Daniel and Kelly’s Extraordinary Universe - Why does physics even work?

Episode Date: September 29, 2022

Daniel talks to Prof. Tim O'Connor about why the craziness of the world around us seems to resolve into things we can understand.See omnystudio.com/listener for privacy information.

This is an I-Heart podcast. December 29th, 1975, LaGuardia Airport. The holiday rush, parents hauling luggage, kids gripping their new Christmas toys. Then, everything changed. There's been a bombing at the TWA terminal. Just a chaotic, chaotic scene. In its wake, a new kind of enemy emerged, terrorism. Listen to the new season of Law and Order Criminal Justice System

On the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. My boyfriend's professor is way too friendly, and now I'm seriously suspicious. Wait a minute, Sam. Maybe her boyfriend's just looking for extra credit. Well, Dakota, luckily, it's back to school week on the OK Storytime podcast, so we'll find out soon. This person writes, my boyfriend's been hanging out with his young professor a lot. He doesn't think it's a problem, but I don't trust her. Now he's insisting we get to know each other, but I just want or gone.

Hold up. Isn't that against school policy? That seems inappropriate. Maybe find out how it ends by listening to the OK Storytime podcast on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Why are TSA rules so confusing? You got a hood of you. I take it all. I'm Mani. I'm Noah. This is Devin. And we're best friends and journalists with a new podcast called No Such Thing, where we get to the bottom of questions like that. Why are you screaming it?

I can't expect what to do. Now, if the rule was the same, go off on me. I deserve it. You know, lock him up. Listen to No Such Thing on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. No such thing. Do we really need another podcast with a condescending finance brof trying to tell us how to spend our own money? No, thank you.

Instead, check out Brown Ambition. Each week, I, your host, Mandy Money, gives you real talk, real advice with a heavy dose of I feel you, sis, like on Fridays when I take your questions for the BAQA. Whether you're trying to invest for your future, navigate a toxic workplace, I got you. Listen to Brown Ambition on the IHeart Radio app, Apple Podcast, or wherever you get your podcast. Science seems to work. We can argue about the philosophical foundations of it. Whether a photon is a particle or a wave, we can wonder whether the universe that we perceive out there is real or is just an elaborate hoax like in the matrix and how we might ever know the difference.

But in the end, what is beyond question is that science does work. We can build airplanes that almost never crash. We can build incredible miniature devices that rely on the quantum properties of electrons. We can, and have, sent robots to crawl over the surface of other planets and send us back pictures. All of this stuff works because of science. Science lets us build and test and refine little mathematical stories about how things work and then confidently use those mathematical principles in totally different contexts. Ideas that we have in the shower, then test in basement labs.

They all work inside your iPhone and on the space station. we can confidently use what we have learned, even if we aren't exactly sure why science works and whether the universe out there is actually real. and a professor at UC Irvine, and I want to know what's real about the universe. I don't want to just have ideas that work. I want to know the truth about the universe. And welcome to the podcast, Daniel and Horhe

explain the universe where our goal is to do just that, to explore with you what we do and don't know about the universe. How microscopic little particles interact at the smallest levels and how all of their towing and frowing and buzzing weaves itself together into the world that we know with very different rules, which is just a small part of the larger context of stars and galaxies and superclusters sloshing around in a web of dark matter to make this glorious and crazy universe. My co-host and friend Jorge is on vacation this week, so I'm taking the opportunity to take a bit of a digression into the philosophy of

science, together with an exciting guest. Now, what's amazing to me about science is that we are capable at all of understanding the universe that jumped up apes with tiny little brains on a little rock in an irrelevant galaxy can just by doing a few experiments and writing down some math symbols build a mental model of how the universe works. And a model that seems to work pretty well. This model has revealed how stars form and how the universe expands and how electrons funnel through weird metals and how the whole universe is filled with an invisible. visible Higgs field that gives matter to microscopic particles.

It's incredible what we have learned about the nature of the universe. The very fact that you are hearing this podcast right now relies deeply on our understanding of the basic rules of the universe and our ability to manipulate and rely on them. But why is that possible? Why does it even work? Because what I said a moment ago was a bit of a stretch of the truth. For all of the successes of particle physics, we don't actually have an understanding of the basic rules of the universe. We don't know what the basic bits of the universe are and what their rules are.

Are they strings? Is it a quantum foam? Is it something completely different than we haven't yet or maybe could never even imagine or grapple with? What we do have is a set of rules that work for the experiments that we can do. But we're pretty sure it's not the final. answer. Not that they're wrong and it's all a hoax, but that it will be eventually replaced by a deeper understanding. The way Newton's physics worked for the experiments that could be done in his day, but were later replaced by Einstein's more general theory. The way you can use F equals MA to calculate how a ball flies through the air, and it certainly works, even if you don't understand the quantum frothing happening inside of it.

What we have in particle physics is the same thing. We don't think it's fundamental. We don't think it describes the basic bits of the universe. We think it's effective, meaning that it works, but it describes things that emerge from the fundamental pieces. But it still works. Even though we don't know what the basic pieces are and the rules that they obey, we have found the non-basic pieces and the rules that those non-basic pieces obey.

For example, we have rules of economic. and they mostly work. But people and money are not fundamental elements of the universe. You can have a universe without people and money and most of the history of the universe didn't have people or money. But once people and money emerge, you don't have to describe the economy of a country using particle physics or string theory. You can find basic mathematical laws that describe economics and are pretty simple. Just like F equals MA is pretty simple, but it ignores all the quantum details underneath. So why does that work?

Why is it possible and what does it mean about whether what we have learned is true and fundamental to the universe, a real description of what's out there? Or if it's just a set of mathematical stories that humans tell ourselves that happen to work very well. So today on the podcast, we'll be asking the question. Why does physics even work? Why is it possible to tell mathematical stories about the universe out there without knowing the deepest underlying truth? We know it's possible to make chicken soup and iPhones without knowing quantum gravity, but why can we?

