Theories of Everything with Curt Jaimungal - Sabine Hossenfelder on Theories of Everything, Consciousness, and Truth

Episode Date: August 13, 2020

Sabine Hossenfelder is a theoretical physicist who researches quantum gravity at the Frankfurt Institute for Advanced Studies, and is the author of Lost in Math: How Beauty Leads Physics Astray. Subscribe at https://www.youtube.com/channel/UCdWIQh9DGG6uhJk8eyIFl1w for more weekly conversations with intellectuals.Sabine's YouTube is: https://www.youtube.com/c/SabineHossenfelder/videosSabine's Twitter is: https://twitter.com/skdhFollow us at http://twitter.com/bluthefilm

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checkout. Sign up for a $1 per month trial period at shopify.com slash theories, all lowercase. That's shopify.com slash theories. Yeah. So, so thanks for your great questions. You know, usually I get a lot of, you know, shallow questions that I've answered a million times already. But yours were really, really well done. I looked at your list of questions and I thought that's going to be a tough one. All right.

I'm here with the scintillating Sabine, Sabine Hossenfelder, and we're going to talk about physics, a bit of consciousness, a bit of something called emergence. So Sabine, why don't you tell us, tell the audience a bit about yourself, as well as what you're working towards. I'm a theoretical physicist, and I presently work at the Frankfurt Institute for Advanced Studies in Germany. And, you know, my day to day research is mostly dark matter, superfluid dark matter in particular. But I also do some stuff in the foundations of quantum mechanics. And, you know, I'm generally broadly interested in the foundations of physics.

Superfluid dark matter. Dark matter is it's dark and it's not clear what it is. And you're qualifying it by saying superfluid dark matter. Why is that? Well, so this is a particular type of dark matter that was proposed by a group around Justin Curry about five years ago. And the curious thing about it is that this kind of superfluid appears like modified gravity. And I don't know if you've been following this whole debate, but there's this big fight in astrophysics about whether it's dark matter, so it's stuff made of particles

or whether we have gotten something wrong with gravity and we need to modify Einstein's theory of general relativity and so that there are benefits to either side I would say and people can't decide what's the right thing and the amazing thing about this type of superfluid dark matter is that it combines the benefits of both without the disadvantages of either. So when I first read about this, I was like, that's the thing to do. And I feel super, super lucky that I actually got a research grant that allows me to further study this type of dark matter. How does it combine the benefits of modifying the field equations of Einstein? Well, it doesn't exactly modify the field equations, but what this super

fluid dark matter does is that there is an additional force in the fluid, which is mediated by the phonons after condensation. And this force appears like it sits on top of gravity. So it makes gravity stronger, which is exactly what we observe. And now the interesting thing about it is that since it's generated by this condensation process, it's a very regular force that has a lot more patterns to it than you would get by normal dark matter that you can distribute however which way you like. So this normal dark matter has a big problem reproducing certain patterns that we observe, like the baryonic-tollifisher relation, just to mention an example. And superfluid dark matter can reproduce these patterns quite easily.

So is that what you're working toward primarily right now, is just fleshing that theory out, making it match with predictions, unless it already does? I mean, making it match with the current data? Yeah, basically. So on the one side, there's this question, like, how do you connect this with So I'm, you know, on the one side, there's this question like, how do you connect this with the data? But there's also on the theoretical side,

they are just things that are, have not been very well explored. So, you know, I'm a theoretical physicist. I work more on understanding the theory part. And, you know, but I have a student and a collaborator who are more on the observational side so of course we're hoping to connect the two and what's your youtube channel what's the goal what's the goal for everyone watching this you should check out I'll include a link to your youtube channel in the description check out her channel because if you're someone

who's interested in physics, and if you're an undergrad in physics, even if you're a graduate in physics, you'll have plenty to learn from her channel. She has music videos as well. As far as I know, Sabine, you've moved your music videos to another channel, though some of the old ones remain. And so what the heck is, why are you doing the YouTube channel? Maybe it's self-explanatory, but I want to hear it from you. And then channel maybe it's self-explanatory but i want to hear from you and then second what's the deal with the music videos well so um i've been in science communication like for almost 15 years now and i used to mostly do writing um as you probably know i've written this blog called Back Reaction for quite a long time.

And I've just found in the long run that writing doesn't appeal to a pretty big group of people. And there's generally an issue with blogging, which is that the audience is pretty much self-selecting. is pretty much self-selecting. So after you've written on a particular topic for some time, which in my case is mostly particle physics, you're pretty much stuck with a certain group of people. So you live in this bubble. And then if you get interested in something else, like it's been the case with we,

you totally talk past your audience. So no one gives a shit, basically. I see. And on YouTube... So you developed too narrow of an audience over time with blogs yeah right and and now the thing is that um search engine um optimization has been going um in a way that doesn't really help this so people don't just go online and search for something on a blog that just doesn't exist.

And now the interesting thing about YouTube is that they will try to find an audience for your content. That's what the search algorithm does. And now, you know, there's a long conversation to be had about how well this actually works. But in principle, the idea is good. You know, they take your content and they try to find people who may be interested in it. And I think this has really helped me to get the stuff that I've more recently been interested in, which leans more towards philosophy, foundations of quantum mechanics, and more generally the sometimes not very well working connection between science and science policy. sometimes not very well working connection between science and science policy.

So, so this is all stuff that I found gets across much better on YouTube. And I mean, then there are obvious things like that. It's easier to explain some things if you can use graphics. Right. Right. And when you say that you're interested in the philosophy of the

foundations of quantum mechanics, are you referring to the different interpretations of quantum mechanics? Well, I'm, you know, I said I'm a theorist, but I'm actually, more strictly speaking, I'm a phenomenologist. It's just that I try to avoid the word because a lot of people don't know what it means. lot of people don't know what it means. Yeah, actually, a quick aside, phenomenology for the majority of our audience, they might be familiar with the philosophy that comes from Husserl. Exactly. And phenomenology, particle phenomenology sounds like, oh, are you talking about the umwelt of a quark? I don't know if you are aware of the philosophical phenomenology, but if you are, can you delineate it between the particle phenomenology?

