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Jacob Barandes Λ Manolis Kellis: What 100 Years of Quantum Physics Got Wrong
February 4, 2025
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Every time a physicist says to you quantum physics has demonstrated that a particle can be in two places at once. They are lying to you.
Biology, consciousness, causation, and quantum physics, what is the connection? My name is Kurt Jaimungal, and this was part of my three-day tour of Harvard, Tufts, and MIT, where I recorded five podcasts, including a frolicsum salon discussion hosted by MIT's Manolis Kellis, one of the world's top computational biologists.
A few weeks ago, Manolis graciously offered to host both me and Harvard's theoretical physicist and philosopher, Jacob Berandes, for a salon on the nature of quantum theory. This event is unlike any podcast that you've seen or heard due to the extemporaneous dynamism of the over 70 people who showed up within just a few days' notice. The other podcasts from this tour feature Michael Levin and Anna Chaunica, as well as a separate discussion, an over seven hours long one, with technical and concrete information regarding Jacob's approach
to indivisible stochastic processes. Subscribe to get notified. For now, enjoy this jazz-like conversation regarding fundamental questions such as, do quantum fields actually exist? What's the problem with many worlds? Do parallel universes solve anything? And what makes observers like you special?
So Jacob, can you just give us a little introduction into what you do? Tell us like maybe two, three minutes about your journey. How did you get where you are? What are you passionate about? What are you the most excited about? And, you know, what do you think we should really, you know, if there's one thing to know, what should we know?
When I was a little kid I was really interested in the philosophy of mind. I didn't know it was called the philosophy of mind but later I would realize that's what this was called. I was confused about why we existed and the nature of consciousness and all these sorts of questions. I had a knack for math and I went to college and I thought well if you like math and you like deep questions then you do physics and so I studied physics and I had a good time
And then I went to graduate school and I worked in high energy theoretical physics. I did my PhD in theoretical physics and you know, I Had some difficulty connecting with the research that was going on in high energy theoretical physics it it didn't it didn't connect with me at some deep level and You know over, you know my PhD Halfway through toward the end. I began to reconnect with my earlier interest in philosophy in particular philosophy of science
I got very interested in a whole bunch of different areas in philosophy of science, in an area that we would now call philosophy of physics, and in related areas that are closer to the sciences like quantum foundations. So when I finished my PhD, I started doing research in the area, writing papers. My partner in crime is right here, David Kagan. We were close friends and collaborators.
And I began interacting more and more with the community of people who work in philosophy of science, and I realized this was my calling. What is philosophy of science? Ah, good question. What is philosophy of science? So, broadly speaking, and this is philosophy of science, it's not exactly, I'll say what I do in a moment, but philosophy of science, broadly speaking,
has several parts. One part is the study of what it is that scientists do. The ornithology of science. Scientists as birds and we observe their habits. There's the old line that this form of philosophy of science is as useful to scientists as ornithology is to birds.
It's actually a valid point, I have to say. It might be helpful to the observers of the birds. It's true, but when bird populations are suffering, you do want to call an ornithologist. I'm not saying that scientists are doing... Birds don't try to do ornithology. That's very, very good, yes. But the other major side of philosophy of science is to go deep into our best, most successful scientific theories,
understand how they work, and you know, either try to glean an understanding, a new way of thinking about traditional questions in philosophy, in particular areas of philosophy like metaphysics, from what are best- And what is metaphysics? Okay, yeah, so good, good question.
I'm such a great questioner. These are all great questions. Have you guys heard of the program called ELIZA? Yeah. It's at that level. You've learned well from ELIZA. Tell me more about metaphysics. ELIZA is this very old computer program. It was a computer therapist and whenever you would tell it, it would just say tell me more about and it would just insert whatever you said.
Metaphysics is a very broad area in philosophy. It's concerned with some of the most fundamental questions about the nature of existence.
There are areas of metaphysics that in philosophy of science we tend to spend a lot of time thinking about. These are questions like, what is the law of nature? What are laws of nature? How do we identify laws of nature?
And our laws of nature are things that are out there in some sense, or are they things that we devise to make sense of the world around us? What is probability? When you say that a particular thing in the world is associated with the probability of 0.72, what information does that convey? Now, you pick up a book on statistics.
I feel like we should have some metabiology because metaphysics is extraordinarily powerful about understanding the nature of the universe but there's something about biology as well that's so fundamental as to why are we thinking? Why is there a soul?
What's the neuronal basis of consciousness? Come here! Wolfram has his metabiological framework, and so same with Gregory Chaitin. Say it again? Wolfram, Stephen Wolfram has metabiology, and Gregory Chaitin as well. That's very, very interesting. Good, good, good. Yeah, yeah, yeah. So, but I should say that metaphysics has the word physics in it, but it's not physics.
It's, you know, the things that metaphysicians, and so metaphysicians, they're not called metaphysicists, they're called metaphysicians, just to make very clear, they're not, they're not physicists. That's so confusing, because metaphysicians are all other things. It's very confusing. Yeah, the name just goes back to the fact that there's a chapter in Aristotle, it comes after, and meta just means after, it's just, it's the next chapter. If anybody should know, it should be the Greek guy.
Physics simply means natural. Physici is just natural. So the natural sciences is actually physics. Well, I mean, to the Greeks, I'm sorry. Physics used to be called natural philosophers, right? I mean, that's what they were called. But so metaphysics is concerned with questions that are broader in, you know, than any particular science and that are relevant to, you know, the questions that metaphysicians often. So here's a really like intense metaphysician talk.
Is there a, you know, what is the precise way to characterize the difference between hypotheticals and counterfactuals? This is the kind of thing that, literally, these are the talks that you'll see. They are very different things. And we know they're different things, but, you know, to spend a lot of time thinking carefully about it, that is the kind of thing that some metaphysicians do, right? Can I hear what Manolis thinks is the difference? Yeah. So I'm going to come back to that in a second, because I have a few more things to ask, which
like might fall into metaphysics. And I hope we get to those questions. You don't have to answer them all right away. And I also want to get to Kurt in a second. But one of the questions that I have is like, does it matter that we exist? In other words, if you look at the whole biomass of the universe, the earth is insignificant and humans within it are, you know, even more so. But if you look at the amount of consciousness or the amount of theorems or the amount of, I don't know, heartbreaks,
in the universe, then we play a very big role, at least in my view. And what's really interesting is that at the heart of quantum physics lies an observer. Some would say. Some would say. Some would say. So basically what I want to ask you is does it matter to the universe that we are here?
Does it matter that we're here?
And introduce yourself. By the way, this has already started. Don't think that this is the first question. We're in it. You can all ask a question. This is an intellectual exchange. This is a salon. People should be asking questions. I want everybody to feel that they should be answering as much as asking. I may pick up the thread, right? So this is a reference to the anthropic principle. The anthropic principle was coined by Brandon Carter, who is a theoretical physicist who works on deep questions in gravity.
you know, a colleague of Stephen Hawking, and the anthropic principle is, it comes in various gradations. One version of it is just, you know, when you look around at the world and you see that it has certain features, some of those features may be the way they are because they're laws of nature. Some of them may be the way they are just because they're random contingent facts, but some of them may be the way they are because of a selection effect.
You know, for example, we look around and we're like, oh, the ambient temperature around us is this nice, this nice temperature between freezing and boiling. Is that because of some deep reason? And the answer is it's entropic. I mean, we wouldn't as, you know, carbon water-based beings be in an environment that had a temperature that was markedly different from that. So the fact that we see that is an effective of us being the humans observing it. And that's called an entropic effect.
I want to build on that a little bit. I volunteer for my kids' schools, and one of the things that I volunteer to do is to go answer all of the questions that they have about the universe. So, small task. A small task, yes. So for three weeks, they gather questions, and you know, then I prepare for that talk more than I have to admit any talk that I've given in the last 15 years, at least. And one of the questions was, why is the sun so bright? And I used exactly the anthropic principle to basically say that
If we lived in Jupiter or even in Neptune, the sun would be just as bright. In other words, there's a range of brightness that our eyesight has evolved towards. And at the tail end of that distribution lies the sun. And there's really no selection to be able to see the sun clearly. And I'm guessing that so many other things just feel completely natural.
because we basically evolved here. But there's another aspect which I thought you were going to get to, which is... Well, you didn't interrupt me. I might have gotten there. We only have an hour for, you know, three hours worth of material at least. It's okay. So what I want to ask you is, what I thought you were going to get to is not just that, yes, biology is well tuned to the physics that we kind of like and enjoy,
but of course there's there's a weirdness about the fact that for example water when it freezes rises to the surface that is fundamental to why life exists at all and i think that's a you know more fundamental principle than the fact that the temperature is well suited to our evolutionary adaptation but what i what i what i thought you were going to get to is that as we observe the universe we're observing perhaps a tiny fraction of maybe the dimensions that exist out there and
There's the laws of physics that we have come up with are a tiny subset of the things that are observable to our biology, if you wish. Am I completely off on this? No, not at all. So one way to visualize just how epistemically limited we are as beings is another Greek word. Yeah. Philosophers like epistemology. So sorry, I have to say that epistemic was one of the four virtues in the library of Celsius.
in what is now Asia Minor in the old Greek. What were the other ones? The other was Arethi, which literally means virtues, to be virtues. The other one was Sophia, wisdom. It's really nice to have episteme, which literally means science, but basically the study of things.
Yeah, so one way to visualize this is to borrow from a geometric tool that was introduced by Herman Minkowski. So Herman Minkowski took the nascent theory of special relativity that Einstein was developing in the early part of the 20th century and provided this geometric picture he called space-time. And so space-time, you visualize
You know, think of graph paper. Graph paper, the horizontal direction on the graph paper is all of space and the vertical direction is time. And you can visualize everything that ever happens as lying somewhere in this diagram. So each of you is a worm in the space-time diagram, a worm that begins somewhere down here and extends some length up here and then no more.
I think about it slightly differently as cones into the possible past and the possible future for every point. The fastest anything can communicate a signal through space is at the speed of lights.
And so if you take any point and consider the light rays that can extend from that point or the light rays that reach that point, they form these things called light cones. The light cone gives you a way to visualize what can influence you in a causal way and what you can causally influence. And also when. What information can get to you. And also when. And also when. Yes, exactly. Basically whenever the cones intersect. That's right, yeah. So think of it like this.
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Can we bring you back to quantum physics? We do a very fascinating first exit
We've hit a few more highways since then. We've hit a few more highways. Well, I have a question about quantum physics. Nice to see you, Kurt. Kurt, can I ask you a question first? Can I ask you a question? So Jacob came here to talk about quantum physics and we've been talking a lot about a bunch of different tangents but
I asked him a few very simple, definitional things, and you are the host of a podcast called Theories of Everything, or is it Theory of Everything? Theories. And I'd like you to just very briefly introduce yourself as to how did you get to where you are, why the heck did you start that podcast, and what have you learned also that shook your own worldview? Because one of the goals of your podcast is to disseminate knowledge.
to the rest of us. But another one I hope is for you to also, you know, I don't know, figure it out. And there's very few people who are so actively asking so many extraordinary folks about that one question that unified us at all. So tell us, what does Tears of Everything mean to you?
And are there some surprising things that you did not know that were like, whoa, realizations that happened on your podcast? Almost weekly. So as for how I got into this, firstly, any story I concoct will be a confabulation because of course, after the fact, you can make up, you can find the path. I like that the root of both fabulous and fable are the same. But since I was a kid, I've been interested in puzzles.
Abstract mathematical puzzles and and I was always interested in math and physics. One time I was thinking about the nature of the universe and how did anything come to be and I was asking my brother who was studying math and physics and I believe the University of Toronto no or UBC at the time.
So I was eight years old and we were walking to Blockbuster, if you remember Blockbuster. And I asked him about how could anything come, how did something come from nothing? And then he explained to me what quantum fluctuations were. And then I remember going home and looking at the ceiling and then thinking, okay, then there is no God. And I, and then I just became an atheist from that point forward. Sorry. Or if there is he rolls dice.
Well, okay, then there's no need for a God. Good, good answer. Good answer. In my eight year old mind. And then I remember telling some schoolmates about that. Then they're like quantum fluctuance. And then I remember feeling so embarrassed because they were like, what are you talking about? And then I never said the word fluctuation until I was 18 after that. Then I was great in math and physics in school. So I was encouraged and I went into that in university and I left that because I was doing standup comedy and filmmaking.
Yeah, so. Oh, and that's another story. After I when I was doing filmmaking, then the pandemic occurred and I thought, OK, I was watching some podcasts online. There's this guy named Donald Hoffman who has this theory of consciousness, at least supposedly a theory of consciousness that reproduces quantum mechanics, perhaps even gravity. I don't know if it's made that claim. But many people were interviewing him and they're just in awe of of Donald and
And they're not asking any what I would consider to be rudimentary questions that are slightly pushing, not even antagonistic questions. And he keeps making Donald keeps making reference to his papers. He's like, I can prove this in my, in my research. And then I was thinking, okay, so are there any people here who are
who are reading his research and then speaking to him and I couldn't find any so I thought let me reach out to him and read his research and then question him about that and it was a quite a technical interview so I treated the podcast like office hours and I was even going to call it office hours instead of theories of everything initially and that's how I still treat it like when I was speaking with Jacob yesterday we spoke for seven hours as if and you even have classes where well potential classes where they could be seven hours long they don't last that long but
I just go until the students give up. It's an endurance contest. The class can last that long but the students won't.
And I'm extremely interested in the nature of reality. What is this? You mentioned metaphysics, you mentioned epistemological limitations. And so one of the issues I have with anthropic principles is we're speaking about life as we know it. Now I know you have some claims about life as we don't know it, must be similar to life as we know it. I find that dubious. It must have similar properties. I hope not DNA. DNA would be such a boring thing if we find it elsewhere. Well anyhow, it's not clear to me that this is the typical state.
Red dwarfs last for trillions of years. Red dwarfs last for trillions of years. They don't know if there's some life form in the sun and the most typical life form would be a conscious agent in the sun or if we invent AI and AI takes over and AI has many trillions of times more conscious experiences than us and thus the most typical conscious experience is us being an AI or grey goo.
Don't know if this is the most typical. I don't buy these entropic arguments. Furthermore, you can't look at quantum fields and derive biology, let alone it's difficult to derive chemistry. It's somewhat easy to derive chemistry when you know where you're headed. But it's not clear to me if you vary the laws that then you can't have life as we don't know it. Like we can. OK, so anyhow, that's what the podcast is about. And you actually care about life in your podcast. It's not just about physics. Well, you asked about what matters. And then you gave this
My standard atheist eight-year-old response, which would be, oh, well, we don't matter because we're a speck of dust among many stars, among many planets. And then you look at the world spatially and you say, well, because we're insignificant spatially, then we don't matter. Well, why are we privileging what happens spatially? Are we to say that what happened to Auschwitz? Oh, it doesn't matter because you were just a tiny moment in history. I think what happened there matters. And I think when we start saying that we don't matter, then you have to
Question your definition of matters or question. Why do you think what matters matter? Matters matters. All right, feel free to jump in anyone burning questions. So when I was when I was 12 years old, I asked my mom, Hey mom, did God sit around completely bored out of his mind for the first 13 billion years?
until life started evolving on the planet and then for another 3.8 billion years until we finally evolved so that we can honor him. And my mom answered in the most mind-blowing way. She basically said, Manolis. And I was 12. Manolis, do you think that the creator of space and time experiences space and time the way we do? And that blew my mind.
And one of the problems that I have with praying and miracles is that if I pray for something to happen, for my friend to show up, that prayer better go back in time, you know, affect my friend who will then decide to start taking a trip and eventually show up and see me. And if instead, whatever supreme being
experiences time and space differently. They can answer my prayer by affecting things in an uncausal way. You know, that's something I think about as well. I don't know if there's a creator, but something I think about is we often, even if you're an atheist, at least sometimes you think, Oh, I wish so and so doesn't happen. Or maybe you get a diagnosis and you wish it's not going to be serious. And then you have no idea how many of these wishes have come true already.
There's an episode of The Simpsons where...
the
Somehow, you know, so I'd love to hear your thoughts on that. So basically, we've talked about these cones of intersections. And how would you envision miracles? Or is there a possibility
For some other type of form, it doesn't need to be the creator of the universe, but it could be some other occupant of the universe that doesn't actually obey causality and constraints. And maybe, you know, quantum could be one of those things where you basically have these long range influences. I'm going to pull the most annoying philosopher trick ever. And I'm going to return the question by asking, what do you mean by miracle?
I think it's pretty clear from the context. I have a technical question. Is there any counter-argument to quantum gravity that you think is
I mean, do you believe string theory is a good theory? Well, string theory is not a belief system. Tell us about quantum gravity and string theory. Quantum gravity and string theory, okay. But also to make the question clear, when you say a counter argument to quantum gravity, you mean a counter argument to the existing theories of quantum gravity, such as string theory, or a counter argument to the idea that gravity must be quantum? Because those are different.
Gravity must be quantum. Well, this devolves down to the question of what you mean by quantum. And that's sort of what I've been thinking about for quite some time. Yeah, yeah. So the standard way we think about quantum theory is there's a very important role played by the observer. There's an intricate mathematical apparatus.
And this mathematical apparatus engages in a form of quietism about what's really out there. But what it does is it delivers us a precise instrumentalist recipe for telling us what will happen when you do certain things. When observers do what's called a measurement on a quantum system, the theory furnishes a probability for getting a particular kind of outcome. That's what it does. But it doesn't tell us what's going on in between. So when you read a book about
You know, modern physics, you look up about quantum mechanics. The book says, well, you know, the reason why this particular thing happens is because this electrons going like this and a photon comes off of it and does that. As far as the standard way that we teach and formulate quantum mechanics today, the form of quantum mechanics you find in all the standard textbooks, all of that is just for color. All of that is just fables.
The theory only says that when you have an observer, and the observer does this particular thing called measurement, then there will be these results with these probabilities, and that's it. It doesn't furnish anything else in terms of a physical picture. Now, that's the standard way that we teach, you know, it's in the books, but of course people have been dissatisfied with this picture for a very long time, and one of the things that Einstein was dissatisfied with about quantum theory, it wasn't a probabilistic aspect of quantum theory, it wasn't that, you know, God played dice with the universe, he could live with that. After all, one of Einstein's great breakthroughs
was Brownian motion, right, which was instrumental in us understanding the nature of atoms. It was, you know, one of the papers that was part of his great year as Anas Mirabilis in 1905. So probability wasn't the issue for him. It was that there wasn't a metaphysical picture of what was out there happening between the measurements. And, you know, it's what one one concern you might have is that maybe quantum theory is such a weird mathematical theory that any time you try to propose some kind of physical reality, a so-called ontology,
We're going
This was the worry I think a lot of people may have had. And so the attitude was, we just shouldn't talk about what's going on. And this became known as the Copenhagen interpretation. The Copenhagen interpretation just says, our brains cannot understand what's going on between measurements. All we can talk about are measurements. Measures are done by big, classical objects like us that obey classical rules of physics. And what's going on in between the measurements? We can't understand that. We have a mathematical apparatus for it, but we can't actually visualize it or write a picture down.
And that's what we're trying to fill that picture. We're trying to fill that picture. I mean, dissect that one word, which I think might mean two things. The word goes on between measurement. There's two types of betweens. There's between in quantum time, if you wish. There's between, of course, observations, but there's also between in quantum space. And the real numbers are a beautiful thing, but they might be completely fictitious because the physics
of the universe don't obey real numbers. And then there's another, I'm not fond at all of the whole simulation hypothesis, terrible, terrible hypothesis. But I've known too many computer programmers, I'm skeptical. However, one interpretation of quantum physics is that there's just too much to compute. And therefore you don't compute something, you're kind of you have a lazy computer, that physics is basically running lazy computation.
Hi, I'm here to pick up my son Milo. There's no Milo here. Who picked up my son from school? I'm gonna need the name of everyone that could have a connection. You don't understand, it was just the five of us.
So this was all planned? What did you get it to? I will do whatever it takes to get my son back. I honestly didn't see this coming. These nice people killing each other. All Her Fault, a new series streaming now only on Peacock. Sorry? Can I have an introduction? Of course, of course. I had a good point here. What's your name? Sresht. Introduce yourself. I'm a freshman at Northeastern. I recently started working at the media lab as a researcher and I started getting into all of this.
What I was working on a few days ago was actually inspired by your post on Twitter about Lagrangian savanna folds. That is very cool. This moment must feel very good to you, right? Inspiring the young generation is so great.
What the student is referring to is my post on Lagrangian sub-menifolds which went viral on Twitter, LinkedIn and Substack. Feel free to follow me on Twitter at Toe with Kurt on LinkedIn. You can add me by searching for Kurt Jymongol and for Substack you can visit kurtjymongol.org. Links are in the description. That is very cool. You know, this moment must feel very good to you, right?
Inspiring the young generation is so great. So I have a GitHub number where I had a bunch of Python notebooks which I was working on and I used a program-synthetic approach to try to prove some natural laws using Lagrangian sub-manifolds and it was actually working. I was proving conservation of energy both from the classical mechanics and the quantum mechanics side of things and honestly it was interesting because
I don't think the in-between factor is in fact being computed, like you were saying. Because if you're able to compute the functions of natural laws from such a probabilistic approach, it's so weird that you can end up with both approaches on the macro scale and the quantum scale. So I think it's completely unsolved, the gaps between everything that we know. In space, in time, or in computation.
in terms of computation.
It's nice to meet you. That's a very good question. Thank you. There's some seats in the back. Do you mind coming and sitting on the white chair over there? The white cube?
Yes, I'll repeat the question. Yeah, yeah. Yeah, so the question was... Is this good or bad? We have the tomatoes. Notice there's a few more chairs. Let me repeat the question. The question was...
So the question was, what the hell could I mean by saying that quantum theory doesn't say what's going on between the measurements? I mean, there's the Schrodinger equation and there's wave functions and there's all this apparatus, right? So what Heisenberg meant when he talked about the Copenhagen interpretation. So he wrote about the Copenhagen, he introduced the term the Copenhagen interpretation. It's a chapter in his book, Physics and Philosophy in 1958.
And the way he described it was he said, okay, classical objects, those have physical reality, we understand what they are, they're phrased in terms of objects that live in three-dimensional space. But we don't have the mental architecture to understand the reality of what's going on with quantum mechanical particles, tiny particles, so we use this mathematical formalism, but the formalism is not real. It's not physical. The wave function is just a mental construct, just a piece of mathematics. There isn't really a wave function anywhere. But let me turn the question back to you. Classic. Classic move.
Are you suggesting that you believe that the wave function is a physical entity in the way that for example a chair is a physical entity?
I'm going to take a stand and I'm going to say that right now I think that fields are metaphysically real. Fields are
localized intensities that are distributed physically metaphysical. They are real in the same kind of way that I think chairs are real or that you are real. Now it's easy to take that stand, I agree with you. Now we're not in lightweight, we're already... But there's a reason for it. But there's a reason for it. The reason I think that fields are physically real in the way that chairs are is because fields are intensities in physical space.
and you can, you know, they propagate energy and signals around through physical space. And so I have good reason to think that they are physical things. Now, why don't I think that wave functions, that Schrodinger wave functions are physical things? Where do Schrodinger wave functions live?
Not just the complex world. No, no. They live in... They live in our minds. They live maybe in our minds, but if they were purportedly to live in some kind of reality outside of our minds, where would that be? What about potential? What about potential? I've got lots. How about you? Yes.
