AMA | April 2026

Introduction

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Host Introduction

1:01Hello, everyone, and welcome to the April 2026 Ask Me Anything edition of the Mindscape podcast. I'm your host, Sean Carroll. Back when I lived in Chicago, one of the great things about living in Chicago, the food was my favorite aspect. The restaurant scene was really good, but also good was the theater scene. I mean, live theater, like plays that you would go to and see people on stage acting. It's my favorite theater scene in the United States. Not that I'm a super expert, but compared to, you know, Los Angeles, where there's an actor on every street corner,

1:33but most of them want to be in TV and movies for obvious reasons. Or even New York, where there's a lot of live theater, but, you know, you want to be a Broadway star or whatever, or have your one-episode arc on Law & Order. Chicago doesn't have a lot of either Broadway-style theater or TV movie production going on. So the people who were there to act in plays were really about acting in plays. And there were a lot of relatively small-scale independent theaters, some relatively big ones like Steppenwolf and the Goodman, but also a bunch of smaller ones

2:05that were really—it really added to the cultural dimension of living in the city.

Physics and Theater

2:10And I got to know some of the different places, and I even was involved in a play now and then, not as an actor, believe me, but sometimes plays like modern movies have science themes. And either I could help talk to the actors or the director about the science in their play, or I could give a little talk in front of a performance to the audience about the science that was going on. And I remember one play—I forget the name of it. I'm really sorry that I forget the name of it,

2:44but there's a point to the story anyway. The central protagonist of the play was a physicist, and he was a physicist who specialized in black holes. And there were various metaphors in the play about black holes and things like that. But it was very explicit in the play that a big reason why this person had become a physicist is because he had trouble dealing with human beings. He had trouble with interpersonal relationships because there were just too many variables. Like, you didn't know what to do. You didn't know what people were thinking. It was just too hard.

3:18Whereas in physics, there are spherical cows. They didn't put it in exactly those terms. But the idea is that there are equations, and sometimes you can solve the equations exactly. And you know exactly what's going on. You have some feeling of control and mastery over it that you just can never get from human relations. And therefore, in a real sense, according to the play, physics can be an

Physics as Escape

3:42escape from the difficulties of the human realm. And I think that there's actually something to this. Not for everybody. I'm not saying that all physicists or mathematicians or engineers are motivated in this way. But some of them are. And even, you know, when you're not doing that for a living, you can get some solace from thinking about science questions that we do think some certain philosophical niceties set aside for the moment have a right answer, right? You know, there's a there's some fact of the matter about what the dark matter is. We don't know it, but we can try to

4:17look for it and find out and eventually we'll discover it. There's a fact of the matter about how to solve the Schrodinger equation, right? Or Einstein's equation, etc. The reason why I'm bringing

AMA Questions

4:28all of this up is because in today's AMA, this month's AMA, there were a lot of physics questions. I get the impression. I have not actually scientifically looked through this. Maybe there's no more physics questions in recent months than there ever have been. But there's usually, you know, a good number of physics questions and a good number of other questions. And they're all this is not a normative, me judging the questioners kind of thing. I love all the questions. So bring them on. But I wonder if, you know, the world here in the United States where I live and where some of you

5:02live, and also at other places in the world, the world is kind of shaky in different ways. Some bad things are going on. And maybe thinking about science gives us a little bit of escape from that. That's not a bad thing. You know, that's perfectly good. You can find escape in watching basketball games or listening to good music or watching TV or going for long walks. Escape is important. Escape is part of the balance of a well-lived life. You want some engagement. You want some struggle in a good life.

5:36But then you also want some relaxation, some escape. Maybe you want to not completely relax. You want to engage your brain. But you want to do it in a way that is not quite as fraught with consequences for the world, as we often get. We do have a world in which, you know, the problems around us, there have always been problems around us over the years. But now we have technology that brings those problems to us in a much more vivid way. So maybe that's providing a little bit extra motivation for people to think about the measurement problem of quantum mechanics or what the dark matter

6:06is. I don't know. That's a speculation. Let me know what you think. So nevertheless, in today's

Patreon Supporters

6:13AMA, we're going to get lots of questions about physics, lots of questions about other things. They'll all mix together in the usual fun way. Let me, as usual, give a huge thank you to the Patreon supporters of Mindscape who make the AMAs possible. For those of you who are new here, you can subscribe on Patreon for a nominal fee. I used to be able to say that the fee was $1 per episode. But because of capitalism, that is changing. I don't mean capitalism in the sense of me wanting to make more money. I'm perfectly happy with the

6:45system. But Apple, where many apps are sold and many people are pointed to, won't let Patreon use their old model and they're changing the way that things get charged. So we're going to have to change from a charging per episode model to a charging per month model. Not a big deal. It's just that since we haven't done it yet, I can't tell you what the charge is actually going to be. Anyway, you can go to patreon.com slash Sean M. Carroll. You can sign up. It's a feel-good thing. You'll feel better about yourself and the world for doing that. And it is the support

7:20we get from Patreon that really enables and encourages me to do these AMAs. It's the Patreon listeners who get ad-free versions of the podcast. And they also get to ask the AMA questions. So many, many thanks to everyone who's been supporting on Patreon. All these years, who knew that we'd be going on for this many years when I started this whole thing before the pandemic even came along. So thanks to them. And I think that's it. So let's go.

Many Worlds Theory

8:04Brandon Wheeler says, what are the biggest flaws in the many worlds version of quantum mechanics? You vaguely mentioned them here and there, but if it's not too hard to explain, can we have all of them? Yeah, that's a perfectly good question. I think that I have said what they are, but maybe not laid them out in perfect detail. And in fact, I'm not going to give a very long answer to this one, because I'm toying with the idea that this would make a good solo episode. Not so much the very idea of the flaws in many worlds, but a particular challenge that I'm going to mention in a second.

8:36I basically think that there's two, not flaws, but important things that need to be better understood before we can say that many worlds is a perfectly successful theory of reconciling quantum mechanics with our experience. The first is the probability problem. Let me actually, before even mentioning that, let me mention that there's a bunch of things that are claimed to be flaws that just aren't. The ontological extravagance of the theory, the question of what happens to me in the future, which branch will I end up on? Where does the energy come from

9:10to make all these worlds? None of those is really a problem, okay? These are problems. Sometimes you ask questions, and they're good questions, but there are answers. There are answers to all of those questions. I'm not going to go into them right now, because that's not the point of the question. The real questions outstanding are the probability question, which, again, I think is more or less solved, but the short version of the problem is many worlds is deterministic. We know that for any allowed measurement outcomes, there will be a world in which any measurement outcome appears,

9:40so why are we allowed to say that predicting the future, we have a certain probability of getting some answers rather than the others? Again, I think that's more or less we understand the answer to that question, but not everyone agrees, and I'm sympathetic with the fact that our understanding there is not absolutely airtight. So I would say it's at the 90-95% level, but still there's some lingering question there. The other one, which I think is a real question that I think is fascinating, and I'm devoting my research energies to trying to study, is the problem of structure. And what I mean

10:16by that is many of you will have heard me say before that quantum mechanics describes the state of the world as what is called a vector in Hilbert space. That's a fancy way of saying that a certain mathematical object that is the quantum state. That mathematical object by itself doesn't have any way of saying, well, this part of the universe is a planet, and this part is a star, and this part is a puppy dog or whatever. It's just a vector pointing in some direction in some giant direct dimensional

10:48space. So how do you decide to divide up that giant dimensional space to be subsystems that look like the classical parts of the world that we know and love? Again, I think that there are answers to this question, but the answers here are much fuzzier. This is something where I think a lot of people don't pay any attention to it. This is kind of my favorite kind of problem now that I'm in my old age, problems where no one thinks they're problems because they think they know the answer. But nevertheless, the reasoning that gets them to the answer, I think, is highly sketchy.

11:20So I think there's a lot of work to be done there. Ever-Ready and quantum mechanics, frankly, is almost too simple to explain the world. I think that you have to really think carefully about where the ordinary everyday picture of the world comes from in many worlds, and I think that's a good open question. Emmett Francis. Oh, so yeah, so by the way, therefore chime in, especially Patreon supporters, but everyone, do you think that would be a sufficiently good topic for a solo episode?

11:51It would be more technical than average. You know, we just had the Daniel Harlow episode not too long ago, so there's some technicalities of quantum mechanics floating around, but I would try to make it as understandable as possible. I'd have more time to explain what is meant by, you know, a vector in Hilbert space and things like that. We did have the episode a little while ago about whether time is emergent, so space and matter and stuff is all that emergent in a similar way.