Yes, so the phenomenology in particle physics has nothing to do with the philosophical area of phenomenology, but it basically sits in the middle between theory and experiment. So you're trying to develop a model that you can connect to what is actually measurable. So the theoretical side, in particular in particle physics, tends to be pretty much only math. That's what you do. And then on the experimental side, you measure. And the phenomenology is that group of people where we are making a connection between the two. So it would be as if Newton came up with a theory of gravity, and then someone said, well, here's how we can test the theory of gravity.

That's the phenomenologist. And then the experimentalists go out and do the actual testing. Is that the divide? Yeah, roughly speaking. Except that normally it's the case that you have a theory which is much, much more complicated than Newtonian gravity. So you have to coax something out of it that you can actually go and measure. I see. I see. And I'm sure you've heard of some of these new theories of everything that have been developed recently, two major ones.

for example, Weinstein's and Wolfram's. And I want to know if you're familiar with it and if you see, as a phenomenologist, any clear way of getting a prediction from them. No, I don't see such a way. I'm sure that they both have been thinking about it. But it's, you know, this is a really complicated process. I'm not even, sorry, I'm not even one to say that a prediction is necessary in the short term when you're exploring. I know that in your book Lost in Math it's

it's like hey there's been 20 years with string theory maybe more and it seems like right right right well these two new theories don't have that long of a history so it's not such a detriment at least in my estimation that they don't have prediction predictions associated with it even Feynman said that Feynman had this great talk I don't know if you saw it, but he was saying, don't prematurely throw out a new physics theory just because it doesn't comport with the data and doesn't make experiments. And he gave a great analogy. Imagine the Mayans 500, 600 years ago, and they had wonderful predictions. It was based on a wrong model, but it all fit with the data of how the sun

of when the sun is going to come out and then someone says hey i think that the sun actually revolves that the earth revolves around the sun and and then they say well can you predict when the moon is going to have an eclipse and i don't know i haven't i haven't gotten it that far. And they're like, oh, forget your theory then. Yeah, certainly. I mean, it can take a long time to understand a theory on a depth so that you can reliably make a prediction. And that's certainly a problem that we see in the foundations with a lot of people who are working alone or in very small groups, it can take like a really long time to get anywhere. And as long as they don't have, as long as they have nothing to show for, everyone else is like, yeah, no, I don't want to even think about it. Right. So it's kind of, it's a process where the rich get richer and the poor never get anywhere. Have you read Lee Smolin's book on the trouble with physics?

Yes, I read that. It seems like there's plenty of parallels between lost in math and the trouble with physics. Do you see any disagreements with your point of view and Lee Smolin's in the theory of, sorry, in the trouble with physics? Well, there are some parallels, of course, in that I think we're both concerned about where the foundations of physics are headed and that there are, there's too much emphasis on some few research directions. My book is more broadly about the foundations of physics, while Lee's book is more specifically about string theory. What's the difference, you ask? I think I'm far less critical of string theory than Lee is, but I'm somewhat more critical of low quantum gravity than he is. Right, right, right. So, you know, there are differences.

So how do you define the theory of everything? Is it simply unifying gravity with the other three forces, or is there something more? Well, you want to unify it so that it's consistent. You know, if you just take the standard model and you lump gravity on top of it, that's kind of a theory which describes both particle physics as we use it today and general relativity, but it's internally inconsistent. So what people mean with the theory of everything is a theory that combines all these four forces,

but is mathematically consistent. And it is widely believed that this will require quantizing gravity. So quantum gravity is kind of part of the picture. Should a theory of everything have as one of its ingredients an explanation for dark matter or dark energy or is that unnecessary? It's just purely about grand unified theory unifying these well you definitely need to do something about dark matter um because you need some resolution to that um i mean look dark matter makes up like 85 of the matter in the universe um so if your theory of everything does not describe most of what's

in the universe, that's a pretty poor theory of everything, I'd say. It's a theory of a few, of a minority. Yeah, basically. So when it comes to dark energy, there really isn't anything to explain. You know, you can just fit all the observations that we have quite well by just saying, well, it's a cosmological constant and that's just a constant of nature. And here we have quite well by just saying well it's a cosmological constant and that's just a constant of nature and here we have measured it and that's the value so there's there's nothing wrong with that so in the theory of everything in your eyes the there's some constants that simply need to be measured they can be taken for granted? They don't need to be explained by some other fundamental process?

They don't need to be explained, no. But it would certainly be nice if we were able to reduce the number of constants that we have right now. So this is certainly something that a lot of people hope for. But strictly speaking, it's not necessary, no. Do you think it's in principle possible to actually reduce all the physical constants to something else that's emergent, to just one? Well, it kind of depends on how you would define that.

Because, I mean, so it depends on what you mean by constants. The thing is that we have in our physical theories, we don't just have numbers, like numbers without units, but we also have dimension for constants. And you need these to come from somewhere. Like, I mean, I'm talking about things like the speed of light, Planck's constant, you know, Boltzmann's constant, that kind of stuff. constant, you know, Boltzmann's constant, that kind of stuff. And I don't really see how you can get around actually measuring them. Like how can we possibly derive them?

Yes. Which is also something that I think most people don't have in mind when they're talking about the theory of everything. You know, I mean, theoretical physicists like to just set all these constants equal to one. Right, right, right, that's true. So just to ease the calculation. So these are not the constants that they normally talk about when they say we want to derive this, but usually what they talk about are constants that do not have any units. So this may be, for example, the ratio between the masses of, I don't know, the Higgs boson and the electron or something like this. So this would be a typical example for a number that you would hope you can actually derive from your theory of everything. And then that theory may well maybe only require one constant.