Does that mean that the stories we are telling the physics ideas we have developed are not real in some deep true sense? Would alien scientists come up with the same theories or have a different concept of how to describe the universe? To help us probe these questions, I've invited an expert in this area, Professor Tim O'Connor. Tim is a professor of philosophy and cognitive science at Indiana University, where he specializes in these types of questions and especially the phenomenon of emergence, cases where it's possible to describe things at a higher level without knowing the underlying pieces. my pleasure to introduce to the podcast, Professor Tim O'Connor. Tim, thank you very much for joining us today. Glad to be with you, Daniel. As well as being an expert on philosophy of science and emergence, I see that you also claim the title of Philopong World Grand Champion or the world's leading table tennis player among properly credentialed philosophers. Tell us about how you

figured that out, how you determined that you could claim that title. Uh-oh. Uh-oh. I declared the title And the interesting thing is that no philosophers have disputed that I hold the title. And I think the reason is that those who like to play serious table tennis figured out that great, then all I have to do is beat you. And then I get to claim the title. So I have defended the title on a few occasions. But I expect to be losing the title the next time I go back to China. Well, I think it maybe says something about philosophy that you can just declare yourself champion.

And then, you know, see if it stands up to scrutiny. That's it. It's kind of like a homesteading thing. If no one disputes it, then at a certain point, I own it. Exactly. So when you're not winning ping pong matches, you're a philosopher of science. Tell us about that. What got you into philosophy of science? What are the most important questions in your mind that we should be asking about our universe? Great. So, well, I start out and still think of myself fundamentally as a metaphysician, where metaphysics asks the really most general foundation. questions about reality, about fundamental categories like object, property, space, time. Does the physics wholly determine what one should think about space and time? It certainly constrains what one should say. And I'm more in the latter camp, it constrains, but doesn't wholly determine how we think about it.

But the relationship of philosophy, metaphysics, to science is a challenging question in its own right. And of course, these two subjects originally were fused in the history of Western thought, going all the way back to thinkers like Aristotle, but well on up to the time of Newton. You had a one job title, Natural Philosopher, which was a description of science, as we think of it, as those philosophical questions that concern the natural world. And I think it's beginning with Newton, who famously, when pressed for an account or an explanation of how his theory of gravitational attraction action at a distance, how we could, it seemed inconceivable, how we could make sense of that. He famously said, you know, about that, I feign no hypotheses.

And he's beginning to show a certain sort of, well, you know, you might ask a certain kind of philosophical question, but as far as doing science, which is what fundamentally Newton was up to, the theory works beautifully. The mathematics works. It's predictively successful. And so he was willing to go with that. So I want to talk to you specifically in a bit about emergence and how the world that surrounds us arises and how we make sense of it. But first I want to start with a bigger picture of why we ask these questions. As you say, we see that science works. We know that it does. It's the reason that we're talking right now. So if Newton doesn't care about questions like why does it work or, you know, is the universe out there real or is it just a story in our

minds, why do we care about those questions? Why are those questions important to figure out? Because ultimately, I think we were driven to wanting to have a conception of reality on which it's explicable. It makes sense. I mean, explicable, not in the sense necessarily if involving purpose or anything like that, but just rationally explicable. And so simply retreating to an instrumentalist view, say, of science, We're saying science just delivers sophisticated instruments that enable you to predict future observations and ultimately control future patterns to a degree through technology. That sort of conception leaves open, you know, why, but why does it work?

It can seem like a cosmic coincidence that reality exhibits deep patterns if all you're willing to say is there are these deep patterns and there's no rational intelligibility. behind them. So not everyone shares it, but it's the fundamental philosophical impetus, I guess, to want to understand why things are as they are. And so depending on one's conception of science, science may or may not even give you that, right? So there are famous scientists who insisted that in a sense science doesn't yield explanation. I mean, Richard Feyneman did make noises along those lines, famous 20th century physicists, and there have been others. He said, yeah, he's got a great quote somewhere.

He says, you know, you want to understand, you know, what reality is like? Go ask a philosopher. You're dripping with disdain. And you're saying, physics doesn't give you that. Physics gives you these sophisticated instruments or devices in the form of theories, powerful, mathematic, mathematicized theories that are predictively successful, and that's it. But most scientists, in my experience, they are, you know, scientific realists. They think that the things that we're probing are really out there.

I mean, the reason that I'm a particle physicist and not a mathematician is that I want to know what's really out there. I think of myself as revealing the truth. And when I'm at CERN, if I, you know, ask people, hey, do you think the Higgs boson that we discovered is real? Or is it just something in our models that lets us accurately predict experiments? Most of them would look at me like I'm crazy, you know, like I had something bad for lunch. it feels to me like they're doing philosophy by rejecting the question, even though they don't imagine they're doing philosophy. Why do you think that's sort of the natural position of most physicists to imagine a strong philosophical argument that everything we're out there is actually

real? Why do you think that most physicists don't consider the whole spectrum of philosophical positions there? I think because it's a sort of natural or default human inclination, first of all, to be a metaphysical realist in the minimal sense of there is a way the world is, objectively speaking. And then to go beyond that, to think, if we have powerfully, predictively accurate ways of describing the patterns of our experiences, then those must correspond to something objective. I'm being very vague here, but something in reality is accounting for the fact that our induction are successful. It may not be a perfect isomorphic

overlap between what we say either in common sense predictions or categorizations or even in high-level theory, but there's some degree of congruence there. We're tracking, I guess, of what I'm trying to say.

We must be tracking something real. And then when you think about fundamental physics because it's going so deep into the foundations, the inclination, I guess, it becomes natural to think we're getting closer and closer to it, isomorphism as the categories we're using are tracking very directly these entities. But it feels something more squishy than we usually find in physics.