Oh, right. This question about gauge potentials. Do gauge potentials have a reality? Can you guys let us in? Phrase the whole sentence, please. Please go ahead and explain gauge potentials to the audience. It will be like the real thing.
the thing that you could measure because you have a force and they will derive from some mathematical abstract object that we call potential that will be able to change based on the way you define them so they're less real but then you have physical effect like Aaron of bone for which they are there they have physical effect and put in the field is zero and the question of which one is real potential feel in fact we don't know in fact it doesn't make sense it's not very relevant question
Now that the question is complete, can you now give us a little bit of an introduction for the rest of us? Okay, let me see how to do this. Okay, I got this, okay. So there are these things called electric fields. We know about electric fields, right? And we know magnetic fields. You've all been inside of an MRI machine. You know about MRI machines. In an MRI machine, they turn a very strong magnetic field. Okay, great. I'm not going to talk about why they turn a strong magnetic field because I don't have time to do that.
We have a bunch of equations, laws that describe how these fields change with time. The laws are called the Maxwell equations. They go back to James Clerk Maxwell in the 19th century.
Now, there's a bunch of these equations. The Maxwell equations are complicated. There's a whole collection of them. It turns out there's a way to write them in a simpler way by introducing these mathematical things called gauge potentials. These things called gauge potentials are a little weird, but they're simpler. They have fewer moving parts.
And you can boil down the Maxwell equations into a smaller set of equations for these, these potentials. And you might go, well, this is just great. Let's just take these potentials to be the fundamental things. I mean, they'll kind of like fields. You can associate them with places in space. What's the problem? The problem is that they are not uniquely defined. There are infinitely many different distinct configurations of the gauge potential that all correspond to the exact same electric and magnetic field. So you're like, well, I mean,
Does nature secretly have just one of them? But if it does, there's massive empirical under-determination. We could never know what the true gauge potential is. And so what most physicists would say is the gauge potentials are not physical. The electric field is physical, the magnetic field is physical, and the gauge potentials are just useful pieces of mathematics, not altogether distinct from maybe how we might think of wave functions, just a mathematical tool to simplify the mathematical procedure. And that's what we might have thought
And then these really annoying people, so David Bohm and Yakir Aronov, decided to make our lives difficult and show that in some circumstances when you have charged quantum mechanical particles moving through certain kinds of an apparatus, where the electric and magnetic fields apparently are switched off, but the gauge potentials are switched on,
There can seemingly be empirically observable effects on the landing sites of the particles at the end of these experiments. And this raises the question, well, but if the fields are off where the particles are going, and the only thing that's on are these gauge potentials, but I didn't think gauge potentials had any physical meaning, how can they be producing an empirical effect on the behavior of the particles? I think that was pretty good type.
You said something which I think is some logical problem. You said the reason you don't believe that prevention exists is because it's not unique, there are infinitely many of them. By that argument, a human does not exist. If you ask it, what is a human? There are so many of us, potentially there are infinitely many of us. What is a human?
But there's no equivalence class for you, Xiaoli. There's only a unique Xiaoli.
What Jacob is basically saying is that if there are so many different ways to explain the reality by having equations that are so powerful that they can explain this,
They're completely undetermined. For example, if I take like, I mean, that's one of my issues with string theory, for example, or one of the criticism of string theory, that there are so many different possible ways of sort of creating today's world, that it doesn't narrow down and therefore the predictive value for things that are not observable is very small.
because you have way too many parameters for the problem at hand. Didn't they just give up on string theory? So, undetermined rather than there are so many, is that what you meant? Did you mean undetermined? It's radically undetermined. So, Shelly, for example, I can do experiments on you and pin down which human you are and eventually... I'm not sure about that.
you're not you're not under determined in other words are like couldn't you though say that the gauge potentials encode aspects of reality in so far as you know those aspects don't change when you change the gauge you know what i mean like it's a redundant it's not that they don't exist it's there's every it's a redundant description yeah so one way one way they give a gauge potentials is like
Suppose you want to describe Earth's surface. Perhaps you believe, like I do, that Earth's surface physically is there, but you want to describe it in some quantitative way. So you decide I'm going to work with latitude and longitude. You say, I'm going to describe where things are with latitude and longitude. And then you start building theories out of latitude and longitude, and you begin to believe, I think latitude and longitude are real things. They're physically there, those lines, they really mean something. And then someone comes along and says,
Well, actually, I think that where I live should be the origin of your coordinate system. So I'm going to use this other slightly different coordinate system. And you go, you can't do that because we all know that the fundamental, the prime meridian is definitely a thing, right? The Big Ben. Right.
And so, you know, but when you realize, wait a second, there are infinitely many coordinate systems you can use to describe the Earth, and not just things that are akin to latitude and longitude, but you've got the Mercator projection, you've got all these different coordinate systems you can write down, you begin to wonder, because there's no true coordinate system for the Earth,
the coordinate system is really just you know mathematical you know descriptive tool set and what's fundamental is is the earth surface right and so the attitude here is that the electric magnetic fields are like earth surface in this analogy they're the physical thing and the gauge potentials are like different you know coordinate systems we can use for these things the gauge potentials are equivalent to the wave function in that kind of
So John Bell, whose name comes up a lot in quantum foundations, John Bell was a theoretical particle physicist who also did groundbreaking work in the foundations of quantum mechanics from the 1960s all the way through the end of the 20th century. He introduced a lovely word.
for distinguishing between things that we think, at least we have good reason maybe to think are physically real and things maybe like wave functions or maybe like gauge potentials that we reason not to think are real. So he was distinguishing between, so there's a term of art in quantum mechanics called an observable. An observable are those features of a physical system that observers go and measure, the position of a particle, the momentum of a particle, the energy, whatever, those are called the observables.
He wanted a word that was kind of like observable, but words for things that described how things could really be, ontologically speaking, like what they really were, right? What was physically there. And so he called these things beables, not observables, but beables. And you know you meet someone who's learned quantum foundations only from books because they come to you and they say, tell me about beables. What are beables?
Beables.
Okay, go for it.
One of the most important pivotal moments in the development of quantum mechanics was the early 1920s. 1920s was a period when physicists decided they were not going to be able to come up with good laws, that were going to be able to be empirically adequate based on the pictures they were describing. If you took high school chemistry, you learned about the Rutherford atom where the electrons are going in circles around the nucleus of the atom. People still draw these pictures.
Well, up until the early 1920s, physicists were trying to make that work. They were trying to come up with a set of equations and laws that would build on that physical picture and be empirically adequate, meaning they would agree, they'd make the predictions that would agree with the things they were seeing in experiments, and they couldn't find the right set of laws. They were using all the different kinds of laws that they were familiar with, that they'd inherited from centuries of work in physics, and then in the early 1920s, people like Wolfgang Pauli and Niels Bohr began to doubt that this was possible.
And Bohr had a pivotal conversation set of conversations with Werner Heisenberg who was very young at the time. He was early 20s. Bohr had already won the Nobel Prize in which Bohr divulged his big secret he didn't believe.
that there were orbits anymore, electrons going around it, and this, you know, Heisenberg, you know, processed this, was thinking about it, you know, and then in spring of 1925, Heisenberg was a Ph.D. student at Munich, but he was visiting Gertingen, which was a center of theoretical physics and mathematics. He was working with Max Born and Pascal Jordan, and he was looking at all these formulas, and everything that Born told him was just sort of marinating his brain, and he was suffering from a massive case of hay fever, the worst and most important case of hay fever in history, okay?
So think about it like this. You think that you've got hay fever or something like that. It's a terrible quality. You wish you didn't have it. Well, the whole history of science may be different if it hadn't been for this case of hay fever because Heisenberg was miserable. People said his face was so swollen up, it looked like he got into a fight. And so he goes off to this island called Heligoland where the tree pollen levels are very low. And he went with two goals. One was to memorize a huge amount of Goethe.
And the other was to solve quantum theory. He accomplished one of these goals, one of them. Okay. But here's the thing.
He created a paradigm shift in Kuhnian language. He created paradigm shift in science. He said, I'm going to banish the physical pictures. We should not be formulating physical theories in terms of pictures. We should formulate it only in terms of quantities that are in principle, experimentally measurable. He says this in the opening lines of this. It is a philosophy of science, like 101 great paradigm shift statement. He says we're going to banish them and we're going to build a theory just out of mathematics.
And this theory he builds eventually becomes what we call matrix mechanics. And it's a theory without pictures. It's a theory that's just raw mathematics. And this was the beginning of the end for the world pictures. Everyone was amazed. Einstein said Heisenberg had laid a great quantum egg, is how he described it, right? The idea that if you banish the pictures, suddenly you get equations and laws that seem to work and give the right predictions. This was incredible, right? But then Schrodinger comes along right afterward and brings the pictures back.
He brings pictures back and he does it by introducing the wave function. And how does he get the wave function? It doesn't just come out of nowhere. It doesn't just come out of mathematics. It comes out of classical physics. It comes out of classical physics. So there's a way to take classical physics. You don't know force equals mass times acceleration. Well, it turns out you can take force equals mass and acceleration. You can write it in mathematically very complicated ways.
And there is a very abstract way to write classical mechanics. It's called the Hamilton-Jacobi formulation. And we almost never teach the students anymore. Almost no students who come up in physics have ever heard it anymore. But Schrodinger learned about it. And the Hamilton-Jacobi formulation, you reformulate classical physics in a distinctly wave-like way, with a distinctly wave-like quantity called the Hamilton's principal function, or the Hamilton-Jacobi function.
which obeys this gnarly partial differential equation. And Schrodinger looked at this wave-like thing in classical physics. Now to be clear, this wave-like thing
doesn't appear to have any physical reality to it. It's just an alternative way to describe what all the Newtonian particles are doing. But he took this wave-like thing and the differential equation and it satisfied. He looked at it and he realized, oh my gosh, that looks like the Iconal Approximation to a wave equation. I'm going to call the wave function that it's the... I'm going to call that the Schrodinger... the wave function. He didn't call it the Schrodinger equation, that was himself. That would have been very... yeah. But they use this Greek letter Psi for it, right, maybe because that's the symbol of Poseidon and its waves. I mean, I've always wondered what that was, but
He introduced this, but the wave function was an outgrowth. The wave function was an outgrowth of a clear mathematical appurtenance of classical physics. No one would have imbued the Hamilton's principle function as this weird wave-like abstract quantity.
that satisfies this bizarre partial differential equation. No one would have imbued that with any ontological meaning, and the wave function was a direct descendant from that structure. Now, physicists loved wave mechanics. Actually, he called it undulatory mechanics, originally, which is just a better name. So much more interesting. Anyway, and physicists loved it because now it was back to differential equations, they had this picture of this wave function, and Schrodinger, for at least two years, he took his wave function seriously as a physical object. He said, these wave functions
They don't live in physical space. They don't live in 3D space, the space we live in. They live in possibility space. And there are statisticians around. Of course, parameter spaces. Wave functions live in parameter spaces, not physical space. And so Schrodinger found himself arguing, maybe a high dimensional parameter space where wave functions live, maybe that is the seat of physical reality.
And maybe in that reality, all the possible things that could really be happening to a system are all playing out in an embryonic version of the many worlds interpretation. He held this view for a couple of years. Now, many of you have heard of Einstein saying this famous quotation, I don't believe God plays dice with the universe. That was in a letter to Max Born on December 4th, 1926. He says, you know, quantum theory is very imposing
But I don't think it's the real thing yet. I, for one, don't believe that God plays dice. People don't know the next sentence in that letter. And they don't know the next sentence letter because it was mistranslated. In the canonical translation of the Einstein-Born letters by Irene Born, the next sentence was mistranslated. And I know this because
I thought the English was kind of weird, and I went back and looked at the German, and the German was clearly different. And I put the German through Google Translate, and it was clearly a different translation. Here's the difference. In the English translation I had read, Irene Bourne's translation, the next sentence is Einstein saying, waves in three-dimensional space, as if by rubber bands. And he actually puts a little ellipsis dot dot dot.
Gosh, Einstein didn't like waves in 3D? That's a weird thing to say. I mean, Einstein certainly seemed to like light a lot. Light is a wave in 3D. But in the original letter, it's not waves in 3D space. It's waves in 3N dimensional space. She dropped the N, and that's crucial, because when you have N particles, the parameter space is 3N dimensional. And what Einstein didn't like was that Schrodinger was asserting that the seed of reality was an abstract parameter space, and that Schrodinger was asserting that a physical mechanical wave
In this abstract.
that at every point in space, if you were to measure where the particle is, the probability with which you'll find it at one point in space is given by a particular mathematical procedure done to the wave function. So you can think of the wave function as an assignment of kind of a number to every point in space. It's a bit like a field, if you want to think of it that way. And if I measure where the particle is, I'll get one of the answers, and what the field is telling me is where I'll find the particle.
And this picture is how quantum theory is usually presented to incoming students because incoming students will usually learn about quantum mechanics, the quantum mechanics of a single particle. It's like the first, you know, two-thirds of the book is quantum mechanics of one particle. And they get really used to thinking, oh, the quantum wave function is like a field in 3D space. Right. But here's the problem. The moment you've got two particles,
Two particles require six parameters now, you see, because you have to specify, if you do a measurement, you ask where am I going to find the system, right? Where am I going to find the two particles? There's the x-coordinate, y-coordinate, z-coordinate of the first particle, and then there's also the x-coordinate, the y-coordinate, z-coordinate of the second particle. And those six variables define a six dimensional space.
three times two, two particles. N is now two, three times two particles. And that's where the wave function lives. The wave function is a function who lives in this six dimensional configuration space. And for N particles, it's three N dimensional space. So Schrodinger took it seriously. He's like, I think maybe this is what the scene of reality is. And then in 1928, in his fourth lecture on wave mechanics, he recanted that view. He said, you know, Max Born has come along and said that the wave function is not a mechanical object. It really is related to measurement probabilities.
And I just no longer hold this view anymore. But I think by then it was too late. And many physicists went on to think that wave functions were physical just as physical as anything else. Can we talk about the superposition now because we were talking about action at a distance earlier and this whole concept of you have now these multiple particles.
they can be in some kind of superposition. Explain to us a little bit about this whole action at a distance. Yes, yes. So the thing about quantum mechanics is that wave functions are actually reflections. So what Heisenberg was doing and Schrodinger was doing were actually just aspects of a deeper mathematical structure, the structure of Hilbert spaces. And this formulation of quantum theory in Hilbert spaces was done by Paul Dirac in 1930 and John von Neumann in his book in 1932.
And in this picture, the state of a quantum system is basically the wave function. The state of a quantum system is the kind of thing that if one is possible and another is possible, then you can superpose them and that's also possible. So if there is a wave function that assigns certain probabilities to the particle and a different wave function that would assign different possibilities to the particle, you can superpose the two wave functions together. That's called a superposition.
This is very weird, right? That's very different than classical physics. Yeah, different from classical physics. For example, if one of the wave functions assigns a very, very high probability to a measurement showing the particle to be here, and the other wave function assigns a very, very, very high probability of the particle being here, and you superpose the two wave functions,
What have you done? Are you saying the particle is in both places? Well, the Dirac phenomenon axioms, the standard textbook axioms, don't say that because they don't paint the picture at all. All they say is that if you have a superposed wave function, then if you measure what the particle is, there's some probability of finding it here, and some probability of finding it here, and anything else you want to say about it, like the particle's really in the two places. That is, strictly speaking, outside the axiomatic ambit of the axioms. That's just for color. So every time a physicist says to you, I'm going to tell you this is a secret, every time a physicist says to you,
Quantum physics has demonstrated that a particle can be in two places at once. They are lying to you. Now, I don't mean they're lying to you in the sense that it's definitely wrong. Maybe it's right. It could be right. But it's not right based on any interpretation of quantum theory we have except possibly for the many-worlds interpretation.
None of the other interpretations, including Copenhagen interpretation, including... In simple English terms, tell us what are these three or four interpretations? Three or four? Yeah. Oh, there's quite a few. Well, tell us three or four of them. And Jacob has his own, by the way. Yes, yes, we all get one. Tell us the three dominant and then the fourth will be yours.
So the instrumentalist textbook Dirac-Vaughan formulation just says nothing except that you do measurements and we predict what we're going to get. That's it. There's very little interpretive work. The Copenhagen interpretation we already talked about, that's the idea that there are classical things and the classical things follow classical laws and quantum things we just use to mathematics to describe them and between experiments we can't really say physically what's going on. That's the Copenhagen interpretation. In the 1920s, Louis de Broglie
Introduced the first pilot wave interpretation of quantum theory and the pilot of interpretation says that there are wave functions, but there are also particles, actual particles, classic like particles that really are in certain places. And what the wave function is doing is guiding the particles around piloting them. That's why it's called a pilot wave interpretation.
And, you know, the reason why you're more likely to find the particle in certain places where the wave function is stronger is because where the wave function is stronger is where the wave function guides the particle to. My interpretation was that the particles manifest where the wave function collapses. Not according to the pilot wave interpretation. So they're actually physically manifested. The particles are physical corpuscles, physical particles, yeah. And this was a very rudimentary picture that de Broglie put together and it was torn to shreds by his colleagues at the time. 25 years later,
David Bohm, the same David Bohm from the Arne of Bohm effect, he was at Princeton. He wrote a book called Quantum Theory 1951. He tried to explain the measurement process as best he could with, you know, the standard approach to quantum mechanics. He presented his book to Einstein. Einstein was very dissatisfied, says try harder. Bohm, the next year, publishes papers where he introduces independently the pilot of interpretation, much more sophisticated, much more complicated, and along the way, invents a huge amount of important physics.
Okay. And importantly, he introduces the concept of decoherence, which is one of the central ideas in practical realizations of, I mean, people talk about decoherence time scales all the time. This comes from the work of David Bohm, trying to make his pilot wave interpretation work. And this notion of decoherence, which I can talk about, but I'll punt for a moment, is what makes, what solves the problems that de Broglie was having and makes the pilot wave approach work, at least for systems of fixed numbers of finitely many non relativistic particles, which is very narrow.
What's decoherence? Good. What's decoherence? When you want to calculate something in ordinary, familiar, classical probability theory, we consider all the possible ways it can be. We assign them probabilities. We add the probabilities together. It works out just nicely.
If you want to consider the average of something, what you would do is you would consider all the different possible values that you could have, you weight them by the probabilities, add them together, and it works out just nicely. When you try to do the same thing with certain quantum systems, you get the wrong answer. For certain quantum systems, when you have superpositions in particular, wave functions are superposed, what you find is that in general
In addition to the, you know, quantities assigned to the different probabilities, these extra terms, these extra factors, these extra things that come in and mess up the calculation, those things are called interference effects. They make the probabilities you calculate from quantum systems behave differently from what you'd expect classically, and they ruin the sort of pilot wave picture that de Broglie was trying to develop. But Bohm realized
that if you take a system, a particle, and you actually have some kind of measuring device interacting with the particle and you put the measuring device in there and you model it and describe it physically, like really put it in and try to treat it quantum mechanically, what you find is that interacting with this big complicated measuring device with lots and lots of degrees of freedom, lots of moving parts, suppresses the interference effects dramatically, suppresses them so much that now your probabilities look like they would look according to classical statistics.
The Observer doesn't need to be conscious.
The observer could be any particle that interacts with it and therefore consciousness is not needed for quantum mechanics. It's not enough just to have a single particle because to get decoherence to work you actually need a lot of degrees of freedom. So for example, one electron cannot measure another electron. Sorry. But a huge object made of lots of atoms can yield decoherence. So when do you become an observer? How many atoms do you need to become an observer?
How many hairs on your head do you have to lose before you're bald? She's going to ask you a question. Can you, can you please? No, no, no, no, explain, explain. Just, just tell us, like. There is no, wait, there is no definition of an observer in these, in these, these pictures. There is no fundamental definition of an observer. A decoherer. Yes, please. Yes. I've been thinking about some related questions during the reading. It's a fact that every measurement has an observer.
Because if some conscious person doesn't look at the result, we don't know it was there. The problem with measurement is an ill-defined concept. Yes, that's right. A decoherary doesn't need to be a measure, it doesn't need to be an observer. Exactly. The language of observers was required for the original axiomatic formulation of quantum mechanics because the axioms say observers do measurements.
What Boehm was trying to do, what people who are trying to provide these sort of physical interpretations of climate theory, Boehm was an example, Hugh Everett with the Many Worlds interpretation was an example, is to eliminate the observer and measurements. And you just have systems. Some systems are small, some are big. The bigger systems cause more decoherence. That's exactly right. And more decoherence means you're getting results that look more and more classical, but it's on a gradient. There's no sharp dividing line between what is an observer and what is not an observer. Can you tell us how big is that gradient? In other words,
So, because I work in foundations of physics and philosophy of science and high energy theoretical physics, I didn't know the answer to that question, so I went and talked to a friend, a chemist.
Because chemists do worry about exactly those questions. They worry about when can you begin to pretend that things are more or less classical and not classical. And it's okay if there's a big thing in between where we don't know, that's fine. It's a blurry line, but it's around the size of large molecules. Okay, like for example? I think he said something like large sugar molecules maybe or polymers. I forget exactly what he said. Okay, so like 10 atoms or something? No, not 10 atoms. You need more like a thousand atoms, something like that. Whoa, okay. Now I'm just, it's bigger than 10, it's smaller than a mole,
I don't remember exactly what the number is. Well, okay, I should say at normal, okay, so at normal temperature conditions, right? Because you can have macroscopically many particles that still behave in a distinctly quantum mechanical way if you keep them very cold.
So for example, squids, superconducting quantum interference devices, right? Or Joseph's injunctions. They're systems that under very, very carefully controlled, isolated, low temperature conditions, you can get distinctly quantum phenomena at large scales. But first, I have a question for everyone. Who's having a good time?
Is this amazing? Who wants another seven hours of this? Right? This is amazing. Thank you, Jacob. This is extraordinary. Let's open it up for a few questions. We're going to do a flash round. I'm not speaking anymore. Go ahead. This is fascinating. And then at some point, you'll tell us about your own interpretation. But for now, let's open up for questions. Yes. So we'd like to go from history to the future. What are the big advances that have used cases that we can all
I'm glad you asked that question. I'm very glad you asked that question. If someone's got some money to throw around, where should they throw their money around? What would be a good thing to invest over the next 10, 20 years? Okay. So I don't want to just throw it, I want to see it grow. You want to see it grow? Okay, so I'm going to tell you right now.
The number of spin-offs that have come out of like philosophy of physics, foundations of physics, quantum foundations, relative to the number of people who have worked in the field is staggering.
So if I make a list of important things that have played a central role in modern quantum technologies, right, quantum communication, quantum photography, quantum computing, all of it. GPS. Well, atomic clocks, I guess. Yeah, that's right. Yeah. So you want to make a list, right? And I mentioned decoherence, which came out of David Bohm's philosophical work on quantum theory, right?
But there's an entanglement itself. There's the famous EPR paper, which introduced the idea of EPR states, GHZ states, and quantum Turing machines, and quantum teleportation, and important theorems, the no-cloning theorem, the no-signaling theorem. So an extremely small number of people are responsible for these foundational results. And if our field of foundations of physics and philosophy of physics, if our field got royalties,
If every time a paper in atomic physics mentioned a GHD state, we got a nickel, there'd be no funding problems in my field at all, okay? So the question, if you want to think about where to invest is, would another million dollars in quantum computing make a marginal difference? I would say no. And this is not to say that quantum computing is a bad idea. Quantum computing could be really great. But the cost benefit, right, for quantum computing, you'd have to really spend a huge amount of money to make a major dent in that field.