I don't see why this would be impossible, but no one has managed to actually do that. Is there some current theory of everything that you feel like is on the right track? Is there one that in your mind is the best candidate? Well, I mean, there are... So we didn't settle before I answer the question. If by theory of everything you want to include a grand unification. So the grand unification is a certain kind of symmetry for the other three known forces besides gravity, the forces in the standard model, like there's electromagnetism and the strong and the weak

nuclear force. So what physicists usually call a grand unified theory is one that combines these three forces. And you could say, well, they are already in the standard model. So what's wrong with that? And the answer is, well, nothing really. But, you know, it would be nicer if we could combine them to only one force, which in a certain limit gives rise to these three forces. And so normally when people talk about the theory of everything they include grand unification in that so the theory of everything is this combination of quantum gravity with

the gut the grand unified theory and so there are very few theories that do that. For example, we were talking about loop quantum gravity. Loop quantum gravity doesn't really say anything about the particle sector. So it does not have a grand unification. So I think, and this is always a matter of definition, of course, but I think a lot of physicists would not call it a theory of everything. They would just say it's a theory of quantum gravity. And so string theory is a theory of everything.

Because both gravity and all these forces come out of the same thing. So it's all strings, basically. So that's the idea. the same thing so it's all strings basically so that's the idea and then there are some other approaches where people say that's what they do but it's you know it's difficult as I said because these tend to be pursued by very few people so they never seem to really be getting anywhere and I have some of these examples in my book like Garrett Lisi for example with his E8 theory. In principle, that's something that could be a theory of everything, but he's pretty much working alone.

And so it's a very long, tedious process. And then there are things like causal Fermion models, and you may put on this list Eric Weinstein and maybe Steve Wolfram. Things like that. Though Wolfram actually, from what my understanding is, he doesn't say anything about the unification of the interaction. On the other hand, he claims he has to say something about the foundations of quantum mechanics. So, you know, you get into the details very, very quickly. There's also asymptotically safe gravity, which a lot of people seem to be missing and I would say that's the proper theory of everything because you can very well combine that with grand unification and

people have studied that kind of thing and it basically removes the discrepancy between the standard model and the classical theory of gravity. And it basically removes the discrepancy between the standard model and the classical theory of gravity. So, you know, I don't have very strong opinions about which one of those is the best. As I said, I'm a phenomenologist, you know, for me, that's just, there are different approaches. And the question is, how can you test them? So that's the question that I'm most interested in. I see, I see. Do you mind outlining for our audience your views on strong emergence? You had a great paper, and from my understanding of it,

it was first defining what strong emergence is and then refuting it, but then at the end you save it. And I could be incorrect in my reading of it. But do you mind outlining and correcting me? So I think that the definition of strong emergence that I'm using there, so there's strong and weak emergence, and I'm just using the common definition. and I'm just using the the common definition so if you have a system which is made of small entities so it's composed of some smaller stuff roughly

speaking then you can observe some behavior on macroscopic scales which you would say is emergent from the behavior of the underlying macroscopic things. And this is a weak emergence if you can actually derive from the interactions and the properties of these microscopic constituents what is happening on the macroscopic level. of these microscopic constituents, what is happening on the macroscopic level. So, a typical example would be that you can derive, say the properties of molecules,

if you have a theory of atoms, because the properties of the molecules actually follow from what the atoms do and the orbital and all that kind of stuff. And what you're describing is, so, it sounds synonymous with reductionism. Well, it's kind of, well, reductionism goes the other way around, right? So, so weak emergence is kind of, so reductionism, you dig into the smallest scales, weak emergence, you derive the macroscopic scales for the underlying.

I see. Okay. And, and so weak emergence is compatible with this reductionist picture. And a strong emergence says that, no, you can have entirely new phenomena on larger scales that you cannot derive from the properties of the constituents of the system. So there's something really new coming into play

there. And this reductionism hierarchy basically breaks down somewhere. And now, as a particle physicist who has dealt with reductionism all the time, of course, it's a question that I'm very interested in, like, can you actually make strong emergence work? Because if you know that stuff is made of particles and we have the laws for these particles, then in principle, everything derives from that. So that brings up the question, like, is there some place where this derivation can go wrong? And that's actually, that's really, really hard to make sense of theoretically. And people have tried for some time.

There is a very interesting paper by Michael Nielsen and someone else, I've forgotten the name of the co-author, which is called More Really Is is different you know that's an echo of anderson's paper more is different and so they try to show that there are certain systems um so so they use a very simplified system with with uh it's kind of like a board with spins where you can define certain quantities. The example that they use is the overall magnetization. But you cannot derive them from the properties of the underlying system. So this would be an example where you could really speak of strong emergence.

But, you know, the fine print on this example, which they use is that it only becomes impossible to actually calculate this if you have a system that is really infinitely large. So it's this infinity that brings up this impossibility. And of course, nothing in nature is really ever infinite. So it's not a particularly good example. And there are some other examples that people have played with. And so with my background in particle physics, I was trying to look more directly at the theories that we're actually using in particle physics. So in the standard model, just to be concrete, that's a quantum field theory and in quantum field theory we have a well-defined process of deriving a theory on larger scales from the theory on shorter scales that's called effective field theory and

it's just a mathematical thing it's fairly new in a sense that I mean it's been around for half a century but it it has really only entered, I would say, you know, the consciousness of the community in the past 20 years, or something like this. It's just technically, there have been some things that were not very well understood in the early days. But today's kind of something that everyone pretty much uses. So you have these equations that you can just use to derive, in principle, what happens on the macroscopic scales from the underlying physics. Now, in many cases, of course, you can't actually solve the equations, but they are there. So if you think that

strong emergence is a real thing, these equations have to break down at some point. You know, something has to go wrong. And the only way that you can actually have really new laws on large scales is if something goes wrong in this derivation. And so in this paper, I was making this argument, you know, first I was explaining why we don't actually have something like strong emergence, why all these examples that people have come up with are not realistic because they all draw on something being infinitely large in one way or the other. And then to say, but look, if you look at effective field theory, there is a way in which this derivation can go wrong.