You know, physics we have math and calculations and these sorts of things. Here we're talking about like a feeling that what we're seeing out there is real and, you know, our ideas about the universe must be real. It feels a little bit more susceptible to, you know, cultural bias or parochialism or thinking the way people have always thought. To me, one way to make sense of this question to make it a bit more concrete is to imagine a scenario like we meet alien physicists and we talk to them about the universe. If what we're learning about the universe is real in a sense that it's not just biased by our human conception, then we can imagine maybe they have discovered the same things. They also found the Higgs boson and they have group theory as a foundation of their. description of the fundamental particles. But if it's not, if instead we have some human element

to this understanding or that what's out there has no relationship, you know, to the model that we've built other than that it works, then maybe aliens would have completely separate ideas about physics. You think that's a reasonable way to frame this question of whether what we're probing is real, whether it could also exist in the minds of other intelligent creatures? Sure. I mean, imagine, first of all, that at some stage in physics, clever theorists were able to come up with two very different ways of categorizing phenomena, but they were equally predictively successful. Then I think the natural conclusion we would all draw is it's underdetermined.

At most one of these, if they're incompatible frameworks, at most one of these is true, perhaps neither. We need more information. But one of the great, of course, achievements of physics has been to increasingly try, to break away from a narrowly, provincially human way of looking at things. That's very difficult to do. And at some point, I expect, we'll come back to this. I think there are limits to how far one can go with that rationally because at the foundation of the evidence for our scientific theories, the epistemology

of science, are scientists in the activity of science. And we can't end up endorsing frameworks in which we cannot locate the rationality. inquirer in the community of inquirers and the activity of inquiring and I have questions it's very challenging but you know some of the more speculative attempts to unify fundamental particle physics and large-scale cosmology I worry that they're budding up against these kinds of limits that they're they're positing models that we could imagine for some entirely disconnected reality right they're perfectly coherent models for describing something, but could they describe our reality? Could we have reason

to believe, right? You know, there we are, right, in that question. Could we have reason to believe that we inhabit a world correctly depicted by this model? There's a tricky question there at the limit. It's certainly interesting to wonder about whether humans can imagine what humans can't imagine, right? Can we think our way out of our own box? It's certainly unknown. I'm really curious about a point you made earlier about whether there could be alternative. and completely functional descriptions of the universe that are conceptually different. Like if I describe the universe with my theory of everything and it has squiggles in it and I say, look, my theory works, squiggles must be real. And you know, you have your theory and it has squaggles

in it. And you're like, no, squaggles are totally different from squiggles and my predictions are just as good as yours. Then you're saying we're faced with a question. Are squaggles real? Are squiggles real? Is anything actually real? Is that the basic idea? And doesn't that sound very similar to the current situation about the nature of fundamental particles and the questions about quantum mechanics, right? We have very, very different conceptions of like what is real at the smallest scale, relational quantum mechanics, bohmian mechanics, all apart from the, you know, sort of orthodoxical Copenhagen interpretation, aren't we sort of in that situation? None of those theories give any real variation in their predictions, but they have completely different stories

about what's happening in the microscopic stale. Does that mean that nothing is real or just that we have found which one is real? I think the latter that we haven't found which one is real. And of course, you're the expert here, not me, but I like to chat with philosophers of physics and the occasional particle or theoretical physicist about the conceptual challenges in quantum mechanics and in unifying quantum mechanics with space-time theories.

And so as I'm told, for example, so you got this Bohemian interpretation, one interesting feature of which, of which is it's a deterministic theory about the dynamics of the universe, unlike at least a couple of the other leading theories, whether or not we call many universe theory a deterministic theory is a somewhat subtle question, I think. But I'm told that while these four frameworks all have the same predictive consequences for the kinds of experiments we can do now or have done, that there are, in principle, boeemian mechanics could have different predictions.

And so we could potentially, I don't know how far off this might be, but we could potentially have evidence that bore differentially between boeemian mechanics and at least some of the alternatives. So that suggests, yeah, we don't know. So then we're just right currently, you know, but we're still interested in the question. It may not happen in our lifetime. So the question is, should we be completely agnostic?

And here the different theories have different kinds of theoretical virtues and vices, insofar as one is willing to say purely general characteristics of theories, in terms of simplicity, of ontology and things like that, or whether it requires you to make certain very outlandish-seeming hypotheses, whether you give that any kind of evidential weight at all might determine. whether or not you think we have reason to lean in one direction or the other, even if we don't have conclusive evidence. Well, I hope that experimentalists are clever enough to come up with ways to test these various hypotheses and tell us what's actually happening at the smallest scale one day. So I have a lot more questions for you, especially about emergence. But first, let's take a quick break. LaGuardia Airport.

The holiday rush, parents hauling luggage, kids gripping their new Christmas toys. Then, at 6.33 p.m., everything changed. There's been a bombing at the TWA terminal. Apparently, the explosion actually impelled metal glass. The injured were being loaded into ambulances. Just a chaotic, chaotic scene. In its wake, a new kind of enemy emerged. and it was here to stay. Terrorism.

Law and order criminal justice system is back. In season two, we're turning our focus to a threat that hides in plain sight. That's harder to predict and even harder to stop. Listen to the new season of Law and Order Criminal Justice System on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. My boyfriend's professor is way too friendly, and now I'm seriously suspicious. Oh, wait a minute, Sam. Maybe her boyfriend's just looking for extra credit.

Well, Dakota, it's back to school week on the OK Storytime podcast, so we'll find out soon. This person writes, my boyfriend has been hanging out with his young professor a lot. He doesn't think it's a problem, but I don't trust her. Now, he's insisting we get to know each other, but I just want her gone. Now, hold up. Isn't that against school policy? That sounds totally inappropriate. Well, according to this person, this is her boyfriend's former professor, and they're the same age.