Human Pattern in Quantum Fields

12:18Anyway, back to Emmett Francis, who says, I find myself going to Dan Brown books as a guilty pleasure of sorts, and I can't help truly feeling a bit guilty, since he often sensationalizes the science and everything else, and he definitely has had a strange fictional take on previous Mindscape guest Jeremy England. Jeremy England appeared as a character, sort of an unauthorized appearance in one of Dan Brown's books. You've written on the scientific mistakes from Brown before, but I'm curious if you have any updated thoughts, especially given his most recent book, which heavily focuses on the science of consciousness. I have no special thoughts on his most recent book,

12:54because I didn't read it, but you know, I don't, I've said this before, once again, but I don't get too upset about bad science in fiction, okay? Bad science, by which I mean science that doesn't exactly map onto the real world science as we know about it. You know, I was an advisor on Thor, who is an Asgardian who comes over on the Rainbow Bridge from Asgard to Earth. There's no accurate science there or anything like that. You're telling a story, and that's okay. Now, a book like

13:28a Dan Brown book that sort of pretends to be or purports to be closer to reality than a Marvel comic book, you might have different questions about, and that would be fine. But it depends. If it bugs you so much that you can't enjoy it, then that's okay. If it doesn't bug you and you get pleasure out of reading the book, that's also okay. You should not feel guilty about it. I'm brought to mind, we had a conference at the Santa Fe Institute a little while ago. I forget what topic it was. We have all these crazy topics here at SFI. But Anthony Durr,

14:02D-O-E-R-R, who's a very accomplished author, novelist himself. He wrote Cloud Cuckoo Land and some other things. I highly recommend him. He gave a talk, and he opened his talk by, I think it was something about reality, the topic of the symposium. But he opened his talk by reading like the first page of a novel. And he didn't tell anyone what novel it was, but I guessed because I knew it was The Da Vinci Code by Dan Brown. And what he was doing by reading it out loud was pointing out how

14:35very little sense it made, okay? So in many ways, in multiple ways, if you actually paid attention to the text of just the first page of The Da Vinci Code, you'd be like, no, that makes no sense. I actually looked it up so I can read it to you so you know what Tony, Tony Durr, was talking about. I'll just read you a couple sentences from page one of The Da Vinci Code. The scene is that a curator

15:06of a museum pulls down a painting and falls down, and he hears a noise, and there's someone threatening him. So here's the text. On his hands and knees, the curator froze, turning his head slowly. Only 15 feet away, outside the sealed gate, the mountainous silhouette of his attacker stared through the iron bars. He was broad and tall with ghost pale skin and thinning white hair. Okay, there. I read three sentences, and they might seem perfectly fine, but look at them

15:40carefully. So the very first sentence, the curator froze, turning his head slowly. You don't get to do both of those things. You freeze or you turn your head slowly. If you're turning your head slowly, then you're not frozen, okay? That's a tiny, you know, mismatch there, but it's there. The next one, the mountainous silhouette of his attacker stared through the iron bars. Fine. What does that mean? The silhouette means you're seeing a dark outline, right? You're seeing nothing but darkness with bright light behind. But then the very next sentence says that the attacker had ghost pale skin and

16:15thinning white hair. His irises were pink with dark red pupils. You don't know that if you're just seeing a silhouette. How do you know the color of someone's eyes if all you're seeing is their silhouette? Again, it completely contradicts the very sentence before it. And part of the point is nobody cares. Like, maybe you care. Maybe for the kind of reader who reads very, very carefully and this stuff is very noticeable to you, very important, then you're going to care. But clearly there are plenty of people who don't care because Dan Brown sells billions of books. And so I had the question,

16:49and I was asking both Ted Chiang, who's also there for the workshop, and Tony, I said, look, aside from the fact that this is sort of sloppy writing or whatever, people like it. So why? What is it that Dan Brown does if he's making all these mistakes? There's clearly some skill, some talent, some craft that he has because he is giving some people what they want. It's enjoyable. And Ted told me that in his opinion, the explanation was that Dan Brown sacrifices everything

17:23for narrative velocity, the speed with which you're pulled through the text. You know, famously, Dan Brown has these very short chapters. They end on cliffhangers. You want to keep reading. But even at the level of sentences and paragraphs, you want to keep reading. He somehow puts you in a mental state where you are pulled or pushed or however you want to put it to figure out what happens next. And that's a skill. Okay. I mean, that's not sloppiness. Like you can try to do that. Other people have tried to do it and they don't quite succeed. So the point is that you can read

17:58things for different purposes. You can read things just for guilty pleasures. You don't have to feel guilty about it. Honestly, pleasure is a good thing. You don't need to feel guilty about it. You can read Dan Brown books or whatever. Harlequin romances, if that's your thing. The Twilight books. I don't know. But if you get pleasure out of reading it, that's fine. If you don't get pleasure out of reading it because you read very carefully and you want everything to make sense, that's also fine. That's just a different thing that you're trying to get out or a different kind of reading that

18:28you're doing. And when I say it's fine, you know, it's not just narrative consistency or inconsistency. The same thing is true for scientific mistakes or whatever. If you don't care that Back to the Future has a theory of time travel that is entirely incoherent, that's fine. Back to the Future is a great movie. But if it does bug you, like it bugs me, then you're going to want to look for something that is a little bit more consistent. And that's also perfectly fine.

Jürgen Habermas

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19:59free with the purchase of a razor. Just head to HensonShaving.com slash Mindscape or use code Mindscape at checkout. That's H-E-N-S-O-N Shaving.com slash Mindscape. We shop for everything at home now. Why can't we shop for blinds at home too? That's why I love 3-Day Blinds. Instead of wandering around a store, 3-Day Blinds sends a professional design consultant straight to you. They bring all the samples, help you see what actually works in your space, take expert measurements, and even handle the installation. We've all bought something that

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21:06former Mindscape guest, it's my duty, I need to point out to you when anyone mentioned is a former Mindscape guest, has described the pattern of humans through space, a human through space-time, as like a tube or braid of trajectories, a much messier thing than, say, a planet. How would a poetic naturalist who knows quite a bit about quantum field theory describe the pattern of a human being in quantum fields? Would I shimmer and swirl? So I'm going to try to answer this, but I'm not exactly sure what either Thomas or Max has in mind when they're saying these things. So

21:37there's going to be some guesswork involved on my part. But let's back up. You know, in Newtonian mechanics, there's the idea that you have a particle. A particle's an idealization. A point-like particle has no extent, okay? But, you know, you can mathematically talk about it. And in Newtonian mechanics, you would say a particle has a position. It has a location. There it is. It's a dot. But it will evolve over time at different times. The position of the particle will be different. That's fine. It's not until relativity comes along and space and time are unified into space-time

22:12that the dot as a particle at one moment of time becomes less fundamental than the world line of that particle. The line that stretches through space-time going from the past to the future telling you at each time where the particle is. And maybe there's a beginning and an ending to the world line of the particles created and destroyed or something like that. If you have an extended body like a human being or a planet that is made of many, many particles, then a traditional thing to talk about is the world tube of the extended thing. It's the volume at any one moment of time stretching

22:48through all of space-time. If you're a little bit knowledgeable about relativity, you might get worried that we're talking about the volume at any one moment of time. But the whole point of talking about the world line or the world tube is that it doesn't matter what reference frame you're in or how you divide up space-time into space and time. The whole four-dimensional thing, the world line or the world tube, is completely invariant that way. I think that what Tegmark is getting at is that if you have a planet or something like that, it will have a world tube

23:20stretching through time, but it'll be fairly simple, right? The planet doesn't do anything very complicated. It goes around the sun. It obeys Kepler's laws. It rotates on its axis. Whereas a human being, which will also have a world tube, does all sorts of weird things, standing up, running around, blinking their eyelashes, waving their arms, right? So a lot more information is involved in tracking the human being over time. I think that's what Max is getting at here. So how would you update that to quantum field theory is Thomas's question. And I feel bad

23:54saying this, but I kind of feel you shouldn't update that to quantum field theory because this is part of the poetic naturalist credo is that there are many different ways of talking about the world, but they should all be respected for their own sake, right? For their own sakes. You should either talk a quantum description or a classical description where they're appropriate, and they need to be consistent where they overlap. But all of this talk about world lines and world tubes, that's classical talk. That's as if classical Newtonian mechanics or relativity were true. And in the quantum world,

24:31as you know, as we were just talking about, particles don't live in space. They live in Hilbert space, which is a whole different kind of thing. And a world tube is not what it would be in Hilbert space. You can kind of vaguely approximate what's going on by imagining a classical particle as being a bit smeared out because there's some uncertainty in where you would measure its position to be, but you're already giving up on some of the accuracy of your description. You might as well just talk classically at that point. The other thing to mention is that this shimmering and swirling thing

25:02worries me a little bit. I want to emphasize that if you have a, let's say, an electron in an atom, okay, so the electron is orbiting a proton in a hydrogen atom, let's say, it is not moving in the quantum mechanical description. An electron in its lowest energy state, that lowest energy state is smeared out. And sometimes we can't help but speak as if there are quantum fluctuations, right? What we mean by that is if somehow we were to measure the position of the electron,