And loosely speaking, it's because there are certain functions that connect the theory on short distances with the theory on long distances that can run into a singular point and let me be clear that just because the point is singular does not mean that it's actually infinitely large but it can be a point where the function is actually zero and all the derivatives are also zero. The thing is that if you're trying to predict how this function is going to continue from the short distances to the long distances you can't. So and this is exactly what you would need for strong emergence to be a real thing, because in that case, you would not be able to derive anything past that point. And I think that's a theoretical possibility. And that's what I wrote this paper about, which is called A Case for Strong Emergence. This was one of the FQXI essay contests, by the way, if someone wants to look that up.

But I don't know any physical system that would actually have this property. So theoretically, I think it's possible. But I don't have any reason to think that it is actually realized in nature. Have you heard of Lee Smolin's principle of precedence? Probably. Is that the thing that kind of sounds like Leibniz's principle of, what's it called, something with reason? I believe it's that somewhere in the universe, let's say electrons have conglomerated to form some property by chance, well then in other parts of the universe, the electrons know about this. Rupert Sheldrake, if you were to be more mystical, he would call this morphic resonance.

I'm actually speaking with him in a few hours. I'm going to probe him on this. But if this is true, I'm going to probe him on this. But if this is true, this to me sounds like a case for strong emergence as well. Am I incorrect? So first, I confuse these principles. You know, Lee likes to introduce definitions and principles, and they're easy to mix up. And I think you're talking about what he calls like the ensemble interpretation. Okay, I could be wrong with my terminology. So he wrote a book about this recently. Is this what you're referring to?

Yeah. So I never thought about whether this would be whether this would be a case of strong emergence. So I'm sorry, I just... Okay, that's fine. That's fine. What does this, What does strong emergence have to say about free will? Well, so as long as you only have weak emergence, free will does not exist for the simple reason that we know that the underlying laws in particle physics, they are all deterministic. You know, you give me an initial state of the universe at some time,

I apply my equations to it, and I can calculate the state of the universe at any later time. It's kind of the same thing as with Laplace's demon. The one difference is that we now have quantum mechanics. So in addition to this deterministic time evolution, there's an element of randomness sprinkled over this, which comes from the measurement in quantum mechanics. So you have a combination of this deterministic time evolution, and then every once in a while,

there's something which is unpredictable. And neither of which is anything like what we normally kind of intuitively refer to as free will. And now I know, of course, that there are a lot of philosophers who have bent over backwards to try and find a definition for free will that would be compatible with that. You know, this is this whole idea of compatibilism. And I don't really like to argue about, you know, the use of words, but I, you know, I would think that this notion of free will that the philosophers are discussing is not a notion of free will that, you know, someone on the street would remotely understand, you know. You're referring to the philosophers who say

that free will can be saved under compatibilism, but their definition of free will doesn't comport with people's intuitive definition of free will. And the intuitive definition of free will is called libertarianism, libertarian free will. But it doesn't matter. So in your opinion, do you believe that we have this? So I think like intuitively the idea that people have is that there are like, there are different futures and you're using this thing you call free will, which is basically you and you pick one of these futures. And now what I just said about the underlying fundamental laws is that it's a combination of determinism and randomness doesn't leave place for anything like that um and now the thing is that um if you um have

this breakdown of the connection between the underlying law and um the the law on larger scales like human beings you and i like that, or maybe already at the level of viruses or God knows what, then in principle, you can have entirely different laws. And of course, that would bring up the question, well, what are these laws? But well, nobody knows. But at least in principle, if you have strong emergence, there's room for that. Do you believe in free will personally?

No. Do you believe in God? No. Okay. Let's move on. Why not agnostic? So that sounds like atheist. Yeah, I was about to say that.

It kind of depends on whether you're asking me in my profession as a scientist. I would say I'm agnostic. I don't care one way or the other. If you ask me personally, you know, the way that I arrange my life, the way that I think about things, I just don't believe it. There's one way of getting around Bell's inequality, and it's called super determinism. And I'm curious if you've heard of it and if you don't mind explaining it to our audience and then giving what your thoughts are on it. Yes, I've heard of it. As I said in the very beginning, I'm partly working in the foundations of quantum mechanics and that's what I'm working on. So as you correctly say, super determinism is one of the ways to get around the conclusions of

bell's theorem which could be summarized as if you have a local and deterministic theory like roughly speaking you know know, very roughly, like the way that we are used to from Newtonian mechanics, you know, there's no randomness in that. It's all deterministic. There's no spooky action at a distance, that kind of stuff,

in which the outcomes of quantum mechanics are actually determined, but you cannot predict them just because you're missing information. So in this case, the quantum mechanics would be probabilistic for the exact same reason that you normally have probabilistic predictions if you're throwing dice or something like this. You just don't, you're missing information. And so Bell's theorem tells you, you can't do that. Because any theory that has these properties will be in conflict with certain experiments

that have been done. So there's this thing that's called Bell's inequality and all theories of the type that I was just talking about tell you have to obey this inequality, but experimentally, you know that it can be violated. So this just rules out this type of theory. And a lot of people take this to mean that quantum mechanics is non-local and it's a non-realist theory and so on. Now, there is one assumption of Inbell's theorem, which is called statistical independence. And this is really, really essential to arrive at this conclusion.