So you want to look for fields that are significantly underfunded like real funding opportunities that fields that are artificially like with the expectations are artificially low, but where you know that actually these fields are generating a huge amount of insights and a huge amount of things that end up playing a huge role in modern science and I would humbly argue.
that philosophy of physics, foundations of physics, and the more philosophical side of quantum foundations are significantly underfunded relative to the contributions they routinely make through science. Fantastic. Does that answer your question? So if anyone wants to endow any professorships, this would be huge. This would have a huge impact on the field. Let's restate the question. I'm a boring use case engineer looking for what can I use advances in quantum from the next 10 to 20 years. Give me some real things that I can
Hang on. Practical applications of quantum theory.
The project I'm working on, this is a new formulation of quantum theory, is not just an interpretation, but it also comes with it a precise mathematical relationship between the theory of stochastic processes, which is an old non-quantum way to talk about systems that behave in a probabilistic way, and quantum mechanical systems. It's this mathematical bridge between the two things. And its own main coin.
We could do a meme coin. We could do a meme coin, yeah, that would be great. It's quantum. It's absolutely, but not quantum, okay. It's quantum and not quantum at the same time. But here's the point, right? On the one hand, what this does is it provides a different way to think about quantum systems because if every quantum system is mathematically dual or representable or equivalent to just a boring stochastic system evolving in some probabilistic way without all of the
What if I've got some really complicated stochastic process I'm trying to model?
complicated. Maybe it's a process that goes beyond the usual approximations we like to make. There's this famous approximation called the Markovian approximation, which just says that we can ignore like past effects, right? We make this approximation all the time. But what if we can't? What if we have a system that's distinctly non-Markovian? Well, not clear how to simulate those in an efficient way. But with a bridge between these kinds of systems, these non-Markovian systems and quantum systems, there's the possibility that some of these systems that might have been very difficult to simulate on a computer, that might have real-world applications,
may be efficiently simulatable on quantum hardware. All you have to do is take the process, which is some non-Markovian, very complicated process, figure out what kind of quantum system it corresponds to, and then see if you can build that kind of quantum system on quantum hardware and a quantum computer. And so there's the hope that you might be able to simulate some very difficult stochastic processes that could have practical applications throughout the sciences and economics and finance and whatever, right?
Some of them may be efficiently simulable on quantum hardware. Unfortunately, we don't have any quantum computers around. But one day if we do, this potentially could be a new use for quantum computers. One of the big mysteries... See what? How big do you need them to be? I don't yet know. But I'll just say, one of the big mysteries about quantum computers is... How many qubits? Don't know yet. But one of the mysteries about quantum computers is what are they good for? You might think, well, quantum computers, right? They take every classical computation, they do them all simultaneously,
Right? And that's why they're powerful, but it turns out that's not how they work. They don't work that way. So many things you might think they give you a speed-up for, they don't give you a speed-up for. There's actually a pretty narrow set of problems that quantum computers, at least as far as we know, give you an appreciable speed-up with. Famously, one of them is cracking RSA encryption. So quantum computer would make it very efficient to crack RSA encryption, prime factorizations, that kind of thing. There are a couple of other problems that we know that quantum computers could be very useful for. One of them is just simulating quantum systems very efficiently. This could open up a whole other avenue.
Simulating very complicated real-world non-quantum stochastic systems using quantum hardware. And anytime you find some potential new use for quantum computers, that's a potential thing that they might be useful for. Can I ask a question there? When you said Markov systems, I'm wondering about the thought that there are concepts mainly in finance, that past information tells you nothing about where the next move will be in something.
Is that maybe too limited a view? If you had enough quantum computing, could the Markov process be different? Is there information in the past?
said there is. Yeah, yeah. So, so now to be clear, I am not an expert in finance, or an algorithmic trading or anything that's super related to this. So I couch anything I'm about to say here with the huge huge. But now you've convinced us anything you say will take. There is a very narrow set of subjects of which I have any sense whatsoever. Anyone who knows me would know that. But but okay, but I'll just say, one always runs the risk when modeling anything,
That one is making too strong an approximation in some way, right? But, of course, we have to make approximations all the time. I mean, there's an old saying that every model is wrong. Yeah, because it's an abstraction. Absolutely. Every model is an abstraction. Every model entails some kind of simplification so that if we tried to do the whole thing all out, it would just be the original thing, right? A model is, by definition, some kind of simplification that we can work with. And we always have to make some kinds of approximations. The question is, are all those approximations legitimate? Are they all justified?
Now, if there are good, strong grounds for justifying the Markov approximation, the idea that all we care about is the present when predicting the future, if that's justified, we'll then make it. But if the only justification is, well, that's where the light is,
The lamppost is shining there, so I'm going to look there. I just don't know how to do anything else. That's not a good justification. And I would say that having a formalism for being able to handle it in an elegant, potentially efficient way, processes that do take the past into account, would be useful. Useful at least to model and see if it's useful for a planet. We're on to the flash round. Raise your hands. Go ahead. So, so... Introduce yourself. I'm Samson, I'm a pediatric pathologist and also a chronic complication of genomic sludge. This has been fascinating, but I'm tinged with a little bit of it.
The modeling that you're talking about and measurements, you know, in health and disease, we make measurements all the time. And historically, we've come to understand human health and disease through classical physics, the heart is a pump, there's the fusion, there's chemistry. Is any of the things that you're talking about, space and time, waves, is that going to help us understand how molecules work in cells, or how cells work together, or how a doctor measuring blood pressure impacts the way we interpret it and what we do about it? My answer to that question is most likely no.
At least not directly. However, there could be indirect consequences for how you do medicine. And the reason is because one way we do medicine is using causal modeling. And this brings us, now, you see how cleverly it segues back to the sort of question about what causation is, right? So, you know, if you're thinking about the heart as a pump, I mean, whatever model of quantum theory you have is probably gonna, you know, we're gonna demand of it that it's able to replicate the, you know, observed behavior of macroscopic classical systems. The heart appears to be a big macroscopic classical system.
Some of us have bigger hearts than others, but all of our hearts appear to be big enough that we can treat them classically. But if you're trying to do drug discovery, if you're trying to understand how certain medical interventions will have a causal influence on the outcomes of diseases, you're interested in a subject called causal modeling.
Now, causal modeling has become a very sophisticated area of statistics, a very sophisticated area of, I mean, do double blind, random controlled, randomized, double blind studies, these sorts of things, right? We're doing causal modeling. We have a set of variables, a set of things we're trying to study, and we're trying to understand how they're related to each other. We're trying to understand how
you know, certain quantitative features of some physical condition are related to other conditions, are related to medical interventions or drugs. You want to have a causal modeling to understand why it's happening, a predictive modeling to say what will that intervention end up impacting in the future? That's correct. So how much increased explanation or how much of an explanation will come from incorporating some of the theories you want? So not directly.
But the causal modeling framework gives a very interesting way to think about causation itself. For example, if you want to understand why we think a certain drug has a certain effect on a population, of course, we will administer the drug to some of the population, we will not administer it to the population, we're basically controlling a variable and we're studying whether the physical correlations that show up, and we're not just looking for correlation, we're looking for causal relationships, correlations of my causation,
And in order to suss out causal relationships, not just statistical correlations between things, we have to have in mind that we can do interventions. We have to imagine that some agents, the agent being the person running the study, can choose to activate a variable or not activate a variable, and then suss out what kinds of consequences we get from this. This is the do operator. But in an observation-independent way, that's the whole point of double-blind. It is in an observation-independent way, but it does rely on the idea of an agent doing an intervention.
And this idea that we do causal modeling with this interventionist conception of causation has become pervasive and how people talk about causal modeling for good reason. Because in everyday life when you're doing medical testing or we're trying to understand interventions of a more general concept of medicine, right?
We do have people, and people are agents, and agents can choose to intervene or not intervene in certain ways, and we can study the correlations involved from them. That's how we can assess that causal relationship. As an agent, can I intervene? So I want to open this question to the whole room and rephrase it a little bit. How much evidence is there that biology is dealing with quantum effects, and in what biological processes have quantum effects been observed?
There are some theories that consciousness arises from quantum. Let's turn it off, please. That's exactly right. And this is a question for everyone here. For example, microtubules in neurons have been postulated to have quantum properties.
I have absolutely no qualms with so many different aspects of biology very early on. It doesn't need to be humans and the epitome of evolution as we like to think, which is ridiculous. But it could be bacteria, it could be like bats, it could be anything that's doing some type of sensing or some kind of
Who's going to give a very brutal answer to this, to this response? Brutal answer is the only thing we take. Yeah, yeah. So I understand this. I would say that this is a very similar proportion of how much we know about the system.
because I think that we are using this possibility in biology to replace the lack of measurement events or the lack of detailed, you know, a signal. Yeah, because because you mentioned incidentally the two things to really be the three things that we know the least about it, which neuronal function and you measure a little bit of microtubules and in the early life.
I work on a lot of fields where people will use that field to explain stuff that they don't understand, for example, epigenomics.
They say, oh, it must be an epigenetic effect. I'm like, bullshit. So I did not say these just because we don't know much about them. On the contrary, I say them for very, very specific reasons. But we have a neuroscientist up there in psychiatry as well. I'm curious if anybody wants to take this on with, yes, there is quantum here. Because that's what I think you're getting at, right? So John, John, go ahead. Yeah, exactly.
Yeah, so that's at the limit of physics. And let me make a very quick trivia here. It's a parenthesis, but I think you guys are going to love it. Just picture to close the parenthesis, otherwise you'll get an error. So in a sequoia tree, where does all the biomass come from?
Very simple interpretations. Oh, it must be the soil. It just sucks up nutrients. It's the carbon. It's the carbon. The decarbonization of the atmosphere. All of the wood actually comes from exactly that process that John just mentioned. So the fixing of carbon atoms from the air. And when you lose weight, where does the weight go? Why is that quantum? Go ahead, John. Why is it quantum?
Well, one is at the top of that. It has very defined chemical reactions that they can be reproduced further and interfere in a measure of the way. So if understand anything from the lectures about... So quantum does not mean uncertainty. This is here. When the photon shifts something, then there's a quantum effect and then the reactions. Well, then everything is quantum, which is fine. We're going to do the star exploratory.
This is the flash round, so I'm happy to go to the next question. I wanted to ask what you meant by conscious coming out of quantum mechanics. We'll come back to that. That might be the ender. Flash round, continue. Go ahead.
Does quantum field theory naturally explain non-locality?
So the problem with the word non-locality is it needs to be precise-ified. What do you mean by non-locality? No, this is not me being an annoying philosopher. There are different definitions of non-locality. I need something more precise for that answer. But tell us, give us a few options. We have two electrons that are entangled. They were here one day and then they were brought apart. One is on the moon, one is on the earth. You make a measurement, whatever that is, on one and you determine the spin of the other.
But since you have only a single electron field everywhere,
We can entangle a photon and an electron, too, and then you have two different fields, right? So, yeah. A quantum field does not resolve the fundamental problems of quantum mechanics, the measurement problem or the problem of non-locality, yeah. A very naive question. That assumes that nobody has observed either of the two during that entire time that they've been apart, right? But notice something really important about this question.
Notice that in all these discussions about non-locality and quantum mechanics, going back to Einstein-Podolsky-Rosen, the EPR paper, and the example, there's a particle here, there's a particle, they were interacted, they entangled, they went far away, and then someone measured one of them. And so measured the other one. Notice you've got agents' interventions again. You've got observers playing a central role in this picture. They hit something, right? If they hit something. Yes, the observer. If they hit something and it doesn't count as an observer and you don't do the axiom.
You said that it's spin determined. What do you mean by spin determined? Meaning that it now has in that moment in time, it has
Where are you to measure it? Yes. But no, no, no. But you see, that's exactly the point, right? If you get rid of the idea that there's a fundamental axiomatic role to be played by the observer, eliminate the observer and just go back to the. So look, before the advent of quantum mechanics,
Physics had moved into a very impersonal picture, right? The Laplacian paradigm of physics is there's just a bunch of stuff everywhere, particles moving around, different positions, different velocities, and a giant differential equation describing how this state of the universe was to be updated moment to moment.
There's no role for observers. There isn't even a role for causal influences between things. Observers, causal influences, these are all just colorful language, descriptive language, ways to summarize the things you're seeing, ways to paint a picture, but ultimately all of it is irrelevant, right? And then quantum theory comes along and suddenly the observer comes right back in again. The observer plays the central role.
A lot of the interpretive approaches to quantum theory, not just mine, but Bohmian mechanics, all these approaches demote the observer back down to being an ordinary system. There's no fundamental role to be played but observer. When you've entangled systems and some system comes along like the moon, not an observer or whatever, and in some way interacts with the particle, there's no collapse that happens. And so the seeming causal influence that's supposed to be traveling superluminally, it actually becomes much more murky to say that's happening in this picture. Jacob, can I jump in for a second?
Let's talk about the moon for a second. So basically you have this entanglement and there hasn't been a human observer, let's say, but, but this touches the moon and now you've just kicked the can down the road. You've basically passed the uncertainty to, you know, the next, like every time it bounces somewhere, that secret gets propagated and carried along. And sort of my, my trouble with all that is,
The concept that there hasn't been an intervention to either of these two particles is something where it fundamentally breaks down. This whole sort of nonlocality assumes that, hey, nobody touched that for a while. And then there needs to be, of course, some communication and coordination for nobody to touch it so that eventually I can kind of like pass that information over there. And then, yes, that thing gets observed.
And I knew something about here, but to even pass that information back is, you know, just when Schrodinger introduced the term entanglement. So Schrodinger wrote in, he also wrote in German. We also wrote in English. He introduced the word entanglement. He introduced this word in 1935 and the paper, which he introduced the idea. He talked exactly about what you're talking about. He called it a, um,
a regress problem, right? Tracing it back. Tracing it back. Systems interact with entangled systems. More and more systems start to participate in entanglement. And he called it entanglement. He said entanglement was not one but the feature that in his mind made quantum theory different from pre-quantum physics. He was very clear about this in the opening page to this paper. So this infinite regress question is a very interesting question, but here's the thing.
When you take a physical theory, an unintuitive physical theory, and we've had lots of unintuitive physical theories, special relativity is a great example of an unintuitive theory. Unintuitive theories often lead to situations that prima facie look paradoxical. In special relativity, there's this famous paradox, not really a paradox, called the twin paradox. The twin paradox is the statement that if I am moving relative to you,
then you will see my clock running slow, but I will see your clock running slow. How can I see your clock running slow and you see my clock running slow? That seems to be a paradox, right? It seems obvious that there's some kind of paradox that I see your clock running slow, but you, because I'm moving relative to you, you see my clock running slow. This can't both be right. But when you carefully try to pin down whether this paradox is really happening, if you very, very carefully describe the situation, describe how you would actually check to see if the paradox is happening, you find it doesn't happen. If the paradox doesn't actually happen, the paradox was an illusion.
The non-locality in quantum mechanics, at least if the non-locality is to be given a causal valence, you'd think this non-locality is not just the kind of non-locality where two things are correlated, but that there's some kind of influence actually propagating faster than light. It does seem kind of like there is, and when you model quantum systems in the traditional way with observers doing interventions,
It looks like causal things are happening. And this goes back to the causal modeling. When you think of causation, causal modeling, in terms of interveners, agents intervening, and that's how you define causal relationships, it certainly does look like there's a causal influence propagating. But if you remove the observer as a fundamental primitive from the axioms of the theory, if you say, don't talk in terms of Alice and Bob as observers, tell it to me in terms of the atom.
What are the atoms doing? Tell me the story of this causal influence propagating at the level of the atoms, the microphysical level. It goes away because there's no interveners, there's no agents anymore. And so what you need now is to find some other way to talk about causation. You need to do some other definition of causation. And there was one person who did that, John Bell.
In John Bell's second version of his famous Bell theorem, 1975 paper, the theory of local beables is what it was called, the term beables. He tried to find a version, a way to formulate this non-locality in quantum theory that showed that it was causally non-local, that it was causal influences propagating instantaneously, but without relying on agents and interveners. He tried very hard to do it, and arguably he did not succeed.
So it does look on the surface like some nomenclature causal factors happening. But if you try to phrase in terms of the atoms without a good robust theory of causal influence, it's very hard to say that it's happening. Bell tried to do it, but arguably he was unsuccessful. Okay, last chance for questions, people who have not spoken to me so. The model was probably out of this stuff when we were 22 year olds or 20 year olds inspired by learning just a scratch more than high school physics.
And I'm struck looking back, you know, 30 years since 35 years since how you're still just then you're quoting the 1975 book, right?
Can you give us a flavor of what's happened in the last 50 years? And I wonder if you're just not saying much because we're not. We're not ready. We're not worthy. That would be a theory. But but if you could like what what's at? Are we really that frozen that we're still talking about these hundred and fifty year old theory was as if they're the stick of the art? Yes. That's what I needed to know. Jacob, you wrote your paper.
I'm going to slightly expand on it just a little bit and just say this. This thing that we're doing here, this thing that... The decoherence. No, this thing that you have brought into being, this intellectual exchange, this discourse that we're engaging in right now, this intellectual engagement that we're experiencing right now, there is so little of this in physics right now.
We must all sit around in the physics department and talk like this and talk about what's going on. We do not. This does not happen in physics departments. That does happen in philosophy departments. It does not happen in physics departments.
Okay. Why does it happen to physics departments? Complicated historical reasons. Now in the early, the first half of the 20th century, right? You look at the great physicists in the early 20th century. That was happening. Right. That was happening all the time. Yeah. Right. They were deeply engaged with philosophers. They were deeply engaged with the Vienna circle and the positivists and they were reading Karl Popper and they were arguing about Schopenhauer and they were arguing, but they were all claiming on all sides of the debates, but quantum theory that they were the true Vickers of Kant and Kantian philosophy. All of them were doing that. Right.
and then something shifted in the intellectual environment in physics and the best i can say is it was the war it was the shift of physics to america and it was also money okay when there's a lot of money at stake people suddenly feel like they're in a huge hurry to get concrete practical results there's no time to sit around and talk about philosophy it'd be good then for you to study finance
Alright, more questions, more questions. We need more of this, I'm saying we need more of this. Right here and there, right there, those two. Can you give us some sense of what is beable? It seems like, what is reality, right? You told him waves are not it, maybe the fields are, I can kind of have a sense of what observable means, but what is, at least in the... You, sir, are a beable.
He's a bee. He's actually instantiated. You are a bee. So not just a bee able, you're a bee is. No. So what I mean by this, what I mean by this. So I don't know what the fundamental beables of nature are.
We don't yet know the fundamental beables of nature. We don't know. We're aware of atoms. Atoms are made of smaller things. We don't know what the most fundamental constituents of nature are. At electrons, photons appear to be manifestations of perhaps quantum fields. Maybe quantum fields aren't fundamental. We don't know what the fundamental beables are. However, just because something is not fundamental doesn't mean it doesn't exist.
Imagine you came in from a rainstorm and you come in and you say, gosh, I'm really wet. And your friend says, no, you're not. Of course, I'm wet. I'm clearly wet. The person says, no, you're not. In what sense do you say I'm not wet, sir? And your friend says, well, at the level of the individual water molecules, wetness doesn't exist.
Water molecules are fundamental. Wetness is not a fundamental thing. Therefore, it doesn't exist. You go, oh, come on. Things can exist without being fundamental. You exist, even though you're not fundamental. Jacob, I have an answer to your earlier question. You asked me, what's a miracle? I have an answer. Do you want to hear it? Yes, please. OK, so, so, so what's a miracle? I was talking earlier about wishing for something and then that wish needing something non-causal
and outside the cone of the present and the future to happen. And I have the distinction between a miracle and the opposite. If I want something done, I don't just wish for it. I make a phone call and I cause the series of causal events for my reality to come through. And I just expect that it will appear somewhere in that cone of future possibilities.
A miracle is a wish that does not causally result from that cone outside. In other words, a miracle is something that I should have done earlier if I wanted that to happen. And I'm sorry for saying this so openly, but I think it's hopefully a lesson to all of the young people in the room. If you want something done, start working on that cone ahead.
Don't worry about that non-causality. Anyway, so... But on the beableness... I don't know what the fundamental beables are, but I do know that at some emergent level, there are non-fundamental beables like yourself. So Jacob, tell us now about your view. We talked about the Copenhagen view, about a few other use-tels, about your view. Good. So my view is that physical systems,
have actual physical configurations, just like we would have imagined in the pre-quantum world, but that the laws we didn't have that we couldn't come up with back in the early 1920s, they couldn't come up with the right laws in the 1920s because they were stuck in some old paradigms. They thought laws had to be Markovian. All the known physics up until that point was Markovian. You know what's going on right now, you can predict the future.
They were working on this in the 20s. This was before there was a modern theory of stochastic processes. This is certainly before people were talking about non-Markovian stochastic processes. Yeah, there was Brownian motion, there were Wiener processes, but like a sophisticated, comprehensive theory of stochastic processes, certainly out of the mark of approximation was unavailable. And as best I can tell from having plumbed this literature in depth, there is nobody, nobody who conjectured
that you could take classical-like ingredients, physical ontology, physical configurations, and give them non-Markovian laws and see if you can get quantum mechanics out of it. This was never done by anybody, ever. So what you're saying is that just non-Markovian-ness... Non-Markovian-ness alone is not enough. You need a particularly strong form of non-Markovianity called indivisibility. It's called indivisibles stochastic processes. The term was introduced in a 2021 review article. Explain what's indivisible.
If you know what a Markov chain is or a Markov process, these are processes where you can kind of concatenate
You can do the evolution of the system in steps. At every moment, you've got a law that tells you what happens next. You have another one that happens next. And notice you can divide it up. And an individual process simply fails to have that property. It fails to have the property that you can take any duration and break it up into sub-durations that have lawful descriptions. And once you get that up, you have a much more general class of processes, processes that naturally exhibit phenomena that look like interference,
And if you want to know like why quantum computers are so useful, I mean, so there's another interpretation of the many worlds interpretation. And one of the reasons why David Deutsch, one of the founders of quantum computing, wanted to develop quantum computers was to prove that many worlds was right because he said quantum computers can do more than classical computers can do. And the only way to explain this is that they're doing the calculations in all these parallel universes. But he was very disappointed. We all very disappointed when we discovered that many calculations
cannot be made faster on quantum computers. And then people began to wonder, well, if there really are all these many worlds out there, and the calculation really is happening in all these worlds, why is it that so many calculations cannot be made more efficiently on quantum computers? This strongly suggests to me that those are the worlds aren't really there, and that you're getting the advantage for quantum computers from a different source. And the different source is, if you try to model a computer using Markov processes, and all computers basically are Markov chains. They're deterministic Markov chains.
Once you allow yourself to have not just probabilistic computing but indivisible probabilistic computing, you have a much more general set of systems. And with a more general set of systems, you can do more things. Good, but they're less predictable because basically the cloth allows you to sort of know it. And which things you can do that give you an advantage over the classical case is not obvious a priori. Amazing, thank you. Alright, next question. Hi, Chris Flynn from Fidelity Investments. Thanks a lot, this is fun. You kind of answered my first question, but
Is there a way to actually observe or measure a quantum system without actually physically interfering with it? Alas, no. However, there is a very interesting protocol known as weak measurements. It was introduced by some quantum foundations people, interestingly enough. Aronov is one of them.
Yeah, so Arnav was involved, a couple of people involved, David Albert was involved, he went from physics to actual philosophy. So a lot of people who work in philosophy started as physicists, which he did and ended up doing philosophy of physics. Weak measurements work in the following way. Don't study just one system. Take 10,000 identically prepared copies of your system.
