Theories of Everything with Curt Jaimungal - QBism: The New Theory That Shatters Our View of Reality

Episode Date: July 9, 2024

Links Mentioned: - Amanda Gefter's "Trespassing on Einstein's Lawn": https://amzn.to/3XUVfwr - Richard Hamming’s “Learning to Learn” Series: https://www.youtube.com/playlist?list=PL2FF649D0C4407B30 - Christopher Fuchs Lecture on QBism: https://www.youtube.com/watch?v=I2w-BtI01sA - Amanda’s Talk: https://www.youtube.com/watch?v=sOwSoAC2tEs - Karl Friston’s TOE Episode: https://www.youtube.com/watch?v=2v7LBABwZKA - John Vervaeke’s TOE Episode: https://www.youtube.com/watch?v=GVj1KYGyesI Timestamps: 00:00 - Intro 00:56 - John Wheeler 07:42 - Participatory Universe / Quantum Mechanics 13:00 - QBism 18:38 - Probability and Bell’s Theorem 24:28 - Writing About Physics 30:26 - Simplifying Physics 36:02 - Philosophy and Physics Connection 40:02 - Quantum States 52:02 - Belief and QBism 01:11:30 - Quantum Field Theory 01:15:43 - Consciousness Please consider signing up for TOEmail at https://www.curtjaimungal.org   Support TOE:  - Patreon: https://patreon.com/curtjaimungal (early access to ad-free audio episodes!)  - Crypto: https://tinyurl.com/cryptoTOE - PayPal: https://tinyurl.com/paypalTOE  - TOE Merch: https://tinyurl.com/TOEmerch    Follow TOE:  - *NEW* Get my 'Top 10 TOEs' PDF + Weekly Personal Updates: https://www.curtjaimungal.org  - Instagram: https://www.instagram.com/theoriesofeverythingpod  - TikTok: https://www.tiktok.com/@theoriesofeverything_  - Twitter: https://twitter.com/TOEwithCurt  - Discord Invite: https://discord.com/invite/kBcnfNVwqs  - iTunes: https://podcasts.apple.com/ca/podcast/better-left-unsaid-with-curt-jaimungal/id1521758802  - Pandora: https://pdora.co/33b9lfP  - Spotify: https://open.spotify.com/show/4gL14b92xAErofYQA7bU4e  - Subreddit r/TheoriesOfEverything: https://reddit.com/r/theoriesofeverything   

The shock is so great in quantum mechanics that we still have not figured out how to really process it. How does quantum mechanics confront our view of reality, even shattering it? Amanda Gefter, science writer and author of Trespassing on Einstein's Lawn, dismantles long-held notions about quantum mechanics, proposing a revolutionary perspective where observers don't just perceive reality, they actively participate in its creation. In this episode, we'll delve into how our beliefs shape the quantum world, why Descartes' subject-object split is fundamentally flawed, and how emergence could redefine our scientific understanding. Prepare to have your concept of reality transformed as we venture into the quantum realm, where nothing is quite as it seems.

Probably the most formative conversation that I had, even though it was a very, very brief conversation, was one with the physicist John Wheeler. So Wheeler was this legendary American physicist who came up with the terms black hole and wormhole and he did revolutionary work in everything, general relativity, nuclear physics, quantum mechanics, and had a very profound philosophical mind but also spoke in this very enigmatic Yoda-like way. I had the chance to meet him, well, this is a whole long story, but my father and I snuck

into a physics conference that was being held in Wheeler's honor. It was in honor of his 90th birthday at Princeton. And this is in 2002, I believe. And it was this amazing conference and all the best physicists were up there giving talks and everything. And Wheeler was just sort of sitting at the front. And he was 90 at this point, he was a bit hard of hearing, but he was still deeply obsessed with all of these big questions about, you know, how come existence and why the quantum and all of the questions that I think you, Kurt, are interested in.

And so, you know, at some point after the talks, we kind of waited our turn and we got to go up and talk to him. And Wheeler had had this idea that somehow observers are implicated in reality, in the nature of reality. And the question that I really wanted to ask him was, if observers create reality, where do the observers come from? So I asked him this, we had to repeat it a few times because he was a bit hard of hearing, and then he said, the universe is a self-excited circuit.

Okay. And then we said, okay. And then my dad and I were very obsessed with this question about what is nothingness. And Wheeler had talked a lot about nothingness. And so our second question was, does everything come from nothing? And he said, the boundary of a boundary is zero.

And we said, okay, thanks. And we walked away and then we were sort of, what the hell just happened? So Wheeler had basically presented us with these kind of riddles. And I, in a certain way, have spent like much of my career trying to figure out what he meant by those phrases. So I think that was definitely the shortest, much of my career trying to figure out what he meant by those phrases.

So I think that was definitely the shortest, strangest, but most influential conversation that I had. So what's meant by it's a self-excited circuit and the boundary of a boundary is zero. How is that at all connected to your question? So Wheeler passed away in 2008, but he, throughout his whole career, had kept journals, these very, very detailed journals, every conversation he ever had, every thought he ever had are in these notebooks. And he donated them all to the American Philosophical Society Library in Philadelphia, so you can go there and read through all the journals. So I spent a very, very long time combing through

these journals, trying to figure out what was he really getting at. And yeah, so the idea of a self-excited universe, I mean, in a nutshell, he had this notion that, well, first of all, he saw quantum mechanics as giving us a kind of participatory reality, as he would put it, where you don't have some reality that's just sitting out there some particular way, independent of observers, but observers and the universe sort of come together and participate in the creation of reality, and reality is sort of

ever on the make in this story. And so he wanted to give a story, there's a famous diagram he drew that was a U, the letter U, with an eyeball at the top. And this is supposed to capture this idea of a self-excited universe. So the U is for universe. And the idea is kind of the universe comes into being and gives rise to an observer, and then the observer looks back in time. This is related to Wheeler's delayed choice experiments. The observer looks back in time and through the act of a quantum

measurement participates in creating the very universe that created the observer. So it's this kind of strange loop and this was his idea of a self-excited universe which he never fully was able to flesh out but that was the, he called it like an idea for an idea. And then the boundary of a boundary is zero. This is a trickier one. There's a sense in which it's a very basic concept in, I guess, topology that once you bound a space, you don't have to put a boundary on the boundary.

The boundary of the boundary is always equal to zero, which apparently you can actually derive a lot of physics out of this very sort of tautological statement. But he wanted to say something a little deeper with it, like that there are ways, he called it a principle of austerity, that there are ways that you can get so much out of so little. So he was trying to reduce physics essentially to something like the identity of like zero equals zero and then be able to say that you could derive all of physics from this. I mean this was just one program that he worked on that again it was an idea for an idea. Yeah, I mean it's not that I don't think these were the answers but they

were very inspiring to me in my thinking and also just sort of presenting physics as this great mystery that needs to be solved. John Wheeler, one of the most influential physicists of the 20th century, proposed a controversial idea that physicists are still debating to this day. The idea that we live in a participatory universe. Wheeler said to imagine a cosmic version of the double slit experiment, where light from a distant quasar passes by a gravitationally lensing galaxy. It can go either to the left or to the right of the galaxy. Now here's the twist.

We could choose to measure which path the light took, or we could choose to observe an interference pattern after the light has already passed the galaxy. But this choice, where we determine if a photon is a so-called particle or so-called wave, is made billions of years later, after the light began its journey. This idea is captured in his self-excited diagram where the universe creates observer self-excited diagram where the universe creates observer participancy, which in turn creates information which creates the universe. Are we passive observers of a predetermined universe or active participants in an ever-evolving interdependent web that we call reality? So the participatory universe is just one of several interpretations of quantum mechanics.

Can you explain what are these so-called interpretations of quantum mechanics? And then what is the participatory universe and transition into cubism? Yeah, so quantum mechanics, it's funny, I just watched there's a mathematical physicist, Marcus Appleby, who gave this talk at Dartmouth College last week, this past week, who he was comparing our understanding of quantum mechanics to long COVID. So he was sort of saying that, you know, there's been all these revolutions in science over the centuries and normally it's, you know, Copernicus comes along and, you know, it says, oh my God, everything you thought was wrong.