25:35write it down, and then reset so that once again the electron is in its ground state in the hydrogen atom and measure it again and measure it again, etc., we would get different answers each time because there's a probability that comes into the Born rule. That makes us think inevitably that somehow when we are not doing the measurements, the electron is moving and jittering back and forth. But we know that's not true. That's just excess baggage from our classical intuition. The actual quantum wave function is perfectly 100% static. So you might be a little bit smeared out in that

26:09description, but there's no shimmering and swirling going on. Your quantum wave function would just do what it does, which is actually other than the center of mass of your wave functions when you move your arms around or whatever. Other than that, it's a pretty stationary kind of description. Mark Kummeri says, a few months ago, there was an excellent interview of Edward Witten by Brian Green, former Mindscape guest, as part of his World Science Festival program. At around minute 49 of the

26:39YouTube video, Witten talks about the many worlds approach to quantum mechanics, and he gave a critique I had never heard before. He starts talking about the Copenhagen interpretation. He states that Niels Bohr would say that when a measurement is made, the measuring device records the outcome and the observer learns the answer. But Bohr didn't say in what sense the observer knows. And it can't be that it means measuring the measuring device, as that would be an infinite regress. Witten then says that Everett shifts this logic one step further than Bohr, with the observer's

27:10memory replacing the measuring device, but claims that he didn't also solve the issue, as Everett leaves undefined what it means to access the observer's memory, as it can also create this infinite regress. Is this a valid criticism? He seems to imply some mystery about what it means to know something. I listened to this several times, but I'm still confused. I really hope you watch this and can elaborate. So I did not watch the particular video that Mark is talking about, but I watched a seminar that Witten gave, that is also on YouTube, where he mentions exactly the same ideas, where he's talking about these very worries. It's clearly

27:42on his mind. And we know why it's on his mind. It's on his mind for exactly the reasons that Daniel Harlow was talking about in the recent episode there. Thinking about quantum gravity in the Sitter space leads to these weird issues where you just have a one-dimensional Hilbert space, and you just start thinking about what it means to be an observer, and all these questions in the foundations of quantum mechanics. It's great. And Witten has been thinking about that, along with Moldecena and a bunch of other people, Raphael Busso, former Mindscape guest, etc. So, but I don't think that this

28:14particular worry that Witten has has anything to do with Copenhagen versus Everett. It's a semi-respectable worry I have, I guess I would say, concerning epistemology. Like, what does it mean to know something? Okay, that's a perfectly good question that philosophers have engaged with, but I don't think there's any special physics or quantum mechanics worry there. As a physicalist, what you would say is that what it means to know something is that somehow there are configurations of neurons

28:47or your synapses between neurons in your brain that represent a certain piece of knowledge. What does it mean to know that you know something, a different particular set of neurons and their firings and synapses in your brain, the strength of the connections between them? So I don't know what particular configurations of synapses in our connectomes correspond to knowledge, but that's a job for the neuroscientists, okay? It's not really a job for quantum mechanics. Whatever the answer to that is, it's going to be the same answer in Copenhagen or Everett or Bohm or anything else. And I don't

29:22think that there's any sense in which the answer is deeply mysterious. It just seems to be technically hard to know what is going on in the brain. So I do think that Witten has been worrying about this stuff, but I don't think that particular worry is especially salient. I will close with telling one little story, which is when I was at Caltech, Edward Witten came to give a seminar, and I was briefly chatting with him before the seminar, and I mentioned that I was thinking about Everett and quantum mechanics and things like that. And he goes, oh yes, I read Everett's paper a while ago. I didn't

29:53really understand what the point of it was. I'm not sure that he really solved any problems. And I wanted to keep talking, but he had to go give a seminar. So he went up and gave a seminar, and he didn't have any notes. He just stood at Blackboard and wrote for an hour and a half all this high-level math stuff about brains and gauge theories and stuff like that. And the funny thing to me was, immediately when it was done, when the last question was answered, he came back up to me and said, so here's why I didn't like Everett's paper. So the amazing thing was not only did he give

30:25an off-the-cuff, high-level math talk for an hour and a half, but clearly there was a little subroutine running the whole time that was thinking about Everett and the foundations of quantum mechanics. That's what makes Edward Whitten, Edward Whitten. So the rest of us just enjoy talking to him and learning things. Okay, then Ed says, not Ed Whitten. Well, I don't know. Maybe it's Ed Whitten. Hi there, Ed, if you're writing questions here on the Patreon. Our Ed says, when a society is heading toward authoritarianism, do you think there is a case for deciding in advance the criteria under which

30:57you push back or leave? I.e., should you set a this far and no further point to avoid being the metaphorical frog in boiling water? E.g., I've often wondered if you could show the German-Jewish population in 1933 what would happen 10 years later, how many would have left before it was too late? So roughly the answer is no. I do not think that there are criteria that you would decide in advance. Okay. Partly this is, you know, people sometimes ask, do I learn things by doing the

31:31Mindscape podcast? I learned something from talking to Elizabeth Anderson, the famous philosopher who is a Mindscape guest. And Anderson is a big critique of the idea of ideal theory in political philosophy. Ideal theory is basically the idea that what we should do is decide what would the perfect society would be. That's the first step. And then the second step is we try to make our real society closer to the perfect society. And her point was, if instead you start with the real society and just

32:04say, of all the ways we could change it, what would make it better? A little bit better. You might, after making it better, realize something that you hadn't realized when you were in your previous state. You might learn something that teaches you more about what a perfect society would be like. And therefore, rather than starting by thinking of the ideal society and trying to move toward it, we should start where we are and try to make things a little bit better. I thought that was actually super convincing and super plausible given the nature of complex systems, right? You can't

32:34always predict ahead of time what it is you will actually want, whether or not what you think you want will actually work or anything like that. So likewise, I don't think you decide in advance the criteria under which you would leave a society or push back against creeping authoritarianism. Furthermore, there's just a whole bunch of complicating factors here that really make it extra clear that it would be weird to decide ahead of time. You know, I think it'd be perfectly sensible if you were a part of the German Jewish population in 1933, and somehow you had a crystal clear vision of what

33:09was going to happen over the next 10 years that you would want to leave. That doesn't mean you can leave, right? It might be hard. I mean, it might be hard for very practical reasons. Maybe they wouldn't let you leave, but also for semi-practical reasons. Do you have the money to leave? Do you have the wherewithal to sort of give up your house and your home and your friends and things like that? Can you bring along all of your family and everyone you know, or would it be okay to not do that? All of these really very difficult real-world questions are very, very hard to decide ahead of time. Finally,

33:40I think it depends a lot on who you are and who you are in that society. Like, everyone in Germany in 1933 should have been appalled by what was about to happen over the next 10 years. Not everyone was, clearly, but some people have more power to resist what would be happening, and some people, just because of the way the society is organized, are just going to be the victims here. And I think that the people who are just much more likely to be the victims have a much better case for picking

34:13up and leaving rather than staying and resisting. I don't judge people who make either choice. I think that in different circumstances, either choice is perfectly viable, but I think that the right choice depends just as much on who you are and what your position is as it does on what is happening in

Geopolitics and UAPs

34:31that society. I'm Jake Stauk, co-founder and CEO of Serval. We built Serval to automate the IT work that slows companies down. Onboarding, password resets, access to applications, my laptop stopped working. While employees wait for help, their real work is put on hold. IT desperately wants to automate this work, and that's why they need Serval. You just tell Serval what you want to automate in plain English, and it's built. No drag-and-drop workflows, no expensive consultants. Employees get unblocked,

35:03and IT teams go from drowning in tickets to building what actually matters. With Serval, IT becomes the AI engine powering the entire company. This is a new way to run IT. We guarantee you'll automate 50% of all tickets, and we'll prove it to you in a free four-week pilot. Go to serval.com slash listen. That's S-E-R-V-A-L dot com slash listen.