And don't do what we call a projective measurement. Do a very, very, very gentle measurement. Interact with it in just the most gentle way. Now, if you do this in this very gentle way, you're not going to get an answer from each system. The interaction is going to be so weak that when you send a measuring device in, you let it interact super duper weakly. You then bring the measurement device out and you look at the measuring device. And you gain very little information about the system you've measured. Very little.
The benefit, though, is that you don't lead to this projective collapse happening to the system. And you might go, well, but if I'm not getting any information out of it, what's the point? It's a partial collapse. That's right. You do this very, very gently. But you do this with 10,000 systems, with 10,000 of them, and they're authentically prepared. And for each one, you just you just very, very slightly graze it. Just get a little just a just scoop a little bit off the top, just a teeny teeny little bit off the top. Right. And you collect all the data. You can actually gain some information from all the data.
Now, here's where the interpretational problem comes in. So this is an experimental protocol that you can actually do. You can do this experimental protocol, you can actually do this, and lo and behold, you'll get results on your, you know, you'll take all the data, you'll put them in a computer, and you'll get a number out. And the fact that you can get a number out from measurements made everyone super excited. There's a kind of philosophy, not a small p philosophy, a kind of attitude, right, towards science, that if you can do a measurement on it, it's science, and that makes it great, regardless of whether you have any good interpretation for what you're doing.
There's no question we can do these measurements, these so-called weak measurement protocols. People have been doing them. The question is, when that number comes out, what the fuck does it mean? Right? And there's been a huge dispute over the years. Like, you get a number, okay, but what is that number telling me? It's not, I haven't done a standard measurement of my quantum system, so I can't say I'm measuring some property of my quantum system. I get some number, what does that number mean?
And people have tried to interpret what that number means and they've said some rather outlandish things about what that number is. And the question about what that number means is now kind of a almost philosophical question. So yes, there are ways to do measurements where you're barely interacting with the system and you can get a number out. And I should say the number does have a mathematical significance. The number is computing what's called a matrix element of a self-adjoint operator. But the question is like, does it tell you something physical about the system that you're measuring? And that's very murky.
So I would say is that at least according to the standard picture of quantum mechanics and all the interpretive frameworks that we know of, to get an actual reliable robust result out of the measurement process, you're going to have to get a decoherent process involved and that will inevitably produce some deviation or change in the system. And one way to see this is just that measurements in quantum mechanics are inherently non-commutative. If you measure A, non-commutative. If you measure property A and you measure another property or observable B,
And B has to have a certain feature. It's got to be incompatible with A. It has to satisfy what's called a complementarity relationship or uncertainty principle. But if you measure A, then B, then A again, you may get a different answer for A. And no matter how gently you measure B, as long as you measure it strongly enough to get some reliable robust information out, then invariably there will be some consequence for the measurement of A. Final quick question. It's a very small one. What's the relationship between consciousness and quantum?
There is absolutely no way that I can answer that question without telling a little story. Can you tell the story? We'll take the story. How many of you know, have ever heard of Mary's room? A couple of you have heard of Mary's room. So philosopher, philosopher Frank Jackson introduced a thought experiment called Mary's room. Mary's room works like this. Mary is a super brilliant scientist. She lives in a sealed room. And in this sealed room, everything is black, white and shades of gray.
Even her skin, somehow she's been, they, you know, altered her skin. She has never seen a color before. Never, ever, ever seen a color before. But she's very smart. She has access to a black and white grayscale version of the internet. She has access to all the information there is. She has advanced scientific equipment. She's got an electron microscope. She has every, she can even call in people. Of course, they have to be decolored before they come in. And she can slice their brains open and she can peer in their brains. She can electrode. She can do absolutely everything. And she has unlimited intellectual ability.
Can she ever cross what's called the explanatory gap? There are two problems in the philosophy of consciousness, the easy problem and the hard problem. The easy problem is not an easy problem. The easy problem is will science ever get to the point at which we can have a sufficiently sophisticated model of the brain that we can describe and explain the behavior of conscious beings?
And most people would say that's a hard problem, but you can imagine science getting to the stage at which maybe with enough technology and we can simulate, we can model brains and simulate them on sufficiently powerful computers, we can say, okay, when a brain is conscious and does these things, we can predict what we'll do, at least probabilistically, and others who can't. So that's still a pipe dream at this point, but maybe one day we can imagine doing it. The hard problem of consciousness, this was coined by David Chalmers, a philosopher, is, okay, well, once you have that model,
Why does it feel like anything? What about the subjective experience? Like, the fact that, yeah, the brain does these things, there are these sort of neural correlates, these states of the brain, neural correlates of conscious experience, the neural correlates of conscious NCCs. But like, why do they come along with redness, like the distinct feeling of redness? And now there are people who doubt that there is a hard problem. They're like, oh, it's an illusion or something like that. When Mary's Room thought experiment, part of what it's supposed to do is technically what Mary's Room was originally introduced was the argument's physicalism. But I read it in a different way.
Mary can do all science, all the science you can imagine. She's immortal. She can do science for centuries. She can develop all the science you can imagine. She can do every experiment ever done. But will she ever, and she may even be able to get to the state in which she can like figure out what to do to her brain, like which electrodes to push so that she'll have an experience of red. Okay, maybe she can even do that.
But can she ever explain how you get from the physical thing in the brain to suddenly having the experience of the actual color? How do you get from the physical stuff? Where does that come from? That's the explanatory gap between the easy problem and the hard problem. And there are many people who doubt the hard problem is solvable precisely because of the Mary's Room argument. Because even if you imagine unbounded scientific expertise, even if you could characterize, okay, this brain state corresponds to feeling red, this brain state corresponds to feeling green to blue,
You have the brain states written down, but you still don't know why they come along with these particular feelings. And that's the hard problem of consciousness. Now, some people doubt it exists. I feel sorry for you if you do. But, so, now let's go back to the quantum case, okay? Suppose we were able to say, okay, certain brain processes inherently use quantum mechanical phenomena. So what? Does that get us across the gap from the easy problem to the hard problem? Just because quantum mechanics is happening in the brain, maybe, and playing an instrumental role in certain processes, even if you know that, even if you can model that,
Okay, well, how do you get from that to and then when this is happening, this is how I'm gonna read this This is read I'll actually have experience of red and when you first have that experience of red when Mary first has experience of red She's learned something When she leaves the room for the first time and suddenly sees color Something new has been learned to her and she doesn't know why and none of her scientific experience up at that point can explain Why suddenly she's having these experiences? So I think the hard problem is not solvable and I think that's just fine. I
I think there are deep problems in nature that maybe we'll never be able to get to, and I don't think that understanding whether quantum mechanics is working in the brain or not is going to let us transcend the explanatory gap from the easy problem to the hard problem. That's just my point of view, and I could be wrong. In my view, it is insolvable in principle. The hard problem, insolvable in principle. That's my view.
Well, that's an interesting question, right? So, is Mary's room an argument against AGI? I don't necessarily think so. AGI might be just the easy problem. That is, if we can figure out how to model a system that behaves consciously, could we simulate it, and wouldn't the simulation be AGI? Artificial general intelligence, like a computer that really does behave in distinguish from human. However, if you then ask, does that computer have internal subjective experience? That we can't know.
And I don't think any scientific investigation will tell us the answer to that. There's a term that was introduced before David Chalmers in the 70s called the P-zombie, which haunts the nightmares of metaphysicians all over the place. The P-zombie is not, you know, a zombie. P-zombies function and observerly behave exactly like conscious beings. They're like your AGI computer.
carefully designed so that it simulates the same exact processes that go on in the brain of a normal human being, and it's plugged into a robot, and the robot looks like a person and walks around and talks and says, ah, that hurts, so it feels bad, or I see red, or whatever they're saying, right? Okay. But does that computer have it? Is there something that it is like to be that computer? Does it have an internal subjective experience like the kind that we believe we have? If it does not, it is called a pee zombie.
Now there is a view among some metaphysicians and some philosophers of mine that P-zombies, philosophical zombies, it's short for P-zombies, are conceptually impossible, they're inconceivable, that anything that behaves sufficiently like a conscious being
As somebody who studies neuroscience and biology and, you know, all of that, and by the way, our next salon will be on consciousness. What if we're just faking it?
In other words, if you look at the neuronal basis of subjective experiences, there are many experiments where, for example, if you cut the corpus callosum, you can actually have part of the brain unaware of the commands that were given to the other half that then led to an action. And that part of the brain that never saw that command will interpret the action as something that it really wanted.
And then the question is, is the brain a very, very good employee who just never wants to be caught not knowing and who will always make up a story, including when asked, why are you thinking? In other words, do we, like, do we know that we ourselves have any consciousness beyond what we are, you know, claiming that we do? And, and yes, sure. Your answer was very provocative by basically saying, maybe you don't, but I do.
Like there's no experiment that can prove to me that any of you have a consciousness. However, if I disconnect myself from my brain, maybe my brain is saying, oh yeah, of course you're super conscious. Like here's all the great things that you have that prove to you that you're conscious. Like why would I believe it?
All the humans are P zombies and lack internal conscious experience and a world in which they in fact have internal conscious experience and they'll observably look the same by construction. And this just is telling us that we're probably not going to be able to get at this question. If you transport yourself from the self to the other person looking at the self, is there anything you can do to prove
that you're actually conscious. Like I said, anything you could do in a world without internal conscious experiences, but P-zombies, could be done in a world with internal conscious experiences, and so I don't think that any... That's true, but either something in the opposite direction. Before we go on, I do want to tell a joke. You want to hear a joke? Of course. Here's a joke. I told this joke to David Chalmers, and he liked it a lot. Okay, here's a joke. And those of you who have some background in high-energy theory will enjoy this joke, okay? Okay. What do string theory
He sent me back a zombie emoji. I have a zombie emoji from David Chalmers on my phone. I've saved it all these years. Remember the part where we were going to end by 7.45? I looked at my clock and I'm like, oh, is it like maybe 7.55? It's 8.55.
Who had an amazing time tonight? So Kurt, Jacob, I can't thank you guys enough. Thank you for gracing us with your extraordinary thoughts and also with bringing so many new guests to our salons. Somebody commented, ooh, the crowd looks a little different. There's like more energy and all of that. So this is you guys. So thank you to all of the first time comers. I hope you will continue coming.
New update! Started a sub stack. Writings on there are currently about language and ill-defined concepts as well as some other mathematical details.
Several people ask me, hey Kurt, you've spoken to so many people in the fields of theoretical physics, philosophy, and consciousness. What are your thoughts? While I remain impartial in interviews, this substack is a way to peer into my present deliberations on these topics.
Also, thank you to our partner, The Economist. Firstly, thank you for watching. Thank you for listening. If you haven't subscribed or clicked that like button, now is the time to do so. Why? Because each subscribe, each like helps YouTube push this content to more people like yourself. Plus, it helps out Kurt directly, aka me. I also found out last year that external links count plenty toward the algorithm.
Which means that whenever you share on Twitter, say on Facebook, or even on Reddit, etc., it shows YouTube, hey, people are talking about this content outside of YouTube, which in turn greatly aids the distribution on YouTube. Thirdly, there's a remarkably active Discord and subreddit for theories of everything, where people explicate toes, they disagree respectfully about theories, and build as a community our own toe.
Links to both are in the description. Fourthly, you should know this podcast is on iTunes. It's on Spotify. It's on all of the audio platforms. All you have to do is type in theories of everything and you'll find it. Personally, I gained from rewatching lectures and podcasts. I also read in the comments that, hey, toll listeners also gain from replaying. So how about instead you re-listen on those platforms like iTunes?
for watching.
You also get early access to ad free episodes, whether it's audio or video. It's audio in the case of Patreon video in the case of YouTube. For instance, this episode that you're listening to right now was released a few days earlier. Every dollar helps far more than you think. Either way, your viewership is generosity enough. Thank you so much.
▶ View Full JSON Data (Word-Level Timestamps)
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"text": " Football fan, a basketball fan, it always feels good to be ranked. Right now, new users get $50 instantly in lineups when you play your first $5. The app is simple to use. Pick two or more players. Pick more or less on their stat projections."
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"text": " anything from touchdown to threes and if you write you can win big mix and match players from any sport on prize picks america's number one daily fantasy sports app prize picks is available in 40 plus states including california texas"
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"text": " Every time a physicist says to you quantum physics has demonstrated that a particle can be in two places at once. They are lying to you."
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"text": " Biology, consciousness, causation, and quantum physics, what is the connection? My name is Kurt Jaimungal, and this was part of my three-day tour of Harvard, Tufts, and MIT, where I recorded five podcasts, including a frolicsum salon discussion hosted by MIT's Manolis Kellis, one of the world's top computational biologists."
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"text": " A few weeks ago, Manolis graciously offered to host both me and Harvard's theoretical physicist and philosopher, Jacob Berandes, for a salon on the nature of quantum theory. This event is unlike any podcast that you've seen or heard due to the extemporaneous dynamism of the over 70 people who showed up within just a few days' notice. The other podcasts from this tour feature Michael Levin and Anna Chaunica, as well as a separate discussion, an over seven hours long one, with technical and concrete information regarding Jacob's approach"
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"text": " to indivisible stochastic processes. Subscribe to get notified. For now, enjoy this jazz-like conversation regarding fundamental questions such as, do quantum fields actually exist? What's the problem with many worlds? Do parallel universes solve anything? And what makes observers like you special?"
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"text": " So Jacob, can you just give us a little introduction into what you do? Tell us like maybe two, three minutes about your journey. How did you get where you are? What are you passionate about? What are you the most excited about? And, you know, what do you think we should really, you know, if there's one thing to know, what should we know?"
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"text": " When I was a little kid I was really interested in the philosophy of mind. I didn't know it was called the philosophy of mind but later I would realize that's what this was called. I was confused about why we existed and the nature of consciousness and all these sorts of questions. I had a knack for math and I went to college and I thought well if you like math and you like deep questions then you do physics and so I studied physics and I had a good time"
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"text": " And then I went to graduate school and I worked in high energy theoretical physics. I did my PhD in theoretical physics and you know, I Had some difficulty connecting with the research that was going on in high energy theoretical physics it it didn't it didn't connect with me at some deep level and You know over, you know my PhD Halfway through toward the end. I began to reconnect with my earlier interest in philosophy in particular philosophy of science"
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"text": " I got very interested in a whole bunch of different areas in philosophy of science, in an area that we would now call philosophy of physics, and in related areas that are closer to the sciences like quantum foundations. So when I finished my PhD, I started doing research in the area, writing papers. My partner in crime is right here, David Kagan. We were close friends and collaborators."
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"text": " And I began interacting more and more with the community of people who work in philosophy of science, and I realized this was my calling. What is philosophy of science? Ah, good question. What is philosophy of science? So, broadly speaking, and this is philosophy of science, it's not exactly, I'll say what I do in a moment, but philosophy of science, broadly speaking,"
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"text": " has several parts. One part is the study of what it is that scientists do. The ornithology of science. Scientists as birds and we observe their habits. There's the old line that this form of philosophy of science is as useful to scientists as ornithology is to birds."
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"text": " It's actually a valid point, I have to say. It might be helpful to the observers of the birds. It's true, but when bird populations are suffering, you do want to call an ornithologist. I'm not saying that scientists are doing... Birds don't try to do ornithology. That's very, very good, yes. But the other major side of philosophy of science is to go deep into our best, most successful scientific theories,"
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"text": " understand how they work, and you know, either try to glean an understanding, a new way of thinking about traditional questions in philosophy, in particular areas of philosophy like metaphysics, from what are best- And what is metaphysics? Okay, yeah, so good, good question."
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"text": " I'm such a great questioner. These are all great questions. Have you guys heard of the program called ELIZA? Yeah. It's at that level. You've learned well from ELIZA. Tell me more about metaphysics. ELIZA is this very old computer program. It was a computer therapist and whenever you would tell it, it would just say tell me more about and it would just insert whatever you said."
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"text": " Metaphysics is a very broad area in philosophy. It's concerned with some of the most fundamental questions about the nature of existence."
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"text": " There are areas of metaphysics that in philosophy of science we tend to spend a lot of time thinking about. These are questions like, what is the law of nature? What are laws of nature? How do we identify laws of nature?"
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"text": " And our laws of nature are things that are out there in some sense, or are they things that we devise to make sense of the world around us? What is probability? When you say that a particular thing in the world is associated with the probability of 0.72, what information does that convey? Now, you pick up a book on statistics."
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"text": " I feel like we should have some metabiology because metaphysics is extraordinarily powerful about understanding the nature of the universe but there's something about biology as well that's so fundamental as to why are we thinking? Why is there a soul?"
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"text": " What's the neuronal basis of consciousness? Come here! Wolfram has his metabiological framework, and so same with Gregory Chaitin. Say it again? Wolfram, Stephen Wolfram has metabiology, and Gregory Chaitin as well. That's very, very interesting. Good, good, good. Yeah, yeah, yeah. So, but I should say that metaphysics has the word physics in it, but it's not physics."
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"text": " It's, you know, the things that metaphysicians, and so metaphysicians, they're not called metaphysicists, they're called metaphysicians, just to make very clear, they're not, they're not physicists. That's so confusing, because metaphysicians are all other things. It's very confusing. Yeah, the name just goes back to the fact that there's a chapter in Aristotle, it comes after, and meta just means after, it's just, it's the next chapter. If anybody should know, it should be the Greek guy."
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"text": " Physics simply means natural. Physici is just natural. So the natural sciences is actually physics. Well, I mean, to the Greeks, I'm sorry. Physics used to be called natural philosophers, right? I mean, that's what they were called. But so metaphysics is concerned with questions that are broader in, you know, than any particular science and that are relevant to, you know, the questions that metaphysicians often. So here's a really like intense metaphysician talk."
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"text": " Is there a, you know, what is the precise way to characterize the difference between hypotheticals and counterfactuals? This is the kind of thing that, literally, these are the talks that you'll see. They are very different things. And we know they're different things, but, you know, to spend a lot of time thinking carefully about it, that is the kind of thing that some metaphysicians do, right? Can I hear what Manolis thinks is the difference? Yeah. So I'm going to come back to that in a second, because I have a few more things to ask, which"
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"text": " like might fall into metaphysics. And I hope we get to those questions. You don't have to answer them all right away. And I also want to get to Kurt in a second. But one of the questions that I have is like, does it matter that we exist? In other words, if you look at the whole biomass of the universe, the earth is insignificant and humans within it are, you know, even more so. But if you look at the amount of consciousness or the amount of theorems or the amount of, I don't know, heartbreaks,"
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"text": " in the universe, then we play a very big role, at least in my view. And what's really interesting is that at the heart of quantum physics lies an observer. Some would say. Some would say. Some would say. So basically what I want to ask you is does it matter to the universe that we are here?"
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"text": " Does it matter that we're here?"
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"text": " And introduce yourself. By the way, this has already started. Don't think that this is the first question. We're in it. You can all ask a question. This is an intellectual exchange. This is a salon. People should be asking questions. I want everybody to feel that they should be answering as much as asking. I may pick up the thread, right? So this is a reference to the anthropic principle. The anthropic principle was coined by Brandon Carter, who is a theoretical physicist who works on deep questions in gravity."
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"text": " you know, a colleague of Stephen Hawking, and the anthropic principle is, it comes in various gradations. One version of it is just, you know, when you look around at the world and you see that it has certain features, some of those features may be the way they are because they're laws of nature. Some of them may be the way they are just because they're random contingent facts, but some of them may be the way they are because of a selection effect."
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"text": " You know, for example, we look around and we're like, oh, the ambient temperature around us is this nice, this nice temperature between freezing and boiling. Is that because of some deep reason? And the answer is it's entropic. I mean, we wouldn't as, you know, carbon water-based beings be in an environment that had a temperature that was markedly different from that. So the fact that we see that is an effective of us being the humans observing it. And that's called an entropic effect."
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"text": " I want to build on that a little bit. I volunteer for my kids' schools, and one of the things that I volunteer to do is to go answer all of the questions that they have about the universe. So, small task. A small task, yes. So for three weeks, they gather questions, and you know, then I prepare for that talk more than I have to admit any talk that I've given in the last 15 years, at least. And one of the questions was, why is the sun so bright? And I used exactly the anthropic principle to basically say that"
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"text": " If we lived in Jupiter or even in Neptune, the sun would be just as bright. In other words, there's a range of brightness that our eyesight has evolved towards. And at the tail end of that distribution lies the sun. And there's really no selection to be able to see the sun clearly. And I'm guessing that so many other things just feel completely natural."
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"text": " because we basically evolved here. But there's another aspect which I thought you were going to get to, which is... Well, you didn't interrupt me. I might have gotten there. We only have an hour for, you know, three hours worth of material at least. It's okay. So what I want to ask you is, what I thought you were going to get to is not just that, yes, biology is well tuned to the physics that we kind of like and enjoy,"
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"text": " but of course there's there's a weirdness about the fact that for example water when it freezes rises to the surface that is fundamental to why life exists at all and i think that's a you know more fundamental principle than the fact that the temperature is well suited to our evolutionary adaptation but what i what i what i thought you were going to get to is that as we observe the universe we're observing perhaps a tiny fraction of maybe the dimensions that exist out there and"
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"text": " There's the laws of physics that we have come up with are a tiny subset of the things that are observable to our biology, if you wish. Am I completely off on this? No, not at all. So one way to visualize just how epistemically limited we are as beings is another Greek word. Yeah. Philosophers like epistemology. So sorry, I have to say that epistemic was one of the four virtues in the library of Celsius."
},
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"end_time": 919.531,
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"text": " in what is now Asia Minor in the old Greek. What were the other ones? The other was Arethi, which literally means virtues, to be virtues. The other one was Sophia, wisdom. It's really nice to have episteme, which literally means science, but basically the study of things."
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"text": " Yeah, so one way to visualize this is to borrow from a geometric tool that was introduced by Herman Minkowski. So Herman Minkowski took the nascent theory of special relativity that Einstein was developing in the early part of the 20th century and provided this geometric picture he called space-time. And so space-time, you visualize"
},
{
"end_time": 970.708,
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"start_time": 944.224,
"text": " You know, think of graph paper. Graph paper, the horizontal direction on the graph paper is all of space and the vertical direction is time. And you can visualize everything that ever happens as lying somewhere in this diagram. So each of you is a worm in the space-time diagram, a worm that begins somewhere down here and extends some length up here and then no more."
},
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"end_time": 995.23,
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"text": " I think about it slightly differently as cones into the possible past and the possible future for every point. The fastest anything can communicate a signal through space is at the speed of lights."
},
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"text": " And so if you take any point and consider the light rays that can extend from that point or the light rays that reach that point, they form these things called light cones. The light cone gives you a way to visualize what can influence you in a causal way and what you can causally influence. And also when. What information can get to you. And also when. And also when. Yes, exactly. Basically whenever the cones intersect. That's right, yeah. So think of it like this."
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"text": " Check out a pop-up art show or even try those limited edition donuts. Because why not? TD Early Pay. Get your paycheck automatically deposited up to two business days early for free. That's how TD makes payday unexpectedly human."
},
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"text": " Can we bring you back to quantum physics? We do a very fascinating first exit"
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"text": " We've hit a few more highways since then. We've hit a few more highways. Well, I have a question about quantum physics. Nice to see you, Kurt. Kurt, can I ask you a question first? Can I ask you a question? So Jacob came here to talk about quantum physics and we've been talking a lot about a bunch of different tangents but"
},
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"text": " I asked him a few very simple, definitional things, and you are the host of a podcast called Theories of Everything, or is it Theory of Everything? Theories. And I'd like you to just very briefly introduce yourself as to how did you get to where you are, why the heck did you start that podcast, and what have you learned also that shook your own worldview? Because one of the goals of your podcast is to disseminate knowledge."
