45:45You might just think about the whole spectrum of things and not focus on Earth-like things at all. So would you argue that definitions are, I mean, they're certainly invented. Yeah. Is a definition ever discovering the nature of the universe? I guess it's always just our way of grappling with stuff. I think definitions are helpful, but categories are often very arbitrary and lead you down the wrong path and make you think something is special or something is different when in reality, there's a spectrum. Think about gender, think about the platypus, which is like, what? And these categories, they're helpful for organizing your thoughts, but you got to remember that there are things we impose on the universe.

46:26They're not always things that emerge naturally from the universe. And that's the point I want to make is that even things that we feel like we are just observing have a lot of our cultural bias in them. I mean, think about the way we represent the solar system when we draw it out, right? Like it's not representative at all. We take the planets and we like magnify them by huge numbers to make them relevant when in reality, they're pretty irrelevant. The solar system is basically the sun plus a few drops of gas, right? So it's obvious once you drill into it, that there's a lot of humanity in our choices of what to study and think about in the universe.

47:01And so it might be that aliens have made different choices, that they grew up in the atmosphere of a star and they're like, planet schmanitz, who cares? Or maybe they evolved in a subsurface ocean on a moon. And so to them, who cares at all about planets? Maybe they think about things fundamentally differently. All right, let's take a break. And when we get back, we will answer the simple question of whether or not there is a truth at all.

47:44We'll be right back.

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50:17And we're back. And we are about to answer, you know, the only question that really matters, which is, is there truth at all? And the good news is Daniel's thought a lot about this, and now we're going to know. Right. Yes, we're just going to wrap up a millennia-old philosophical conversation here on the pod today. So, so far we've been talking as part of the larger question of like, is physics discovered or invented? We've been asking like, could you have several maps of the same territory? But it always, in that sense, assumes that there is a territory, that there is fundamentally something that's going on.

50:50And I heard the sentiment in the listeners' responses, right? well, maybe our description of the universe is human, but there's something going on. And so let's question that assumption. How do we know that there really is something going on out there in the universe? One truth, whether or not we're discovering it or describing it or approximating it, right? How do we know that there really is something that's going on out there? And when I first started digging into this, I thought, well, of course there is, right? something is happening in the universe and there has to be a reason why stuff happens, right?

51:24But not surprisingly, philosophers have responses to that and they've thought about ways that might not be true. Because remember that all of our descriptions of the universe, they are approximate, right? Because we can't do the really complicated calculations. Like we talked about earlier, we can describe a couple of raindrops, we can't describe the hurricane. Or we can't describe like a bunch of hurricanes smashing into each other or really complicated situations is always going to be something that we cannot describe because all of our laws are approximate, right? They only apply in certain situations.

51:56Like for example, take fluid dynamics, right? Fluid dynamics works really well. It helps you think about how water flows down pipes. But we know number one, it's not a fundamental description of the universe, right? It's a description of an emergent phenomena. But number two, it's only valid in certain situations. You freeze that water, you're no longer going to apply fluid dynamics. You turn it into steam, you're no longer going to apply fluid dynamics. In that same way, everything we can do about the universe has boundaries where it's relevant, right? And you go beyond those boundaries, you can no longer use your fluid dynamics or your chemistry.

52:32Even fundamental physics, right? Quantum mechanics and gravity are only relevant down to the Planck scale. And beyond that, who knows what the laws of physics are? So there's a school of philosophy that says, hmm, how do we know there are laws of physics beyond those boundaries? Maybe instead of imagining that we have this patchwork of theories that eventually we could stitch together to describe the truth, maybe between those patches, there's nothing. So Nancy Cartwright wrote this book called How the Laws of Physics Lie. We were like, wow, bold title, right? Yeah. And she imagines a universe where between these patches, where things get complicated, that maybe what happens happens by hap.