35:50Completely different. And somehow, that's exactly where you're supposed to be. I've always had my spots along the way. Starbucks has been one of those constants. Before a session, on the way to a gig, and between conversations that turn into something bigger than you expected. It's part of that movement. Part of that rhythm. The summer's got its own soundtrack, too. You can almost hear it without trying. Life's happening all around you. That feeling of staying open to whatever's next. Sometimes, it's the smallest things that lock you into that moment. What you're holding. What

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36:49Okay, Eric Olav Chen says, does the existence of observers within branches require that the pointer basis be approximately the position eigenbasis? More generally, are there constraints on which pointer bases give rise to branches capable of supporting observers? You know, I always wonder whether I should answer questions like this, because they're somewhat technical. There's a lot of words in there that maybe some of you are not familiar with. And I will, of course, try to explain them a little bit. But maybe I should just skip the question entirely. Every time I mention that

37:21uncertainty, most of the comments say, no, no, no, you should answer those. Even if we don't understand them, we find them fun. Okay. So I'm going to keep answering them occasionally, right? But I do want the podcast to be accessible to everyone. So, you know, people get fun in different ways, as we've already discussed. The idea of pointer states and branches, this is something that we talked a lot with Daniel about. In the wave function of the universe, if you're an Everettian, you know, you say, like, let's do

37:52the Schrodinger's cat thing. You put the cat into a superposition of awake and asleep. And the point is, when you open the box and look, you never see the cat in a superposition. You either see an awake cat or an asleep cat. Now, part of that is a motivation for moving on to a discussion about wave function collapse and realism and the role of observers and all this stuff. But there's also a very down-to-earth technical issue. Why do I specifically see either the awake cat or the asleep cat, even though quantum

38:24mechanically, I can describe a state that is one over the square root of two awake plus asleep, and its perpendicular state, one over the square root of two awake minus asleep. In other words, the states in quantum mechanics that are superpositions of definite states of sleepiness for the cat are just as real, just as valid, just as honest within Hilbert space as the states that we actually see, either the cat awake or asleep. So this is called the preferred basis problem

38:57in quantum mechanics. And it's definitely a problem for Everett. It's less of a problem if you have hidden variables or whatever, because they just pick out what the right states are, or even if you have objective collapses or things like that. But this is a problem within Everett that has been solved, okay? We essentially know the solution to this one through the work of people like Zurek and others who have been talking about decoherence for a very long time. The idea being that the environment of the world interacts with these different states in different

39:28ways and becomes entangled. And when you have a superposition of the cat awake and the cat asleep, the environment, all the photons and all the air molecules, interacts differently with the awake cat and the asleep cat. Whereas if you just had the awake cat, the environment would interact with it, the light and the air molecules would hit the cat, but it doesn't interact with it differently. There's only one thing there. There's the awake cat. So what happens is you branch and you branch in a very specific way onto very preferred states where things look more or less coherent. Things

40:03look like they have a shape, like they have a classical existence. That's why classical mechanics is such a good approximation to quantum mechanics. So what Eric is asking is, is there some relationship between this idea of being a pointer state? A pointer state is a state in which the pointer of a measuring apparatus is pointing in a definite place. It's not the best nomenclature in the world, but the idea is instead of you looking, let's imagine you had a cat observation device looking and a big arrow,

40:34a pointer that could either point to cat awake or cat asleep. The pointer ends up in either pointing cat awake or cat asleep, never a superposition of both. So a pointer state is one where the pointer of your measuring apparatus has a definite position or whatever you want to call it, a definite notion of where it's pointing. And that happens to coincide with what we call position, right? Things that are more or less pointer states have definite coherence in space. Is that an accident? Does it have something

41:07to do with observers or something like that? So the short answer is, I don't know. The long answer is, yes, they're certainly related in very, very definite ways. I know some of the arguments here. I wrote a paper with Ashmeet Singh called Quantum Myriology, where we talked about exactly this issue, and I'm following it up now with another graduate student. We're still thinking about this problem. How and why do pointer states, which are defined by being robust under being monitored by the

41:40environment, happen to coincide with states where things have definite positions or pretty close to it, okay? Those are two different statements. Robust under environmental monitoring, having a more or less coherent configuration in space. There's no a priori reason why those two things have to coincide, but they do in the real world. So is that purely dynamical? Does it have something to do with observers and the existence of people? Is it anthropic in some way? I think that all of those

42:12things are possible and even plausible and even probably true, but I don't think that they have been completely worked out. I think the logic is something like, in order to get observers as we understand them, you need something like classical behavior. And in order to get something like classical behavior, you need something like locality in space. And once you have locality in space, and you have a past hypothesis and increasing entropy and things like that, decoherence will pick out states that look approximately static and coherent in space as their pointer states. But all of those

42:47statements I just made are up for grabs and need a lot better job of actually showing that they are true. Henry Jacobs asks a two-word question, simply, Jürgen Habermas. You may know Jürgen Habermas was a famous German philosopher who just died very recently. He was quite prolific and quite active, even deep into the later years of his life. He died at age 96. Habermas was a big, big name in social and political philosophy. And I did know a little bit about him. I presume that I'm supposed to

43:22interpret Henry's question as, what do you think? Do you have any thoughts about Jürgen Habermas? So I do actually have some. They're not especially educated or anything like that. I'm certainly not an expert. But when I was an undergraduate, being a philosophy minor, among other things, at Villanova, my philosophy mentor, Jack Doody, he had Jürgen Habermas as his favorite philosopher. Jack actually got his PhD from Notre Dame in philosophy of science under Ernan McMullen, but then later switched to

43:55thinking about social and political philosophy himself. So I think a couple of different classes that we had talked about Habermas quite a bit. And Thomas McCarthy, who is currently a philosophy professor at Notre Dame, is sort of the biggest proponent of Habermas's thought in bringing it to the English-speaking world. And he came to give a guest lecture, translated Habermas, things like that. So yes, I have some exposure there. And I am a fan of Habermas in general. But I'll tell you,

44:27this was many years ago. And I haven't done a lot of reading, even then, when I was supposed to be reading Habermas. I forget what it was we read. I think something from the theory of communicative action. But Habermas is not an easy read, let me tell you. And he's not a sparkling, sprightly writer, which is OK. He's, like I said, a prolific writer. He just finished, I don't know, a three-volume history of philosophy, thousands of pages long in his 90s. So, you know, he could churn them out. But it was hard to figure out sometimes what he was talking about. So I came

45:02away with, I think, two ideas that have stuck with me over this large number of years. And who knows how accurate my current understanding of those ideas are. But just for those of you who have zero idea about Habermas, but may be interested, I can tell you what I remember. The two big ideas, one of them is communicative action. Both words are important there, communication and action. Habermas was a big believer in the power of reasoning. And this is a non-trivial thing. You

45:33would think most philosophers are indeed big believers in the power of reasoning. But Habermas was sort of the last great name in what is called the Frankfurt School. The Frankfurt School, it still exists, but it had a heyday starting in the 1930s. So this was people like Max Horkheimer, Theodore Adorno, Eric Fromm, Herbert Marcuse, a bunch of other people. And they basically founded what is known as critical theory. Critical theory being a way of looking at the world in which you try

46:09to figure out that what the world tells you about itself. And we're talking about the social world here more than the physical world. So this is not a sort of a science statement. This is a social science statement. What the world tells you that it's doing might not always be what it's doing. So you have to sort of be careful to be critical about what is actually going on versus the story you're being told. And just so we're clear, this school of critical theory does lead directly to more contemporary ideas like critical race theory and critical legal theory. You might have heard sort

46:44of cartoonish, crazy versions of critical race theory from modern provocateurs like Christopher Ruffo. But the original idea of critical race theory is there can be varieties of racism that are not that explicit, that are not that blatant, right? Systemic racism. The very idea of wokeness, the motto, stay woke, was an exhortation to be on the lookout for systemic racism in society, for ways in which the system systematically discriminated against one group or another without necessarily just coming out

47:20and saying, oh, yes, this group is bad. You know, you sort of hide the racism or the discrimination in the system. And that's why you need critical theory to bring it out. And so the early critical theorists of the Frankfurt School, they lived in a world, so you think about Germany in the 1930s, right? There was a lot going on, both politically and intellectually. They were still in the aftermath of the ideas of people like Marx and Freud and Nietzsche, for that matter. And politically, there was real communism going on, right? They just had the Russian Revolution. So there was Marxism,

47:56Leninism. There was certainly real capitalism going on. And there was a rise of fascism going on. So trying to figure out how to negotiate all these things in an intellectually respectable way was one of the things that critical theory tried to do. And there's a version of thinking about Karl Marx, Sigmund Freud, Nietzsche, and people like that, which says that these people are a little bit too anti-reason. Or let's put it this way, they don't give enough credit to the

48:28power of reasoning and rationality in human action. They reduce it to either economics or the unconscious or some various cultural factors that are so deeply hidden in our way of living that we don't even really know what they are. And part of the critical theory pushback was to say, you know, yes, there are these sort of non-rational things going on, but there is also culture and ideas that are important

48:59to us, and we should make a space for them. And I think that that's very much the world that Habermas was still living in, trying to balance an understanding of how rationality and reason work with an understanding that sometimes the things that happen to us are not because of rationality and reason. So communicative action was his idea that, you know, when things are going well, human beings, agents really do try to come to mutual understanding back and forth. It's action,

49:30but it's communicative. And all of this is very, very applied to making the world a better place. This is not ivory tower kind of philosophy. Habermas and his predecessors in the Frankfurt school were very active in politics and trying to critique the world that they saw around him. So that push for an ideal of communicative action that analyzes how it works and also tries to boost it is one of Habermas's big themes. The other one that I still remember, again, I'm sure this is a tiny,

50:03slightly imperfect way of talking about Habermas's big ideas, but there was what he called the system life-world distinction. So these are two things that are all around us, basically the structures that are all around us that are shaping us in society and countries and other institutions. Habermas were divided up into system kind of things and life-world kind of things. And the system is all of those structures that sort of kind of are self-perpetuating via structures of power, right?