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"text": " to the rest of us. But another one I hope is for you to also, you know, I don't know, figure it out. And there's very few people who are so actively asking so many extraordinary folks about that one question that unified us at all. So tell us, what does Tears of Everything mean to you?"
},
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"text": " And are there some surprising things that you did not know that were like, whoa, realizations that happened on your podcast? Almost weekly. So as for how I got into this, firstly, any story I concoct will be a confabulation because of course, after the fact, you can make up, you can find the path. I like that the root of both fabulous and fable are the same. But since I was a kid, I've been interested in puzzles."
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"text": " Abstract mathematical puzzles and and I was always interested in math and physics. One time I was thinking about the nature of the universe and how did anything come to be and I was asking my brother who was studying math and physics and I believe the University of Toronto no or UBC at the time."
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"text": " So I was eight years old and we were walking to Blockbuster, if you remember Blockbuster. And I asked him about how could anything come, how did something come from nothing? And then he explained to me what quantum fluctuations were. And then I remember going home and looking at the ceiling and then thinking, okay, then there is no God. And I, and then I just became an atheist from that point forward. Sorry. Or if there is he rolls dice."
},
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"text": " Well, okay, then there's no need for a God. Good, good answer. Good answer. In my eight year old mind. And then I remember telling some schoolmates about that. Then they're like quantum fluctuance. And then I remember feeling so embarrassed because they were like, what are you talking about? And then I never said the word fluctuation until I was 18 after that. Then I was great in math and physics in school. So I was encouraged and I went into that in university and I left that because I was doing standup comedy and filmmaking."
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"text": " Yeah, so. Oh, and that's another story. After I when I was doing filmmaking, then the pandemic occurred and I thought, OK, I was watching some podcasts online. There's this guy named Donald Hoffman who has this theory of consciousness, at least supposedly a theory of consciousness that reproduces quantum mechanics, perhaps even gravity. I don't know if it's made that claim. But many people were interviewing him and they're just in awe of of Donald and"
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"text": " And they're not asking any what I would consider to be rudimentary questions that are slightly pushing, not even antagonistic questions. And he keeps making Donald keeps making reference to his papers. He's like, I can prove this in my, in my research. And then I was thinking, okay, so are there any people here who are"
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"text": " who are reading his research and then speaking to him and I couldn't find any so I thought let me reach out to him and read his research and then question him about that and it was a quite a technical interview so I treated the podcast like office hours and I was even going to call it office hours instead of theories of everything initially and that's how I still treat it like when I was speaking with Jacob yesterday we spoke for seven hours as if and you even have classes where well potential classes where they could be seven hours long they don't last that long but"
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"text": " I just go until the students give up. It's an endurance contest. The class can last that long but the students won't."
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"text": " And I'm extremely interested in the nature of reality. What is this? You mentioned metaphysics, you mentioned epistemological limitations. And so one of the issues I have with anthropic principles is we're speaking about life as we know it. Now I know you have some claims about life as we don't know it, must be similar to life as we know it. I find that dubious. It must have similar properties. I hope not DNA. DNA would be such a boring thing if we find it elsewhere. Well anyhow, it's not clear to me that this is the typical state."
},
{
"end_time": 1460.043,
"index": 58,
"start_time": 1432.944,
"text": " Red dwarfs last for trillions of years. Red dwarfs last for trillions of years. They don't know if there's some life form in the sun and the most typical life form would be a conscious agent in the sun or if we invent AI and AI takes over and AI has many trillions of times more conscious experiences than us and thus the most typical conscious experience is us being an AI or grey goo."
},
{
"end_time": 1489.616,
"index": 59,
"start_time": 1460.043,
"text": " Don't know if this is the most typical. I don't buy these entropic arguments. Furthermore, you can't look at quantum fields and derive biology, let alone it's difficult to derive chemistry. It's somewhat easy to derive chemistry when you know where you're headed. But it's not clear to me if you vary the laws that then you can't have life as we don't know it. Like we can. OK, so anyhow, that's what the podcast is about. And you actually care about life in your podcast. It's not just about physics. Well, you asked about what matters. And then you gave this"
},
{
"end_time": 1519.019,
"index": 60,
"start_time": 1490.06,
"text": " My standard atheist eight-year-old response, which would be, oh, well, we don't matter because we're a speck of dust among many stars, among many planets. And then you look at the world spatially and you say, well, because we're insignificant spatially, then we don't matter. Well, why are we privileging what happens spatially? Are we to say that what happened to Auschwitz? Oh, it doesn't matter because you were just a tiny moment in history. I think what happened there matters. And I think when we start saying that we don't matter, then you have to"
},
{
"end_time": 1543.899,
"index": 61,
"start_time": 1520.06,
"text": " Question your definition of matters or question. Why do you think what matters matter? Matters matters. All right, feel free to jump in anyone burning questions. So when I was when I was 12 years old, I asked my mom, Hey mom, did God sit around completely bored out of his mind for the first 13 billion years?"
},
{
"end_time": 1571.937,
"index": 62,
"start_time": 1544.428,
"text": " until life started evolving on the planet and then for another 3.8 billion years until we finally evolved so that we can honor him. And my mom answered in the most mind-blowing way. She basically said, Manolis. And I was 12. Manolis, do you think that the creator of space and time experiences space and time the way we do? And that blew my mind."
},
{
"end_time": 1599.565,
"index": 63,
"start_time": 1572.637,
"text": " And one of the problems that I have with praying and miracles is that if I pray for something to happen, for my friend to show up, that prayer better go back in time, you know, affect my friend who will then decide to start taking a trip and eventually show up and see me. And if instead, whatever supreme being"
},
{
"end_time": 1628.968,
"index": 64,
"start_time": 1600.998,
"text": " experiences time and space differently. They can answer my prayer by affecting things in an uncausal way. You know, that's something I think about as well. I don't know if there's a creator, but something I think about is we often, even if you're an atheist, at least sometimes you think, Oh, I wish so and so doesn't happen. Or maybe you get a diagnosis and you wish it's not going to be serious. And then you have no idea how many of these wishes have come true already."
},
{
"end_time": 1648.029,
"index": 65,
"start_time": 1629.394,
"text": " There's an episode of The Simpsons where..."
},
{
"end_time": 1678.063,
"index": 66,
"start_time": 1648.387,
"text": " the"
},
{
"end_time": 1696.92,
"index": 67,
"start_time": 1678.387,
"text": " Somehow, you know, so I'd love to hear your thoughts on that. So basically, we've talked about these cones of intersections. And how would you envision miracles? Or is there a possibility"
},
{
"end_time": 1723.336,
"index": 68,
"start_time": 1697.5,
"text": " For some other type of form, it doesn't need to be the creator of the universe, but it could be some other occupant of the universe that doesn't actually obey causality and constraints. And maybe, you know, quantum could be one of those things where you basically have these long range influences. I'm going to pull the most annoying philosopher trick ever. And I'm going to return the question by asking, what do you mean by miracle?"
},
{
"end_time": 1749.002,
"index": 69,
"start_time": 1724.77,
"text": " I think it's pretty clear from the context. I have a technical question. Is there any counter-argument to quantum gravity that you think is"
},
{
"end_time": 1774.411,
"index": 70,
"start_time": 1750.06,
"text": " I mean, do you believe string theory is a good theory? Well, string theory is not a belief system. Tell us about quantum gravity and string theory. Quantum gravity and string theory, okay. But also to make the question clear, when you say a counter argument to quantum gravity, you mean a counter argument to the existing theories of quantum gravity, such as string theory, or a counter argument to the idea that gravity must be quantum? Because those are different."
},
{
"end_time": 1790.981,
"index": 71,
"start_time": 1774.889,
"text": " Gravity must be quantum. Well, this devolves down to the question of what you mean by quantum. And that's sort of what I've been thinking about for quite some time. Yeah, yeah. So the standard way we think about quantum theory is there's a very important role played by the observer. There's an intricate mathematical apparatus."
},
{
"end_time": 1818.2,
"index": 72,
"start_time": 1791.323,
"text": " And this mathematical apparatus engages in a form of quietism about what's really out there. But what it does is it delivers us a precise instrumentalist recipe for telling us what will happen when you do certain things. When observers do what's called a measurement on a quantum system, the theory furnishes a probability for getting a particular kind of outcome. That's what it does. But it doesn't tell us what's going on in between. So when you read a book about"
},
{
"end_time": 1839.07,
"index": 73,
"start_time": 1818.456,
"text": " You know, modern physics, you look up about quantum mechanics. The book says, well, you know, the reason why this particular thing happens is because this electrons going like this and a photon comes off of it and does that. As far as the standard way that we teach and formulate quantum mechanics today, the form of quantum mechanics you find in all the standard textbooks, all of that is just for color. All of that is just fables."
},
{
"end_time": 1869.087,
"index": 74,
"start_time": 1839.497,
"text": " The theory only says that when you have an observer, and the observer does this particular thing called measurement, then there will be these results with these probabilities, and that's it. It doesn't furnish anything else in terms of a physical picture. Now, that's the standard way that we teach, you know, it's in the books, but of course people have been dissatisfied with this picture for a very long time, and one of the things that Einstein was dissatisfied with about quantum theory, it wasn't a probabilistic aspect of quantum theory, it wasn't that, you know, God played dice with the universe, he could live with that. After all, one of Einstein's great breakthroughs"
},
{
"end_time": 1898.66,
"index": 75,
"start_time": 1869.36,
"text": " was Brownian motion, right, which was instrumental in us understanding the nature of atoms. It was, you know, one of the papers that was part of his great year as Anas Mirabilis in 1905. So probability wasn't the issue for him. It was that there wasn't a metaphysical picture of what was out there happening between the measurements. And, you know, it's what one one concern you might have is that maybe quantum theory is such a weird mathematical theory that any time you try to propose some kind of physical reality, a so-called ontology,"
},
{
"end_time": 1918.78,
"index": 76,
"start_time": 1899.599,
"text": " We're going"
},
{
"end_time": 1946.408,
"index": 77,
"start_time": 1919.019,
"text": " This was the worry I think a lot of people may have had. And so the attitude was, we just shouldn't talk about what's going on. And this became known as the Copenhagen interpretation. The Copenhagen interpretation just says, our brains cannot understand what's going on between measurements. All we can talk about are measurements. Measures are done by big, classical objects like us that obey classical rules of physics. And what's going on in between the measurements? We can't understand that. We have a mathematical apparatus for it, but we can't actually visualize it or write a picture down."
},
{
"end_time": 1974.65,
"index": 78,
"start_time": 1946.408,
"text": " And that's what we're trying to fill that picture. We're trying to fill that picture. I mean, dissect that one word, which I think might mean two things. The word goes on between measurement. There's two types of betweens. There's between in quantum time, if you wish. There's between, of course, observations, but there's also between in quantum space. And the real numbers are a beautiful thing, but they might be completely fictitious because the physics"
},
{
"end_time": 2005.094,
"index": 79,
"start_time": 1975.282,
"text": " of the universe don't obey real numbers. And then there's another, I'm not fond at all of the whole simulation hypothesis, terrible, terrible hypothesis. But I've known too many computer programmers, I'm skeptical. However, one interpretation of quantum physics is that there's just too much to compute. And therefore you don't compute something, you're kind of you have a lazy computer, that physics is basically running lazy computation."
},
{
"end_time": 2031.186,
"index": 80,
"start_time": 2005.555,
"text": " Hi, I'm here to pick up my son Milo. There's no Milo here. Who picked up my son from school? I'm gonna need the name of everyone that could have a connection. You don't understand, it was just the five of us."
},
{
"end_time": 2059.394,
"index": 81,
"start_time": 2031.749,
"text": " So this was all planned? What did you get it to? I will do whatever it takes to get my son back. I honestly didn't see this coming. These nice people killing each other. All Her Fault, a new series streaming now only on Peacock. Sorry? Can I have an introduction? Of course, of course. I had a good point here. What's your name? Sresht. Introduce yourself. I'm a freshman at Northeastern. I recently started working at the media lab as a researcher and I started getting into all of this."
},
{
"end_time": 2076.476,
"index": 82,
"start_time": 2060.145,
"text": " What I was working on a few days ago was actually inspired by your post on Twitter about Lagrangian savanna folds. That is very cool. This moment must feel very good to you, right? Inspiring the young generation is so great."
},
{
"end_time": 2099.275,
"index": 83,
"start_time": 2077.346,
"text": " What the student is referring to is my post on Lagrangian sub-menifolds which went viral on Twitter, LinkedIn and Substack. Feel free to follow me on Twitter at Toe with Kurt on LinkedIn. You can add me by searching for Kurt Jymongol and for Substack you can visit kurtjymongol.org. Links are in the description. That is very cool. You know, this moment must feel very good to you, right?"
},
{
"end_time": 2130.179,
"index": 84,
"start_time": 2101.152,
"text": " Inspiring the young generation is so great. So I have a GitHub number where I had a bunch of Python notebooks which I was working on and I used a program-synthetic approach to try to prove some natural laws using Lagrangian sub-manifolds and it was actually working. I was proving conservation of energy both from the classical mechanics and the quantum mechanics side of things and honestly it was interesting because"
},
{
"end_time": 2160.503,
"index": 85,
"start_time": 2130.691,
"text": " I don't think the in-between factor is in fact being computed, like you were saying. Because if you're able to compute the functions of natural laws from such a probabilistic approach, it's so weird that you can end up with both approaches on the macro scale and the quantum scale. So I think it's completely unsolved, the gaps between everything that we know. In space, in time, or in computation."
},
{
"end_time": 2171.647,
"index": 86,
"start_time": 2161.186,
"text": " in terms of computation."
},
{
"end_time": 2197.705,
"index": 87,
"start_time": 2172.449,
"text": " It's nice to meet you. That's a very good question. Thank you. There's some seats in the back. Do you mind coming and sitting on the white chair over there? The white cube?"
},
{
"end_time": 2224.07,
"index": 88,
"start_time": 2200.452,
"text": " Yes, I'll repeat the question. Yeah, yeah. Yeah, so the question was... Is this good or bad? We have the tomatoes. Notice there's a few more chairs. Let me repeat the question. The question was..."
},
{
"end_time": 2247.637,
"index": 89,
"start_time": 2224.531,
"text": " So the question was, what the hell could I mean by saying that quantum theory doesn't say what's going on between the measurements? I mean, there's the Schrodinger equation and there's wave functions and there's all this apparatus, right? So what Heisenberg meant when he talked about the Copenhagen interpretation. So he wrote about the Copenhagen, he introduced the term the Copenhagen interpretation. It's a chapter in his book, Physics and Philosophy in 1958."
},
{
"end_time": 2276.425,
"index": 90,
"start_time": 2248.046,
"text": " And the way he described it was he said, okay, classical objects, those have physical reality, we understand what they are, they're phrased in terms of objects that live in three-dimensional space. But we don't have the mental architecture to understand the reality of what's going on with quantum mechanical particles, tiny particles, so we use this mathematical formalism, but the formalism is not real. It's not physical. The wave function is just a mental construct, just a piece of mathematics. There isn't really a wave function anywhere. But let me turn the question back to you. Classic. Classic move."
},
{
"end_time": 2288.524,
"index": 91,
"start_time": 2277.193,
"text": " Are you suggesting that you believe that the wave function is a physical entity in the way that for example a chair is a physical entity?"
},
{
"end_time": 2319.906,
"index": 92,
"start_time": 2290.401,
"text": " I'm going to take a stand and I'm going to say that right now I think that fields are metaphysically real. Fields are"
},
{
"end_time": 2347.807,
"index": 93,
"start_time": 2320.094,
"text": " localized intensities that are distributed physically metaphysical. They are real in the same kind of way that I think chairs are real or that you are real. Now it's easy to take that stand, I agree with you. Now we're not in lightweight, we're already... But there's a reason for it. But there's a reason for it. The reason I think that fields are physically real in the way that chairs are is because fields are intensities in physical space."
},
{
"end_time": 2365.179,
"index": 94,
"start_time": 2348.234,
"text": " and you can, you know, they propagate energy and signals around through physical space. And so I have good reason to think that they are physical things. Now, why don't I think that wave functions, that Schrodinger wave functions are physical things? Where do Schrodinger wave functions live?"
},
{
"end_time": 2389.582,
"index": 95,
"start_time": 2368.08,
"text": " Not just the complex world. No, no. They live in... They live in our minds. They live maybe in our minds, but if they were purportedly to live in some kind of reality outside of our minds, where would that be? What about potential? What about potential? I've got lots. How about you? Yes."
},
{
"end_time": 2407.363,
"index": 96,
"start_time": 2390.026,
"text": " Oh, right. This question about gauge potentials. Do gauge potentials have a reality? Can you guys let us in? Phrase the whole sentence, please. Please go ahead and explain gauge potentials to the audience. It will be like the real thing."
},
{
"end_time": 2434.002,
"index": 97,
"start_time": 2407.363,
"text": " the thing that you could measure because you have a force and they will derive from some mathematical abstract object that we call potential that will be able to change based on the way you define them so they're less real but then you have physical effect like Aaron of bone for which they are there they have physical effect and put in the field is zero and the question of which one is real potential feel in fact we don't know in fact it doesn't make sense it's not very relevant question"
},
{
"end_time": 2457.858,
"index": 98,
"start_time": 2434.36,
"text": " Now that the question is complete, can you now give us a little bit of an introduction for the rest of us? Okay, let me see how to do this. Okay, I got this, okay. So there are these things called electric fields. We know about electric fields, right? And we know magnetic fields. You've all been inside of an MRI machine. You know about MRI machines. In an MRI machine, they turn a very strong magnetic field. Okay, great. I'm not going to talk about why they turn a strong magnetic field because I don't have time to do that."
},
{
"end_time": 2478.985,
"index": 99,
"start_time": 2458.251,
"text": " We have a bunch of equations, laws that describe how these fields change with time. The laws are called the Maxwell equations. They go back to James Clerk Maxwell in the 19th century."
},
{
"end_time": 2496.357,
"index": 100,
"start_time": 2479.343,
"text": " Now, there's a bunch of these equations. The Maxwell equations are complicated. There's a whole collection of them. It turns out there's a way to write them in a simpler way by introducing these mathematical things called gauge potentials. These things called gauge potentials are a little weird, but they're simpler. They have fewer moving parts."
},
{
"end_time": 2525.981,
"index": 101,
"start_time": 2496.357,
"text": " And you can boil down the Maxwell equations into a smaller set of equations for these, these potentials. And you might go, well, this is just great. Let's just take these potentials to be the fundamental things. I mean, they'll kind of like fields. You can associate them with places in space. What's the problem? The problem is that they are not uniquely defined. There are infinitely many different distinct configurations of the gauge potential that all correspond to the exact same electric and magnetic field. So you're like, well, I mean,"
},
{
"end_time": 2553.046,
"index": 102,
"start_time": 2526.408,
"text": " Does nature secretly have just one of them? But if it does, there's massive empirical under-determination. We could never know what the true gauge potential is. And so what most physicists would say is the gauge potentials are not physical. The electric field is physical, the magnetic field is physical, and the gauge potentials are just useful pieces of mathematics, not altogether distinct from maybe how we might think of wave functions, just a mathematical tool to simplify the mathematical procedure. And that's what we might have thought"
},
{
"end_time": 2579.48,
"index": 103,
"start_time": 2553.592,
"text": " And then these really annoying people, so David Bohm and Yakir Aronov, decided to make our lives difficult and show that in some circumstances when you have charged quantum mechanical particles moving through certain kinds of an apparatus, where the electric and magnetic fields apparently are switched off, but the gauge potentials are switched on,"
},
{
"end_time": 2602.09,
"index": 104,
"start_time": 2580.299,
"text": " There can seemingly be empirically observable effects on the landing sites of the particles at the end of these experiments. And this raises the question, well, but if the fields are off where the particles are going, and the only thing that's on are these gauge potentials, but I didn't think gauge potentials had any physical meaning, how can they be producing an empirical effect on the behavior of the particles? I think that was pretty good type."
},
{
"end_time": 2625.572,
"index": 105,
"start_time": 2603.063,
"text": " You said something which I think is some logical problem. You said the reason you don't believe that prevention exists is because it's not unique, there are infinitely many of them. By that argument, a human does not exist. If you ask it, what is a human? There are so many of us, potentially there are infinitely many of us. What is a human?"
},
{
"end_time": 2637.363,
"index": 106,
"start_time": 2626.288,
"text": " But there's no equivalence class for you, Xiaoli. There's only a unique Xiaoli."
},
{
"end_time": 2662.858,
"index": 107,
"start_time": 2638.012,
"text": " What Jacob is basically saying is that if there are so many different ways to explain the reality by having equations that are so powerful that they can explain this,"
},
{
"end_time": 2683.643,
"index": 108,
"start_time": 2663.439,
"text": " They're completely undetermined. For example, if I take like, I mean, that's one of my issues with string theory, for example, or one of the criticism of string theory, that there are so many different possible ways of sort of creating today's world, that it doesn't narrow down and therefore the predictive value for things that are not observable is very small."
},
{
"end_time": 2708.49,
"index": 109,
"start_time": 2684.224,
"text": " because you have way too many parameters for the problem at hand. Didn't they just give up on string theory? So, undetermined rather than there are so many, is that what you meant? Did you mean undetermined? It's radically undetermined. So, Shelly, for example, I can do experiments on you and pin down which human you are and eventually... I'm not sure about that."
},
{
"end_time": 2732.329,
"index": 110,
"start_time": 2708.729,
"text": " you're not you're not under determined in other words are like couldn't you though say that the gauge potentials encode aspects of reality in so far as you know those aspects don't change when you change the gauge you know what i mean like it's a redundant it's not that they don't exist it's there's every it's a redundant description yeah so one way one way they give a gauge potentials is like"
},
{
"end_time": 2761.561,
"index": 111,
"start_time": 2732.466,
"text": " Suppose you want to describe Earth's surface. Perhaps you believe, like I do, that Earth's surface physically is there, but you want to describe it in some quantitative way. So you decide I'm going to work with latitude and longitude. You say, I'm going to describe where things are with latitude and longitude. And then you start building theories out of latitude and longitude, and you begin to believe, I think latitude and longitude are real things. They're physically there, those lines, they really mean something. And then someone comes along and says,"
},
{
"end_time": 2778.933,
"index": 112,
"start_time": 2761.937,
"text": " Well, actually, I think that where I live should be the origin of your coordinate system. So I'm going to use this other slightly different coordinate system. And you go, you can't do that because we all know that the fundamental, the prime meridian is definitely a thing, right? The Big Ben. Right."
},
{
"end_time": 2799.565,
"index": 113,
"start_time": 2779.445,
"text": " And so, you know, but when you realize, wait a second, there are infinitely many coordinate systems you can use to describe the Earth, and not just things that are akin to latitude and longitude, but you've got the Mercator projection, you've got all these different coordinate systems you can write down, you begin to wonder, because there's no true coordinate system for the Earth,"
},
{
"end_time": 2821.613,
"index": 114,
"start_time": 2799.565,
"text": " the coordinate system is really just you know mathematical you know descriptive tool set and what's fundamental is is the earth surface right and so the attitude here is that the electric magnetic fields are like earth surface in this analogy they're the physical thing and the gauge potentials are like different you know coordinate systems we can use for these things the gauge potentials are equivalent to the wave function in that kind of"
},
{
"end_time": 2837.585,
"index": 115,
"start_time": 2822.415,
"text": " So John Bell, whose name comes up a lot in quantum foundations, John Bell was a theoretical particle physicist who also did groundbreaking work in the foundations of quantum mechanics from the 1960s all the way through the end of the 20th century. He introduced a lovely word."