And there's this initial deep, deep shock, which is sort of the disease that you have to get over but then eventually you just get over it and you move on and he said quantum mechanics is is unlike that because you know, it's been well over a hundred years and You know and and we're still suffering from from the disease. He called it long classicality you know, and we're still suffering from the disease. He called it long classicality. Interesting. So, it's just the shock is so great in quantum mechanics that we still have not figured out how to really process it.

And because of that, we have all these different interpretations that try to give almost a narrative account of what the mathematical formalism of quantum mechanics is trying to tell us about reality. And so you have, you know, the many worlds interpretation, you have objective collapse, you have relational quantum mechanics, you have Bohmian mechanics, you have cubism. So there's all these different interpretations that try to say what it is that quantum mechanics is really telling us. And they differ substantially. I mean, it's sort of remarkable that you can give such radically different interpretations

of the same theory. And in a sense, it's philosophical temperament. It's what do you want your reality to be? And then you try to construct a story that's consistent with quantum mechanics. And the thing about quantum mechanics is it makes it very, very hard to give a consistent story. You have to, I mean, I think the central lesson is whatever the story is, it can't be classical physics. We can't go back. So something has to give.

And so, for instance, people who like, you know, Bohmian mechanics or something, they, I would say, I imagine they would agree, really want something as close to a classical reality as possible. So they really want there to be a free standing reality that just is some particular way. And if we have any uncertainty, it's just because we don't know what the truth is, but there is a truth out there with a capital T.

But when you look at what you have to do, the kind of contortions you have to twist yourself into to say anything that, I mean, they're so extreme. You have to give up on relativity. You have to allow for, you know, crazy non-local effects. You have to allow for what they call non-contextuality. You have to, or sorry, you have to allow for contextuality. What you end up with is still not a classical reality. It's something incredibly, incredibly strange. It's the same with many worlds. Many worlds also kind of has a classical impulse there. But the price that you pay is this infinite number of universes where everything that can happen is

happening and an infinite number of you in all these universes. So the point is these interpretations make it very clear that whatever quantum reality is, it's not your grandfather's reality. What's interesting is he called it long classicality. So he sees classical, well, our adherence to thinking classically as the disease. Yes. He doesn't think of quantum mechanics as the disease that needs to be tamed. No, no. I mean, I think and that's that's the real spirit of Cubism, which we can talk about is Cubism is sort of saying, okay, let's

Let's embrace what quantum theory is saying and and just get over these kind of classical impulses that we have. So there's someone named Richard Hamming. I'm not sure if you know who that person is. He's a physicist slash engineer, has a fantastic series on YouTube about learning. It's from the 80s, I believe. It's just a fantastic watch. He said that people form their interpretations of quantum mechanics based on their prior

metaphysical beliefs. Yes. So he said this is true of Einstein and this is true of Bohr. Christopher Fux had this lecture on cubism and he said that what was different about cubism is that it started with let's take quantum mechanics seriously and then let's see what occurs from there. Let's let that dictate our interpretation rather than our prior beliefs dictating it. At least that's what he said.

But that's how most scientists view their work is they're the rational person who goes in without preconceptions and then I let the data tell me and I am so disjoint from my ego that I'll follow the data wherever it goes. Yeah. So I take that with a grain of salt when he says that, but you know the history much more. So please outline what Cubism is and if my reiterating of Christopher's story is apt. Yeah, well, it's funny. I mean, to defend him a little, I would just say, I mean, I think he does, he does sort of freely admit a certain philosophical temperament. So, you know, he talks about really wanting free will, for instance, and really in that sense,

not wanting a block universe story, you know, where the world just is sitting there deterministically and just sort of is some particular way and our actions have no real hold on the world. So I think he would acknowledge some of his sort of philosophical biases in that sense. And he also, to connect back to what we were talking about earlier, he studied a bit with Wheeler when Wheeler was at the University of Texas at Austin. So this is Leighton Wheeler's career. Chris Fuchs was there in Texas. And so I think he was very deeply influenced by Wheeler. And then also he read a lot of William James and early American pragmatist philosophy

and is very influenced by that too. So I think that's sort of- Wonderful, wonderful. Where that's coming from, yeah. So Cubism, yeah. I mean- Cubism. So yeah, what Chris to saying is that the name is similar to KFC, where it originally stood for Kentucky Fried Chicken, but at some point they just decided it's just KFC.

It doesn't stand for anything. So Cubism is like that. It originally stood for quantum Bayesianism, but now it's just Cubism. Okay. Well, why don't you start with it historically, because why was it called quantum Bayesianism, and why did it change? Yeah, so quantum mechanics is very much about probabilities, right? Classical mechanics just gave us values for things, you know, this is the position, this

is the momentum, and quantum mechanics gives us probabilities for what we might measure. And that's part of why it's so strange as a theory because probabilities sort of normally are thought of as reflections of some kind of ignorance on the part of the observer, but these probabilities seem to sort of be fundamental to the world in some way. And so then the question is, are we talking about the observer? Are we talking about the world? And then you get into all these deep questions. And so how to understand probabilities, you know, there's something called the wave function

in quantum mechanics, which is the most you can say about the state of some quantum system is encoded in this wave function, but the wave function just gives you probability or it gives you a way of getting probabilities out of it. And so how to understand probability becomes really essential to how to think about quantum mechanics. And so there are different philosophies of probability. And so you could say, you know, I think probably the intuitive one that most people have is what's known as the frequentest interpretation of probability. So if I say, you know, the odds of a coin flip landing heads is 50%, what do I really mean by that? Well, I mean, if I flip the coin an infinite number of times, it would come out to 50-50, right?

And that's like philosophically a really complicated story to defend because first of all, nobody can do anything an infinite number of times. Second of all, like, why does that tell you anything about what's going to happen the one time that you do it? And then also, what's the causal story you're giving about why that probability has any hold on what the coin actually does and so then people talk about like the coin has a propensity you know because it's a an unbiased coin it has propensity to do a certain thing and then it's like now

you're like imbuing the world with propensity like it's just like a whole complicated thing. As we're talking about probability and wave functions, later Amanda will discuss the Born Rule, but a preview is warranted now. The Born Rule is something you'll hear plenty about in quantum mechanics, and what it is, is a method from translating from the wave function to probabilities.

Also, the topological principle of the boundary of a boundary is zero, has deep-seated connections in physics and we'll explore that later. Born proposed that the probability of finding a particle is the absolute square of its wavefunction. This forms a bridge between these abstract so-called wave functions and measurable probabilities, though the rigorous treatment of this involves fancy machinery called projection-valued measures and density functions. That's for another episode, though. Now, the boundary principle, where the boundary of a boundary is zero, stems from combinatorics, so counting principles

in something called homology. In differential geometry, which is the language of Einstein, this becomes the statement that the differential of a differential is zero, also known as the Poincare Lemma. When applied to general relativity's Riemann curvature tensor, it leads to energy and momentum conservation in spacetime. In electromagnetism, it gives us Maxwell's equations. These principles demonstrate how the cosmos speaks an obscure yet simple language.