53:17That's her phrase. That there is no fundamental rule. And every instinct in me, every fiber of my being says, no, that's crazy, right? The universe follows laws. But then I ask, well, how do I know that exactly? I only know that because it seems to work in simple situations where I can set up a simplified experiment and I can do a calculation to predict it. And that's really what experiments are. It's ways you've like tricked the universe into only doing something simple enough that we can calculate it. That's the whole job of experimental physics is to concoct these artificial scenarios where things are simple enough for us to predict.

53:56most of the stuff that happens in the universe from, you know, like tiny particles to hurricanes, to even like the leaves swirling outside my office, we could never hope to calculate. So how do we know that it follows rules? If you're going to be a skeptic about it, you got to say like, hmm, I guess we actually don't know, right? It could be that when things get complicated, there aren't laws that are being followed. And I don't believe that, but I don't have a scientific reason to not believe it. And my brain has trouble wrapping itself around how that could possibly be true, but that might be the limit of my imagination.

54:33Yeah, and I think even Nancy Cartwright probably doesn't like believe this in her soul, but it's a very valuable exercise to think, well, is it possible for the universe to be different from what we expect at some deep fundamental way? Because historically we've seen that happen, right? The universe turns out it violates lots of our intuition. You know, the way things operate near the speed of light or microscopically, the fact that cause and effect has a stochastic element to it. These things would have been rejected out of hand initially. Like, that's crazy. There's no way the universe works that way.

55:05And yet it does. And so we do need to be prepared to have our minds blown. And that's the whole joy of this exercise is to imagine, like, what if aliens show up and they tell us the universe is really fundamentally different from the way that we expect? That's why we want the aliens to show up, to shock us, to reveal an amazing, mind-blowing truth. And yeah, it'd be kind of disappointing to discover that the laws of physics only apply in simplified situations. And beyond that, there is this darkness, right, where the universe doesn't follow laws. But we don't know that it's not true. I feel like if the aliens came and they were like, nah, you guys are totally wrong.

55:43Like, I mean, it would be, wouldn't it be decades before you could convince yourself that they were right instead? If the alien said, Daniel, you're wrong, would you just be like, all right, I'm throwing away everything we know. The alien said so, and I'm a super fan. Yeah, that's a really fun question. So in the book, I actually imagine a bunch of different alien contact scenarios. And one of them is that exact one. The aliens show up and have a competing theory of physics. And in that hypothetical example, I imagine that some humans are like, oh, you know, our theory never made sense to me. I really like this alien idea.

56:15And they go over to the alien camp. And some aliens are like, oh, you know what? I really prefer the human way. And people have different ways of thinking. The way that some people need to see something written out and other people need to hear it. Or some people need to play with something. There's different kinds of learners. So maybe some people will find the alien description of the universe more intuitive and easier to play with. And other people will feel the opposite. It would be fascinating how that breaks out. Yeah, it would. I hope I'm alive to see it. Another objection people make to the idea that we could be getting physics all wrong or that physics could have a lot of humanity into it is the idea that you raised at the beginning of the episode.

56:56You know, what if we have a bunch of data and it describes the universe? Doesn't that tell us that our theory is right? And this is this question of uniqueness, right? Do we know that there has to be one explanation for the universe? And earlier we were giving the examples of having a superseded theory. Like, well, maybe you have a theory and it works for now, but then later you get more data. So you got to toss out that theory for a new one. That's cool. And that's almost certainly what we're doing today, right? That in the future, we'll have a theory of quantum gravity that tells us a different story about what's happening in the universe than any of the stories we have now.

57:31So we'll toss out our whole explanation for what's really out there and come up with a new one. Cool. but what if we find the fundamental layer of reality? We discover it and we explain it. And we have a theory that works perfectly and incorporates dark energy and dark matter and the expansion and everything. And all of our questions are answered and it tells us this beautiful story about what's happening. Then aliens show up. Could they have a different theory that explains the same experiments? Could they have done the same experiments, made the same observations, but draw a different line through the same data points?