},
{
"end_time": 2863.541,
"index": 116,
"start_time": 2837.585,
"text": " for distinguishing between things that we think, at least we have good reason maybe to think are physically real and things maybe like wave functions or maybe like gauge potentials that we reason not to think are real. So he was distinguishing between, so there's a term of art in quantum mechanics called an observable. An observable are those features of a physical system that observers go and measure, the position of a particle, the momentum of a particle, the energy, whatever, those are called the observables."
},
{
"end_time": 2888.865,
"index": 117,
"start_time": 2863.541,
"text": " He wanted a word that was kind of like observable, but words for things that described how things could really be, ontologically speaking, like what they really were, right? What was physically there. And so he called these things beables, not observables, but beables. And you know you meet someone who's learned quantum foundations only from books because they come to you and they say, tell me about beables. What are beables?"
},
{
"end_time": 2910.23,
"index": 118,
"start_time": 2891.578,
"text": " Beables."
},
{
"end_time": 2929.957,
"index": 119,
"start_time": 2910.23,
"text": " Okay, go for it."
},
{
"end_time": 2958.848,
"index": 120,
"start_time": 2930.674,
"text": " One of the most important pivotal moments in the development of quantum mechanics was the early 1920s. 1920s was a period when physicists decided they were not going to be able to come up with good laws, that were going to be able to be empirically adequate based on the pictures they were describing. If you took high school chemistry, you learned about the Rutherford atom where the electrons are going in circles around the nucleus of the atom. People still draw these pictures."
},
{
"end_time": 2988.456,
"index": 121,
"start_time": 2958.848,
"text": " Well, up until the early 1920s, physicists were trying to make that work. They were trying to come up with a set of equations and laws that would build on that physical picture and be empirically adequate, meaning they would agree, they'd make the predictions that would agree with the things they were seeing in experiments, and they couldn't find the right set of laws. They were using all the different kinds of laws that they were familiar with, that they'd inherited from centuries of work in physics, and then in the early 1920s, people like Wolfgang Pauli and Niels Bohr began to doubt that this was possible."
},
{
"end_time": 3001.442,
"index": 122,
"start_time": 2989.121,
"text": " And Bohr had a pivotal conversation set of conversations with Werner Heisenberg who was very young at the time. He was early 20s. Bohr had already won the Nobel Prize in which Bohr divulged his big secret he didn't believe."
},
{
"end_time": 3030.316,
"index": 123,
"start_time": 3001.613,
"text": " that there were orbits anymore, electrons going around it, and this, you know, Heisenberg, you know, processed this, was thinking about it, you know, and then in spring of 1925, Heisenberg was a Ph.D. student at Munich, but he was visiting Gertingen, which was a center of theoretical physics and mathematics. He was working with Max Born and Pascal Jordan, and he was looking at all these formulas, and everything that Born told him was just sort of marinating his brain, and he was suffering from a massive case of hay fever, the worst and most important case of hay fever in history, okay?"
},
{
"end_time": 3055.418,
"index": 124,
"start_time": 3030.316,
"text": " So think about it like this. You think that you've got hay fever or something like that. It's a terrible quality. You wish you didn't have it. Well, the whole history of science may be different if it hadn't been for this case of hay fever because Heisenberg was miserable. People said his face was so swollen up, it looked like he got into a fight. And so he goes off to this island called Heligoland where the tree pollen levels are very low. And he went with two goals. One was to memorize a huge amount of Goethe."
},
{
"end_time": 3064.155,
"index": 125,
"start_time": 3055.845,
"text": " And the other was to solve quantum theory. He accomplished one of these goals, one of them. Okay. But here's the thing."
},
{
"end_time": 3092.875,
"index": 126,
"start_time": 3064.838,
"text": " He created a paradigm shift in Kuhnian language. He created paradigm shift in science. He said, I'm going to banish the physical pictures. We should not be formulating physical theories in terms of pictures. We should formulate it only in terms of quantities that are in principle, experimentally measurable. He says this in the opening lines of this. It is a philosophy of science, like 101 great paradigm shift statement. He says we're going to banish them and we're going to build a theory just out of mathematics."
},
{
"end_time": 3120.265,
"index": 127,
"start_time": 3092.875,
"text": " And this theory he builds eventually becomes what we call matrix mechanics. And it's a theory without pictures. It's a theory that's just raw mathematics. And this was the beginning of the end for the world pictures. Everyone was amazed. Einstein said Heisenberg had laid a great quantum egg, is how he described it, right? The idea that if you banish the pictures, suddenly you get equations and laws that seem to work and give the right predictions. This was incredible, right? But then Schrodinger comes along right afterward and brings the pictures back."
},
{
"end_time": 3143.285,
"index": 128,
"start_time": 3120.794,
"text": " He brings pictures back and he does it by introducing the wave function. And how does he get the wave function? It doesn't just come out of nowhere. It doesn't just come out of mathematics. It comes out of classical physics. It comes out of classical physics. So there's a way to take classical physics. You don't know force equals mass times acceleration. Well, it turns out you can take force equals mass and acceleration. You can write it in mathematically very complicated ways."
},
{
"end_time": 3171.937,
"index": 129,
"start_time": 3143.643,
"text": " And there is a very abstract way to write classical mechanics. It's called the Hamilton-Jacobi formulation. And we almost never teach the students anymore. Almost no students who come up in physics have ever heard it anymore. But Schrodinger learned about it. And the Hamilton-Jacobi formulation, you reformulate classical physics in a distinctly wave-like way, with a distinctly wave-like quantity called the Hamilton's principal function, or the Hamilton-Jacobi function."
},
{
"end_time": 3180.35,
"index": 130,
"start_time": 3172.159,
"text": " which obeys this gnarly partial differential equation. And Schrodinger looked at this wave-like thing in classical physics. Now to be clear, this wave-like thing"
},
{
"end_time": 3209.531,
"index": 131,
"start_time": 3180.947,
"text": " doesn't appear to have any physical reality to it. It's just an alternative way to describe what all the Newtonian particles are doing. But he took this wave-like thing and the differential equation and it satisfied. He looked at it and he realized, oh my gosh, that looks like the Iconal Approximation to a wave equation. I'm going to call the wave function that it's the... I'm going to call that the Schrodinger... the wave function. He didn't call it the Schrodinger equation, that was himself. That would have been very... yeah. But they use this Greek letter Psi for it, right, maybe because that's the symbol of Poseidon and its waves. I mean, I've always wondered what that was, but"
},
{
"end_time": 3226.715,
"index": 132,
"start_time": 3209.531,
"text": " He introduced this, but the wave function was an outgrowth. The wave function was an outgrowth of a clear mathematical appurtenance of classical physics. No one would have imbued the Hamilton's principle function as this weird wave-like abstract quantity."
},
{
"end_time": 3256.766,
"index": 133,
"start_time": 3227.073,
"text": " that satisfies this bizarre partial differential equation. No one would have imbued that with any ontological meaning, and the wave function was a direct descendant from that structure. Now, physicists loved wave mechanics. Actually, he called it undulatory mechanics, originally, which is just a better name. So much more interesting. Anyway, and physicists loved it because now it was back to differential equations, they had this picture of this wave function, and Schrodinger, for at least two years, he took his wave function seriously as a physical object. He said, these wave functions"
},
{
"end_time": 3280.35,
"index": 134,
"start_time": 3257.125,
"text": " They don't live in physical space. They don't live in 3D space, the space we live in. They live in possibility space. And there are statisticians around. Of course, parameter spaces. Wave functions live in parameter spaces, not physical space. And so Schrodinger found himself arguing, maybe a high dimensional parameter space where wave functions live, maybe that is the seat of physical reality."
},
{
"end_time": 3308.183,
"index": 135,
"start_time": 3280.93,
"text": " And maybe in that reality, all the possible things that could really be happening to a system are all playing out in an embryonic version of the many worlds interpretation. He held this view for a couple of years. Now, many of you have heard of Einstein saying this famous quotation, I don't believe God plays dice with the universe. That was in a letter to Max Born on December 4th, 1926. He says, you know, quantum theory is very imposing"
},
{
"end_time": 3331.169,
"index": 136,
"start_time": 3308.456,
"text": " But I don't think it's the real thing yet. I, for one, don't believe that God plays dice. People don't know the next sentence in that letter. And they don't know the next sentence letter because it was mistranslated. In the canonical translation of the Einstein-Born letters by Irene Born, the next sentence was mistranslated. And I know this because"
},
{
"end_time": 3358.695,
"index": 137,
"start_time": 3331.613,
"text": " I thought the English was kind of weird, and I went back and looked at the German, and the German was clearly different. And I put the German through Google Translate, and it was clearly a different translation. Here's the difference. In the English translation I had read, Irene Bourne's translation, the next sentence is Einstein saying, waves in three-dimensional space, as if by rubber bands. And he actually puts a little ellipsis dot dot dot."
},
{
"end_time": 3388.319,
"index": 138,
"start_time": 3359.053,
"text": " Gosh, Einstein didn't like waves in 3D? That's a weird thing to say. I mean, Einstein certainly seemed to like light a lot. Light is a wave in 3D. But in the original letter, it's not waves in 3D space. It's waves in 3N dimensional space. She dropped the N, and that's crucial, because when you have N particles, the parameter space is 3N dimensional. And what Einstein didn't like was that Schrodinger was asserting that the seed of reality was an abstract parameter space, and that Schrodinger was asserting that a physical mechanical wave"
},
{
"end_time": 3408.609,
"index": 139,
"start_time": 3389.104,
"text": " In this abstract."
},
{
"end_time": 3426.954,
"index": 140,
"start_time": 3408.814,
"text": " that at every point in space, if you were to measure where the particle is, the probability with which you'll find it at one point in space is given by a particular mathematical procedure done to the wave function. So you can think of the wave function as an assignment of kind of a number to every point in space. It's a bit like a field, if you want to think of it that way. And if I measure where the particle is, I'll get one of the answers, and what the field is telling me is where I'll find the particle."
},
{
"end_time": 3445.674,
"index": 141,
"start_time": 3426.954,
"text": " And this picture is how quantum theory is usually presented to incoming students because incoming students will usually learn about quantum mechanics, the quantum mechanics of a single particle. It's like the first, you know, two-thirds of the book is quantum mechanics of one particle. And they get really used to thinking, oh, the quantum wave function is like a field in 3D space. Right. But here's the problem. The moment you've got two particles,"
},
{
"end_time": 3467.329,
"index": 142,
"start_time": 3446.732,
"text": " Two particles require six parameters now, you see, because you have to specify, if you do a measurement, you ask where am I going to find the system, right? Where am I going to find the two particles? There's the x-coordinate, y-coordinate, z-coordinate of the first particle, and then there's also the x-coordinate, the y-coordinate, z-coordinate of the second particle. And those six variables define a six dimensional space."
},
{
"end_time": 3496.92,
"index": 143,
"start_time": 3467.756,
"text": " three times two, two particles. N is now two, three times two particles. And that's where the wave function lives. The wave function is a function who lives in this six dimensional configuration space. And for N particles, it's three N dimensional space. So Schrodinger took it seriously. He's like, I think maybe this is what the scene of reality is. And then in 1928, in his fourth lecture on wave mechanics, he recanted that view. He said, you know, Max Born has come along and said that the wave function is not a mechanical object. It really is related to measurement probabilities."
},
{
"end_time": 3515.691,
"index": 144,
"start_time": 3497.466,
"text": " And I just no longer hold this view anymore. But I think by then it was too late. And many physicists went on to think that wave functions were physical just as physical as anything else. Can we talk about the superposition now because we were talking about action at a distance earlier and this whole concept of you have now these multiple particles."
},
{
"end_time": 3539.872,
"index": 145,
"start_time": 3516.664,
"text": " they can be in some kind of superposition. Explain to us a little bit about this whole action at a distance. Yes, yes. So the thing about quantum mechanics is that wave functions are actually reflections. So what Heisenberg was doing and Schrodinger was doing were actually just aspects of a deeper mathematical structure, the structure of Hilbert spaces. And this formulation of quantum theory in Hilbert spaces was done by Paul Dirac in 1930 and John von Neumann in his book in 1932."
},
{
"end_time": 3563.234,
"index": 146,
"start_time": 3539.872,
"text": " And in this picture, the state of a quantum system is basically the wave function. The state of a quantum system is the kind of thing that if one is possible and another is possible, then you can superpose them and that's also possible. So if there is a wave function that assigns certain probabilities to the particle and a different wave function that would assign different possibilities to the particle, you can superpose the two wave functions together. That's called a superposition."
},
{
"end_time": 3583.131,
"index": 147,
"start_time": 3563.746,
"text": " This is very weird, right? That's very different than classical physics. Yeah, different from classical physics. For example, if one of the wave functions assigns a very, very high probability to a measurement showing the particle to be here, and the other wave function assigns a very, very, very high probability of the particle being here, and you superpose the two wave functions,"
},
{
"end_time": 3612.108,
"index": 148,
"start_time": 3583.49,
"text": " What have you done? Are you saying the particle is in both places? Well, the Dirac phenomenon axioms, the standard textbook axioms, don't say that because they don't paint the picture at all. All they say is that if you have a superposed wave function, then if you measure what the particle is, there's some probability of finding it here, and some probability of finding it here, and anything else you want to say about it, like the particle's really in the two places. That is, strictly speaking, outside the axiomatic ambit of the axioms. That's just for color. So every time a physicist says to you, I'm going to tell you this is a secret, every time a physicist says to you,"
},
{
"end_time": 3631.015,
"index": 149,
"start_time": 3612.585,
"text": " Quantum physics has demonstrated that a particle can be in two places at once. They are lying to you. Now, I don't mean they're lying to you in the sense that it's definitely wrong. Maybe it's right. It could be right. But it's not right based on any interpretation of quantum theory we have except possibly for the many-worlds interpretation."
},
{
"end_time": 3650.401,
"index": 150,
"start_time": 3632.056,
"text": " None of the other interpretations, including Copenhagen interpretation, including... In simple English terms, tell us what are these three or four interpretations? Three or four? Yeah. Oh, there's quite a few. Well, tell us three or four of them. And Jacob has his own, by the way. Yes, yes, we all get one. Tell us the three dominant and then the fourth will be yours."
},
{
"end_time": 3675.35,
"index": 151,
"start_time": 3650.401,
"text": " So the instrumentalist textbook Dirac-Vaughan formulation just says nothing except that you do measurements and we predict what we're going to get. That's it. There's very little interpretive work. The Copenhagen interpretation we already talked about, that's the idea that there are classical things and the classical things follow classical laws and quantum things we just use to mathematics to describe them and between experiments we can't really say physically what's going on. That's the Copenhagen interpretation. In the 1920s, Louis de Broglie"
},
{
"end_time": 3696.596,
"index": 152,
"start_time": 3675.555,
"text": " Introduced the first pilot wave interpretation of quantum theory and the pilot of interpretation says that there are wave functions, but there are also particles, actual particles, classic like particles that really are in certain places. And what the wave function is doing is guiding the particles around piloting them. That's why it's called a pilot wave interpretation."
},
{
"end_time": 3726.084,
"index": 153,
"start_time": 3697.21,
"text": " And, you know, the reason why you're more likely to find the particle in certain places where the wave function is stronger is because where the wave function is stronger is where the wave function guides the particle to. My interpretation was that the particles manifest where the wave function collapses. Not according to the pilot wave interpretation. So they're actually physically manifested. The particles are physical corpuscles, physical particles, yeah. And this was a very rudimentary picture that de Broglie put together and it was torn to shreds by his colleagues at the time. 25 years later,"
},
{
"end_time": 3757.108,
"index": 154,
"start_time": 3727.193,
"text": " David Bohm, the same David Bohm from the Arne of Bohm effect, he was at Princeton. He wrote a book called Quantum Theory 1951. He tried to explain the measurement process as best he could with, you know, the standard approach to quantum mechanics. He presented his book to Einstein. Einstein was very dissatisfied, says try harder. Bohm, the next year, publishes papers where he introduces independently the pilot of interpretation, much more sophisticated, much more complicated, and along the way, invents a huge amount of important physics."
},
{
"end_time": 3787.312,
"index": 155,
"start_time": 3758.131,
"text": " Okay. And importantly, he introduces the concept of decoherence, which is one of the central ideas in practical realizations of, I mean, people talk about decoherence time scales all the time. This comes from the work of David Bohm, trying to make his pilot wave interpretation work. And this notion of decoherence, which I can talk about, but I'll punt for a moment, is what makes, what solves the problems that de Broglie was having and makes the pilot wave approach work, at least for systems of fixed numbers of finitely many non relativistic particles, which is very narrow."
},
{
"end_time": 3809.275,
"index": 156,
"start_time": 3788.046,
"text": " What's decoherence? Good. What's decoherence? When you want to calculate something in ordinary, familiar, classical probability theory, we consider all the possible ways it can be. We assign them probabilities. We add the probabilities together. It works out just nicely."
},
{
"end_time": 3831.391,
"index": 157,
"start_time": 3810.128,
"text": " If you want to consider the average of something, what you would do is you would consider all the different possible values that you could have, you weight them by the probabilities, add them together, and it works out just nicely. When you try to do the same thing with certain quantum systems, you get the wrong answer. For certain quantum systems, when you have superpositions in particular, wave functions are superposed, what you find is that in general"
},
{
"end_time": 3857.159,
"index": 158,
"start_time": 3831.92,
"text": " In addition to the, you know, quantities assigned to the different probabilities, these extra terms, these extra factors, these extra things that come in and mess up the calculation, those things are called interference effects. They make the probabilities you calculate from quantum systems behave differently from what you'd expect classically, and they ruin the sort of pilot wave picture that de Broglie was trying to develop. But Bohm realized"
},
{
"end_time": 3885.282,
"index": 159,
"start_time": 3857.637,
"text": " that if you take a system, a particle, and you actually have some kind of measuring device interacting with the particle and you put the measuring device in there and you model it and describe it physically, like really put it in and try to treat it quantum mechanically, what you find is that interacting with this big complicated measuring device with lots and lots of degrees of freedom, lots of moving parts, suppresses the interference effects dramatically, suppresses them so much that now your probabilities look like they would look according to classical statistics."
},
{
"end_time": 3908.422,
"index": 160,
"start_time": 3885.555,
"text": " The Observer doesn't need to be conscious."
},
{
"end_time": 3934.735,
"index": 161,
"start_time": 3908.422,
"text": " The observer could be any particle that interacts with it and therefore consciousness is not needed for quantum mechanics. It's not enough just to have a single particle because to get decoherence to work you actually need a lot of degrees of freedom. So for example, one electron cannot measure another electron. Sorry. But a huge object made of lots of atoms can yield decoherence. So when do you become an observer? How many atoms do you need to become an observer?"
},
{
"end_time": 3964.019,
"index": 162,
"start_time": 3935.384,
"text": " How many hairs on your head do you have to lose before you're bald? She's going to ask you a question. Can you, can you please? No, no, no, no, explain, explain. Just, just tell us, like. There is no, wait, there is no definition of an observer in these, in these, these pictures. There is no fundamental definition of an observer. A decoherer. Yes, please. Yes. I've been thinking about some related questions during the reading. It's a fact that every measurement has an observer."
},
{
"end_time": 3988.524,
"index": 163,
"start_time": 3964.753,
"text": " Because if some conscious person doesn't look at the result, we don't know it was there. The problem with measurement is an ill-defined concept. Yes, that's right. A decoherary doesn't need to be a measure, it doesn't need to be an observer. Exactly. The language of observers was required for the original axiomatic formulation of quantum mechanics because the axioms say observers do measurements."
},
{
"end_time": 4015.282,
"index": 164,
"start_time": 3989.002,
"text": " What Boehm was trying to do, what people who are trying to provide these sort of physical interpretations of climate theory, Boehm was an example, Hugh Everett with the Many Worlds interpretation was an example, is to eliminate the observer and measurements. And you just have systems. Some systems are small, some are big. The bigger systems cause more decoherence. That's exactly right. And more decoherence means you're getting results that look more and more classical, but it's on a gradient. There's no sharp dividing line between what is an observer and what is not an observer. Can you tell us how big is that gradient? In other words,"
},
{
"end_time": 4031.323,
"index": 165,
"start_time": 4015.282,
"text": " So, because I work in foundations of physics and philosophy of science and high energy theoretical physics, I didn't know the answer to that question, so I went and talked to a friend, a chemist."
},
{
"end_time": 4060.811,
"index": 166,
"start_time": 4031.869,
"text": " Because chemists do worry about exactly those questions. They worry about when can you begin to pretend that things are more or less classical and not classical. And it's okay if there's a big thing in between where we don't know, that's fine. It's a blurry line, but it's around the size of large molecules. Okay, like for example? I think he said something like large sugar molecules maybe or polymers. I forget exactly what he said. Okay, so like 10 atoms or something? No, not 10 atoms. You need more like a thousand atoms, something like that. Whoa, okay. Now I'm just, it's bigger than 10, it's smaller than a mole,"
},
{
"end_time": 4078.456,
"index": 167,
"start_time": 4061.305,
"text": " I don't remember exactly what the number is. Well, okay, I should say at normal, okay, so at normal temperature conditions, right? Because you can have macroscopically many particles that still behave in a distinctly quantum mechanical way if you keep them very cold."
},
{
"end_time": 4095.247,
"index": 168,
"start_time": 4078.456,
"text": " So for example, squids, superconducting quantum interference devices, right? Or Joseph's injunctions. They're systems that under very, very carefully controlled, isolated, low temperature conditions, you can get distinctly quantum phenomena at large scales. But first, I have a question for everyone. Who's having a good time?"
},
{
"end_time": 4124.565,
"index": 169,
"start_time": 4097.705,
"text": " Is this amazing? Who wants another seven hours of this? Right? This is amazing. Thank you, Jacob. This is extraordinary. Let's open it up for a few questions. We're going to do a flash round. I'm not speaking anymore. Go ahead. This is fascinating. And then at some point, you'll tell us about your own interpretation. But for now, let's open up for questions. Yes. So we'd like to go from history to the future. What are the big advances that have used cases that we can all"
},
{
"end_time": 4151.323,
"index": 170,
"start_time": 4124.991,
"text": " I'm glad you asked that question. I'm very glad you asked that question. If someone's got some money to throw around, where should they throw their money around? What would be a good thing to invest over the next 10, 20 years? Okay. So I don't want to just throw it, I want to see it grow. You want to see it grow? Okay, so I'm going to tell you right now."
},
{
"end_time": 4163.848,
"index": 171,
"start_time": 4152.142,
"text": " The number of spin-offs that have come out of like philosophy of physics, foundations of physics, quantum foundations, relative to the number of people who have worked in the field is staggering."
},
{
"end_time": 4182.807,
"index": 172,
"start_time": 4164.275,
"text": " So if I make a list of important things that have played a central role in modern quantum technologies, right, quantum communication, quantum photography, quantum computing, all of it. GPS. Well, atomic clocks, I guess. Yeah, that's right. Yeah. So you want to make a list, right? And I mentioned decoherence, which came out of David Bohm's philosophical work on quantum theory, right?"