50:37Not by talking to each other and trying to reason things out, but by other factors like the economy is governed by money and how it flows and people's desires for money or the government, or, you know, it might be described as being organized in terms of power and law giving. It's not all necessarily bad, but it's not communicative rationality, right? So the system is all those things, whereas the life world is more the side of our world that has to do with communication, meaning, ideas, knowledge,

51:16things like that. So the intellectual world, the cultural world, the values we have, all the ways that we communicate, and so forth. So they're both there. They're both necessary. The system and the life world. But the motto that comes out of Habermas is that the system tends to colonize the life world so that we start off with ideas and we talk to each other and we reason together. But there's a tendency, and this is sort of a very German sociological kind of way

51:46of thinking, there's a tendency of things to systematize, for the system to colonize the life world by turning ideas and talk and communication into structures that are sort of stuck there without necessarily relying anymore on some particular rational underpinning. And of course, Habermas is in favor of resisting the colonization of the life world by the system. And anyway, that's what I remember from all that. And, you know, it's all very, it makes a lot more sense. It has a lot

52:20more impact in the context of all the different discussions that were going on among philosophers, social theorists, political thinkers, and social thinkers of all various sorts. Habermas has, basically, there's Wikipedia entries for Habermas and his dialogue with Thinker X for a large number of X. Habermas and Gadamer, Habermas and Chomsky, Habermas and Rawls, Habermas and Derrida, Habermas

52:50and Foucault, right? They're all talking to each other in different ways. Apparently, I don't really know a lot about this, and I'm not in favor, as you know, of heroism turning people into heroes. I think we should try to understand people's ideas and even admire them for their actions and their ideas, but not trick ourselves into thinking that, therefore, they're good people, if we don't know them personally. But all the news stories, all the reports are that Habermas was a really good person, as well as a brilliant philosopher. One story that was bouncing around Blue Sky was by this

53:22woman, and I'm not going to remember it exactly because I wasn't planning to tell it, but it's apropos here. This woman was helping to organize a public lecture by Habermas, and she was either, you know, at the door where they were letting people in with their tickets, or she was standing around there, and there's a long line, you know, going to see Habermas was a very exciting thing in Germany. And then, you know, she's taking the tickets or whatever, and she looks up, and there's Habermas. He was standing in line for his own lecture. And she's like, oh my goodness,

53:52Professor Habermas, you do not need to stand in line. You're giving the lecture. You can just come in. So that's, you know, that's a nice thing to hear about the people who you think. It's, you know, we're in a world where sometimes we have people who have done intellectually impressive things, and later we learn that they've been unimpressive in other ways, or even bad in other ways. So it's nice to know that, you know, most of the reports you get about a person were very positive in nature at the human level. So yeah, Habermas obviously led a big, long, productive life. He had his

54:26controversies. He's well worth understanding. I'll confess, I did toy with the idea a while back of, like, inviting him on the podcast, right? Why not? But, you know, he's in his 90s. German is his native language. He's writing a several thousand page history of philosophy. I figure he has other things to do than appear on the Mindscape podcast. So I never did ask him. So you can't have everybody. That's okay. But maybe we should have someone to talk about that kind of thing, because I'm clearly not the world's expert on it. But for those of you who are not familiar with

54:58Habermas's work, it's the kind of thing that is worth studying up on just a little bit.

55:04Owe, O-W-E, says, at the end of February's AMA, you talked about how it's still financially worth going to college. I think that's true on average still, but the variance has gotten way wider with the increase in loans and reduction economic opportunity they provide. That's not to say that I disagree. Normatively, I think education is a positive. Rather, your comment struck me in how hard it is to talk about outcomes and choices in terms of their ranges and probabilities without reducing to binary classifications like worth it or not worth it. Especially as a physicist,

55:35I'm curious if you think there's a better way we can have such discussion. I don't know if there's a better way we can have such a discussion. I get it that it's frustrating to have these very complicated, multidimensional questions reduced to a worth it, not worth it kind of distinction. But at the end of the day, there's a lot of factors that go into it, but any individual person is either going to go to college or not. They will decide whether it is worth it or not worth it for them to go to college. My major point in the AMA and the solo episode I did or the holiday message on

56:13the romance of the university is that it's worth it, not because it gets you a higher income, but because it makes you a better human being. That's not necessarily true. You can go into college and come out a worse human being than you went in. But I'm thinking about those people who would like to become a better human being. That is part of their goals. And I do think that there's a lot of tools and resources that are there in the four years of undergraduate college experience that are almost irreplaceable elsewhere and that are super duper useful for becoming a better person

56:48if that's what you want to do. Now, how do you value that against the amount of money it will cost and the student loans you will accrue and things like that? That has to be an individual choice. I can't provide you an algorithm for that. I do think that a lot of people, I don't know if it's everybody or not, but a lot of people end up spending too much on college because they want to go to the fanciest one that they can get into, right? I think this is maybe less true than it used

57:18to be just because all colleges are pretty expensive these days. But I'm one of the people who believe that almost any good college or university has way more resources than any individual undergraduate can possibly absorb in five years. So the difference for an undergraduate in going to the world's best and fanciest university versus their local state university is not that big in terms of what they can learn and what they can experience. There are big differences, especially in the other people

57:53you get to know. If you're the kind of person who cares about having a good Rolodex, as we used to say, of influential and important people in other areas of life, then going to Harvard or Princeton or Yale is definitely valuable. If you're the kind of person who really, as a matter of socializing and your personal life, prefers to be surrounded by nerdy people who are doing all technological things, then going to Caltech or MIT might be for you. But in general, to get the worthiness of the college

58:25experience, I think that there's plenty of different kinds of places you can do it. And one simple way of saving money is to go to the least expensive of the ones that you think would serve that purpose. I guess the final thing to say is, look, it's a system versus life world kind of thing going on here, right? Going to college and getting that university experience should be a life world question. It should be about thoughts and ideas and talking to each other about them and learning. And so often it gets squeezed into a question of acquiring skills and getting a better job,

58:58okay? Purely economic considerations. And I think that I can't tell you how to balance all the considerations because they're all real and I respect all of them. But don't go too far in just thinking about one rather than the other. That's the best I can do. Very far from a perfect answer to your question, but that's what you're going to get from me right now. I'm Jake Stauk, co-founder and CEO of Serval. We built Serval to automate the IT work that slows companies down. Onboarding, password resets, access to applications, my laptop stopped working.

59:31While employees wait for help, their real work is put on hold. IT desperately wants to automate this work and that's why they need Serval. You just tell Serval what you want to automate in plain English and it's built. No drag and drop workflows, no expensive consultants. Employees get unblocked and IT teams go from drowning in tickets to building what actually matters. With Serval, IT becomes the AI engine powering the entire company. This is a new way to run IT. We guarantee you'll automate 50%

1:00:02of all tickets and we'll prove it to you in a free four-week pilot. Go to serval.com slash listen. That's S-E-R-V-A-L dot com slash listen.

1:00:18Ryan Reynolds here from Mint Mobile. I don't know if you knew this, but anyone can get the same premium wireless for $15 a month plan that I've been enjoying. It's not just for celebrities. So do like I did and have one of your assistant's assistants switch you to Mint Mobile today. I'm told it's super easy to do at MintMobile.com slash switch. Upfront payment of $45 for three-month plan equivalent to $15 per month required. Intro rate first three months only, then full price plan options available. Taxes and fees extra. Default terms at MintMobile.com.

1:00:48Michael Bright says, the James Webb Space Telescope has seen things that no other space telescope has seen. For example, it has helped us deepen our understanding of the accelerated expansion of the universe. But I believe the JWST is built to focus on small regions of space, whereas the Nancy Grace Roman Space Telescope is a wider view. Can you help those of us who want to support science research understand the importance of supporting Nancy Grace Roman and other science exploration missions that have paid off very well for NASA so that we can advocate for their continued support? Sure. And I think this is actually a really good question because it's not always

1:01:23clear when we hear about these different telescopes, these different satellites, why we need, you know, more than one. Why don't you just build the best satellite out there that does all the telescoping you need? Sometimes it's kind of a little bit obvious or clear. For example, a satellite that is measuring the cosmic microwave background is going to be very different than one that measures optical visual light or even infrared, which is what JWST does. But among those, the Roman Space Telescope is different than JWST, even though they're both sort of optical, approximately

1:01:58visible light wavelength telescopes. And the biggest single difference, as Michael says, is that JWST has a narrow field of view and Nancy Grace Roman has a wide field of view. And this is with mirrors, the collecting area of the mirror in the telescope. So anyway, what happens in these telescopes ever since, I don't know who invented the reflecting telescope as opposed to the refracting telescope? In the refracting telescope, you send light through glass lenses to focus it so you can collect a lot of light

1:02:31onto a small region. But going through glass inevitably messes you up a little bit. So a reflecting telescope where you use mirrors to collect the light is actually more efficient for precision astronomy. It's also just easier to make these mirrors than to make perfect lenses. So the mirror collecting area, the size of the mirror, basically tells you how many photons the telescope can bring in. The more photons, the better. Okay, so far so good. But the difference here being that you can still affect the