So if you throw out this assumption of statistical independence, So if you throw out this assumption of statistical independence, you can very well have mind-numbing stuff about having a non-realist interpretation that is somehow, you know, always drawing on macroscopic concepts like detector measurements or agents and their knowledge and that kind of stuff, and yet still somehow compatible with reductionism. still somehow compatible with reductionism. The only thing that this requires is that you give up on this rather mathematical assumption of statistical independence. Now, you may ask, well, what does it mean to give up on statistical independence? So just technically, it means that the outcome of the measurement depends on the setting of the detector.

And if you want to interpret this more broadly, it basically means that there are no places in the universe that are entirely disconnected from each other. It's basically everything is connected with everything else in very, very subtle ways so that you don't normally notice it like in everyday life. We don't notice quantum effects and so we also don't notice these subtle correlations. But if you do a bell type test or some other quantum experiment, then you become sensitive to that. How's this congruent with special relativity that is that you can't break the speed of light? How is it that we can be connected to what is outside the the cone? Well you can have in special relativity you can very well have um correlations between um

you know distant points um they they will be within some light cone of something um just you know just because they're in in distant places does not mean they were created at a distance you know they can have been created locally right right do you have any thoughts on the emergence of possible emergence of consciousness or whether or not consciousness is fundamental well um i don't think there's that consciousness is all that mysterious um so you know i'm a particular person i'm a reductionist of course i think that uh consciousness is weakly emergent as i guess most people uh in my discipline um you know it's it's it comes from um the way that complex systems uh process information i would say and at

some level um it becomes beneficial for the system in terms of natural selection to have a self-monitoring process um so that's a peculiar thing about consciousness is that most of the time we're actually not really aware of a lot of stuff that's going on so that that's all the stuff that we put into the subconsciousness, which basically frees up, I guess, some processing power on the higher levels. And I don't think that consciousness is specific to, you know, biological forms of life. But that sooner or later, there will be some computers that will reach some levels of consciousness. later there will be some computers that will reach some levels of consciousness. So that is the sun even has a level of consciousness and the planets do.

Well, you know, there's, there's some, it depends on exactly how you define it. Right. So if you define consciousness by information processing capacity together with some level of self-awareness, then you may find that pretty much any system has a very, very small level of consciousness at some point, but it's rather meaningless's I guess that you would have to pretty arbitrarily at some point just say okay we call it consciousness if it's larger than I don't know something right now how do we test that I can see that we can come up with a measurement for consciousness but it's not as if we can it sounds like we're simply defining consciousness as being a certain level of self-monitoring information processing

but it's not well you know on this verbal level of course you can't test it you actually need to write down a particular model that you know quantifies just what it takes um what's what exactly needs to be happening in the brain, and so on and so forth. And then I think you can very well go and measure it. Okay. Well, what I'm saying is that if you measure it, let's imagine there's someone who has a low level of what we would predict to be consciousness. So let's just give it a number.

They have consciousness. We would predict that we consciousness. So let's just give it a number. They have consciousness. We would predict that they have, we can, we can figure out their brain state almost exactly. And we can imagine that from our data, from our theory that they should have consciousness at level 10, but they say, and somehow we have to get,

we have to have a way of saying this. They're like, no, no, no. I have consciousness at level 20 or someone who we predict're like, no, no, no, I have consciousness at level 20. Or someone who we predict at level 10 said, no, no, I'm actually consciousness level 5. Well, how does this... It just sounds like a definition.

Yes, there's probably something fishy about your definition, is what I would say. Look, of course, you want a definition that actually agrees, you know, to quite some extent with what we normally mean by consciousness, right? I mean, we have an idea of consciousness, like you're conscious, I am conscious, you know, other people are conscious. My computer is not conscious, at least not on a noticeable level you know you could say that maybe the the task manager or something is is some level of self awareness but it's so tiny that you know I can't have a meaningful conversation with my computer let me put it like this and so if we manage to come up with some definition of consciousness, we will want it to agree with our intuition, basically. Razor blades are like diving boards. The longer the board, the more the wobble, the more the wobble, the more nicks, cuts, scrapes.

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If you use that code, you'll get two years worth of blades for free. Just make sure to add them to the cart. Plus 100 free blades when you head to h-e-n-s-o-n-s-h-a-v-i-n-g.com slash everything and use the code everything. For our audience, do you mind explaining? I know that Wolfram's theory is not something you've studied immensely, but Wolfram does say that the universe is inherently computational.

What does that mean? Well, I think you should ask Wolfram about this, not me. Okay. So you would say that the mind-body, you know, in philosophy, there's something called the mind-body problem. The mind-body problem is solved. It's just body. And then after a certain amount didn't say i didn't say it's solved i said it's solvable it's there seem to be a lot of people who have this kind of this mystic attitude like there's there's something so special about consciousness we'll never be able to figure out how it works with science and i'm like you know let's talk about this again

in 100 years and i'll tell you we'll have figured it out i see i see okay let's get to your music what does oh what does music do for you are you do you have this creative urge this itch inside you that you have to just get it out there or or you just do it for fun or or what there's not many physicists that i know that that post music videos both i would say um you know i definitely have some need for a creative outlet for a long time i used to paint actually i used to paint and then you know i had kids and you know oil colors and small children don't mix well so I had to find something else and that's when I started writing songs and you know the the I'll admit like the first five years probably the output was pretty terrible but you know I've learned something since and I really enjoy it

you know I sometimes feel like if I'm thinking too much about physics, I get a headache. Like literally I find it really stressful. And the good thing about creative enterprise is that it clears out your mind. You know, you, you get something else in there. And so I do music. I've tried to teach myself how to sing something that YouTube is,

is really good for, by the way, you know, learning something new. Did you teach yourself how to edit or does someone else edit those music videos and do you use after effects or what all the so so i use uh premiere pro um um and yeah it's pretty much learning by doing i guess i've just made every possible mistake that you can make and at some point it starts looking kind of okayish you know in the sense that if you watch it on your phone you won't be able to see most of the glitches so that's kind of I mean I sometimes

I watch like professionally made videos and I'm always aw. I'm like, this is so great, you know. But, you know, I do what I can do, you know, with my little camera, with the autofocus. And sometimes it goes wrong and focuses on the wrong thing or, you know, stuff like I forget to plug in the microphone cable or stupid things. And then I talk for like an hour and in the end I haven't recorded stuff. And in the end, I haven't recorded stuff. And it can get really frustrating. But yeah, you know, after doing this for a while, you kind of develop a work routine. And so I really do it all myself.