},
{
"end_time": 4211.817,
"index": 173,
"start_time": 4182.807,
"text": " But there's an entanglement itself. There's the famous EPR paper, which introduced the idea of EPR states, GHZ states, and quantum Turing machines, and quantum teleportation, and important theorems, the no-cloning theorem, the no-signaling theorem. So an extremely small number of people are responsible for these foundational results. And if our field of foundations of physics and philosophy of physics, if our field got royalties,"
},
{
"end_time": 4239.838,
"index": 174,
"start_time": 4212.807,
"text": " If every time a paper in atomic physics mentioned a GHD state, we got a nickel, there'd be no funding problems in my field at all, okay? So the question, if you want to think about where to invest is, would another million dollars in quantum computing make a marginal difference? I would say no. And this is not to say that quantum computing is a bad idea. Quantum computing could be really great. But the cost benefit, right, for quantum computing, you'd have to really spend a huge amount of money to make a major dent in that field."
},
{
"end_time": 4258.882,
"index": 175,
"start_time": 4240.299,
"text": " So you want to look for fields that are significantly underfunded like real funding opportunities that fields that are artificially like with the expectations are artificially low, but where you know that actually these fields are generating a huge amount of insights and a huge amount of things that end up playing a huge role in modern science and I would humbly argue."
},
{
"end_time": 4288.37,
"index": 176,
"start_time": 4259.394,
"text": " that philosophy of physics, foundations of physics, and the more philosophical side of quantum foundations are significantly underfunded relative to the contributions they routinely make through science. Fantastic. Does that answer your question? So if anyone wants to endow any professorships, this would be huge. This would have a huge impact on the field. Let's restate the question. I'm a boring use case engineer looking for what can I use advances in quantum from the next 10 to 20 years. Give me some real things that I can"
},
{
"end_time": 4311.664,
"index": 177,
"start_time": 4288.899,
"text": " Hang on. Practical applications of quantum theory."
},
{
"end_time": 4335.862,
"index": 178,
"start_time": 4311.869,
"text": " The project I'm working on, this is a new formulation of quantum theory, is not just an interpretation, but it also comes with it a precise mathematical relationship between the theory of stochastic processes, which is an old non-quantum way to talk about systems that behave in a probabilistic way, and quantum mechanical systems. It's this mathematical bridge between the two things. And its own main coin."
},
{
"end_time": 4358.029,
"index": 179,
"start_time": 4336.698,
"text": " We could do a meme coin. We could do a meme coin, yeah, that would be great. It's quantum. It's absolutely, but not quantum, okay. It's quantum and not quantum at the same time. But here's the point, right? On the one hand, what this does is it provides a different way to think about quantum systems because if every quantum system is mathematically dual or representable or equivalent to just a boring stochastic system evolving in some probabilistic way without all of the"
},
{
"end_time": 4374.36,
"index": 180,
"start_time": 4358.029,
"text": " What if I've got some really complicated stochastic process I'm trying to model?"
},
{
"end_time": 4403.626,
"index": 181,
"start_time": 4374.36,
"text": " complicated. Maybe it's a process that goes beyond the usual approximations we like to make. There's this famous approximation called the Markovian approximation, which just says that we can ignore like past effects, right? We make this approximation all the time. But what if we can't? What if we have a system that's distinctly non-Markovian? Well, not clear how to simulate those in an efficient way. But with a bridge between these kinds of systems, these non-Markovian systems and quantum systems, there's the possibility that some of these systems that might have been very difficult to simulate on a computer, that might have real-world applications,"
},
{
"end_time": 4428.302,
"index": 182,
"start_time": 4404.275,
"text": " may be efficiently simulatable on quantum hardware. All you have to do is take the process, which is some non-Markovian, very complicated process, figure out what kind of quantum system it corresponds to, and then see if you can build that kind of quantum system on quantum hardware and a quantum computer. And so there's the hope that you might be able to simulate some very difficult stochastic processes that could have practical applications throughout the sciences and economics and finance and whatever, right?"
},
{
"end_time": 4457.176,
"index": 183,
"start_time": 4428.848,
"text": " Some of them may be efficiently simulable on quantum hardware. Unfortunately, we don't have any quantum computers around. But one day if we do, this potentially could be a new use for quantum computers. One of the big mysteries... See what? How big do you need them to be? I don't yet know. But I'll just say, one of the big mysteries about quantum computers is... How many qubits? Don't know yet. But one of the mysteries about quantum computers is what are they good for? You might think, well, quantum computers, right? They take every classical computation, they do them all simultaneously,"
},
{
"end_time": 4487.193,
"index": 184,
"start_time": 4457.346,
"text": " Right? And that's why they're powerful, but it turns out that's not how they work. They don't work that way. So many things you might think they give you a speed-up for, they don't give you a speed-up for. There's actually a pretty narrow set of problems that quantum computers, at least as far as we know, give you an appreciable speed-up with. Famously, one of them is cracking RSA encryption. So quantum computer would make it very efficient to crack RSA encryption, prime factorizations, that kind of thing. There are a couple of other problems that we know that quantum computers could be very useful for. One of them is just simulating quantum systems very efficiently. This could open up a whole other avenue."
},
{
"end_time": 4515.708,
"index": 185,
"start_time": 4487.79,
"text": " Simulating very complicated real-world non-quantum stochastic systems using quantum hardware. And anytime you find some potential new use for quantum computers, that's a potential thing that they might be useful for. Can I ask a question there? When you said Markov systems, I'm wondering about the thought that there are concepts mainly in finance, that past information tells you nothing about where the next move will be in something."
},
{
"end_time": 4529.428,
"index": 186,
"start_time": 4516.203,
"text": " Is that maybe too limited a view? If you had enough quantum computing, could the Markov process be different? Is there information in the past?"
},
{
"end_time": 4557.602,
"index": 187,
"start_time": 4530.35,
"text": " said there is. Yeah, yeah. So, so now to be clear, I am not an expert in finance, or an algorithmic trading or anything that's super related to this. So I couch anything I'm about to say here with the huge huge. But now you've convinced us anything you say will take. There is a very narrow set of subjects of which I have any sense whatsoever. Anyone who knows me would know that. But but okay, but I'll just say, one always runs the risk when modeling anything,"
},
{
"end_time": 4583.302,
"index": 188,
"start_time": 4558.046,
"text": " That one is making too strong an approximation in some way, right? But, of course, we have to make approximations all the time. I mean, there's an old saying that every model is wrong. Yeah, because it's an abstraction. Absolutely. Every model is an abstraction. Every model entails some kind of simplification so that if we tried to do the whole thing all out, it would just be the original thing, right? A model is, by definition, some kind of simplification that we can work with. And we always have to make some kinds of approximations. The question is, are all those approximations legitimate? Are they all justified?"
},
{
"end_time": 4598.063,
"index": 189,
"start_time": 4583.968,
"text": " Now, if there are good, strong grounds for justifying the Markov approximation, the idea that all we care about is the present when predicting the future, if that's justified, we'll then make it. But if the only justification is, well, that's where the light is,"
},
{
"end_time": 4623.985,
"index": 190,
"start_time": 4598.285,
"text": " The lamppost is shining there, so I'm going to look there. I just don't know how to do anything else. That's not a good justification. And I would say that having a formalism for being able to handle it in an elegant, potentially efficient way, processes that do take the past into account, would be useful. Useful at least to model and see if it's useful for a planet. We're on to the flash round. Raise your hands. Go ahead. So, so... Introduce yourself. I'm Samson, I'm a pediatric pathologist and also a chronic complication of genomic sludge. This has been fascinating, but I'm tinged with a little bit of it."
},
{
"end_time": 4654.036,
"index": 191,
"start_time": 4624.326,
"text": " The modeling that you're talking about and measurements, you know, in health and disease, we make measurements all the time. And historically, we've come to understand human health and disease through classical physics, the heart is a pump, there's the fusion, there's chemistry. Is any of the things that you're talking about, space and time, waves, is that going to help us understand how molecules work in cells, or how cells work together, or how a doctor measuring blood pressure impacts the way we interpret it and what we do about it? My answer to that question is most likely no."
},
{
"end_time": 4683.695,
"index": 192,
"start_time": 4654.838,
"text": " At least not directly. However, there could be indirect consequences for how you do medicine. And the reason is because one way we do medicine is using causal modeling. And this brings us, now, you see how cleverly it segues back to the sort of question about what causation is, right? So, you know, if you're thinking about the heart as a pump, I mean, whatever model of quantum theory you have is probably gonna, you know, we're gonna demand of it that it's able to replicate the, you know, observed behavior of macroscopic classical systems. The heart appears to be a big macroscopic classical system."
},
{
"end_time": 4697.363,
"index": 193,
"start_time": 4683.695,
"text": " Some of us have bigger hearts than others, but all of our hearts appear to be big enough that we can treat them classically. But if you're trying to do drug discovery, if you're trying to understand how certain medical interventions will have a causal influence on the outcomes of diseases, you're interested in a subject called causal modeling."
},
{
"end_time": 4720.35,
"index": 194,
"start_time": 4697.739,
"text": " Now, causal modeling has become a very sophisticated area of statistics, a very sophisticated area of, I mean, do double blind, random controlled, randomized, double blind studies, these sorts of things, right? We're doing causal modeling. We have a set of variables, a set of things we're trying to study, and we're trying to understand how they're related to each other. We're trying to understand how"
},
{
"end_time": 4744.206,
"index": 195,
"start_time": 4720.606,
"text": " you know, certain quantitative features of some physical condition are related to other conditions, are related to medical interventions or drugs. You want to have a causal modeling to understand why it's happening, a predictive modeling to say what will that intervention end up impacting in the future? That's correct. So how much increased explanation or how much of an explanation will come from incorporating some of the theories you want? So not directly."
},
{
"end_time": 4770.503,
"index": 196,
"start_time": 4744.821,
"text": " But the causal modeling framework gives a very interesting way to think about causation itself. For example, if you want to understand why we think a certain drug has a certain effect on a population, of course, we will administer the drug to some of the population, we will not administer it to the population, we're basically controlling a variable and we're studying whether the physical correlations that show up, and we're not just looking for correlation, we're looking for causal relationships, correlations of my causation,"
},
{
"end_time": 4799.889,
"index": 197,
"start_time": 4770.503,
"text": " And in order to suss out causal relationships, not just statistical correlations between things, we have to have in mind that we can do interventions. We have to imagine that some agents, the agent being the person running the study, can choose to activate a variable or not activate a variable, and then suss out what kinds of consequences we get from this. This is the do operator. But in an observation-independent way, that's the whole point of double-blind. It is in an observation-independent way, but it does rely on the idea of an agent doing an intervention."
},
{
"end_time": 4817.073,
"index": 198,
"start_time": 4800.23,
"text": " And this idea that we do causal modeling with this interventionist conception of causation has become pervasive and how people talk about causal modeling for good reason. Because in everyday life when you're doing medical testing or we're trying to understand interventions of a more general concept of medicine, right?"
},
{
"end_time": 4846.681,
"index": 199,
"start_time": 4817.073,
"text": " We do have people, and people are agents, and agents can choose to intervene or not intervene in certain ways, and we can study the correlations involved from them. That's how we can assess that causal relationship. As an agent, can I intervene? So I want to open this question to the whole room and rephrase it a little bit. How much evidence is there that biology is dealing with quantum effects, and in what biological processes have quantum effects been observed?"
},
{
"end_time": 4868.951,
"index": 200,
"start_time": 4847.005,
"text": " There are some theories that consciousness arises from quantum. Let's turn it off, please. That's exactly right. And this is a question for everyone here. For example, microtubules in neurons have been postulated to have quantum properties."
},
{
"end_time": 4889.974,
"index": 201,
"start_time": 4869.258,
"text": " I have absolutely no qualms with so many different aspects of biology very early on. It doesn't need to be humans and the epitome of evolution as we like to think, which is ridiculous. But it could be bacteria, it could be like bats, it could be anything that's doing some type of sensing or some kind of"
},
{
"end_time": 4920.162,
"index": 202,
"start_time": 4890.486,
"text": " Who's going to give a very brutal answer to this, to this response? Brutal answer is the only thing we take. Yeah, yeah. So I understand this. I would say that this is a very similar proportion of how much we know about the system."
},
{
"end_time": 4948.131,
"index": 203,
"start_time": 4920.828,
"text": " because I think that we are using this possibility in biology to replace the lack of measurement events or the lack of detailed, you know, a signal. Yeah, because because you mentioned incidentally the two things to really be the three things that we know the least about it, which neuronal function and you measure a little bit of microtubules and in the early life."
},
{
"end_time": 4970.247,
"index": 204,
"start_time": 4949.65,
"text": " I work on a lot of fields where people will use that field to explain stuff that they don't understand, for example, epigenomics."
},
{
"end_time": 4997.534,
"index": 205,
"start_time": 4970.486,
"text": " They say, oh, it must be an epigenetic effect. I'm like, bullshit. So I did not say these just because we don't know much about them. On the contrary, I say them for very, very specific reasons. But we have a neuroscientist up there in psychiatry as well. I'm curious if anybody wants to take this on with, yes, there is quantum here. Because that's what I think you're getting at, right? So John, John, go ahead. Yeah, exactly."
},
{
"end_time": 5013.507,
"index": 206,
"start_time": 4997.995,
"text": " Yeah, so that's at the limit of physics. And let me make a very quick trivia here. It's a parenthesis, but I think you guys are going to love it. Just picture to close the parenthesis, otherwise you'll get an error. So in a sequoia tree, where does all the biomass come from?"
},
{
"end_time": 5041.613,
"index": 207,
"start_time": 5015.043,
"text": " Very simple interpretations. Oh, it must be the soil. It just sucks up nutrients. It's the carbon. It's the carbon. The decarbonization of the atmosphere. All of the wood actually comes from exactly that process that John just mentioned. So the fixing of carbon atoms from the air. And when you lose weight, where does the weight go? Why is that quantum? Go ahead, John. Why is it quantum?"
},
{
"end_time": 5072.261,
"index": 208,
"start_time": 5042.534,
"text": " Well, one is at the top of that. It has very defined chemical reactions that they can be reproduced further and interfere in a measure of the way. So if understand anything from the lectures about... So quantum does not mean uncertainty. This is here. When the photon shifts something, then there's a quantum effect and then the reactions. Well, then everything is quantum, which is fine. We're going to do the star exploratory."
},
{
"end_time": 5101.971,
"index": 209,
"start_time": 5072.5,
"text": " This is the flash round, so I'm happy to go to the next question. I wanted to ask what you meant by conscious coming out of quantum mechanics. We'll come back to that. That might be the ender. Flash round, continue. Go ahead."
},
{
"end_time": 5129.787,
"index": 210,
"start_time": 5103.234,
"text": " Does quantum field theory naturally explain non-locality?"
},
{
"end_time": 5157.892,
"index": 211,
"start_time": 5130.111,
"text": " So the problem with the word non-locality is it needs to be precise-ified. What do you mean by non-locality? No, this is not me being an annoying philosopher. There are different definitions of non-locality. I need something more precise for that answer. But tell us, give us a few options. We have two electrons that are entangled. They were here one day and then they were brought apart. One is on the moon, one is on the earth. You make a measurement, whatever that is, on one and you determine the spin of the other."
},
{
"end_time": 5171.578,
"index": 212,
"start_time": 5158.2,
"text": " But since you have only a single electron field everywhere,"
},
{
"end_time": 5195.35,
"index": 213,
"start_time": 5171.937,
"text": " We can entangle a photon and an electron, too, and then you have two different fields, right? So, yeah. A quantum field does not resolve the fundamental problems of quantum mechanics, the measurement problem or the problem of non-locality, yeah. A very naive question. That assumes that nobody has observed either of the two during that entire time that they've been apart, right? But notice something really important about this question."
},
{
"end_time": 5224.906,
"index": 214,
"start_time": 5195.811,
"text": " Notice that in all these discussions about non-locality and quantum mechanics, going back to Einstein-Podolsky-Rosen, the EPR paper, and the example, there's a particle here, there's a particle, they were interacted, they entangled, they went far away, and then someone measured one of them. And so measured the other one. Notice you've got agents' interventions again. You've got observers playing a central role in this picture. They hit something, right? If they hit something. Yes, the observer. If they hit something and it doesn't count as an observer and you don't do the axiom."
},
{
"end_time": 5247.125,
"index": 215,
"start_time": 5225.077,
"text": " You said that it's spin determined. What do you mean by spin determined? Meaning that it now has in that moment in time, it has"
},
{
"end_time": 5269.872,
"index": 216,
"start_time": 5247.432,
"text": " Where are you to measure it? Yes. But no, no, no. But you see, that's exactly the point, right? If you get rid of the idea that there's a fundamental axiomatic role to be played by the observer, eliminate the observer and just go back to the. So look, before the advent of quantum mechanics,"
},
{
"end_time": 5287.824,
"index": 217,
"start_time": 5270.333,
"text": " Physics had moved into a very impersonal picture, right? The Laplacian paradigm of physics is there's just a bunch of stuff everywhere, particles moving around, different positions, different velocities, and a giant differential equation describing how this state of the universe was to be updated moment to moment."
},
{
"end_time": 5309.343,
"index": 218,
"start_time": 5288.063,
"text": " There's no role for observers. There isn't even a role for causal influences between things. Observers, causal influences, these are all just colorful language, descriptive language, ways to summarize the things you're seeing, ways to paint a picture, but ultimately all of it is irrelevant, right? And then quantum theory comes along and suddenly the observer comes right back in again. The observer plays the central role."
},
{
"end_time": 5338.148,
"index": 219,
"start_time": 5309.889,
"text": " A lot of the interpretive approaches to quantum theory, not just mine, but Bohmian mechanics, all these approaches demote the observer back down to being an ordinary system. There's no fundamental role to be played but observer. When you've entangled systems and some system comes along like the moon, not an observer or whatever, and in some way interacts with the particle, there's no collapse that happens. And so the seeming causal influence that's supposed to be traveling superluminally, it actually becomes much more murky to say that's happening in this picture. Jacob, can I jump in for a second?"
},
{
"end_time": 5366.886,
"index": 220,
"start_time": 5338.507,
"text": " Let's talk about the moon for a second. So basically you have this entanglement and there hasn't been a human observer, let's say, but, but this touches the moon and now you've just kicked the can down the road. You've basically passed the uncertainty to, you know, the next, like every time it bounces somewhere, that secret gets propagated and carried along. And sort of my, my trouble with all that is,"
},
{
"end_time": 5393.899,
"index": 221,
"start_time": 5367.295,
"text": " The concept that there hasn't been an intervention to either of these two particles is something where it fundamentally breaks down. This whole sort of nonlocality assumes that, hey, nobody touched that for a while. And then there needs to be, of course, some communication and coordination for nobody to touch it so that eventually I can kind of like pass that information over there. And then, yes, that thing gets observed."
},
{
"end_time": 5417.841,
"index": 222,
"start_time": 5394.735,
"text": " And I knew something about here, but to even pass that information back is, you know, just when Schrodinger introduced the term entanglement. So Schrodinger wrote in, he also wrote in German. We also wrote in English. He introduced the word entanglement. He introduced this word in 1935 and the paper, which he introduced the idea. He talked exactly about what you're talking about. He called it a, um,"
},
{
"end_time": 5445.964,
"index": 223,
"start_time": 5418.251,
"text": " a regress problem, right? Tracing it back. Tracing it back. Systems interact with entangled systems. More and more systems start to participate in entanglement. And he called it entanglement. He said entanglement was not one but the feature that in his mind made quantum theory different from pre-quantum physics. He was very clear about this in the opening page to this paper. So this infinite regress question is a very interesting question, but here's the thing."
},
{
"end_time": 5472.978,
"index": 224,
"start_time": 5446.561,
"text": " When you take a physical theory, an unintuitive physical theory, and we've had lots of unintuitive physical theories, special relativity is a great example of an unintuitive theory. Unintuitive theories often lead to situations that prima facie look paradoxical. In special relativity, there's this famous paradox, not really a paradox, called the twin paradox. The twin paradox is the statement that if I am moving relative to you,"
},
{
"end_time": 5503.814,
"index": 225,
"start_time": 5474.206,
"text": " then you will see my clock running slow, but I will see your clock running slow. How can I see your clock running slow and you see my clock running slow? That seems to be a paradox, right? It seems obvious that there's some kind of paradox that I see your clock running slow, but you, because I'm moving relative to you, you see my clock running slow. This can't both be right. But when you carefully try to pin down whether this paradox is really happening, if you very, very carefully describe the situation, describe how you would actually check to see if the paradox is happening, you find it doesn't happen. If the paradox doesn't actually happen, the paradox was an illusion."
},
{
"end_time": 5526.852,
"index": 226,
"start_time": 5504.394,
"text": " The non-locality in quantum mechanics, at least if the non-locality is to be given a causal valence, you'd think this non-locality is not just the kind of non-locality where two things are correlated, but that there's some kind of influence actually propagating faster than light. It does seem kind of like there is, and when you model quantum systems in the traditional way with observers doing interventions,"
},
{
"end_time": 5554.94,
"index": 227,
"start_time": 5527.363,
"text": " It looks like causal things are happening. And this goes back to the causal modeling. When you think of causation, causal modeling, in terms of interveners, agents intervening, and that's how you define causal relationships, it certainly does look like there's a causal influence propagating. But if you remove the observer as a fundamental primitive from the axioms of the theory, if you say, don't talk in terms of Alice and Bob as observers, tell it to me in terms of the atom."
},
{
"end_time": 5574.889,
"index": 228,
"start_time": 5555.282,
"text": " What are the atoms doing? Tell me the story of this causal influence propagating at the level of the atoms, the microphysical level. It goes away because there's no interveners, there's no agents anymore. And so what you need now is to find some other way to talk about causation. You need to do some other definition of causation. And there was one person who did that, John Bell."
},
{
"end_time": 5602.892,
"index": 229,
"start_time": 5575.555,
"text": " In John Bell's second version of his famous Bell theorem, 1975 paper, the theory of local beables is what it was called, the term beables. He tried to find a version, a way to formulate this non-locality in quantum theory that showed that it was causally non-local, that it was causal influences propagating instantaneously, but without relying on agents and interveners. He tried very hard to do it, and arguably he did not succeed."
},
{
"end_time": 5626.834,
"index": 230,
"start_time": 5603.37,
"text": " So it does look on the surface like some nomenclature causal factors happening. But if you try to phrase in terms of the atoms without a good robust theory of causal influence, it's very hard to say that it's happening. Bell tried to do it, but arguably he was unsuccessful. Okay, last chance for questions, people who have not spoken to me so. The model was probably out of this stuff when we were 22 year olds or 20 year olds inspired by learning just a scratch more than high school physics."
},
{
"end_time": 5635.009,
"index": 231,
"start_time": 5627.09,
"text": " And I'm struck looking back, you know, 30 years since 35 years since how you're still just then you're quoting the 1975 book, right?"
},
{
"end_time": 5660.845,
"index": 232,
"start_time": 5635.452,
"text": " Can you give us a flavor of what's happened in the last 50 years? And I wonder if you're just not saying much because we're not. We're not ready. We're not worthy. That would be a theory. But but if you could like what what's at? Are we really that frozen that we're still talking about these hundred and fifty year old theory was as if they're the stick of the art? Yes. That's what I needed to know. Jacob, you wrote your paper."
},
{
"end_time": 5689.309,
"index": 233,
"start_time": 5661.101,
"text": " I'm going to slightly expand on it just a little bit and just say this. This thing that we're doing here, this thing that... The decoherence. No, this thing that you have brought into being, this intellectual exchange, this discourse that we're engaging in right now, this intellectual engagement that we're experiencing right now, there is so little of this in physics right now."