And it's even more likely that they're cheating. He insists there's nothing between them. I mean, do you believe him? Well, he's certainly trying to get this person to believe him because he now wants them both to meet. So, do we find out if this person's boyfriend really cheated with his professor or not? To hear the explosive finale, listen to the OK Storytime podcast on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. I had this, like, overwhelming sensation that I had to call her right then. And I just hit call, said, you know, hey, I'm Jacob Schick.

I'm the CEO of One Tribe Foundation, and I just wanted to call on and let her know. There's a lot of people battling some of the very same things you're battling. And there is help out there. The Good Stuff podcast, Season 2, takes a deep look into One Tribe Foundation, a non-profit fighting suicide in the veteran community. September is National Suicide Prevention Month, so join host Jacob and Ashley Schick as they bring you to the front lines of One Tribe's mission. I was married to a combat army veteran.

and he actually took his own life to suicide. One tribe saved my life twice. There's a lot of love that flows through this place and it's sincere. Now it's a personal mission. I don't have to go to any more funerals, you know. I got blown up on a React mission. I ended up having an amputation below the knee of my right leg and a traumatic brain injury because I landed on my head.

Welcome to Season 2 of the Good Stuff. Listen to the Good Stuff podcast on the IHeart Radio app, Apple Podcast, or wherever you get your podcast. A foot washed up a shoe with some bones. in it. They had no idea who it was. Most everything was burned up pretty good from the fire that not a whole lot was salvageable. These are the coldest of cold cases,

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I first came to read your work because I was very interested in the question of emergence, cases where we can describe things we see in the world using rules that are very different. from the rules of the underlying bits. It's like if you have a set of rules for how Legos work, but once you put the Legos together into complicated objects, you're better off describing their behavior in a new set of rules, like in a game of life, where simple objects with simple rules come together and very complex behavior emerges.

How would you define this concept of emergence and why, in your view, is emergence an important question in philosophy of science? Yeah, so it's always been a controversial idea and it emerged in the 19th century. People began thinking in emergentist terms. It's a question about the relationship of science at different levels of grain. So how does physics relate to chemistry, chemistry, to molecular biology, to organismic biology, and so on?

Then our biology to human psychology, neuroscience and the brain to human psychology. And the emergentist is a person who, in very general terms, thinks that organization, of certain kinds gives rise to new features, new patterns that have a certain degree of autonomy with respect to the lower level underlying dynamics. It's a new form of dynamics of patterns, the kinds of concepts you need to describe what's going on are different than the kind of concepts you need

to do the lower-level science. And left at that that there is emergence is entirely uncontroversial, There is such a thing as chemistry. Chemistry can be understood to a degree, at least at an elementary level, apart from quantum mechanics and certainly biology can be understood without knowing anything about quantum physics and psychology. You know, one can even do psychology of various kinds, social psychology, abnormal psychology,

and so on, without knowing anything about physics or chemistry. So there are patterns in the world that have to do with organized systems of a certain kind, robust patterns, patterns where you can predict phenomena. I mean, think about the fact that if I were to go agree to fly out to California to meet up with you, and three days later, I show up at your office door, and you quite confidently believe that that's going to happen, and that involves the movement of a hunk of matter that's coalesced in a fairly organized way, transporting itself across a great deal of distance. and could you predict that in terms of physics?

Well, certainly not given your and given our computational limits, right? But, you know, psychology works beautifully well, right? I mean, we can predict human behavior to a certain degree just by attributing to people beliefs, desires, intentions, and so on. And you can be completely ignorant. People were doing this a thousand years ago, knowing nothing about the physical underlying physical structure of the world. So there's a sense in which it's obviously true that there are emergent phenomena.

So weak emergence is the uncontroversial kind. Weak emergence says there are organized phenomena that have their own characteristic forms of activity, their own characteristic features and kind of dynamics for how this activity unfolds. But the weak emergentist says all of that is fixed in some sense determined by the underlying most fundamental dynamics in our world, the fundamental physical dynamics, whatever that turns out to be. That lies at the root of everything, fix that across space and time, all the fundamental physics, right? And you've thereby fixed all higher level phenomena and their patterns. So for example, if we're playing a game of ping pong, or saying that we can describe the motion of the ping pong ball using fairly simple rules.

But fundamentally, even though we can't calculate it today, those basic rules of the ping pong ball come from the basic rules of its constituents, that the towing and froing of all the particles inside the ping pong ball adds up somehow to F equals MA, that is determined by the basic elements. Is that the idea? Yes. And it's just computational limits on our part that we can't discern it. So Laplace, the 19th century physicist, mathematician, famously imagined a kind of disembodied intelligence

who was subject to zero computational limits, could track all the fundamental entities constituting space and time in their trajectories and discern the patterns, the fundamental dynamics that drive those things, their interactions. And then the thought is, You could, so to speak, step back and see the forest for the trees and could also notice then that there are these structured features of larger regions of space and time

and their interactions and discern they have dynamics and could, in a very laborious way for us at any rate, show that these high-level patterns don't disturb, you might say, or add to what's going on at the fundamental level. They're just a structured consequence of it. It's a surprising fact, right? We could imagine a boring flat world where there's just fundamental physics,

but there was no interesting structured phenomena. Well, our world's not like that. And so that gives rise to an interesting question, even for the weak emergence, why is our world such that there are not just fundamental physical patterns that fix everything, but also these higher level structured phenomena. It seems conceivable that,

that there could be alternative physics where that just never happens. So to me, that's a really fascinating question. I can't let you go past that without exploring it more deeply. To me, that's one of the deepest questions like in the weak emergent case where everything is determined by the most fundamental principles, why is it then possible to find this structure? Why is it possible to find fairly simple mathematical laws with hugely reduced degrees of freedom, right?

When you talk about the ping pong ball and moving across the table, you don't have to talk about all the particles that are inside of it. As you say, there are these simpler descriptions, the structure that emerges. Is it necessary that structure emerges? Why isn't it just the fundamental bits and then basically chaos above that? You know, why isn't everything like a hurricane out of raindrops impossible to predict no larger structure? Why does these simple explanations emerge? Do we understand that?