It's just like a whole complicated thing. And so a very different way of looking at probability is Bayesian probability, where you just say, I have some prior expectations based on my prior experiences flipping coins and then I'm going to assign a probability and I'm going to flip the coin and then based on the outcome I'm going to update my prior probabilities for the next round. And so then now you can talk about like well if I

take that story objectively then I would say the more I learn the more I act on the world and get consequences of my actions and update my beliefs I like inch closer and closer to some truth about what the coin really is right and then that's problematic too. And so then there's a variant of Bayesianism called personalist Bayesianism, which says, I'm never really trying to get to the truth of the capital T. I'm just trying to make my own beliefs consistent with one another. And I'm doing that through acting on the world and then updating. But I'm not claiming that my beliefs have some ontic hold on what the world

has to do as a result. An ontic hold just means it's corresponding to some capital T truth out there? Yeah, either corresponding to or compelling the world to do something. Okay. A law of physics would compel the world to act a certain way or something. So cubism came from a personalist Bayesian interpretation of probability. So the idea was let's treat probabilities in quantum mechanics in this way and that way you don't run afoul of things that no go there, like a bell inequality or something

like that where if you really think that like basically like if you really want to say my the probabilities I assign or the uncertainties that I have come from my own ignorance about the actual state, but the actual state is something. I just may not know what it is. You know, we can do these experiment, these Bell experiments that show you get into trouble if you think about it that way. So just a moment. Are you suggesting that quantum, that cubism, I'm not sure if we're at the point where we've transitioned but

Let's just say it's cubism. Does cubism get over so-called get over Bell's theorem or Bell's inequality Does it get over it somehow does it bypass it? Does it give it a different interpretation? Like what does cubism have to say about Bell's theorem? Yeah, so So the idea of Bell's theorem is like, you have multiple assumptions that you put in, and those assumptions are like locality and realism, in Bell's version. And so you say, I'm going to assume the world is local,

so there's no spooky action in the distance, and I'm going to assume the world is local, so there's no spooky action in distance, and I'm going to assume realism, meaning like things have some state in and of themselves, regardless of measurement. I'm going to assume those things, and then I'm going to calculate like an upper limit on how distant events might be correlated. This is how Bell worked it out, right? So then he says, given those assumptions, there's some upper limit for those correlations. And then you run the experiment and you see it violates that upper limit.

It's much more strongly correlated than that. And so the world and quantum theory violate Bell inequality. And it's such a complicated way of talking about it. This is how physicists talk about it, but it's like this weird double negative that's like hard to think about. But the point is just that the world and quantum theory can't be both local and realist.

Yeah, at least one of those assumptions have to be false. One of those assumptions has to be false. But it doesn't tell you which one. It's up to you to pick which one you're willing to give up. And this, by the way, gets like, is said wrong all the time. And it makes me crazy. All right. All right. Let's hear it. It's like one of my like pet peeves in science journalism because people say like, oh, it proves that the quantum mechanics is non-local. But like, that's absolutely not true. It's like you could have locality or you can have realism. It just proves you can't have both.

So one thing that many people do is say, okay, I'll give up locality. But then you have a real problem. You have to give a story of that you end up violating, like you don't have relativity anymore because you don't have larenzariens anymore and you've a preferred frame and it's a whole complicated thing where that nobody's given it like a convincing account of what you do if you give up locality in that way and then it's like so weird that like The world's non-local but only a little and only in these rare circumstances

I don't know that to me that's like not a not a convincing story So the other option is you say, I'm gonna give up realism. I'm gonna give up this idea that there are outcomes that are just determinately sitting out there. And so that's what cubism does. So cubism, it's not getting around, you know, Belle, it's just the choice that cubism makes

is to give up the realism, not the locality. So Cubism is still local. In your book, just to bring it to something that the viewers may want to look up, there's a book that you have called Trespassing on Einstein's Lawn, and we covered it in the introduction. But please outline for us, in the book, it's a personal quest that you embark on with your father. And I want you to tell us about this father-daughter dynamic and how that influenced the writing, especially the writing of physics. Yeah, so the book tells this story. It's sort of this weird mashup of like a physics book and a memoir and it tells this

story of like when I was, it starts when I'm like 15 years old and my father who was this very like, had a very Zen guru, I mean still does, has a very Zen guru kind of vibe about him, you know, took me out to dinner at a Chinese restaurant and says, how would you define nothing? And we ended up having this whole deep conversation. I mean, I was like this really rebellious kid. I was not taking physics. I was in remedial science.

I was like failing math. I was not the person you would like talk about physics with for sure. But I think I, I think I always kind of had like philosophical leanings and I think he sensed that and he did as well. And so, so he asked me this question about nothing and we ended up having this whole long conversation. He had had this idea that he was very excited about, about how to define nothing. It's usually defined in the negative. So you would say like nothing is the absence of everything. And then if you try to ask a question like how do you get something from nothing, you're

sort of like foiled from the beginning because you've defined nothing as like, know something. And so like, how could you ever have something? So he wanted to define nothing in the positive and say what it is, not what it isn't. And so he had had this idea that like, nothingness is a state of complete sameness that extends without bound infinitely, that that would be nothing. And so, I mean, this is not physics, this was just like an idea, but we started talking about it and it just triggered this like insane thing

where it was like, well, you know, if the universe came from nothing, like how do scientists think that that happened? And like, I don't know, let's do a little research. And like, you know, cut to like many, many years later, I'm like still doing the research. But basically we like just went on this like insane journey that we really like doubled down on

of like trying to understand, teaching ourselves physics and trying to understand, you know, cosmology and how physicists think about all of these ideas and then crashing conferences, like I was telling you. And then I had always wanted to be a writer, but at some point I sort of realized, you know, I snuck us into these conferences by claiming to be a journalist. And then I was like, oh, there's actually this field called like science journalism where you can do this.

And then, you know, like when we have a question, like we can just ask the physicists. Like we don't have to read popular books to try to find this one little thing. We can just like ask them. So basically like little by little, this like fake career that I had invented for myself morphed into an actual career in science journalism.

And then it was the dream. I got to interview all of these amazing people. And so the book just tells this whole story. But the physics part of it is basically we realized early on that physicists have a way of defining what's real in like a pretty rigorous way. So I always thought this question of like what's real seemed kind of vague and philosophical, but you can define something as real in physics if it's invariant in any reference frame. And so with that definition in mind, we were able to sort of like, you know, we made this

list of like, here are all the things that could be the ingredients of reality. So like particles, fields, forces, space, time, the universe, whatever. And the we is your father and you? Yeah. And so we were your father and you? Yeah. And so we were like in a restaurant, we wrote this on a napkin and then we were like, okay, we're gonna just figure out like each one of these things, is it real or not? And then we start going through, you know,

and that took us through these amazing ideas and at the cutting edge of physics and little by little, it was like crossing one after the next off this list and realizing like, none of these things are invariant. But what is invariant is this state of nothingness that my dad had like started with. Like that by definition, it's kind of like the ultimate invariant.

And so anyway, so it became this whole wild journey, but through it, I got to really learn some deep physics. And so I wanted to take the reader, I didn't feel like I was in this position, most popular science books are written in this professor model, where it's like, let me tell you how the world works.

The reader's the student and the writers, the professor. But it was like, you know, I had come into this as like this kid who was just like messing around and like sneaking into conferences. And like I was in no position to tell anyone, you know, here's how the world is. So instead I was like, let me just tell you this story of what I did. And like you can learn the stuff that I learned with me. So that's how I wrote it. I remember watching a talk of yours and saying that there are these unconnected facts when you first learned physics, plenty of new terminology, it's difficult to make them into a coherent

framework and then the insight dawned on you or was given to you about what is real is what's invariant in any reference frame and then that helped you crystallize and connect different facts. Yes. Were there any other insights that helped you see almost all of physics or almost all of philosophy perhaps because you have a degree in philosophy? Almost all of a certain field was made much more simple and more easy to be digested because of a single insight. I mean that's the one.

Like, that insight, it sounds so simple, but there's no way I would have learned the physics I learned without it because it just cuts right through. Like, I mean, if that's what you're interested in. Obviously, if what you're interested in is like engineering something, this is not the insight for you. But if what you're interested in is like, what's real, you know, this idea of like, what's real is what's invariant.

It just, it's exactly what you said, it like cuts through all the complication and lets you see what's important. So like for instance, I remember coming across like Stephen Hawking's work, right? And obviously, Stephen Hawking was the most famous physicist since Einstein, and everyone's heard of Hawking. If you ask them, what did he do that was so important, people kind of know. It might be something with black holes. And then it's like, even if you know, okay, he discovered the black holes like radiate It's like it's not obvious why that's such a big deal

All right black holes ready like we thought they were black. They're not really black like yeah, and even if they're not black They're still mostly black even if they do ready exactly like for you know a Long long millions of years. They're gonna to be pretty much, you know, dark, dark, dark brown. But... Yes, exactly. And it pales in comparison to the accretion disk, which is around it anyhow. Right, right. Which exactly. So like, you can imagine being like, all right, that's cool. But like, with this idea in mind of like, things are real if they're invariant, when you look at what's really happening in the situation with like Hawking radiation,

these are particles that are being created at the horizon of a black hole. The horizon of a black hole is not invariant. So if you're outside the black hole, which means you're in like an accelerated state of motion from a relativity perspective, because you have to like keep yourself out, then there's a horizon. It's very real to you. If you fall in, you're an inertial observer in like a uniform motion.