},
{
"end_time": 5708.643,
"index": 234,
"start_time": 5690.06,
"text": " We must all sit around in the physics department and talk like this and talk about what's going on. We do not. This does not happen in physics departments. That does happen in philosophy departments. It does not happen in physics departments."
},
{
"end_time": 5736.903,
"index": 235,
"start_time": 5708.933,
"text": " Okay. Why does it happen to physics departments? Complicated historical reasons. Now in the early, the first half of the 20th century, right? You look at the great physicists in the early 20th century. That was happening. Right. That was happening all the time. Yeah. Right. They were deeply engaged with philosophers. They were deeply engaged with the Vienna circle and the positivists and they were reading Karl Popper and they were arguing about Schopenhauer and they were arguing, but they were all claiming on all sides of the debates, but quantum theory that they were the true Vickers of Kant and Kantian philosophy. All of them were doing that. Right."
},
{
"end_time": 5763.097,
"index": 236,
"start_time": 5737.295,
"text": " and then something shifted in the intellectual environment in physics and the best i can say is it was the war it was the shift of physics to america and it was also money okay when there's a lot of money at stake people suddenly feel like they're in a huge hurry to get concrete practical results there's no time to sit around and talk about philosophy it'd be good then for you to study finance"
},
{
"end_time": 5785.265,
"index": 237,
"start_time": 5763.422,
"text": " Alright, more questions, more questions. We need more of this, I'm saying we need more of this. Right here and there, right there, those two. Can you give us some sense of what is beable? It seems like, what is reality, right? You told him waves are not it, maybe the fields are, I can kind of have a sense of what observable means, but what is, at least in the... You, sir, are a beable."
},
{
"end_time": 5800.196,
"index": 238,
"start_time": 5785.862,
"text": " He's a bee. He's actually instantiated. You are a bee. So not just a bee able, you're a bee is. No. So what I mean by this, what I mean by this. So I don't know what the fundamental beables of nature are."
},
{
"end_time": 5826.578,
"index": 239,
"start_time": 5801.084,
"text": " We don't yet know the fundamental beables of nature. We don't know. We're aware of atoms. Atoms are made of smaller things. We don't know what the most fundamental constituents of nature are. At electrons, photons appear to be manifestations of perhaps quantum fields. Maybe quantum fields aren't fundamental. We don't know what the fundamental beables are. However, just because something is not fundamental doesn't mean it doesn't exist."
},
{
"end_time": 5846.954,
"index": 240,
"start_time": 5827.039,
"text": " Imagine you came in from a rainstorm and you come in and you say, gosh, I'm really wet. And your friend says, no, you're not. Of course, I'm wet. I'm clearly wet. The person says, no, you're not. In what sense do you say I'm not wet, sir? And your friend says, well, at the level of the individual water molecules, wetness doesn't exist."
},
{
"end_time": 5874.94,
"index": 241,
"start_time": 5847.654,
"text": " Water molecules are fundamental. Wetness is not a fundamental thing. Therefore, it doesn't exist. You go, oh, come on. Things can exist without being fundamental. You exist, even though you're not fundamental. Jacob, I have an answer to your earlier question. You asked me, what's a miracle? I have an answer. Do you want to hear it? Yes, please. OK, so, so, so what's a miracle? I was talking earlier about wishing for something and then that wish needing something non-causal"
},
{
"end_time": 5904.224,
"index": 242,
"start_time": 5875.026,
"text": " and outside the cone of the present and the future to happen. And I have the distinction between a miracle and the opposite. If I want something done, I don't just wish for it. I make a phone call and I cause the series of causal events for my reality to come through. And I just expect that it will appear somewhere in that cone of future possibilities."
},
{
"end_time": 5935.06,
"index": 243,
"start_time": 5905.947,
"text": " A miracle is a wish that does not causally result from that cone outside. In other words, a miracle is something that I should have done earlier if I wanted that to happen. And I'm sorry for saying this so openly, but I think it's hopefully a lesson to all of the young people in the room. If you want something done, start working on that cone ahead."
},
{
"end_time": 5960.128,
"index": 244,
"start_time": 5935.691,
"text": " Don't worry about that non-causality. Anyway, so... But on the beableness... I don't know what the fundamental beables are, but I do know that at some emergent level, there are non-fundamental beables like yourself. So Jacob, tell us now about your view. We talked about the Copenhagen view, about a few other use-tels, about your view. Good. So my view is that physical systems,"
},
{
"end_time": 5980.691,
"index": 245,
"start_time": 5960.589,
"text": " have actual physical configurations, just like we would have imagined in the pre-quantum world, but that the laws we didn't have that we couldn't come up with back in the early 1920s, they couldn't come up with the right laws in the 1920s because they were stuck in some old paradigms. They thought laws had to be Markovian. All the known physics up until that point was Markovian. You know what's going on right now, you can predict the future."
},
{
"end_time": 6006.8,
"index": 246,
"start_time": 5981.323,
"text": " They were working on this in the 20s. This was before there was a modern theory of stochastic processes. This is certainly before people were talking about non-Markovian stochastic processes. Yeah, there was Brownian motion, there were Wiener processes, but like a sophisticated, comprehensive theory of stochastic processes, certainly out of the mark of approximation was unavailable. And as best I can tell from having plumbed this literature in depth, there is nobody, nobody who conjectured"
},
{
"end_time": 6032.91,
"index": 247,
"start_time": 6007.176,
"text": " that you could take classical-like ingredients, physical ontology, physical configurations, and give them non-Markovian laws and see if you can get quantum mechanics out of it. This was never done by anybody, ever. So what you're saying is that just non-Markovian-ness... Non-Markovian-ness alone is not enough. You need a particularly strong form of non-Markovianity called indivisibility. It's called indivisibles stochastic processes. The term was introduced in a 2021 review article. Explain what's indivisible."
},
{
"end_time": 6055.691,
"index": 248,
"start_time": 6033.541,
"text": " If you know what a Markov chain is or a Markov process, these are processes where you can kind of concatenate"
},
{
"end_time": 6083.353,
"index": 249,
"start_time": 6056.084,
"text": " You can do the evolution of the system in steps. At every moment, you've got a law that tells you what happens next. You have another one that happens next. And notice you can divide it up. And an individual process simply fails to have that property. It fails to have the property that you can take any duration and break it up into sub-durations that have lawful descriptions. And once you get that up, you have a much more general class of processes, processes that naturally exhibit phenomena that look like interference,"
},
{
"end_time": 6106.561,
"index": 250,
"start_time": 6083.353,
"text": " And if you want to know like why quantum computers are so useful, I mean, so there's another interpretation of the many worlds interpretation. And one of the reasons why David Deutsch, one of the founders of quantum computing, wanted to develop quantum computers was to prove that many worlds was right because he said quantum computers can do more than classical computers can do. And the only way to explain this is that they're doing the calculations in all these parallel universes. But he was very disappointed. We all very disappointed when we discovered that many calculations"
},
{
"end_time": 6134.838,
"index": 251,
"start_time": 6106.561,
"text": " cannot be made faster on quantum computers. And then people began to wonder, well, if there really are all these many worlds out there, and the calculation really is happening in all these worlds, why is it that so many calculations cannot be made more efficiently on quantum computers? This strongly suggests to me that those are the worlds aren't really there, and that you're getting the advantage for quantum computers from a different source. And the different source is, if you try to model a computer using Markov processes, and all computers basically are Markov chains. They're deterministic Markov chains."
},
{
"end_time": 6160.452,
"index": 252,
"start_time": 6135.162,
"text": " Once you allow yourself to have not just probabilistic computing but indivisible probabilistic computing, you have a much more general set of systems. And with a more general set of systems, you can do more things. Good, but they're less predictable because basically the cloth allows you to sort of know it. And which things you can do that give you an advantage over the classical case is not obvious a priori. Amazing, thank you. Alright, next question. Hi, Chris Flynn from Fidelity Investments. Thanks a lot, this is fun. You kind of answered my first question, but"
},
{
"end_time": 6182.654,
"index": 253,
"start_time": 6161.561,
"text": " Is there a way to actually observe or measure a quantum system without actually physically interfering with it? Alas, no. However, there is a very interesting protocol known as weak measurements. It was introduced by some quantum foundations people, interestingly enough. Aronov is one of them."
},
{
"end_time": 6203.609,
"index": 254,
"start_time": 6183.234,
"text": " Yeah, so Arnav was involved, a couple of people involved, David Albert was involved, he went from physics to actual philosophy. So a lot of people who work in philosophy started as physicists, which he did and ended up doing philosophy of physics. Weak measurements work in the following way. Don't study just one system. Take 10,000 identically prepared copies of your system."
},
{
"end_time": 6232.688,
"index": 255,
"start_time": 6204.48,
"text": " And don't do what we call a projective measurement. Do a very, very, very gentle measurement. Interact with it in just the most gentle way. Now, if you do this in this very gentle way, you're not going to get an answer from each system. The interaction is going to be so weak that when you send a measuring device in, you let it interact super duper weakly. You then bring the measurement device out and you look at the measuring device. And you gain very little information about the system you've measured. Very little."
},
{
"end_time": 6260.725,
"index": 256,
"start_time": 6232.978,
"text": " The benefit, though, is that you don't lead to this projective collapse happening to the system. And you might go, well, but if I'm not getting any information out of it, what's the point? It's a partial collapse. That's right. You do this very, very gently. But you do this with 10,000 systems, with 10,000 of them, and they're authentically prepared. And for each one, you just you just very, very slightly graze it. Just get a little just a just scoop a little bit off the top, just a teeny teeny little bit off the top. Right. And you collect all the data. You can actually gain some information from all the data."
},
{
"end_time": 6290.964,
"index": 257,
"start_time": 6261.288,
"text": " Now, here's where the interpretational problem comes in. So this is an experimental protocol that you can actually do. You can do this experimental protocol, you can actually do this, and lo and behold, you'll get results on your, you know, you'll take all the data, you'll put them in a computer, and you'll get a number out. And the fact that you can get a number out from measurements made everyone super excited. There's a kind of philosophy, not a small p philosophy, a kind of attitude, right, towards science, that if you can do a measurement on it, it's science, and that makes it great, regardless of whether you have any good interpretation for what you're doing."
},
{
"end_time": 6315.879,
"index": 258,
"start_time": 6291.596,
"text": " There's no question we can do these measurements, these so-called weak measurement protocols. People have been doing them. The question is, when that number comes out, what the fuck does it mean? Right? And there's been a huge dispute over the years. Like, you get a number, okay, but what is that number telling me? It's not, I haven't done a standard measurement of my quantum system, so I can't say I'm measuring some property of my quantum system. I get some number, what does that number mean?"
},
{
"end_time": 6345.981,
"index": 259,
"start_time": 6316.408,
"text": " And people have tried to interpret what that number means and they've said some rather outlandish things about what that number is. And the question about what that number means is now kind of a almost philosophical question. So yes, there are ways to do measurements where you're barely interacting with the system and you can get a number out. And I should say the number does have a mathematical significance. The number is computing what's called a matrix element of a self-adjoint operator. But the question is like, does it tell you something physical about the system that you're measuring? And that's very murky."
},
{
"end_time": 6374.548,
"index": 260,
"start_time": 6346.408,
"text": " So I would say is that at least according to the standard picture of quantum mechanics and all the interpretive frameworks that we know of, to get an actual reliable robust result out of the measurement process, you're going to have to get a decoherent process involved and that will inevitably produce some deviation or change in the system. And one way to see this is just that measurements in quantum mechanics are inherently non-commutative. If you measure A, non-commutative. If you measure property A and you measure another property or observable B,"
},
{
"end_time": 6400.196,
"index": 261,
"start_time": 6374.889,
"text": " And B has to have a certain feature. It's got to be incompatible with A. It has to satisfy what's called a complementarity relationship or uncertainty principle. But if you measure A, then B, then A again, you may get a different answer for A. And no matter how gently you measure B, as long as you measure it strongly enough to get some reliable robust information out, then invariably there will be some consequence for the measurement of A. Final quick question. It's a very small one. What's the relationship between consciousness and quantum?"
},
{
"end_time": 6432.739,
"index": 262,
"start_time": 6404.514,
"text": " There is absolutely no way that I can answer that question without telling a little story. Can you tell the story? We'll take the story. How many of you know, have ever heard of Mary's room? A couple of you have heard of Mary's room. So philosopher, philosopher Frank Jackson introduced a thought experiment called Mary's room. Mary's room works like this. Mary is a super brilliant scientist. She lives in a sealed room. And in this sealed room, everything is black, white and shades of gray."
},
{
"end_time": 6463.166,
"index": 263,
"start_time": 6433.336,
"text": " Even her skin, somehow she's been, they, you know, altered her skin. She has never seen a color before. Never, ever, ever seen a color before. But she's very smart. She has access to a black and white grayscale version of the internet. She has access to all the information there is. She has advanced scientific equipment. She's got an electron microscope. She has every, she can even call in people. Of course, they have to be decolored before they come in. And she can slice their brains open and she can peer in their brains. She can electrode. She can do absolutely everything. And she has unlimited intellectual ability."
},
{
"end_time": 6486.374,
"index": 264,
"start_time": 6464.206,
"text": " Can she ever cross what's called the explanatory gap? There are two problems in the philosophy of consciousness, the easy problem and the hard problem. The easy problem is not an easy problem. The easy problem is will science ever get to the point at which we can have a sufficiently sophisticated model of the brain that we can describe and explain the behavior of conscious beings?"
},
{
"end_time": 6512.602,
"index": 265,
"start_time": 6486.715,
"text": " And most people would say that's a hard problem, but you can imagine science getting to the stage at which maybe with enough technology and we can simulate, we can model brains and simulate them on sufficiently powerful computers, we can say, okay, when a brain is conscious and does these things, we can predict what we'll do, at least probabilistically, and others who can't. So that's still a pipe dream at this point, but maybe one day we can imagine doing it. The hard problem of consciousness, this was coined by David Chalmers, a philosopher, is, okay, well, once you have that model,"
},
{
"end_time": 6543.217,
"index": 266,
"start_time": 6513.729,
"text": " Why does it feel like anything? What about the subjective experience? Like, the fact that, yeah, the brain does these things, there are these sort of neural correlates, these states of the brain, neural correlates of conscious experience, the neural correlates of conscious NCCs. But like, why do they come along with redness, like the distinct feeling of redness? And now there are people who doubt that there is a hard problem. They're like, oh, it's an illusion or something like that. When Mary's Room thought experiment, part of what it's supposed to do is technically what Mary's Room was originally introduced was the argument's physicalism. But I read it in a different way."
},
{
"end_time": 6565.469,
"index": 267,
"start_time": 6544.121,
"text": " Mary can do all science, all the science you can imagine. She's immortal. She can do science for centuries. She can develop all the science you can imagine. She can do every experiment ever done. But will she ever, and she may even be able to get to the state in which she can like figure out what to do to her brain, like which electrodes to push so that she'll have an experience of red. Okay, maybe she can even do that."
},
{
"end_time": 6593.985,
"index": 268,
"start_time": 6565.998,
"text": " But can she ever explain how you get from the physical thing in the brain to suddenly having the experience of the actual color? How do you get from the physical stuff? Where does that come from? That's the explanatory gap between the easy problem and the hard problem. And there are many people who doubt the hard problem is solvable precisely because of the Mary's Room argument. Because even if you imagine unbounded scientific expertise, even if you could characterize, okay, this brain state corresponds to feeling red, this brain state corresponds to feeling green to blue,"
},
{
"end_time": 6623.933,
"index": 269,
"start_time": 6594.445,
"text": " You have the brain states written down, but you still don't know why they come along with these particular feelings. And that's the hard problem of consciousness. Now, some people doubt it exists. I feel sorry for you if you do. But, so, now let's go back to the quantum case, okay? Suppose we were able to say, okay, certain brain processes inherently use quantum mechanical phenomena. So what? Does that get us across the gap from the easy problem to the hard problem? Just because quantum mechanics is happening in the brain, maybe, and playing an instrumental role in certain processes, even if you know that, even if you can model that,"
},
{
"end_time": 6651.459,
"index": 270,
"start_time": 6623.933,
"text": " Okay, well, how do you get from that to and then when this is happening, this is how I'm gonna read this This is read I'll actually have experience of red and when you first have that experience of red when Mary first has experience of red She's learned something When she leaves the room for the first time and suddenly sees color Something new has been learned to her and she doesn't know why and none of her scientific experience up at that point can explain Why suddenly she's having these experiences? So I think the hard problem is not solvable and I think that's just fine. I"
},
{
"end_time": 6674.718,
"index": 271,
"start_time": 6651.732,
"text": " I think there are deep problems in nature that maybe we'll never be able to get to, and I don't think that understanding whether quantum mechanics is working in the brain or not is going to let us transcend the explanatory gap from the easy problem to the hard problem. That's just my point of view, and I could be wrong. In my view, it is insolvable in principle. The hard problem, insolvable in principle. That's my view."
},
{
"end_time": 6705.503,
"index": 272,
"start_time": 6675.725,
"text": " Well, that's an interesting question, right? So, is Mary's room an argument against AGI? I don't necessarily think so. AGI might be just the easy problem. That is, if we can figure out how to model a system that behaves consciously, could we simulate it, and wouldn't the simulation be AGI? Artificial general intelligence, like a computer that really does behave in distinguish from human. However, if you then ask, does that computer have internal subjective experience? That we can't know."
},
{
"end_time": 6730.794,
"index": 273,
"start_time": 6705.862,
"text": " And I don't think any scientific investigation will tell us the answer to that. There's a term that was introduced before David Chalmers in the 70s called the P-zombie, which haunts the nightmares of metaphysicians all over the place. The P-zombie is not, you know, a zombie. P-zombies function and observerly behave exactly like conscious beings. They're like your AGI computer."
},
{
"end_time": 6755.128,
"index": 274,
"start_time": 6731.101,
"text": " carefully designed so that it simulates the same exact processes that go on in the brain of a normal human being, and it's plugged into a robot, and the robot looks like a person and walks around and talks and says, ah, that hurts, so it feels bad, or I see red, or whatever they're saying, right? Okay. But does that computer have it? Is there something that it is like to be that computer? Does it have an internal subjective experience like the kind that we believe we have? If it does not, it is called a pee zombie."
},
{
"end_time": 6771.032,
"index": 275,
"start_time": 6755.845,
"text": " Now there is a view among some metaphysicians and some philosophers of mine that P-zombies, philosophical zombies, it's short for P-zombies, are conceptually impossible, they're inconceivable, that anything that behaves sufficiently like a conscious being"
},
{
"end_time": 6795.964,
"index": 276,
"start_time": 6771.493,
"text": " As somebody who studies neuroscience and biology and, you know, all of that, and by the way, our next salon will be on consciousness. What if we're just faking it?"
},
{
"end_time": 6826.323,
"index": 277,
"start_time": 6796.664,
"text": " In other words, if you look at the neuronal basis of subjective experiences, there are many experiments where, for example, if you cut the corpus callosum, you can actually have part of the brain unaware of the commands that were given to the other half that then led to an action. And that part of the brain that never saw that command will interpret the action as something that it really wanted."
},
{
"end_time": 6855.759,
"index": 278,
"start_time": 6826.988,
"text": " And then the question is, is the brain a very, very good employee who just never wants to be caught not knowing and who will always make up a story, including when asked, why are you thinking? In other words, do we, like, do we know that we ourselves have any consciousness beyond what we are, you know, claiming that we do? And, and yes, sure. Your answer was very provocative by basically saying, maybe you don't, but I do."
},
{
"end_time": 6872.739,
"index": 279,
"start_time": 6856.63,
"text": " Like there's no experiment that can prove to me that any of you have a consciousness. However, if I disconnect myself from my brain, maybe my brain is saying, oh yeah, of course you're super conscious. Like here's all the great things that you have that prove to you that you're conscious. Like why would I believe it?"
},
{
"end_time": 6892.073,
"index": 280,
"start_time": 6873.609,
"text": " All the humans are P zombies and lack internal conscious experience and a world in which they in fact have internal conscious experience and they'll observably look the same by construction. And this just is telling us that we're probably not going to be able to get at this question. If you transport yourself from the self to the other person looking at the self, is there anything you can do to prove"
},
{
"end_time": 6922.449,
"index": 281,
"start_time": 6892.705,
"text": " that you're actually conscious. Like I said, anything you could do in a world without internal conscious experiences, but P-zombies, could be done in a world with internal conscious experiences, and so I don't think that any... That's true, but either something in the opposite direction. Before we go on, I do want to tell a joke. You want to hear a joke? Of course. Here's a joke. I told this joke to David Chalmers, and he liked it a lot. Okay, here's a joke. And those of you who have some background in high-energy theory will enjoy this joke, okay? Okay. What do string theory"
},
{
"end_time": 6952.329,
"index": 282,
"start_time": 6922.739,
"text": " He sent me back a zombie emoji. I have a zombie emoji from David Chalmers on my phone. I've saved it all these years. Remember the part where we were going to end by 7.45? I looked at my clock and I'm like, oh, is it like maybe 7.55? It's 8.55."
},
{
"end_time": 6980.06,
"index": 283,
"start_time": 6952.671,
"text": " Who had an amazing time tonight? So Kurt, Jacob, I can't thank you guys enough. Thank you for gracing us with your extraordinary thoughts and also with bringing so many new guests to our salons. Somebody commented, ooh, the crowd looks a little different. There's like more energy and all of that. So this is you guys. So thank you to all of the first time comers. I hope you will continue coming."
},
{
"end_time": 7002.5,
"index": 284,
"start_time": 6980.06,
"text": " New update! Started a sub stack. Writings on there are currently about language and ill-defined concepts as well as some other mathematical details."
},
{
"end_time": 7028.916,
"index": 285,
"start_time": 7002.705,
"text": " Several people ask me, hey Kurt, you've spoken to so many people in the fields of theoretical physics, philosophy, and consciousness. What are your thoughts? While I remain impartial in interviews, this substack is a way to peer into my present deliberations on these topics."
},
{
"end_time": 7058.2,
"index": 286,
"start_time": 7030.299,
"text": " Also, thank you to our partner, The Economist. Firstly, thank you for watching. Thank you for listening. If you haven't subscribed or clicked that like button, now is the time to do so. Why? Because each subscribe, each like helps YouTube push this content to more people like yourself. Plus, it helps out Kurt directly, aka me. I also found out last year that external links count plenty toward the algorithm."
},
{
"end_time": 7082.858,
"index": 287,
"start_time": 7058.251,
"text": " Which means that whenever you share on Twitter, say on Facebook, or even on Reddit, etc., it shows YouTube, hey, people are talking about this content outside of YouTube, which in turn greatly aids the distribution on YouTube. Thirdly, there's a remarkably active Discord and subreddit for theories of everything, where people explicate toes, they disagree respectfully about theories, and build as a community our own toe."
},
{
"end_time": 7105.282,
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"text": " Links to both are in the description. Fourthly, you should know this podcast is on iTunes. It's on Spotify. It's on all of the audio platforms. All you have to do is type in theories of everything and you'll find it. Personally, I gained from rewatching lectures and podcasts. I also read in the comments that, hey, toll listeners also gain from replaying. So how about instead you re-listen on those platforms like iTunes?"
},
{
"end_time": 7129.906,
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"start_time": 7107.227,
"text": " for watching."
},
{
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"start_time": 7129.906,
"text": " You also get early access to ad free episodes, whether it's audio or video. It's audio in the case of Patreon video in the case of YouTube. For instance, this episode that you're listening to right now was released a few days earlier. Every dollar helps far more than you think. Either way, your viewership is generosity enough. Thank you so much."
}
]
}No transcript available.