Also the music videos. I mean, every once in a while, you know, I need someone to hold the camera in my house. But my brother or my mother usually. But other than that i i do it all myself you know i i write the songs i record them um i i do the mixing um i i do the videos i do the makeup the clothing the editing um everything pretty much yeah do you find that your days are are structured where at the institute you don't have to teach as far as i know so you pretty much do research do you do you wake up at a specific time and then you go to bed at a specific time and you read papers from a certain time or is it

is every day chaotic no i i'm very much a routine. You know, my days look kind of, yeah, yeah. But it's also, it's not just me. It's because, you know, I have two children who normally would go to school. So right now, of course, the school's all closed. But, you know, you just, you get this routine because you have to wake them up and get them to school. And then they come back at a certain time. And by then you have better done your job, right what does your day look like then in terms of how much time you spend working and what do you specifically work on are you reading papers most of the time are you sitting with a pen looking at the wall like i'm i'm actually interested in the specifics well so i should probably say that right now everything is just different you know

normally i would be at at my institute uh but now of course i've been working from from home for three months uh with the kids in the background and a lot of stuff didn't really get done because you know they're just other things that keep getting in the way. I have to remind them to do their homework. I have to cook for them, that kind of stuff. So it's not normal the way that it is right now. But normally, I mean, so there are many different aspects of being a theoretical physicist, as you already pointed out. So I work at the Research Institute. I don't have teaching duties. And that, of course, is also part of the reason why I'm active in public outreach, is kind of filling in this educational part that I don't have in my job. So I kind of feel like I need to give back something to society.

Because I know some professors professors they love research and they dislike teaching now some are the opposite i think feinman actually left the institute because he's like i gotta teach i can't i have to be in the field but many professors that i know they don't particularly like teaching it seems like you have a need to teach a a need to give back? Is that, you feel like that's missing and so that's why the YouTube videos come about? Well, it's kind of, it's a very different audience. You know, the YouTube videos are not talking to students. They're not meant to prepare people for work in a professional discipline. They're more to generally communicate what are we actually doing. And personally, I find this more relevant. I guess mostly it's because there are a lot of people who teach, but I think there are too few

people who do science communication. And so this is why it's important to me and I like doing it, even though I'm technically not getting paid for it. And so I would not describe my outreach activities as actually being part of my job. You know, it's something that I do on the the side for what my research is concerned um you know it's indeed mostly reading you know it's a lot of it the biggest part is finding out and understanding what other people have done including you know the stuff you go to seminars you give seminars yourself and and that whole game and then of course you get to a point where you feel like you've read everything that was to read on a particular topic. Now, can I add my own thing? And that's where you have to

sit down and actually write down equations and see if there's a problem you can solve, or if there's a new twist, you can turn on something and stuff like this. Then, of course, I also have a postdoc and I have a student who have their own projects that I have to look at and see that they get to where I think they should be getting. And, you know, there are other things like I organize workshops, conferences. I have to review papers. I have to review grant proposals, I have to write grant proposals. This actually sucks up a dramatic amount of time.

There's some administrational stuff that I have to do. Like if you're getting grants, there's always some overhead that comes with it that you have to, you know, you have to keep track of where the money goes and fill in reports. It sounds like there's so much extra on top of the actual research that how much of your time do you get to spend on research with you? Like you said, sitting at your desk with your paper thinking, how can you twist? How can you add your own? How can you contribute to a field? How much of your time do you get to spend doing that?

Let's say, let's say per day, day an hour or two hours a half hour every week you know i i would have to think about this more deeply so the problem is that um the way that i work i kind of i work in phases like i'll have a phase where I pretty much only do research like I've been doing now I've been working on the super determinism stuff like every day for 10 hours basically I wake up it's on my mind you know there's this stuff and then maybe I can do it this way and you you know you know down an equation then you figure out okay I don't know this I have to look this up you know then you try this and it doesn't work and you try something else. And it goes like this the whole day until I go to bed. Then I wake up in the middle of the night with an idea.

And I'm like, oh, I have to write this down. Okay, so then I sleep some more hours and then I wake up again. And I'm like, now I have to look this up. And it may go like this for several weeks or maybe one, two months. And then at some point, I'm like, I'm like either totally frustrated

and stressed out and everything and just have to stop it. Or something else comes up that just has to be done. You know, conference organization, what have you. Proposal deadline is approaching and then something else takes over. So then for some while, I'll be doing something else. And then I'll be getting back to research. So that makes it very difficult for me to answer the question in terms of hours per day. You know, I, it's,

I guess it's something between 30 and 50% roughly speaking that I get to actually work on. That's pretty much. Yeah. I know that I'm in a very lucky position. I'm in a very lucky position. I know that a lot of my colleagues, especially those who work in teaching, you know, have a lot more duties that take time away from their research. You know, on the downside, though,