You just sail right through. There's no horizon. It doesn't exist. So the horizon is not invariant. And what that means is these particles of Hawking radiation, which are created by the horizon, are also not invariant. So if you're an accelerated observer outside, these particles exist. If you're falling in, these particles don't exist. And so all of a sudden you have this scenario, which has never happened before Hawking,

where particles, which is supposed to be, like if you had to pick one ingredient of like, what's everything made of? What is stuff? Like, what am I? What is this? What is, right? It's particles. They're not invariant. So they're not ultimately real. And we were able to like cross that off the list. And that is a huge deal. It's just an example of like, being able to look at something that's like this really complicated physics that you might just be like, oh, all right, that's weird. And be like, oh, I see what's happening here. And this is a big deal. Yes. So this insight, is it what you would say allowed you as someone who doesn't have

a background in math or physics when ordinarily you need one of those to understand high level physics or ideally both. Is it this insight that which is real is invariant in any reference frame that helped you? Yes, 100%. So that was a serendipitous insight. If you were to engineer such an insight to someone who's listening, maybe that insight resonates with them, maybe it doesn't, but they're looking for such a level of insight. How should they go about getting this piece of information or this different perspective

that would align different views and align different pieces of terminology and help them grasp it? Yeah, that's really interesting. I mean, you have to figure out what question you're trying to answer. Because the question we were trying to answer is like, what is something? Right? We had come up with this idea of what is nothing, and now we needed to know what is something.

Which is another way of saying, what is real? What's the stuff of the world? And so by giving this definition, oh, something is real if it's invariant, then we had this way of cutting through all the complicated stuff and just seeing what we needed to see to answer our questions. So I think if you just have, maybe you have a totally different question, but whatever the question is, is going to define the thing that you need to look for, and then that's

going to let you cut through. Because if you're not trying to like do science as a working scientist every day in the lab is trying to like just do something. If you just like are trying to ask some kind of philosophical question about like, what does this all mean? Then the question should steer how you make your way through all the science.

Right, right. So there's this word that keeps coming up, philosophy or philosophers. So many people see philosophy and physics as distinct. Some people see them as overlapping. And those people tend to be philosophers of physics, surprise, surprise. So help me understand this amorphous perimeter between physics and philosophy. How do you see it? Yeah. So I don't think there's any real difference between the two. perimeter between physics and philosophy. How do you see it?

Yeah, so I don't think there's any real difference between the two. And I think the reason it seems like there's a difference between the two is because... Okay, so for the most part, we're all operating with a philosophy. If you think you're not using philosophy, you're just wrong. I mean, like, there's no way to- So Neil deGrasse Tyson is wrong. Amanda Gefter said it. Yes. That's important.

If you think you're not using philosophy, you're probably using bad philosophy. I don't think I'm the first person that said that, but I buy it. So like, for the most part, the philosophy that we inherited from like 17th century thinkers like Alain Descartes, like the start of, like for the most part, the philosophy that we inherited from like 17th century thinkers like Alain Descartes, like the start of, that was the start of modern science, it came out of a philosophy, like very specific philosophical ideas. That philosophy underlies most of everyday science and in most of our everyday lives, which is like where we can use classical physics, that philosophy works well enough. And so we think it makes it seem like you don't need philosophy or you could do science like independent of philosophy, but it's just because your

philosophy is like good enough that you don't think you can like keep it in the background and not think about it. And what happens when you get to like starting with relativity, but then like even more so in quantum mechanics, you find yourself in these places that are very far from our everyday experience. So like, you know, extreme gravitational situations, speeds very close to the speed of light, or scales that are like, you know, getting comparable to like a plank length.

Right. At those, in those regimes, it's not just the physics that breaks down, it's our philosophy that breaks down. That 17th century philosophy doesn't work anymore. And so all of a sudden you feel like you, oh my God, I have to confront not only my understanding of physics,

but also my philosophical assumptions. And it's the reason you have to confront both is because they're all mixed up from the beginning. It's just that like you were able to pretend that they were separate. So I think, you know, and Bell's theorem, which we were talking about is like a perfect example. Like that's like a key result in quantum mechanics, right?

And that led to like, it's not just philosophical, it's like it led to quantum computing, quantum cryptography, teleportation, like all these quantum technologies that we have that came out of work from Bell's theorem. But Bell's theorem is a theorem about realism and locality, which are metaphysical philosophical assumptions that you're making about. So you're testing your philosophy and finding this philosophical worldview can't hold.

And then like, where do we go from there? So like, is that physics? Well, yeah, because you have to run a physics experiment. But is it philosophy? Yeah, you're because you have to run a physics experiment. But is it philosophy? Yeah, you're testing metaphysical assumptions. Like, there's no way to distinguish the two at that level. So I really think that the big takeaway is, like, they're always in combination with one

another. And honestly, like, all the best, deepest thinking physicists like Einstein and Bohr and Wheeler, that's how they were thinking. They were thinking about the philosophy and the physics together because you can't separate the two. And if you do, then you're just working under all these assumptions that you're not acknowledging, basically. Okay. So you're just philosophizing with physics, it's just that you're unaware of it. Yes. I see.

Okay, so let's continue philosophizing. There's a phrase, quantum state, which most people think of as the wave function. So that's an embedded question to this, you can distinguish the two if you like. But some people say the quantum state is informational. Some people say the quantum state is knowledge-based or epistemic is the fancy word or that it's belief-based or doxastic is the fancy word. Or they'll say that it's metaphysical, like there's something real that it corresponds to. So information, knowledge, metaphysical and doxastic, so belief-based. What would be the difference between these

for quantum states? Like different interpretation how different interpretations see yeah What is meant when someone says the quantum state is just informational or someone else says no, you're wrong The quantum state is epistemic. No, you're wrong quantum state is doxastic. No, you're wrong. It's actually metaphysical Yeah, yeah I mean, this is like the thing that all these different interpretations disagree on is exactly, like, that's the heart of it. It's like, how do you understand the quantum state or a wave function? So, like, if I take it to be a metaphysical thing, like, there's

actually a wave function, like, that is, you know, reality, is this wave function. Well, then you're like an Everettian, a many worlds person. So the idea is like, the universe just is this quantum state that's like evolving in this Hilbert space, which is, you know, this mathematical space. And it's just this, you know, vector in Hilbert space. And that's all there is.

So it's a realist view. It's a realist view, yes. Is that what you said? Realist view. Yes. So paradoxically enough, even though it sounds the most anti-realist of almost any of the interpretations, the ever-reading, the multiverse from quantum mechanics is a realist interpretation of quantum mechanics.

Yeah, it's a funny, like, yes, that's definitely correct. I mean, it's taking the wave function, this mathematical object, to be the real thing. Like, sort of ironically, that ends up making, like, all the stuff that we would normally sort of think of as real in our everyday lives not real. Yes, like, interestingly enough, in the Everettian case, unicorns are real. So it's just there would have to be some other universe where... Some other universe. Yes, yeah, right. Sure, sure.

But unicorns are actually real. And so it's quite unintuitive to call it real, but in the technical sense, it's a realist interpretation. Yes, yes. Yeah, if I think it is... I mean, so objective collapse would be another theory that's realist in that way, where you would say the quantum state is a real thing, or at least is a representation of a real thing. Uh-huh.