1:03:05field of view. So you can collect a lot of photons in a very, very narrow area, or you can collect a lot of photons in a very wide area. And what is the difference? Well, obviously, if you're collecting more or less the same number of photons, I know the real astronomers here are going to be mad at me because it's not really the same number of photons. It's the same collecting area, but you know what I mean. You get to see deeper if you focus in on a very tiny area. If what you're interested in is things that are very far away and very dim, then something like James Webb, which really focuses in on a

1:03:41narrow area is what you want. And that's what you have. That's what the telescope actually does. And the reason why they're interested in that is they want to look at the very first galaxies, the formation of things in the early universe. And then also JWST turns out to be very good at looking at exoplanets, which are not very far away at all, but they're very, very faint and very, very specifically located at a place where you can point the telescope. So the advantage of that is that you can get a lot of image of something very faint. The disadvantage is you better know where you're looking. If you just point the JWST at

1:04:17a random part of the sky, you can do tricks. So you get like an ultra deep field kind of thing. But if you focus it as much as you can on the tiniest possible area, most of those parts of the sky are going to be empty. Nothing's going on there. Now, if you do the same thing, the same collecting area in the mirror, but you have a very wide field of view, then what you can do, you're not going to see very deep. You're not going to see things in the very, very early universe. What you're going to

1:04:47see are many, many things in the relatively nearby universe. When you say relatively nearby, we don't still mean very nearby. It's still, you know, billions of light years away, or at least a billion light years away. But you have a huge advantage now if you're trying to survey things, if you're trying to look at many things at once. So if you're trying to measure the large scale structure of the universe, or if you're trying to search for things like supernovae that come and go unpredictably, the only way to do that, you're not going to focus in on one galaxy and look for a

1:05:19supernova. That's going to happen once per century. You have to look at many, many, many galaxies at the same time to have a good number of supernovae collected. So that's why the Virarubin Observatory here on the ground has a very wide field of view. It is actually going to be taking multiple pictures per night and scan as much of the sky as it can. And looking for supernovae is a big part of its mission. Also looking for asteroids and things like that here in the solar system. So Roman is like a compromise. It's not looking at the whole sky, but it's not focusing in on a small patch either.

1:05:54So it has a much clearer view, of course, because there's no atmosphere out there in space. So you have different missions. The JWST will teach us about early galaxies and exoplanets. Roman will teach us about the overall structure of the universe, the acceleration of the universe, the Hubble tension, all of those things. So it's just different science that you're doing with different missions. Both of them are very worth supporting. Jan Drugalia says, priority question. Remember that every Patreon supporter gets to ask a priority question once in their life, and I will do my

1:06:28best to try to answer that question. So Jan says, I've noticed a trend where some of my friends with STEM backgrounds are falling into strong support for the UAP, the Unidentified Aerial Phenomena, what we used to just call UFOs until people thought that that didn't sound respectable enough. They point to the congressional hearings and the anomalies of the Atlas interstellar object as evidence that there is something out there. While I love and respect my friends, Congress, and the witnesses, I struggle with the fact that we still have zero peer-reviewed physical

1:06:59evidence for UAP. Until that evidence exists, I choose not to invest more time in the topic, and that feels almost impolite toward my friends. Did the congressional hearings or the discovery of Atlas update your own Bayesian priors for UAPs at all? No, they did not. My priors are very, very low. Now, of course, UAPs exist or UFOs exist. There are things in this guide we haven't explained yet, okay? That's never a surprise. There will always be such things. The question is, do these have anything to do with aliens or extraterrestrial technologically advanced

1:07:31civilizations? And the credence on that remains hilariously low, low enough you don't really need to worry about it. It's especially a tell if they think that the Atlas interstellar object has anything to do with this at all. We have interstellar objects entering the solar system. They're the solar system. They're basically comets. They're basically icy things that come into the solar system and fly by at high rates of speed. You can be a little bit intrigued because sometimes

1:08:02these things are seen to accelerate, and you go like, oh, how can a dead rock just accelerate? But comets are not rocks. They're actually very icy, and they have all this material on them that heats up when they come close to the sun and pushes them so they are seen to accelerate. But it's not because they have an engine. It's just because they're warming up and sort of outgassing. So there's zero reason to think that the Atlas interstellar object has anything to do with aliens or technology or anything like that. And again, ask yourself the Bayesian question. If it really were technology

1:08:36from aliens, why would it just fly by? Why would it look so much like a comet? Why wouldn't it just stop and say hi? None of these are remotely plausible, these scenarios that you have to cook up to make this be related to aliens in any way. As far as the congressional hearings go, I mean, look at the history of this. For at least the 20 years that I have been talking about this stuff online, every year I say something like, no, the UFOs are not aliens. And I get people saying, oh, there's going

1:09:07to be evidence coming out six months from now. You're going to be sorry. You're going to change your tune. You're going to regret saying this. 20 years later, I'm still waiting to do that. The idea that aliens would come by, be good enough to have technology that can travel across interstellar distances and visit us, but not have the technology to remain hidden from us. The idea that they would just crash and get little fuzzy photographs or, you know, eyewitness testimony from people in airplanes or whatever is just crazy. That's just very, very unlikely to happen.

1:09:43Whereas the idea that human beings would make the mistake of thinking that and keep tantalizing you with evidence that is just beyond actually being concrete, that's 100% believable to me. So having congressional hearings or whatever has not changed my credences at all. Gag Halfront says, what do you consider to be the emergent long-term geopolitical effects of the U.S.-Israeli excursion in Iran? Well, of course, this is just terrible and tragic. I mean, the whole thing

1:10:14is tragic. The ongoing wars for a long time in the Middle East have been tragic. The Hamas attack on Israel was tragic. Israel's total decimation of the Gaza Strip has been tragic. The U.S. and Israel invading, not invading yet, but maybe that will happen. But attacking Iran has been tragic. Israel going to Lebanon has been tragic. It's all just terrible. Like, it's not just annoying. There's people there who are living there and are really suffering because of this. The Iran debacle is

1:10:46especially bad because it serves literally no one's interests. Just, it's only happening because we, I'm only going to talk for the United States here because I don't follow Israeli politics like that. But here in the United States, I can speak with complete confidence that the people who are making the decisions are idiots. They do not know what they're doing. They're very, very stupid. They have very bad motivations. If you listen to Pete Hegseth, our Secretary of Defense, and other people talk about their bloodlust for war and to commit war crimes and to spread Christianity across

1:11:21the globe, etc., it's horrifying. It really just makes you shake your head. And of course, there's no purpose being served here. The purpose that is trotted out, which, by the way, I keep backing up because the whole thing is just so terrible. Ordinarily, if you're going to do something major like this, Iran is not a small country, OK? They're pretty tough. And you would at least, to the general public in the United States, make a case for getting involved in

1:11:53something this dramatic. But the administration did not do that. And the case that they're making ex post facto has to do with Iran's nuclear program and the possibility they would, you know, make weapons of mass destruction, we already had a treaty in place that was preventing Iran from doing that. And Donald Trump, in his first administration, left the treaty unilaterally because he just was annoyed that it had been negotiated by the Obama administration. And so we're doing nothing that

1:12:23has absolutely any purpose whatsoever. And oil prices are going up. Many people have died in Iran. Iran. Apparently, Iran is going to come out of the situation geopolitically stronger than it went in. Now they're saying that the Strait of Hormuz, which is a little tiny strait, I suppose, where many, many tankers go through to bring oil to the rest of the world, not just from Iran, but from other Persian Gulf states, is going to go completely under Iranian control, whereas it was not before. And this

1:12:54affects not only the United States and Iran and Israel, but every country in the world, because all of our supply lines are interconnected in very important ways. And so it's especially heartbreaking to me because I know that the government of Iran is terrible. I mean, there's just nothing good you can say about it. It's an autocratic, repressive theocracy, and it deserves to be gone. But it's also not very popular in Iran, as far as I can understand it. Iran is not, you know,

1:13:25by its nature, an oppressive theocratic regime. There's a lot of strongly liberal currents in the Iranian people. Education and science education in particular in Iran is very high level, especially compared to other countries in that part of the world. We have great physicists who I know personally who've come from Iran, including Qumran Vafa, former Mindscape guest. And a lot of the people in Iran don't want to be led by a repressive theocratic regime. The United States has a lot of responsibility

1:13:57for the fact that they are, because the United States historically, it's not just Donald Trump, just the United States likes to throw its weight around and think that it should decide who runs other countries. And it instituted the Shah of Iran many, many years ago. You know, I'm old enough to have been barely, I sort of, you know, became interested in news and politics and things like that around the time of the Iranian revolution and the hostage crisis and Jimmy Carter versus Ronald Reagan and things like that. So this is us reaping what we've sown a long time ago. And if anything,

1:14:32there was a possibility that the Iranian people would have been able to overthrow their regime. There were demonstrations against them, etc. And the United States, of course, has blown it because, as mentioned already, we are ruled by idiots. You know, they can't get it through their heads that if you drop bombs on the country, that country is not going to like you as much. They, you know, it goes back to Dick Cheney in the Iraq war in the George W. Bush administration saying that he thought that we would be greeted as liberators when we invaded these other countries. And it's become a