I have to say I don't have a permanent position. You know, I sit on a temporary contract that will run out in two years I was talking to Steven Pinker and I was asking him well how much of your time is spent actually writing versus researching and I think he said it's 90% research that is in your case it would be the equivalent of reading papers and then 10% writing for you how much of what does that split look like? Well, between the reading and the writing,

there's the calculation part, right? So for me, the writing is kind of the least amount of effort. You know, it's what I do at the very end. If I have everything together, I sit down. Right, that's that's what i mean sorry i'm also including the calculation in the writing so the reading and then calculating and slash writing so it depends on whether it's a field that i'm already familiar with um like if it's a field like for example the superfluid dark matter stuff okay i've been following the literature on that for five years so now the thing is if something new comes out i only have to read the new part so which reduces the amount of literature that i have to digest so in any case like this you know

it may be something like 50 50 but if it's if it's a topic that i'm really new to um as it was the case up until recently uh with the foundations quantum mechanics, then there's just such a huge amount of literature that you first have to get in and digest that it shifts more to like, it's 95% reading. And then there's this little bit of extra that you may be able to add. I remember one of your videos, and I'm paraphrasing, so please let me know if I'm mischaracterizing you. I don't mean to. You said something along the lines of, that's not, you were referring to something, and I wish I could remember, but you said that's not something I'm interested in. That's not a question that can be answered with science, so I'm not interested. Now, you can tell me if I'm wrong there, but I'm curious,

is all that matters what can be answered with science um so I have no idea what I may have been referring that it sounds like a thing that that that I may have said in the context of the video probably you know I was trying to discuss a scientific question. And then I may have said something to the extent, but I don't want to talk about this, because it's not a question that science can answer. So but this doesn't mean that science is the only thing that's interesting, like we were already talking about creative outlets, right. And I don't think that this is merely, you know, something that's unimportant

you know i don't see myself as a professional artist and i you know i have no aspirations to become one to me it's kind of something that i need to function properly as a human basically but i mean there are professional artists and I think that they fulfill a very important function in our society, you know, by giving pleasure to people's life. You know, that's something that is really important. So science is definitely not the only thing that matters. Or maybe I should add, you know, but also to make people think, you know, art is not only about what is pretty, of course. Are there truths that are non-scientific yes there are mathematical truths okay are there truths that are non-mathematical and non-scientific

um well it depends on what you mean by truth i would say no because for me a truth is an absolute truth you know something that is unshakableable. And you basically only find this in mathematics, if you can actually prove something like two plus two equals four. So already when you come to science, the best you could do is say that something is almost certainly correct, you know, with a certain error bar, to be almost certainly. But colloquially, I guess most people would, at some point, just say it's true.

If the uncertainty is so small that nothing's going to change about it, almost certainly in their lifetime or something, they would just say it's true. Are there truths in fiction? So, for example, if you watch a movie that was made up by someone and you say, there's truth in that. I mean, I don't know, is there truth in fiction? Well again, I think that's something which people would say colloquially, but they wouldn't

literally mean it's true. They would say it maybe to mean this captures something that I have also experienced or something like that. What's the difference in your eyes between physics and metaphysics? And just delineate it for the audience. Well, I think if my Greek doesn't fail me, I think the word meta just means beyond. So the metaphysics or after or something like this, like it's what comes after the physics. If you're done with the physics, then there's metaphysics.

But the way that it's been mostly used by philosophers is to say that in physics, you have certain assumptions that are not themselves empirically testable, but that physicists use nevertheless, just because they have to. Otherwise, nothing works. You have to start with something.

And I guess I'm hoping that I'm using the word in the same way that the philosophers do. Like I mean for example a metaphysical assumption is the idea that theories have to fulfill a certain type of beauty. That's what my book is about, right? There are certain types of beauty that physicists have been using extensively. And, you know, I say that these are ideals of beauty, but what they actually are are metaphysical criteria. It's just that, you know,

it's not particularly catchy to talk about metaphysical criteria. So that's not what I call it. I just say there appeals to beauty. I have a somewhat technical question. Weinstein, Eric Weinstein, was talking about the Einstein field equations, Dirac equations, and then the Yang-Mills equations. And he said that they are provably the simplest in their class.

And as far as I know, there's no theorem in the field of physics that says that they are provably the simplest in their class and as far as I know there's no theorem in the field of physics that says that they're provably the simplest is there and like what the heck what does that mean that they're provably of their kind do you well so it's hard to say what what he may have been referring to the I mean if you what he may have been referring to there. I mean, if you, because it depends on exactly which assumptions you make. Like, let's take, for example,

general relativity. You can just, general relativity is a simple theory in the sense that it takes only like five assumptions to derive it. And these five assumptions are kind of like gravity is described by the curvature of space and time. It couples to the stress energy tensor, which is the conserved quantity.

It reproduces Newtonian gravity in a suitable limit. And I think there are two more, which I've now forgotten. And I think there are two more, which I've now forgotten. And then you can show that general relativity is the simple theory that does that, where the word simple becomes relevant because you can make the theory more complicated if you want to by adding higher order terms. But then you just say, no, I take the simplest one. I see. And, uh, and I guess that, um,

with young mystery and the Dirac equation, it may be something, um, similar, but again, it depends on exactly how you phrase the assumptions. Like if, for example, with the Dirac equation, um, Dirac made this assumption that the theory has to be linear, which is something that you may wonder if you can do it without. So the Dirac equation is basically you're trying to take the square root of Einstein's equation E square minus P square equals M square. And so the peculiar thing about the derac equation is

that you take the square root but you get a linear equation and the only way you can do that is by using these weird matrices but in principle you can take a square root of an operator that's something which exists and you you can define that by using the spectral decomposition and i've no idea why why derac didn't try that or maybe he did and you know he didn't like it or whatever people tried it later there are papers about this and you know then you can I don't know how is one of these solutions simpler than the other I don't know but one is wrong and the other one isn't. Like, I mean, wrong in the sense that Dirac's equation actually describes reality. Well, if you do it the other way around, you also get a theory that kind of solves the problem that

Dirac posed. Like, how do I take the square root of that? But it doesn't describe what we observe. I see. This question doesn't make much much sense but it's fun to think about imagine you're a photon how do you experience time now i know time is defined as the length the path length in space time but proper time is so that means that the photon experiences zero time which is imagining you're the photon it's it It's like you're immersion and then you die instantaneously. What does the experience of a photon look like? I have no idea. I don't know what it means to talk about the experience of a photon.