No, I think they would say the quantum state is a real thing, the wave function is a real thing. The wave function is a real thing. But at certain scales, like for whatever reason, either like gravity comes into play, this is what Penrose would say, or I don't know if there's a certain amount of decoding. I don't know these theories well enough to say, but like at some, for some reason, at some scale, this thing which is actually real actually collapses, and then you get some, some classical outcome in some sense. So that's another way of taking it to be real without being like ever ready and about it. So if you're never ready and you say it never collapses, it's just like the

wave function is eternal reality. Great. Now, the information people would be who? Some people say the quantum state is just about information. Maybe it's a subset of knowledge or a subset of belief. I mean, I think probably Carlo Rovelli's interpretation of relational quantum mechanics would be that sort of a thing where you say, I mean he would say, this is also a little related to Everett, where quantum states are relative states. So in Everett, like the big wave function, the ultimate one is real and absolute and invariant,

so that's the real thing. But then there's all these like relative wave functions within that. And so then Ravelli does away with the big real absolute thing, but just deals in relative. So the idea being like you and I don't have to have the same wave function for the same object. So I can describe an electron with a wave function. You could describe an electron with wave function, but based on the information that we have about the electron, if we have different information, we can give different quantum states for that thing. So I think that would be a very information-based approach. And this becomes really relevant

because there are these paradoxes like the Wigner's friend paradox. Yes. If you don't mind, can you outline Wigner's friend? Yeah. So it's this very mind-bending paradox where let's say, okay, you're my friend, Kurt, and you go into a lab and you're going to measure, you have a qubit, so like, you know, a quantum system that can be in one state or another, and it's an electron that can be spin up or spin down along some axis.

And you're going to make a measurement and say, you know, the electron spin up or it spin down. But I'm Wigner and I'm standing outside the lab and the lab is like a completely isolated system. So from my perspective, quantum mechanics should tell me that you as a physical system and the electron as a physical system, if you interact, you just become tangled with each other and you just end up in this big superposition of Kurt has seen the electron spin up and the electron is spin up plus Kurt has seen the electron has been down and the electron is down and then I can make a measurement and then I'll find like one of those or the other.

Um, so it's a scaled up version of Schrodinger's cat. It's just instead of the cat, it's you. And then you have another friend who's wondering, well, what's going to happen with the superposition? Like the cat's in the box, but then Schrodinger's in a box too. So yeah, it's like these nested measurements and like you, you, what you realize is like the friend can assign one state to the thing.

Like the friend says the electron has spin up, that's the state. Whereas like Wigner is like, no, the electron's still in a superposition of up and down. And so is the friend. And so then you're like, well, if the quantum state is supposed to like say what the state of the electron is if the quantum state is supposed to like say what the state of the

electron is, whose quantum state is right? Because I have one and you have one and they're different. So it sort of points to this fact that you probably can't treat quantum states as not relative and sometimes as being absolute like this is the quantum state of the electron. And so different interpretations have to get around this in different ways. And so like many worlds, like Everett would just say, well, no worries, like in one universe, you know, one outcome happens, in the other universe the other outcome happens, and we're always going to end up in the universes where we agree on our things and so like you just sort of sweep all the disagreements into different universes and then it's fine

but you know or you could have objective collapse people would say well a friend is a big macroscopic system and when they make the measurement the thing actually collapses and so Figner can't really describe it as being a big superposition, because that would just be wrong. And Cubism... Yeah, okay. Let's get to it. Basically, what I was going to ask is, do you have a favorite interpretation? But maybe you're about to answer that.

I'm sympathetic to Rovelli's relational quantum mechanics. But Cubism, I think, would be my, like, preferred. Yes. I don't, you know, as a journalist, like, I'm supposed to be, like, neutral. Trying to give this classical third-person story of, like, what's really, what's the real state of the electron, I think it's just the wrong question. And again, it just goes back to these, like, 17th century philosophical ideas that we have about how reality

works. And so I would prefer to not suffer from long classicality and just say, you know, the world is quantum and so I can write down one quantum state and you can write down another quantum state. So what Cubism says is my quantum state is not a description of the thing. So if we're talking about Schrodinger's cat and I say, I'm going to write down a quantum state that has the cat in a superposition of dead and alive. That is not a description in Cubism of the cat. That tells me nothing about the state of the cat. What it tells me is about the state of my various degrees of belief about what might happen when I interact with the cat.

So it's a very different story. It's not describing the cat, it's describing my beliefs. And then, but the sort of interesting content comes from the fact that while I can have whatever beliefs I want, my beliefs have to be related to each other in a consistent way. So it's not completely unconstrained. It's not like, well, I believe anything I want, you know. What happens in cubism is the Born Rule, which is this like sort of fundamental rule in quantum mechanics for how normally the Born Rule is taken to be like how you get probabilities out of the the wave function. So like you square the amplitude of the wave function and that gives you the probability that's the Born Rule.

Cubism sort of mathematically rewrites the Born Rule in terms of just how different probabilities for different measurements you can make on the same system relate to each other. And this is a really, really interesting move because what it says is like, the difference between quantum mechanics and classical mechanics is in classical mechanics, I can measure anything of a system.

I can measure its position and its momentum. No big deal. In quantum mechanics, you can't do that. There's certain measurements you can make that preclude you from making other measurements at the same time. And that ends up being like really fundamental. That's how you get the uncertainty principle and all this stuff. So that's the like central difference.

And so because I can make, you know, if I'm Vigner, I can measure, I can open the lab and then say, hey, Kurt, what did you get when you measured your electron? That's one measurement I can make. Or I can measure the whole you and the electron in like a superposition basis and get an interference pattern. So I can do these different types of measurements,

but I can't do them both. And so my beliefs about what I think I'm gonna see when I do one type of measurement is constrained by how it's related to the beliefs about what I could do if I take these other measurements. And that constraint ends up being in cubism like sort of the real content of quantum mechanics. So it's just really interesting because it's a totally different way of looking at the physics. Well, the word belief here must be used in some abstract sense because if I was to ask my mom, mom look I have a quantum mechanical experiment.

It's either going to be spin up or spin down. What are your beliefs about this? What are the probabilities you're assigning to this? She's going to cook me food and she's going to think that I've lost my mind. It's a good mom. Yes, exactly. She'll have no idea what I mean. I said the word quantum mechanics. She has

no beliefs about that. I said spin up, spin down, she doesn't know. Maybe she would say 50-50, but that may just happen to be actually what the probabilities are, but it could be 75-25 or what have you. It could be 99, whatever. So what is meant when we say, look, the wave function represents our beliefs. We didn't have any beliefs about wave functions prior to wave functions being invented in the 1900s, and presumably the world was still operating prior to then. So what is meant by the word belief? Yeah, so what's sort of remarkable is it really just means belief.

It means like a numeric, it's a belief that you can put a number on. So I mean, that's like the bare minimum, I guess. But it really is your belief. So it could be your mom coming to it if she's willing to put some numbers on it. The thing is that the born rule, what she has to do is say,

okay, I believe, you know, 90% that this would happen if I did this, I believe 10% that this would happen if I did this, I believe 10% that this would happen if I did this, and I believe 20% this would happen. But then if she plugs all those beliefs in, the born rule is going to either say, you know, proceed or like stop and rethink. So if it doesn't fit this equation, it Born Rule's going to say, hang on, your beliefs are not self-consistent. So you're not just referring to that they don't add up to one.

You're referring to something else. It's related to the fact that they don't add up to one. But it's, yeah, they've rewritten it in this way that they have to, yeah, OK. So the fact that they have to add up to one is like the law of total probability, right? If the world were classical, that would be the whole constraint. You would just need the law of probability, total probability. The Born rule is a slight addition to the law of total probability. So it's classical probability theory plus

this one extra constraint, which is like an empirical fact that comes from the fact essentially that like Planck's constant is not zero. So again, it comes from the fact that our probabilities don't add in the way that they did classically. Like that's what we see in the double slit experiment is like your probabilities. Right, this interference with the probabilities. they did classically. Like that's what we see in the double slit experiment is like your probabilities. Right, this interference with the probabilities.

Yeah, they interfere. And so Richard Feynman was like, this is the whole mystery of quantum mechanics is like, why do probabilities not add in a classical way? It's similar to like the whole mystery of relativity is like, why do velocities not add in a classical way? So you say, okay, what I have to do to make my beliefs consistent is it has to conform to the law of total probability plus the born rule.