1:15:08joke. Because if you invade other countries, even if the people of those countries were against their own regimes, they're not going to like you invading them. They're going to change, they're going to rally around the flag, as it were. And so now we may have even lost any possibility that we might have had for a regime change in Iran. So anyway, I'm not an expert on any of these things. You shouldn't take my view as especially super well informed compared to the people who are well informed. But it just makes my shake my head in sadness. So I did answer that one. But, you know,

1:15:40it's not something that I talk about very much, just because there are smarter and more informed people out there who you can listen to. And I encourage you to do that. Kevin's Disobedience says, Say one good thing about loop quantum gravity and one bad. What's it got going for it? And what are its major shortcomings as you see it? I think it's easy to say both good things and bad things about loop quantum gravity. For those of you who don't know, loop quantum gravity is basically a clever way of trying to quantize general relativity. You've all heard that gravity and general relativity,

1:16:12sorry, general relativity and quantum mechanics are hard to reconcile. So maybe that's because the version of general relativity or the way that we're writing down general relativity is not the most convenient for quantization purposes. That's basically the philosophy behind loop quantum gravity. It started with Abai Ashtakar, who figured out a way to rewrite the fundamental dynamical degrees of freedom of general relativity in a different way. And then people like Lise Mullen, Carlo Ravelli,

1:16:43both former Mindscape guests, worked out how to rewrite those variables in yet a different way based on loops. Basically, the loops in question, you take a vector or something like that, and you transport it around a loop in spacetime. And you ask, how does it get rotated by the curvature of spacetime? So you can try to quantize that representation of general relativity rather than just the usual one where you have a metric and so on. The good thing to say about it is it's a perfectly natural, sensible thing to try, right? You should try to quantize general relativity, see if the reasons

1:17:19why it hasn't been working are just because you didn't use the right variables or something like that. The problem is there's almost no chance it's going to work. And I think it kind of hasn't worked. In fact, I mean, there's not a big understanding that we now have of general relativity because of loop quantum gravity that we didn't have before, or a big understanding of quantum gravity for that matter. And I think we kind of understand why it doesn't work. Unlike other forces of nature, not only is gravity different because, you know, it's the metric of spacetime and whatever, but from a quantum field theory point of view, and general relativity

1:17:55is a classical field theory. After all, from a quantum field theory point of view, you know that if you want to get an exact theory, not just an effective theory, but if you want to get a theory that is valid at all energy scales, then the trouble is going to be at very, very short energy scales, right? Energy scales where there's wild fluctuations in all the fields, the spacetime metric itself, the energies are very high, we have no experimental data, things like that. String theory specifically

1:18:26solves those problems by smoothing everything out at high energies, because instead of point particles, you have strings. They're sort of floppier and looser, and you can show mathematically that all the worrisome infinities that you might have worried about go away in string theory. In loop quantum gravity, there's nothing to guarantee that anything like that is going to happen. And furthermore, loop quantum gravity treats general relativity as separate. It treats the curvature of spacetime as one thing, and then whatever matter fields you have as completely other things. But the

1:18:59infinities and the worries that you would get at short distances in gravity depend not only on gravity, but everything gravity is talking to. And the whole thing about gravity is that it talks to everything. So there's no reason to suspect that somehow gravity will be quantizable until you also understand all of the other fields in the universe. Again, in string theory, that naturally happens. All the fields in the universe come from the propagating strings. It's a complete unification. In loop quantum gravity,

1:19:30all the other fields are completely separate. To imagine that there's some conspiracy that makes everything smooth and finite in loop quantum gravity, despite not knowing what the matter fields are doing, seems implausible to most of us thinking about quantum gravity. That's why, honestly, it's not that popular among people who do quantum gravity. It's maybe the second most popular after string theory, but that's not really saying very much. I am infinity category says in your 2020 podcast episode featuring Sean B. Carroll, you mentioned that

1:20:02you've received looks from peers when they find out that you're active in public science discourse, just as your evil twin did when he took up the writing of biographical material as opposed to just research. You've also mentioned often that doing anything other than research isn't conducive for tenureship for junior researchers. Can you say something about when and how you started breaking away from the research-only mold? As a junior research fellow interested in writing for the public, should I just wait for tenure before doing anything? You know, I can't give anyone precise advice here because, as I always say, everyone's situation is different. In particular, it depends on, you know,

1:20:37where you are. If you're a junior faculty member, what kind of university you're at, what they're interested in, how your research has been going. Like if you're, as I also like to say, if you're a genius, if the whole genius thing is working out for you and everyone recognizes that you're a genius, you can do whatever you want. You'll be fine. It's a matter of shifting probabilities and likelihoods. It's not a matter of absolutely yes or no, should you do this or not. So you have to judge that. It's certainly the safest to wait for tenure before doing anything. Once you have tenure,

1:21:07you can be much more confident that you can mix in research with other kinds of activities and that will be okay. They will not fire you. Indeed, this is one of the reasons why it's dangerous to do that before getting tenure because the universities know that once you get tenure, they have much less leverage over you. And so if you're the kind of person who likes doing other things, they will worry that you will stop doing research. And so that's something that's very hard to prevent. But it can be done. People do do it. People are successful starting with public outreach things at

1:21:41a very young age. I think you have to judge from the department you're in, the university you're in, and things like that, how likely you are to get away with something like that. Igor Kapilov says, The story I've heard about the history of quantum mechanics is that after Schrodinger wrote down his equation, he hoped that the wave would naturally coalesce toward a point over time. That wasn't the case at all, and only later did Max Born propose that the wave should be thought of as a probability distribution. The part I'm missing is why, without the later insight, does the Schrodinger

1:22:11equation appear to be on the right track? What problem does it solve, even if you don't know about the Born rule? That's a good one. It's a good question, because I know the answer. The answer is it solves the spectrum of radiation from hydrogen and other atoms. Remember the big thing that physicists were focusing on. Physicists always like to have a specific, potentially solvable problem to look at and think about. And in the case of quantum mechanics in the 1920s, it was electrons in atoms. And they would both absorb radiation and give off radiation,

1:22:45and that was quantized, right? They would jump up and down in energies by certain discrete amounts. Niels Bohr had come up with a kind of ad hoc rule for what kinds of energy levels were allowed that worked very well for hydrogen, an atom with just one proton and one electron in it. Once you added another electron, and so the electrons are talking to each other, there was no guidance from Bohr's theory about what to do next. So the Schrodinger equation, forget about observations, forget about measurements, forget about probabilities and collapses and

1:23:19things like that. Just solve the Schrodinger equation for what electrons do in atoms. And you turn out to get exactly the right answer. It's very, very beautiful. You can find the energy levels. In fact, if you look at the title of Schrodinger's paper where he proposes the Schrodinger equation, the title is Quantum Mechanics as an Eigenvalue Problem. Eigenvalues are just basically the energies of these specific states that the electron can be in, these specific solutions to the Schrodinger equation. So that's what he was worried about. And the

1:23:51thing you're measuring there is the energy of a photon that is emitted by the electrons as they shift from one energy level to another. So you're not directly measuring the location of the electrons. Indeed, what Heisenberg was saying, contra Schrodinger, is that there's no such thing as where the electrons are or what the wave function of the electron is doing. There is only what you measure at the end of the day. That was the birth of the Copenhagen interpretation. So there is still good quantitative reason to think that Schrodinger

1:24:21was on the right track even before the Born Rule came along. Kyle Cabasares says, This is a really good question. This is unlike the previous one where it's good because I know the answer. This is good because I don't know the answer. It's very, very hard. It's very common

1:24:54for a first-time author to have a topic where they know perfectly well someone else has written about it already or many people have written about it already, but they feel that no one has done a good job. And so their sales pitch to agents or publishers or whatever is, yeah, I know that's been written about, but those books are all bad. Mine will be good. And I can tell you that's not a very convincing sales pitch because everyone thinks their book is going to be good. You're not actually conveying any new information to the publishers or agents when you tell them that.