To the best of my knowledge, no, since I've never encountered anyone, the many thinkers, scientists, and philosophers who talk about emergence, who directly address that question and give kind of a full plausible sounding answers to it. I'm almost thinking it's a question for a mathematician or a physicist

kind of wears dual hats as a mathematician. So you invoke the game of life. So John Conway famous mathematician, he described this cellular automata which sounds complicated but it's actually quite simple, right? It's almost

It's like describing a reality, a two-dimensional reality that has very, very simple property. So simple, much simpler than fundamental physics. But what's really interesting about it is he shows that depending on the initial conditions you set, and then you just watch how this grid changes over time moment to moment, patterns emerge, structured patterns emerge that don't alter. The basic rules of life are unchanged, and yet there are these interesting patterns that can be understood in their own terms. That way of framing it, this very elementary mathematical,

he shows it that it happens in certain life worlds. You get these interesting patterns. And then the question is whether it's almost sounds like the territory of a mathematical proof of certain fundamental dynamics subject to certain constraints that can be given a clear mathematical description necessarily will yield over

given enough time, say, patterns of structured interactions. At least that's, I'm tempted to say it's almost, it's that kind of question. It's fascinating to me. And, you know, maybe like the weakest argument I could make to say that structure has to emerge is that, well, maybe it doesn't always, but we exist in the universe where it has because otherwise we couldn't. I mean, we are structure, right? My mind, my concept of myself, this conversation, all of this is emergent structure.

I'm not a fundamental bit in the universe, neither are you, neither is humanity, maybe not, you know, consciousness. So perhaps, you know, there are many universes out there and only in ones where structure does emerge at larger scales. Can you have consciousness and podcasts and philosophy at those scales? That seems to be sort of a very weak argument. In physics, we have another concept, which is renormalization theory, which lets us say the theory we have about particle physics right now is an effective theory. We know that. We know that electrons and quarks are probably. probably not the answer to the deepest question in the universe, but we can abstract away all the really high energy stuff, the stuff we can't probe today, the smaller bits in terms of a few

parameters. And Robert Wilson theory about renewalization and all this stuff and the decoupling theorem lets us do this. But we don't really understand, to my knowledge, why that is. It seems to work. It's sort of like science at a larger scale. It seems to work. We have these abilities to do this, but there's no theory as far as I can tell that tells us why that happens. I mean, said another way, I gave you a fundamental description of the universe, could you predict whether or not emergence comes out of it, whether or not things emerge, or would you have to run the simulation and observe it? To me, that's a really interesting question, you know, why this stuff emerges at all. Yes. And then, of course, there is the question of a different kind of emergence.

So strong emergence, which is non-trivial, it's not trivially manifest, is a notion of when under certain structured conditions, properties of holes arise, and they have an influence on how things behave, and these properties do add, at the end of the day, they add to the fundamental dynamics of the world. They have a kind of downward influence, and it goes all the way down, right? So it's as if it's a new force-like property or something. I mean, how exactly we might theorize such a irreducible property, irreducible but causally effective property,

perhaps there's more than one way we could do it. But, you know, just as a kind of rough and ready initial start, you know, think of it as like a new kind of structured force property or something that adds to. But this is sort of a shocking idea to me because as a particle physicist, I imagine a reductionism works. If I want to understand big stuff, I go to the small stuff, and eventually I can build up from there if I have infinite computing, power, et cetera. And you're suggesting that's not necessarily the case, that maybe there are rules

that exist at the higher level, the level of ping pong balls and ice cream that don't come out of the smallest bits, but somehow exist only at that level. Is that right? Yeah. And so then I want to say, you know, it's an empirical question. It ought to be thought of as a straightforwardly empirical question of whether there are emergent properties of that kind, emergent properties and patterns and activity of that stronger variety. And for that, I don't think fundamental physics is the domain you go to, or certainly not by itself. I mean, if we were Laplaceans' pure, disembodied, infinite intelligence,

well, we could do it and say, well, do it, do I? Is there any region of space time we're running only with the fundamental dynamics breaks down, right, in certain interestingly structured local regions, right? But we're not such an intelligence. And so it's inconceivable at present and probably forever that we could directly monitor in real time trillions upon trillions of variables corresponding to all the particles both in and immediately within the light cone over an interval of time, you know, of some sort of organized phenomena

and calculate, you know, how we expect all those interactions to go and see whether the particle physics is sufficient for capturing what's going on in, say, a human brain to pick a likely target of a strong emergentist hypothesis. Right. And so that's a very attractive question, obviously. You know, we look at the human brain and it's a lump of stuff. There are other lumps of stuff that don't seem to be conscious. You know, my desk, my chair are also lumps of stuff. They have actually the same, you know, number of protons and neutrons and electrons as my brain does. Why is it that my brain exhibits this crazy behavior that rocks and chairs and tables don't? So are you suggesting that, for example, consciousness might not just emerge from the interactions of those pieces inside the brain, but could come out

at some sort of higher level? Yeah. And so here's where I would say contentiously, we're kind of in the realm of philosophy. But when you reflect on the nature of conscious experience, we seem directly acquainted with qualities, qualities of our own experiences that cannot plausibly, perhaps even conceivably, be mapped onto structured properties of the relevant regions of our brain. So, you know, famous kind of example. If you go into the philosophy literature talking about this, you encounter the story of this neuroscientist, Mary. And Mary is, we imagine 100 years from now the science of the neuroscience of color vision is complete. And so Mary is a credentialed neuroscientist of color vision.