Yes. Now, Amanda, I still don't see how this helps my mom because my mom will say, okay, okay Kurt, okay son, 65, 25. And I'm like, mom, that doesn't add to one. We'll normalize it, Mom. She's like, Okay, I don't know what that means. And then she'll just throw out some other numbers. How is she supposed to know if it adds up to the born rule? How am I supposed to know? It can't be belief means belief in- It does, though. It does. Yeah. Okay, help me through this. This is the amazing thing about Cubism is like, they mean what they say. It really is.

thing about cubism is like they mean what they say. It really is. So the idea is the born will is going to say, look, if you were betting, if you were placing bets, like think about it, like you're betting on like the outcomes of all the different types of measurements you can make on this system. You're saying like, if I choose to measure a position, I'm going to get this. If I choose to measure momentum position, I'm gonna get this if I choose to measure momentum I'm gonna get this and then you're putting like a dollar amount Sure, unlike each thing that you could do if you violate the born rule It means you've you've subjected yourself to a sure loss No matter what you do, you're gonna lose money. So your only goal here is to just Not have a sure loss. You want to just like adjust your bets so

that you're not open to just losing no matter what happens. So if your mom comes up with some numbers and you're like, hold on, this doesn't fit, one of these has to be a little lower, let's say. And then she can search her soul, this is how Chris always says it, she can search her soul and make a decision, you know what, I'm gonna put more on this one, a little less on this, she tweaks it. That's it.

Nothing compels her to believe any particular thing, but quantum mechanics compels her to make her beliefs coherent with one another. And this is a, you know, they emphasize this in Cubism, this is a normative rule. So this is not an ontological rule. This is not saying like this is how the world is. It's saying this is what you should do as an agent in the world who is trying to bet on the outcomes of your measurements.

And that is the whole story. Yes. Chris Fox is throwing some holy water like quantum mechanics compels you, quantum mechanics compels you. Okay, so let's imagine he's doing that to my mom. But it would take two years before she was to articulate by chance some set of probabilities that would happen to align with the Born rule yet the universe is still moving and trucking along and

presumably at any given instant we're making billions of Quantum mechanical measurements and observations and so on so this is happening under the hood It's not just physicists in a lab writing it down when I'm looking at you There are many quantum mechanical effects occurring and this desk here and same with you and the people listening. So at no point are the people who are listening making beliefs about quantum mechanics consciously. In fact, some of them are finding out about quantum mechanics right now. So help me understand how does a belief conscious belief or what we ordinarily, colloquially think of as belief, have anything to do with a quantum system?

So I think the question comes from usually seeing quantum states as being like reality or a description of reality. And then you're saying, well, like, how could reality be my beliefs? description of reality and then you're saying well like how could reality be my beliefs, right? But here in cubism, it's not that's not what reality Your quantum states are just tools that agents use to make better gambling decisions About the measurements that they're gonna make and that's it. I mean, there's a sense in which cubism they they say like it's a small theory. Nobody's saying that's what reality is.

They're just saying quantum theory, everyone is confused by quantum theory because they think quantum theory is describing reality. And quantum theory is not describing reality, it's describing how we ought to bet on our measurement outcomes. And if you're not doing a complicated like double-sit experiment or something, you probably don't need to write down a quantum state and you probably don't need to make these bets. And that doesn't mean the universe is going to fall apart. It just means you're not doing quantum account.

Like you're not an agent who's gambling on these things. So, okay, then you could say, well, hold on. Now we've just made this so small that like, who cares? But the deeper point is the fact that your beliefs have to be consistent with one another in this way, something about that mathematical structure tells you about the character of the world. So you're not learning about reality from the wave function. That's not what the wave function is doing.

If you want to learn about reality, you say, why should I bet this way? Why am I, why am I bets constrained in this way? That's weird. What kind of world is this such that that would be the best way to gamble on measurement outcomes? And then that's the road in to asking these kind of like deep ontological questions about reality. But the road in is not to say like, what is the wave function?

What does it represent? Nothing. It represents our degrees of belief about measurement outcomes. So cubism, it's the wave function is not describing reality, but that doesn't mean that it doesn't tell us something very deep about the nature of reality. So when we look at the fact that we have to organize our bets in this particular way. That's telling us something about the character of the world. So it's very similar to, like Chris Books likes to use this example of the euglena, which I think is some kind of microscopic organism, the euglena's tail. So you can look at the euglena's tail, and it's just a feature of the euglena.

It's not about the world. But the fact that this is a useful tool for the euglena to navigate its world tells you something about the world, like indirectly. And so the idea is supposed to be the same in cubism, that the fact that the born-role constrains our beliefs in this particular way tells us something about the character of the world that we're having beliefs about. And so what does it tell us? Well, this is something cubism is still trying to figure out, but the deep point seems to be that it tells us that the world is not divisible into subject and object in the way that we have thoughts and stake hearts.

So it tells us that reality is participatory in this really deep sense. It tells us that there's not just some way that things are sitting out there independent of us, but that we and the world together through these concrete interactions, these measurement interactions, are creating something genuinely novel. Sometimes the cubists describe it as like there's a spark, there's this novel little bit of creation, almost like a little big bang every time there's a measurement. And so it's not that, like Kurt, when you asked, wasn't the universe just going on before we were making bets and writing down these wave functions?

So the wave functions are not the reality and that, the Cubists would say, like, that's the mistake these other interpretations are making. It's not the reality, but the fact that we should structure our beliefs in this way does tell us that the reality has this character of subject and object not being like neatly and unambiguously divisible. So that does tell us something very deep. And then, you know, Cubism is hoping to go on with this kind of ontological project of trying to say more about the nature of that reality.

But it gives this participatory story because you can't say, you know, when you make a measurement, you can't say that you're revealing something that was already there. You're not finding out what was already there. You're not finding out what was already there. You're participating in the creation of that thing. But the key is also, it's not in you, right? It's in the interaction between you and the world. That's where the novelty is happening. It's not in the subject. Because again, the subject and object can't be like neatly divided in this way. And so, some people hear about Cubism, they say, oh, it's solipsistic because it's all about beliefs. And it's not just anyone's beliefs, it's my beliefs, right?

So if I write down a wave function, it's my beliefs, and they don't have to be the same as yours. And so people think that, they hear that, and they think like, because they're so used to thinking of the wave function as like representing reality, it's like, well, then it's only my universe and only your universe. And like, no, that's not what's happening. It's my beliefs and your beliefs. It's my wave function and your wave function.

But what arises through measurement is something shared between me and the world when I make a measurement. And what arises through measurement is something shared between you and the world when you make a measurement. And then if you and I are interacting with each other, we're creating something shared together.

So there's this participatory story. And sometimes I like to think about Wheeler used to tell this anecdote that I love. Just going back to John Wheeler for a second. So Wheeler liked to tell this story about playing a game of 20 questions. So he tells the story that he was at a dinner party and they were playing 20 questions. They would send someone out of the room and they would decide on a word.

And the person would come back in and start asking yes or no questions and they would have to have 20 questions to be able to guess the word. So then it was Wheeler's turn to leave the room and he leaves and when he comes back in he starts, okay, he leaves, he leaves the room and it takes a very long time it seems for them to decide on the word. And so then he goes back into the room and he starts guessing. He says, you know, is it an animal? And they say, no. And then he says, okay, is it green?

And the next person thinks for a second and says, no. You know, he says, is it white? And the next person thinks and they say yes. And this goes on and he's noticing that the answers are taking longer and longer each time. And finally he says, is it a cloud? And the person, you know, thinks for a long time and then everyone bursts out laughing and they say yes.