1:25:24So I think you not only need to think that you're going to write a book that is good, but you have to have an angle. You have to have, if you're writing about something that's been written about many times before, you have to be doing something new and different, at least usually. You know, there certainly are. If you look at the set of books that get published, there absolutely are books that say nothing new, but are just, you know, well, it's been a while since there's been a book about this topic and we need to sort of freshen it up a little bit, reach a different audience, which is entirely fine. But for the most part, you want to say something either substantively

1:25:58different or in a different way than it's been said before. Maybe write your book in the form of a dialogue or something like that. Have more pictures. You know, when I wrote my quantum mechanics book and something deeply hidden, I talk a lot about quantum mechanics as quantum mechanics, but the main thrust of it was talking about many worlds and immersion space time. So that was something a little bit different. How you actually go about doing that, that's your job. That's, you know, it's, that's what you're going to get paid the big bucks to do, figuring out a way to put a new spin on an old topic. Mikhail Sirotenko says, I have a question about the timeless universe

1:26:35and Boltzmann brains. If the time, if time is not fundamental and the universe is just a static wave function with different moments in time, just components of this wave function, then the amplitude of those components would depend on the chosen basis. And assuming that we cannot choose this basis arbitrarily because we need a basis that allows for observers and loss of physics, does the selection of such a consistent basis mathematically suppress the amplitudes of Boltzmann brain states relative to the classical looking states? No, probably not. I think it's, the question is a little bit

1:27:06difficult to answer directly because I'm not quite sure I agree with what is going on here. So to back up a little bit, you've heard me talk about how in quantum mechanics, the state of the quantum system, whether it's the universe or an electron in a hydrogen atom, is a vector in Hilbert space, this gigantic vector space. And therefore, there's this very special property that quantum mechanics has that different physical states of the system can be literally added together. You can add vectors together. And that's a big part of hoping to explain how emergent time works, because you could

1:27:40take what you would ordinarily think of as the state of the universe at different moments in time and just add them together. And you could actually, if you know what basis to use in the vector space, the basis we're talking about here is literally the set of basis vectors. So if you have a plane that, you know, you have x-axis and y-axis, there is a basis vector pointing along the x direction and a different basis vector point along the y direction. Informally, what you think is that nothing should care about what your basis is. Your basis is something you choose. It's a convenient language

1:28:15in which to express the values of your different vectors. But it's not exactly true that all bases are the same. There are physical states that you will see as an observer and other states that you won't. Schrodinger's cat has the famous property that you will see the cat awake or the cat asleep, not one over square root of two, one plus the other one. And that's because of physics. Physics explains why certain states are more likely to be observed than others. There's no rule that says

1:28:45you have to use those states as a basis in Hilbert space, but you can, and it's often very convenient to do so. So what Mikhail is asking about is, since we cannot choose the basis arbitrarily, does the selection of a consistent basis suppress the amplitude of Boltzmann brain states relative to classical looking states? The selection of a basis does not. No. You can very easily have a classical looking Boltzmann brain. There's a quantum fluctuation that leads to the Boltzmann brain popping into existence, and that would be a perfectly legitimate basis state, just like any of

1:29:20the other states we use, like the cat's awake or the cat's asleep or whatever. So I don't think that's enough to do it. There are plenty of quantum mechanical subtleties about how to deal with Boltzmann brains in quantum mechanics. And I wrote a paper that I've mentioned many times with Kim Boddy and Jason Pollack, saying that in certain circumstances, the dynamics of the state can be such that Boltzmann brains never appear. But it has nothing to do with choosing the basis correctly, and I don't even think it has much to do with the emergence of time, unless I'm just missing

1:29:50something about the question. Wonder says, light cannot escape from a black hole. I understand this when I think of light as a particle. Please explain it in the context of a field. Sure. There is something called the speed of light. Remember, the speed of light was invented and talked about before we knew that light was made of particles, right? The idea of a speed of light, of course, the concept of a speed of light was measured, etc., long before we had electromagnetism as a theory. But once Maxwell wrote down his equations in the mid-1800s for electricity and

1:30:27magnetism, the speed of light suddenly became important in a way it hadn't before. It was always important because it was the speed light moved at. But now it's a constant of nature that seems to be the same to everyone and appears as a fundamental parameter in these equations called Maxwell's equations. And that's when people knew for sure that what light was, was a vibration in the classical electromagnetic field. So the fact that a vibration in the classical electromagnetic field moves at the speed of light is built into Maxwell's equations from the mid-19th century. And it's

1:31:05much like if you have a pond of water and you throw a pebble into the pond and you see a little wave ripple out, that wave moves at some speed, right? Same exact thing is true for light, considered as an electromagnetic wave. So the only other thing you have to know is that when people doing general relativity say light cannot escape from a black hole, what they mean is black holes are regions of space-time bounded by light cones. That is to say, the event horizon, the region surrounding the

1:31:38boundary of the inside of the black hole to the outside of the black hole, is moving outward in a very real sense at the speed of light. The reason why nothing can escape a black hole is because literally you need to move faster than the speed of light to escape a black hole. So light cannot travel faster than the speed of light. That's true whether it's a wave or whether it's a particle. If it's a field, then what light is is a vibration in that field. And those vibrations move at the speed of light. Therefore, they cannot escape a black hole. Nikola Ivanov says, you've argued that if the universe settles into a stationary

1:32:14Desider quantum state, it shouldn't keep producing Wolfsman brains. Aha, that's the paper I just referred to. Yes. Nikola says, but a single Desider horizon patch is also said to have a finite entropy, which makes it sound as if that patch might have only finitely many possible states, and a finite state system is usually expected to recur over long times. So why doesn't that make the Boltzmann brain problem come back? Yeah, this is a perfectly good question. And so again, to try to give some of the background here, we just said that quantum states are vectors in some big dimensional vector space called Hilbert space.

1:32:49But what does big mean? Does big mean infinitely big or finitely big? As Nikola says, the entropy of a region of space of Desider space, that is to say, empty space time with a positive cosmological constant, the entropy is finite. And that points to that region of space being described by a finite dimensional Hilbert space. But the point is, I'm sorry, I should say one more thing. If you are in a finite dimensional Hilbert space, and you're obeying the Schrodinger equation, no matter where you start,

1:33:19you will eventually come back to where you left. Because the Hilbert space is finite dimensional, there's not an infinite number of places you can go, you will eventually have to recur, return to your starting point. And likewise, you will fluctuate forever. You never evolve into a static state and just stay there for all of eternity. Whereas if Hilbert space is infinite dimensional, then the state can keep evolving forever and never return or never fluctuate. It can just go into a region of Hilbert space where everything looks perfectly static to an observer. So how do you reconcile that? Well,

1:33:55the answer is knowing that our observable patch of Desider space is described by a finite dimensional Hilbert space doesn't say anything about what's outside the observable patch. So we say in our paper, very explicitly, there are two choices. One choice is there is a strict finitude for all of Hilbert space that not only is our observable patch a finite dimensional Hilbert space system, but the whole universe is finite dimensional. And then we say you will get Boltzmann brains. But it's also completely

1:34:28allowed, given what we currently know about the universe, to say that outside there's infinitely more dimensions of Hilbert space. And really, we are not a closed system. Our observable universe is connected to the rest of the universe. And therefore, it can basically shake off all of its peculiarities and settle down. It can obey the cosmic no hair theorem that says that no matter what is going on in our universe now, classically, with a positive cosmological constant, the universe settles down into a quiescent state. If Hilbert space is truly infinite dimensional, that can happen quantum

1:35:02mechanically as well. And then you're not going to get any Boltzmann brains. Ryan Cobine says, I found the following martini to be palatable, but a bit off peppery, which isn't a bad thing, and also a touch sour, which is a bad thing. What alterations would you make to bring this above the merely palatable to enjoyable? And then the recipe he gives is one and a half ounces Ford's gin, one quarter, sorry, three quarter ounces of Dolan vermouth, and a dash of Reagan's orange bitters, expressed lemon oil, lemon peel, garlic, stirred. P.S. This is my first time trying a martini.

1:35:35Well, I think this is, I don't see anything wrong with that martini recipe per se. It'll depend on your personal tastes, whether you like it or not. I would say that you're trying a little hard to put stuff in there, right, with the orange bitters and the lemon oil and things like that. Lemon peel garnish, completely 100% fine. I would say just start with a more basic martini. Just do the gin and vermouth and the lemon peel, and then little bit by little bit add, you know, orange bitters,

1:36:07lemon oil. It might depend on the details of the bitters that you're adding, of the gin, etc. But a martini, you know, is driven by mostly the gin and the vermouth, I think, if it's done correctly. And both of those are not, you know, smack you in the face with flavors kind of thing. They're kind of delicate in both cases, both the gin and the vermouth. They have some botanicals, some herbal notes and stuff like that. And so if you add extra stuff, you can easily throw the

1:36:37balance off. So adding extra stuff is fun and fine and good when it succeeds, but I would try with the basics first, and if it's your very first martini, and then just go and see what you might want to add from there. You might want to add nothing at all. David Levitt says, do you ever explain to general relativity students that Earth's surface accelerates outward at 1g? So what David is referring to is the idea that in general relativity, there's no, you know, what can I say? There's no

1:37:08fixed reference frame in which you should be evaluating anything. So there's certainly in any version of relativity, special or general, there's no fixed velocity that you can count as the correct velocity that something is moving at. All there are are relative velocities. And in fact, in general relativity, there are only relative velocities that are well-defined when two things are essentially at the same point in space-time. Since the space-time itself can be dynamical, if you have two things that are far apart from each other, there's no such thing as their relative velocity because there's no unique

1:37:41way to measure it. There can be some circumstances like cosmology where there's sort of a natural way to measure it, and we do. We talk about the velocity of receding galaxies, but it's actually not