So what that means is you put somebody under the relevant scanning device and Mary gets some kind of interpreted feed out from her computer telling her what's going on structurally and she can predict what kind of color experience the person is having just on the basis of that. But now here's the wrinkle you add to the story. Mary herself has never had color experience because Mary's parents were crazed psychologist who thought it was an interesting experiment to raise her to be both a scientist of color vision but to never have. So she only has monochrome shades of gray, right? Everything, she's locked in a room and there's nothing that has color beyond shades of gray and white and black.

She's never cut herself. She happily has never cut herself. She never thought to do that. But one day, you know, she escapes from her room and she looks out on a bright sunny day and sees a red rose. And she knows that when human beings look at roses, right, that they have what she calls red color experience. But for her, it's a purely theoretical quality.

What is that? the way red looks to a normally sighted human under bright, sunny conditions. So now she has the experience, and she says to herself, so that is what a red rose looks like. That is, she's not learning something about the color of the rose. That has to do with the surface of the rose, right, a kind of certain reflectance property. That's not what she exclaims.

She's actually talking about her own experience of a red rose. She's saying that's what an experience of redness is like for a human being. And we think about that thought experiment and we think it makes perfect sense. And we say, right, somebody who's never experienced the color red, you can't communicate. It's kind of ineffable. There's just this simple quality, right, of a certain kind of deep red color, let's say, as opposed to a blue and green. These are just, they're just different. They're distinct qualities, but they're relatively simple qualities.

our experiences. Right. Now, the physics of it, of course, is that photons hit your eyeballs at different energies, different wavelengths, and those stimulate, you know, different paths and different signals up the optic nerve. But of course, there's no color in those signals, right? The color you're saying is experienced by the brain. It gets the signal and it gives you the experience of red or the experience of blue. You're saying that internal experience, we don't know how to describe it or quantify it or make it objective. But it's real and it's something over and above. Mary, seems to learn something new about color experience. Even though she knew what you were just describing in shorthand,

Mary knows all that stuff. She knows the neuroscience of color experience. She knows what goes on in the visual cortex, right? What kind of patterns of firings of neurons are going on when someone has an experience like that, right? But those seem to be all the causal preconditions, the underpinnings of color experience, but not the experience itself, the subjective, the simple subjective quality.

So the suggestion is, right, there are these subjective qualities, qualities of conscious minds, experiential qualities, that are something over and above the physical structures and states and processes that undoubtedly are necessary to undergo those experiences. There's something additional. They seem strongly emergent because now we're not just talking about a pattern of activity. We're talking about a new fundamental quality that can't be described in, terms of any of these sorts of processes, even at the neuroscientific level of description, which would seem to be the relevant level of description here. If it is a wholly physically constituted phenomena, then neuroscience should be the science that

tells you what it is. It's that neural structure and pattern. So you described this as an empirical question. What is the empirical test you could do to figure out whether consciousness or even physics of baseball? is strongly emergent or weakly emergent, whether there really is something new at these larger scales or whether this is determined by the little bits that they're made out of. Right.

Well, it would seem like we would need a much, you know, neuroscience is still in its relative infancy. If you talk to neuroscientists, that's what they say about the state of the science. They know a lot about local interactions and so on neurons and synapses and all that. But large-scale patterns are, something that they're just beginning to get a bit of a handle on. There's a ton that they don't

understand. But it would seem like if we could envision a much more developed systematic neuroscientific theory of neural dynamics of brains as complicated as our brains, and you could show that you could completely predict the unfolding of the relevant processes, say, in the visual cortex when someone's having color experience without recourse to some hypothesized further quality that presumably would be doing something that is if the the look of a red rose really is a quality over and above some kind of structured neural quality then that quality is part of what leads me to talk about it right so that means that in principle a neuroscientist who's paying attention in real time,

what's going on in your brain, when all this is happening, you're having experience and you're talking about it, if the theory was sufficiently well developed and testable could see whether somehow there was an incompleteness. If the neuroscience is just doing it

in terms of neurons and neural assemblies and so forth, and they can perfectly predict the dynamics going on in the relevant portion of your brain without recourse to some further hypothesized, holistic, you strongly emergent property. But in fact, suppose that's just wrong. It's an illusion, but it's somehow hardwired into us, that we have this illusion of there's something further

that's left out of a physical description. That's a conceivable. You might say it's a psychological hypothesis, right? One could go looking for. Is there something about the way our psychology is structured such that, you know, we know there are visual illusions built into our visual system, the Mueller lie, the, you know, the two lines with arrows, I won't go into a description of, right?

There's well-known visual illusions that have to do with certain limits to our visual system, right? We're led to say untrue things about what we're experiencing. Maybe there's something like this that's even deeper, right? We're inclined to attribute qualities to experiences that aren't actually there, right? And so if they're not there, then boom, the problem goes away. Okay, great. So, you know, a scientist who's kind of reductionist-minded should be tempted by this illusionist perspective on conscious experience. We're having experiences.

It's just they're not what they seem to us to be. And to me, that connects really deeply with this larger question of what's out there. And do we know that what we are experiencing and the theories we're building from those experiences really reflect what's real in the universe or whether it's just a sort of a game we are putting together in our minds? And so I want to ask you more about that. But first, let's take another quick break. December 29th, 1975, LaGuardia Airport. The holiday rush, parents hauling luggage, kids gripping their new Christmas toys. Then, at 6.33 p.m., everything changed.

There's been a bombing at the T.W. UA terminal. Apparently, the explosion actually impelled metal glass. The injured were being loaded into ambulances, just a chaotic, chaotic scene. In its wake, a new kind of enemy emerged, and it was here to stay. Terrorism. Law and order, criminal justice system is back. In season two, we're turning our focus to a threat that hides in plain sight.

That's harder to predict and even hard. to stop. Listen to the new season of Law and Order Criminal Justice System on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. My boyfriend's professor is way too friendly, and now I'm seriously suspicious. Wait a minute, Sam. Maybe her boyfriend's just looking for extra credit. Well, Dakota, it's back to school week on the OK Storytime podcast, so we'll find out soon. This person writes, my boyfriend has been hanging out with his young professor a lot. He doesn't think it's a problem, but I don't trust her.