And it turns out that what the game was, was when he left the room, they decided that they weren't going to pick a word. They were just going to answer questions on the fly. But the rule was that whenever they answered a question, they had to have something in mind that was consistent with all the previous answers. So that if he like challenged them, they would be able to like come up with a word that this thing could be. So for Wheeler, this like was the like a perfect example of what happens in quantum mechanics because the point is the word cloud didn't exist before he started asking questions. But he didn't come up with the idea that it was a cloud because he started asking questions. But he didn't come up with the idea that it was a cloud, because he was asking questions in response to the answers

he was getting from the people. But they didn't come up with it either, because they would have given different answers if he had asked different questions. And so the word cloud was this sort of participatory creation that came about between, you know, the person making the measurement, the person asking questions of the world and the world responding in turn. And so

it's like, in the end, shared between all of them. That's super interesting. So this is Wheeler's idea of like a participatory universe. And this is really the kind of ontology or the kind of reality that Cubism gives you because you're asking questions about the world and yes you're structuring your wave function in terms of your beliefs and all of that but that's not what's happening in the actual measurement. In the actual measurement you're asking a question of the world, the world's responding back and the two of you together are like creating something new. So that's the real story that

like Cubism is trying to tell and the whole thing about beliefs is just a way of telling that story really, really consistently. And I guess the other thing I should add is, in terms of the Bayesian part of the story, yes, it's true that your beliefs can be anything you want as long as they're consistent according to the Bourne Rule, but they're informed by all your prior experiences. The whole idea of Bayesian probability is that you make a measurement, you get an outcome, and then you update your probabilities that you're going to assign. So you update your beliefs in reaction to what the world has given you. So the interesting thing here is like in terms of solving like the quote unquote measurement problem is that

like other interpretations, what they would call the collapse of the wave function, in cubism it's just an agent updating her beliefs, right? So she gets an outcome, changes her probabilities. That's it. That's the whole story of like the collapse of the wave function. It's not a big deal because the wave function doesn't refer to reality. But that means that like your beliefs, even though like you are free to believe whatever you want as long as they fit together in this way prescribed by the Born Rule, your beliefs

are not subjective in the sense of being like just, you know, made up in your head because they arise from your whole history of like prior concrete interactions with the world. And so in some sense, the beliefs already straddle that subject-object divide because they already incorporate these interactions that straddle, that divide themselves. And so I think, you know, it's personalist and it's important to say that, but it's also important to realize that like those beliefs, you know, you're not just like coming up with them in your head. You're interacting with the world and updating in response to that. And then like the last thing I should say about about cubism is it's not just the quantum state assignment that you give to a system that's personalist,

but the outcome is personal too. So again, this is what helps us get out of a Vigner's friend paradox is you can make a measurement and get an outcome, and it doesn't mean that outcome is true for me when I'm over here and I'm Vigner. So outcomes are personal, just like quantum state assignments are personal. And so in Cubism, to be consistent,

you end up with all these levels of personalism. But again, you don't want to think of it as being in some agent's head. It's not like the world's in your head. You're interacting with the world in a very real way. And the outcome is something shared between the people participating in that interaction, which is like you and the world, or you and another agent if you're acting

on each other. But anyone who's not in that interaction, like Wigner standing outside, this is not an outcome for Wigner. So it's personal in that sense. Okay. Let's go through a side door. With all these different interpretations of quantum mechanics, there are other foundational issues at the heart of quantum field theory, which is said to be the deeper theory.

Have you heard of some interpretation of quantum mechanics solving any of the foundational problems in QFT? Any of the interpretations? Yeah, any of them. I haven't seen any personally, but I don't know about the relationship between interpretations of quantum mechanics and the foundational issues of quantum field theory. In QFT, it's almost like you're already telling a kind of realist story about like what's happening in the world.

Cubism wants to just be like measurement. We're talking about measurement. That has to be the foundation of anything you're talking about. So I would think like, well, I don't know, tell me what you have in mind. Well, actually one of the interpretations, so Penrose makes some claims about quantum gravity. So then that has to say something about quantum field theory. But then there are other issues like how do we rigorously define the Feynman path integral? Or what about existence of mass gaps or problems with renormalization?

And it doesn't seem to me like interpretations of quantum mechanics have any bearing here. But it seems like they should to me, because quantum mechanics is at the higher level than quantum field theory. Quantum field theory is more foundational. So we're stuck up here trying to interpret when we should be over here interpreting. It's like the interpretation is going to set the terms for what you're counting as real, what you're counting as...

It's going to sort of set the really, really fundamental terms in which any theory that you talk about in physics then has to apply. So for example, people talk about in quantum gravity or something like, or not even quantum gravity, like talking about like, like vacuum fluctuations, let's say. Okay. So you have like, because of uncertainty, you have vacuum fluctuations, you have pair production of particles and things like, so you can tell this whole story. But really, if you're thinking in terms of quantum foundations and interpretations,

what are those fluctuations, fluctuations of? Because it's coming out of uncertainty. So is it fluctuations in your beliefs? Is it fluctuations in your knowledge and information? Because if you're saying it's fluctuations of a thing that's just sitting out there fluctuating, you're already either like fluctuations of a thing that's just sitting out there fluctuating, like you're already either like a bohmean, you've already picked an interpretation at that point.

Do you know what I mean? Yes. So the Cubist would say, Cubist would say, you got to talk about where's your agent has to be in the story from the beginning and what are they measuring and how are they betting on the outcomes of those measurements? So would the Cubists say that your beliefs are actually fluctuating? No. I realize I said that, but no. They would say that the fluctuations come from story, the uncertainty comes in with the fact that you can't make certain

measurements simultaneously. And I mean, that's what's happening, right? Like when you get like a vacuum fluctuation in the standard story, it's coming about because of this non-commuting nature of like time and energy, right? So you say, oh, on really, really, really short time scales, you can get these like huge fluctuations of energy. And so, but what you're really saying, that's like, again, it's like you're just trying to tell

a very realist story at that point, because what you're really saying is, if I were to measure the time, I could get this thing. If I were to measure energy, I could get this thing. And then those are related in this strange quantum, non-classical way. But like, the whole story has to be like, what are you actually gonna measure?

And you can't talk about like, what some field out there is doing independent of what you're measuring. Amanda, to get into some less, we'll see, it could be less hairy or more hairy ground. What is your view of consciousness? Oh boy, that's yeah, that's more hairy. My view of consciousness is related to all of this. Great. And let me try to think of the least painful way

of explaining it. To put a name to it, the view that I find compelling is usually called the inactive view or inactivism. And this is in the world of what's sometimes called 4E cognition. So this is like embodied, embedded, extended, inactive. It's related to ecological psychology as well. So anything that starts with an E tends to fall in this camp. And so, yeah, I would, of the ease, I would choose inactive. But can I give a historical aside for a second?

Please, please. Because I find that this really, really helps explain where I'm coming from. This idea that we have of consciousness was invented in the 17th century. Oh, okay. It does not, it was not always with us. And I think that's like a really key thing

for us to remember because it seems like, oh, that's just so intuitive, but it's not. This was like an, this was an invention. And it was invented mostly by Descartes, even though there were predecessors in going back to Plato and Augustine and stuff, but Descartes is the one I think we can blame most significantly. What you have to remember and what people seem to have forgotten is when Descartes came up with this idea that the mind is in the head and that there's this sort of first-person story, cogeto ergo sum, this whole thing.

He was not coming up with this to explain the mind, which was not yet a problem. He was trying to invent a new theory of physics. So the physics that existed at the time was Aristotle's physics. And when you look at that, there was no real subject-object distinction. So for instance, like, you know, we now, thanks to Descartes, make this distinction between like primary qualities and secondary qualities, right? And like subjective, objective. So in Aristotle, you know, redness or sweetness or all these things were not like in our heads.