58:01The answer is philosophically, yeah, maybe. because you'll never have infinite data. And even if you did, you could always still draw two different curves, right? Just imagine like plotting a bunch of points on a piece of paper. How many curves could you draw through those points? An infinite number, right? Make the curve as complex as you like. You can draw an infinite number. And so we never really know if our explanation is the only one. And this is something philosophers are deeply debating. Like there's a bunch of philosophers who say, look, if you have another theory that explains the data equally well, it's got to be equivalent.

58:38You know, it's got to be like the same theory dressed in different clothes. And they point to good examples. Like we used to have a wave theory of quantum mechanics and a matrix theory of quantum mechanics, each derived by a different German guy. And those two guys disliked each other and called each other's theories crap. And then later, John von Neumann brought them together and said, look, guys, these are actually the same theory. I can draw connections between them and prove it. Or we used to have a bunch of different string theories until Ed Witten showed they're actually just extreme points of the same M theory, right?

59:09Or we have like Hamiltonian mechanics and Lagrangian mechanics, two different ways to think about complex physics that are fundamentally the same. So isn't it just like that? Maybe the aliens have a different description, but, you know, you can make connections. We don't know, right? We don't know if every theory has to be that way. And another group of philosophers say that there might be another explanation that it's possible to have another theory of physics that doesn't map over, that is conceptually different to our theory. But we don't know. We don't have that theory. We don't have a recipe for building this alternate theory.

59:43So it's just like a speculation. It's an argument we don't know how to defeat, which means it might be possible. Okay, so if we ended up discovering a theory of everything and we felt like we had it all figured out, I was going to ask you if you would put up a giant billboard saying, never mind aliens, we got it all figured out. But what you're saying is you'd be interested to see if they had a different way to describe everything. But some philosophers would say, well, that doesn't really matter because it's fundamentally going to be the same theory, even if it's wearing different clothes. There's no scenario in which I'm putting up a billboard saying aliens, never mind.

1:00:19No scenario. But yeah, if we have a theory of everything and they show up and they have a different theory of everything, then that's fascinating, right? Because even if it is fundamentally the same, you're still learning something mathematically or philosophically. And if it's fundamentally different, if you can't make a connection between the two, boom, that tells you something mind-blowing about the universe. That you could have two different maps of the same territory that both work, then like, is there really a territory? What does that say about our sense that there is an objective physical reality that's out there doing things, following some laws that we're figuring out?

1:00:55Like, maybe that's not the case. Maybe things are more complicated or weirder than we imagine. So I'm always in the camp of hoping for the weird, surprising outcome. Daniel, I really hope you get your aliens one day. I hope I do, and I hope that they don't nuke us from space before they tell us the answers to all of these questions. You are a weird one, Daniel. And this is just a taste of all the concepts we describe in the book. Do aliens speak physics? Where we do a really deep dive into these questions. It also includes a bunch of really fun cartoons from my friend Andy Warner, who helped me write the book.

1:01:32And little hypothetical case studies to examine concrete scenarios where aliens could show up and be weirdly different in ways you might not expect. So if you enjoy these questions and enjoyed this conversation, there's lots more in the book. Go check it out. Do Aliens Speak Physics? You can get it at www.alienspeakphysics.com. And I think if aliens do come to visit the U.S., this book is going to be the first thing they grab. Travel across the cosmos for this book? Totally makes sense. Worth doing. I hope they're not offended by our depictions.

1:02:12Daniel and Kelly's Extraordinary Universe is produced by iHeartRadio. We would love to hear from you. We really would. We want to know what questions you have about this extraordinary universe. We want to know your thoughts on recent shows, suggestions for future shows. If you contact us, we will get back to you. We really mean it. We answer every message. Email us at questions at danielandkelly.org. Or you can find us on social media. We have accounts on X, Instagram, Blue Sky, and on all of those platforms, you can find us at D and K universe. Don't be shy. Write to us. Aging is real. And so are the benefits of adding vital proteins, collagen peptides to your daily routine.

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