Now, he's insisting we get to know each other, but I just want her gone. Now, hold up. Isn't that against school policy? That sounds totally inappropriate. Well, according to this person, this is her boyfriend's former professor, and they're the same age. And it's even more likely that they're cheating. He insists there's nothing between them. I mean, do you believe him?

Well, he's certainly trying to get this person to believe him because he now wants them both to meet. So, do we find out if this person's boyfriend really cheated with his professor or not? To hear the explosive finale, listen to the OK. Storytime Podcasts on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. A foot washed up a shoe with some bones in it. They had no idea who it was. Most everything was burned up pretty good from the fire that not a whole lot was salvageable. These are the coldest of cold cases, but everything is about to change. Every case that is a cold case that has DNA right now in a backlog will be identified in our

lifetime. A small lab in Texas is cracking the code on DNA. Using new scientific tools, they're finding clues in evidence so tiny you might just miss it. He never thought he was going to get caught, and I just looked at my computer screen. I was just like, ah, gotcha. On America's Crime Lab, we'll learn about victims and survivors, and you'll meet the team behind the scenes at Othrum, the Houston Lab that takes on the most hopeless cases to finally solve the unsolvable. Listen to America's Crime Lab on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Hey, sis, what if I could promise you you never had to listen to a condescending finance, bro, tell you how to manage your money again. Welcome to Brown Ambition.

This is the hard part when you pay down those credit cards. If you haven't gotten to the bottom of why you were racking up credit or turning to credit cards, you may just recreate the same problem a year from now. when you do feel like you are bleeding from these high interest rates, I would start shopping for a debt consolidation loan, starting with your local credit union, shopping around online, looking for some online lenders because they tend to have fewer fees and be more affordable.

Listen, I am not here to judge. It is so expensive in these streets. I 100% can see how in just a few months you can have this much credit card debt when it weighs on you. It's really easy to just like stick your head in the sand. It's nice and dark in the sand. Even if it's scary,

it's not going to go away just because you're avoiding it, and in fact, it may get even worse. For more judgment-free money advice, listen to Brown Ambition on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. Okay, we're back and we're talking with Professor Tim O'Connor, who's telling us about how things emerge in the world and how we can explore them. And most importantly, what that tells us about what's real out there in the universe. And to me, this question of emergence is very closely connected to the question of scientific realism because even if you believe that the universe is real and there are basic bits and rules about those basic bits, if you take the weak emergence, we haven't learned what those basic bits are.

We've only learned the emergent bits. So in the question of scientific realism of what's out there in the universe, how do we know that what has emerged is real or whether it's just sort of like, our description of it. Even if there is a real universe out there and if we drill down with the biggest particle collider, anybody could ever build, we might find something deep and true. How do we know that what's emerged on top of that is real? Is it possible that the way things emerge to us might be different than the way things emerge to another intelligent race that has a different set of senses perhaps perceives the universe through different fundamental physics properties?

How do we know that the emergent pieces themselves we can, you know, say are actually out there? Good. Right. So it seems, you know, in the abstract, it seems conceivable that there be different but equally effective, coarse-grained ways, you might say, of chunking up, you know, things at the level of middle-sized objects and observers, but just the categories are different. So, you know, we find it natural to group things. Let me acknowledge right. the outset, or I think we all should acknowledge, our senses, right? Our categories are closely tied to our perceptual senses, and our senses are geared to be good at, we know, detecting features that are useful to us, or at least we have reason, right, to believe they would have evolved. And so, you know, this could kind of add scientific reason to be a little bit worried about this question, say certain things get foreground in our experience because they

they're really important to us. You know, colors are signals to us of, you know, food sources and properties, for example, and probably a lot of other things I don't even know about. But maybe to a different kind of a non-carbon-based kind of inquirer who doesn't need organic food sources, maybe color might not be the same salient sort of property, but other properties that do have relevance to its survival and its ability to navigate its environment would be foreground. us, we don't kind of see, we don't, we don't tend to pick out those patterns.

And so it leads, yeah, and then, you know, you generalize the picture, and then, so then the two different types of inquirers, the organic ones like us and the non-organic silicon-based ones that we could imagine, their whole way of representing middle-sized environmental features and patterns are somehow different, but they get along well in their environment, they're able to do science. And so suppose we're at roughly the same level of scientific advancement. And so we have rather similar fundamental physics, but we're different. Maybe that's what you're asking, you know, at the level of kind of more emergent levels. But there's also, there's a question here of scale, because when we talk about emergence, I think you're probably thinking about me and you and ice cream ping pong balls. But for the particle physicist, I'm even talking about electrons. I'm talking about quarks, which we think are probably immersion from something, you know,

mind-bogglingly even deeper in the universe. So basically everything we've ever learned is emerging. We have no knowledge of the fundamental. And we don't even know if there is something fundamental. Maybe there isn't. Maybe it's a infinite tower of effective theories all the way down. There is no deep truth. How do we know that our tower will line up with alien towers? Or if they have another way of looking at what you call coarse-grained theories of the universe, where to me, coarse-grained could be as small as an electron or as large as a planet. Yeah. I don't know if this fully, it certainly doesn't fully address your question, but I would want to throw out the following constraint, unless we become complete systematic skeptics about human knowledge and say, you know, I don't even know whether or not I'm dreaming or even more radically, you know, Descartes way back in the 17th century. Perhaps I'm just a disembodied mind and I have false beliefs about my own past. In fact, there is no physical world. I wasn't born. None of this, and there's just some evil genius bent on deceiving me, who's pumping

my mind with a flow of stream of experience that I naturally interpret as my interacting with my physical environment, but none of it's there, right? Or, you know, the Matrix films, you know, are kind of an updated version of this. You know, the way things really are that what really lies behind our experiences is something very different from what we naively take it to be. Well, you can't do science under those ground rules, right? Science has to presuppose, for example, that we didn't pop into existence just 30 seconds ago with a bunch of built-in false memories about having had past experience. Science has to presuppose that there's some kind of regularity to the way the world unfolds.