They were just like part of the world. But also like objects did things because they had like internal motivation. Like things fell because they like year internal motivation, like things fell because they like yearned to be close to the earth. So there was, objects weren't really objects and subjects weren't really subjects. It was all mixed up. And Descartes came along and he had come up with Cartesian geometry and Cartesian coordinates. And he thought to himself like, if everything were just size, shape, and motion, if that's all that existed, then I could describe the whole universe just using my coordinate system. And I would have this new physics. But like, unfortunately, there's all this other stuff, like thoughts and ideas and colors

and sounds and like, and none of that fits that story. So I need somewhere else to put them. And then he has this realization of like, oh, you know, I can doubt everything that I see, but I can't doubt my doubting. So there's this difference between the things that are like self-knowing and then the things that are only known. And so he creates this distinction between like the kojito, which is like the self-knowing, self-referential thing, the I, the capital I, I,

and the objects in the world. And so then he takes all this subjective stuff that doesn't fit in his coordinate system and he sticks it in the head. And then he takes everything else that's left, it's just objective. And so he write like the words, Kojito ergo sum, like this first appeared

in a treatise on physics. This was a move for physics. And so, and his physics wasn't great, but it did displace Aristotle's very quickly. And then Newton came along and Newton fixed it basically, and it became Newtonian physics. But Newton's physics would not have existed without Descartes. And so it set the stage for classical physics. And at the same time and in the same move, it invented this idea of consciousness as being something self-knowing

that we experience directly, but the world we only experience indirectly, and that there's qualia, and that there's objects, and those are different. This whole story that we tell about consciousness came from this one move, which was to say, I'm going to make a split between subject and object. And so you get from this one single move, subject-object split, you get consciousness and you get classical physics. And so when quantum physics comes along and goes, wait a minute, classical physics is wrong. This story doesn't work.

And if you look at like Bohr and you look at like the origins of quantum mechanics, like what they're realizing is the issue is that subject-object distinction. The world cannot be divided up that way. You can get away with it for so long, but when you look really, really closely, you get this little H-bar Planck's constant which tells you this is measuring like a subject-object overlap that you can't get rid of. And so all of a sudden that story was wrong and you need to remove that subject-object split. But where we've ended up is in this really confused place where we kind of see that on

the quantum mechanics side, but we're doubling down on the consciousness side. So we're walking around with this very incoherent metaphysics where we're saying, okay, yeah, like in quantum mechanics, like objects aren't really just objects, but subjects are still really subject. Like, it just doesn't make sense. Like if you, we need to be like that split was the wrong move. You can't carve the world up that way. It doesn't make sense. Like if you we need to be like that split was the wrong move You can't carve the world up that way. It doesn't work. And

So you have to fix the story you've told on both sides Yes, and so what fixes it on both sides? Okay, so from my perspective Cubism fixes it on the physics side and an activism fixes it Inactivism fixes it on the physics side and inactivism fixes it on the physics side. And do they play well with one another? Is inactivism somehow interpreted in cubism or vice versa? So they're doing very different things, but when you really look at what they're doing, they're both just trying to, like, inactivism is trying to understand mind without the subject-object

split and cubism is trying to understand the world without the subject-object split. Yes, I see, I see. So Carl Friston has something called active inference. Is this related? Sort of. I think it depends how you interpret his stuff. Interesting. There are interpretations of Karl Friston. Of his interpretations. That's another podcast. Yeah, right. I mean, I think the way it's usually talked about is, he talks about these Markov blankets

as being the split, which I think that's very cool. But then it's like you're trying to trying to infer, like he usually refers to it like hidden states on the other side. And I think in like these other stories, you wouldn't want to talk about like hidden, like the world's not hidden to you. Like I think that idea that like I'm in my head and all I know is my own experiences and the actual reality out there is something hidden that I have to infer Like I think that's already a problematic story

But I think probably you could talk about free energy without using that kind of language and then maybe it would be fine so the solution to not Dichotomizing the world into subject and object. Yeah. Is what, everything is object or everything is subject or it's something else? Something else. So I think like, I think that's the problem we've all gotten into is like Descartes was like,

here's the dinner menu. You may have subjects and objects. And then people like are like, well, wait a minute, like this is dualism, I don't want two things. Like that's crazy. you may have subjects and objects. And then people are like, well, wait a minute, this is dualism, I don't want two things, that's crazy. I will just take subjects. Or they're like, I will just take objects. But then there's a few people that are like,

you know what, maybe these aren't the options. Why do I have to pick one of these things? Yes, interesting. So I think that the issue is, I don't think it's, there's a reason those are the options, which are like in any perception, you have to make a subject-object distinction. In any quantum measurement, you have to make a subject-object distinction. But the difference is you want to say, in a participatory way, I am enacting that distinction as my way of making a perception or as my way of making a measurement.

You don't want to say that distinction is given to me from the beginning in some absolute sense. I know I'm speaking very abstractly here, but I think that's the issue. You don't want to take the subject-object distinction as pre-given and absolute and fixed. So you definitely don't want to say it's all subject and you definitely don't want to say it's all object because that's already assuming that distinction is fixed. You want to say it's movable and in any given situation I can carve it up in different ways. Does that mean you can carve yourself out of the situation? Can you carve it up in any way in the sense that it's just assigning different weights

to subject and object? So I'm going to think of this situation as 99% subjective, 1% objective, or I could think of this situation as entire 99.999. That's minimizing my own contribution to the point. You could make it 100% objective. I've never thought of it that way, but I think that sounds right to me in some sense. I mean, you can't, if you take yourself out of it entirely,

you're dead in some sense, right? So like you can't do that. Bohr loved to talk about like a blind man with a cane, like a stick. And he would say, if the man holds the cane very tightly, he can use it to like touch the world. And in that sense, the cane is part of the man, and so it's on the subject side of the subject objectified.

But he could also hold it very loosely in his hand and consider it as an object and then he's not touching the world with it, he's touching the cane. And so now the cane is on the object side of the subject objectified. So it's the same cane, but it could be on either side. So that division is movable. And Bohr thought that was really the essence of quantum mechanics was that that division is not fixed and in cubism this becomes important too because The cubist says the measuring device is an extension of the agent

So so the The line can be drawn You know very differently in a given measurement scenario depending depending on how I want it to be. Okay. I'm much less confused. Good. That's interesting.

In the same way that if you start writing, you become accustomed to writing, the pen is then an extension of you. You don't even think of the pen. You don't think of your individual fingers on the keyboard. So the keyboard is akin to an extension of you. So some people would say it's not just akin, it is. So John Verbecky may say that, that's a cognitive scientist who is also an advocate for 4E cognitive science by the way. You have just outlined that the cubist view is that in quantum mechanics we're making

measurements, the measurement device is at that point an extension of you. Actually, I'm still confused. So I'm going to get some clarification on that. Absolutely. This is how I feel every day. I'm like, I almost know. Exactly. Okay.

Well, anyway, Amanda, thank you for spending so much time with me. I appreciate you taking time out of your day for this and Amanda, please tell me what is it that you're currently working on? for this and Amanda, please tell me, what is it that you're currently working on? So I'm working on a project that's been 10 years in the making that is related to all of the things that we're talking about because it's basically, I was telling you about Wheeler's journals. Yes. In John Wheeler's journals, I found reference to the student of his named Peter Putnam,

who I had never heard of. And I sort of went down this rabbit hole of like, who is this guy? Because Wheeler students were all like, you know, Christopher Feynman and Hugh Everett and these like very famous people. And it was like, who's this Peter Putnam? And long story short, I found that Putnam was, you know, the student of Wheeler's, he did his PhD in physics, but then he became very interested in how the mind works and came up with his own theory of mind.

And then he and Wheeler throughout their lives had this like really intense correspondence because Wheeler's trying to understand like the nature of quantum mechanics and like what role the observer plays and like what's an observer and then Putnam is like working on a theory of the observer and they're trying to like put these pieces together. And in the meantime, Putnam ends up moving down south in rural Louisiana and working as a janitor and living in total poverty and writing all these papers but not publishing any of it. And then he's killed by a drunk driver in the 1980s and when he dies, he leaves $40

million to the Nature Conservancy, which it turned out he had made in the stock market but never touched any of it. And then his papers, all his stuff, ended up like tucked away in this like storage unit. And so I found all of his unpublished stuff and I've been trying to reconstruct like what was his theory of mind, which I think is very related to these inactive embodied ideas that we were talking about and trying to relate that to Wheeler's participatory understanding of reality which is very related to cubism which we were talking about and how to piece those stories together. Amanda thank you for spending so much time with me. You're very welcome. I hope I didn't just add to confusion.

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