Like we were talking about consciousness earlier. And I think that you can define experience in a similar way but it requires that you have a certain amount of particles that are able to actually exchange information and so i would say a single photon just doesn't have any experiences i've no idea what that's supposed to mean so yeah i'm not sure that answers your question but yeah i mean the canonical answer to the question is that photons don't can't have a sense of time basically exactly because of this issue that that you're pointing out so the the length of the curve on which the photon moves is zero and

The length of this curve is usually what you mean by time. Sabine, what's next for you? Why don't you tell our audience where they can find out more about you? Your YouTube link will be included. Well, so I'm lucky in that for all I know, I'm the only person on this planet with the name Sabine Hossenfelder.

So the only thing you have to do is enter my name in some search engine and you will find out more about me than you ever wanted to know, trust me um so that's the easy part um the complicated part is uh what i'm going to do so um like the next uh two years are pretty straightforward because um i'm working on this research project on superfluid dark matter uh so that's what I'll be doing. I also have this running research project on superdeterminism that we talked about and I'm also, you know, I was in the process of organizing a workshop on that

which was supposed to take place in May but then we had to cancel everything. I'm glad because when I wrote that question I wasn't sure if you were familiar with the term superdeterminism and it turns out you're a specialist in the field yeah you know it was lucky because as I keep joking there only three people on the planet who understand what super determinism is so that's that's me and Gerard Tooft and Tim Palmer so you're talking to exactly the right person yes and I'll keep on doing the YouTube thing for some more time definitely um i'm kind of getting into it you know the the more practice you have the easier it gets because you become

more efficient um with producing content if you don't make as many mistakes um but beyond this i really don't know because i'm i'm sitting on this short-term contract and there's always the question like, will I get another research grant or if not, then what am I supposed to do? So your future in the next five years, if this was a job interview, what does your future look like? You're not clear in the next five years. hopefully yeah right i failed the i failed the interview so what if someone gave you a million dollars and said i want you to spend this and just make music videos or just pursue music would you say yes or no is it that much of a passion compared to physics well you know i i wouldn't want to give up my research on the other hand I could put it on pause for some time so I guess it depends on how many right yeah it's

it's a matter of time period that he or she would expect me to spend away from research it's not really amount about the amount of money. Oh, OK, OK. All right. Thank you so much, Sabine. Appreciate this. And have a great day. Everyone, go visit her channel.

Check it out. Subscribe. Are you aware of any other logical approaches to have any other logics that are used in the building of physical theory so for example most of physical theories are grounded in classical logic that is P or not P and you can't have both else do you have principle of explosion well that is the principles okay well there is consistent logics and

intuitionist logics there is something called quantum logic so people have tried to um i i never followed this in much detail but i heard like one two talks about it um yeah as you say that there are different um systems of logic um and people have tried to use them to explain the puzzling aspects of quantum theory as just being a different type of logic, where statements don't have to be mutually exclusive. Which is supposedly where you get all this stuff from that, you know, a state can be both here and there because these options are not exclusive. So that's kind of the vague idea. But, you know, I don't know.

I heard about this first, I think, 10 years ago and not all that much seems to have come out of it. But yeah, this would be the first thing that comes to my mind. I'm curious if there are, from the popularizers of science, much like Neil deGrasse Tyson and so on, if there are myths that you feel like that they sell to the audience that is incorrect, that you wish they wouldn't. So for example, that the electron is both up and down at the same time rather than that being just a method that we use mathematically

to calculate what happens. That's just part of the the wave function it's not necessarily that the electron is both up and down do you happen to know of any other misconceptions that you want to dispel so i i don't know i don't know about uh tyson or yeah it doesn't have... You don't have the name anymore. Yeah, there are a few of these that sometimes come up that... The problem is that I have a hard time pulling them up now because I didn't think about it previously.

But one thing that would come to my mind immediately is this idea that the observations on the bullet cluster rule out modified gravity, which is wrong. And I think everyone who works in the field knows that it's wrong, but it's such a simple and seemingly intuitive explanation that science communicators draw on it all the time.

And I find it really, really misleading, and I think it's really bad for the field because a lot of people in physics who are not really familiar with the subject matter just believe it. And yeah, so this is one example. Another example is that I often hear people say that special relativity cannot deal with accelerated observers, which is wrong. You can perfectly well deal with accelerated observers in special relativity. It's just that a lot of popular science textbooks only talk about non-accelerated observers. The reason this annoys me is that if you believe that, you can't understand the equivalence principle, because the equivalence principle says that acceleration in flat space in special relativity is locally equivalent to gravity in a curved space.

So if you can't deal with acceleration and special relativity, it makes no sense whatsoever. So the whole point about general relativity is that it uses special relativity and generalizes it. So that's another one of these things. Another thing that more recently upsets me is that you have probably heard that there is a type of dark matter that is increasing in popularity right now, which is called the axion.

And the story that they always tell, if you read these popular science articles, is that the axion was proposed in the 1970s by Frank Wojcik and Steven Weinberg independently as a solution to a particular problem in the standard model which is called the strong CP problem and that's true in that they proposed this particle in the 1970s but what they don't tell you is that this particle was ruled out two years after it was proposed it It's just not compatible with observations. And the thing that they search for now is a strongly modified version of this original idea, which is called the invisible axiom. And so the reason this annoys me that

they leave this out is that this is symptomatic to what is going on in the foundations of physics more generally, that after a model has been ruled out, physicists don't give up on it and say, okay, this didn't work. Instead, they will fiddle with the model until it's compatible with data again, then it will do another experiment and it will rule it out again. And then they fiddle with the model again. And that's been going on for 40 years. So I feel that by leaving out this part of the history, people get a very wrong impression of what people are actually looking for today.