And if you say, well, no, science can show that there's regularity by doing experience. and, you know, corroborating results, that presupposes that what you're hearing when you're being informed by another scientist about their results, itself reflects the outputs of another scientist, but why are you trusting your senses, right? That's a really big assumption

that your senses are even effectively registering anything outside you is a big assumption. Well, you can't scientifically verify that, right? Because you'd have to somehow get outside of your senses. You know, you can't do that. You can't get outside of your rational thinking. So the point is, even what we think of as a paradigm of rational inquiry science has to make certain foundational assumptions about the rough and ready at least reliability

of our basic cognitive equipment and the rough and ready predictability or patternedness of the world that we're seeking to describe. It doesn't have to assume a lot more than that, but it does have to assume at least those things. and it has to assume if science is going to deliver a rational set of beliefs of us that we exist, that we persist, that we really are interacting with one another. But once you do that, well, now we've got, I exist, you exist, if we're fellow scientists, I'm part of this community, this distributed community,

I have to assume, since I can't do all the science myself, no scientists can do that, that there is this rational community that's effectively managing to communicate results and theories and descriptions and how they corroborate with theories. A lot is getting baked in. My point, I guess is what I'm getting at here, has to be baked in for us to even ask an interesting question

about have our theories delivered the rational goods. Now, making those assumptions doesn't require that chemistry or biology, as we know it, is very, very, very closely tracks the truth at that level of description. So I'm not suggesting we get our emergent phenomena, but there are constraints. You can either be a total skeptic or you have to say there are inquirers that have certain capacities and certain reasonable assumptions that they make.

I'm not sure how far that gets us, but it gets us a certain ways. I think you're making the point that we can take our skepticism and paranoia too far in throwing out everything and saying we can know nothing. And it's certainly the case that, you know, we would like to know something that's true about the universe. But I think the motivation for examining these fundamental and the foundations of our knowledge and how we know things is because we wonder if we've made a mistake, if we've made some arbitrary choices where we could have, perhaps if Plato had a different mood, you know, founded intellectual thought in another direction and everything would have been built up and conceived up in a completely different way.

And to me, that's what's exciting about potentially meeting alien physicists or even digging back into ancient human knowledge and seeing how independent communities, the Mayans, the Egyptians, the Chinese thought about the universe and their relationship to it, you know, separately from each other. Because it seems to me like it's possible and it's fascinating to me that it's possible that the way we've built our ideas of physics and the universe could have some arbitrariness to it, right? There could be another way to have done this. So to me, it's exciting to probe those and to do the impossible thing that we suggested earlier, which is to imagine what humans haven't yet or maybe cannot yet imagine. So let me ask you as a last question. What do you think are the prospects for making progress? I mean, we've been talking about whether the universe out there is real or just imagined since the Matrix,

since, you know, Descartes, since Plato, in fact. So it's been thousands of years. We've been thinking about these questions. Is it a question we'll be thinking about forever? Or are we likely to see breakthroughs where one day we say, ah, look, we settled that question, Plato was right or Plato was wrong, and then we can move on to other questions.

What do you think? Well, we won't settle it in the sense that there's never the basis for a somewhat reasonable worry or skepticism that we haven't nailed it down. There's always because human inquiry generally in science, as a special, rigorous case of human inquiry is fallible. There's no reason to believe they're perfect. So that's, if we lower our sights and get away from having a perfect congruence, a perfect mapping of reality, maybe we'll never get that,

but we have a closer and closer mapping than that's good enough. Well, it certainly is helping us develop new technologies and I hope revealing something that's true about. what's out there in the universe to me i love these moments of insight and discovery where we feel like not just that we've developed some new tool that describes the universe but we're actually revealing its internal its underlying mechanism you know that the ex boson for example is actually out there and is towing and throwing and doing its bit to create mass for all the other particles and not just a mathematical description that we have in our heads because otherwise my entire life's

work is uh it's just much more theoretical than i ever imagined but uh thanks very much for joining us on the podcast today and for thinking about these crazy questions and allowing me to talk about aliens and philosophy at the same time. I really appreciate you coming on the podcast. All right. Thanks, Daniel. Thanks for having me. wherever you listen to your favorite shows. December 29th, 1975, LaGuardia Airport. The holiday rush, parents hauling luggage, kids gripping their new Christmas toys.

Then, everything changed. There's been a bombing at the TWA terminal, just a chaotic, chaotic scene. In its wake, a new kind of enemy emerged, terrorism. Listen to the new season of Law and Order Criminal Justice System on the IHeartRadio app, Apple Podcasts, or wherever you get your podcasts. My boyfriend's professor is way too friendly, and now I'm seriously suspicious. Wait a minute, Sam. Maybe her boyfriend's just looking for extra credit. Well, Dakota, luckily, it's back to school week on the OK Storytime podcast, so we'll find out soon. This person writes, my boyfriend's been hanging out with his young professor a lot.

He doesn't think it's a problem, but I don't trust her. Now, he's insisting we get to know each other, but I just want her gone. Hold up. Isn't that against school policy? That seems inappropriate. Maybe find out how it ends by listening to the OK Storytime podcast on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Why are TSA rules so confusing? You got a hood of your take it all! I'm Mani. I'm Noah.

This is Devin. And we're best friends and journalists with a new podcast called No Such Thing, where we get to the bottom of questions like that. Why are you screaming? I can't expect what to do. Now, if the rule was the same, go off on me. I deserve it. You know, lock him up.

Listen to No Such Thing on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. No Such Thing. This is an IHeart podcast. Thank you.