Joe Rogan Experience #1352 — Sean Carroll Transcript

Transcript

0:00 and here we go hello sean hey joe how's it going thanks for being here again man i really Well, it is rewarding because it is fascinating. Now, for regular people that don't have a background in physics or that don't – this is – like the whole idea behind it is so bizarre it's like why would anybody Feynman saying nobody understands quantum mechanics, right? And so if he says that,

2:58 They can make phone calls. What are all the details? Probably electrons moving around in there, right? In my mind, what physics is all about is understanding reality and what the world is doing. In my mind, what physics is all about is understanding reality and what the world is doing. It's not just about making It's like, if anybody should be pursuing it, it should be people like you.

5:34 and putting stuff to work was attractive. So I think those attitudes were wrong, but at least they're not completely crazy. up to the task. We need to understand the details a little bit better. The other sadder thing is that in experimental and observational physics. Maybe we can take a broader look and think that we're walking down the wrong path.

8:04 seriously longer than the physicists have, to be honest. technical mathematical paper on quantum field theory just to prove he could do it. And then right? Like completely misrepresenting what he said. And so he went public after that and and you can accept it and take it as what it is, no matter what you like. The other is you can A reality-based guru.

11:01 And it's one of those things where it like this many worlds theory mechanics there was classical mechanics and basically quantum mechanics and classical And the wave function has this weird property that when you're not looking at it, it's a wave. And that's where they want to go woo-woo on you. Right. Now, let me ask you this. It's really exactly like that.

14:30 That's the quantum fact, field or oriented vertically, it will always be deflected up every single time. We know what it we couldn't predict what would happen next. But this is the standard textbook version. little chunk of metal, and you put it in a bubble chamber. So it is emitting radioactive particles, Aaron Powell Evenly. It can go out in higher energy states.

18:20 that are just sort of basically getting the first steps going to understand this stuff. And he was given his first magnetic compass and he could rotate it this way and that way and And it always pointed north. And you and I would go, huh, that's cool. He wanted to know God's thoughts. It's a combination of both. That's its wave function. You measure it, you only ever see spin up or spin

20:19 is two things. Number one, That's one thing. But because momentum is conserved, if they came in at equal velocities, they'll go out at equal velocities in opposite directions. You obey the Schrodinger equation. and you measured it spinning clockwise. other. That can't be right. That can't be the final answer. The wave function must somehow collapse.

23:14 That is the part where my brain broke. is you know sure if i think about it like i believe it. You know, I have a chapter in the book, which They are really, really good at fitting what I do observe in the world and making predictions. But do you think of each choice that you make possibly changing everything about the world He's taking his jacket off. We're getting serious here. I know. It's getting hot in here. Physics is heating us up. So I'm trying to filter it through your understanding of it. Well, I think that –

26:01 It's certainly not true that you making a decision is what branches And then you can deal with that and your therapist, however you like. Yeah, sorry. wave function of the photon goes 50 50 it gets sent left it gets sent right and if you agree and so then it sends back whether you ended up in the branch of the wave function where it went left Really?

28:06 Yeah. But now let's hit the brakes on the woo again. can you violate the conservation of charge, right? So there's plenty of things that don't happen, or how many versions of you there are. both of whom used to be you, but they're not the same person anymore because different things You have to. And the textbook version certainly does. And so everything had to be quantum. And I think that that's another thing that is pushing us

32:38 And that we are thinking of ourselves in this very limited, primitive, biological way, because The signal is so distant. and we're still not really good at it. And how much should we just accept You know, we have to be based on that. And number two, I don't think that anything about nature is impossible to understand for the current human brain. Take time.

36:00 I mean, without people like you, especially describing the computations Just hard. and stuff like that. For AI, right? For AI, yeah. But the Turing complete is basically, language. We can reason symbolically and abstractly. We can write things down and pass them And I think that's enough. don't think there's any person who, you know, can balance their checkbook but not

38:39 time that they know how things work, right? That's why I was curious as to how you apply it is a really good approximation. about the earth going around the sun forget about quantum mechanics just just do classical mechanics enormous handle over what the world's doing, ignoring almost all the data that there is function of the car you're driving, right? And if you needed to know the quantum wave

41:27 You know, it's pretty still. because on the one hand, Einstein teaches us, you know, when you say something is moving, there not moving. It's really not changing appreciably over time. If you were to observe right? Position and velocity are things you measure. it looks pretty stationary. cellular biology, there's ATP is being created and destroyed, and you know, signals are going

45:00 our integrity. sometimes need to mention it max tagmark who is a friend of mine a very smart guy And you do this over and over and over and over and over again. you should take that as good evidence that the many worlds interpretation of quantum mechanics is correct. quantum immortality experiment. I don't buy the move that says, well, in all the branches where

47:41 So basically, you know, if you have an electron and you say, look, when I'm not developed the most respectable version of this. It's sort of therapeutic if you don't like all But these days we use quantum field theory and quantum gravity and things like that. So it's all spread out, but its wave function So somewhere in the table, all the time, if I'm not entangling it, one of the wave functions should spontaneously localize occasionally,

50:46 This is not true. What do you mean observe? So in Everett, what's real is the wave function. electron is a point and the wave function is just telling you where you might see it. There is an exception to that In spontaneous collapse, it's all of reality, is just a tool you use to make a prediction for what the experimental outcome is going to be, don't ask those questions. We don't ask reality questions. We just ask, what are you going to see

54:38 will say it. And so when you press them too much on questions like, you know, is the atom mostly when you write the book. It's hard when you think about these things as a professional physicist. How are you guys working this out? There were a few people, a few plucky souls who really put their efforts into understanding these. So honestly, what it is, is a bunch of people get around a table and talk to each other.

57:28 where everything is perfectly deterministic, right? It's a small community. It was very similar similar but i believe she Is it because you guys work in isolation essentially, and then when you get together, you're so pumped up to be discussing these things with like-minded souls you know in part yeah i mean i there's no one is more common and mainstream?

1:00:40 And by the time they get to the foundations of quantum mechanics, there's usually very little support. Philosophers, their job is being patient and clarifying difficult conceptual questions. wonderful corrective. It's a wonderful reality check when you think, well, reality has to be People like Thomas Kuhn and Paul Feyerabend and so forth. and this idea was not my idea. Apparently, Laplace had a very similar idea as a thought

1:03:40 I've mentioned his name in every book that I've ever written for totally different reasons. and you had arbitrarily large computational capacity, and you have infinite calculational capacity, you could predict the past and the future with You know, I wrote a little article that just appeared in Quantum Magazine, which by the The traditional answer is if you're flipping a coin and you say it's 50-50, what you mean

1:06:15 the lone shooter of JFK? That already happened. That's in the past, right? But we can easily say, is a positive number, In one of these spontaneous collapse theories, it's very much like a frequency. because it's kind of, So I actually do know And the time scale of things happening in my brain is like 10 to the minus 3 seconds at best. The wave function squared is the probabilities.

1:09:28 But what he hoped was that if you had the wave function of an electron all by itself, if you solved his equation, it would sort of show that the wave function becomes localized, peaked at one location. and schrodinger said like oh my god that's awful i'm sad i had anything to do with it he regretted too much, like a little bit, you know, get their foot wet, but they got to work on respectable

1:11:59 visualize that would help yeah and that was i in fact i think that you got a copy of my book that Is that out? But honestly, all of the pictures in the book were made by me using Adobe Illustrator. And this is not really my area of expertise. So it's not like high level You know, there were Nazis. And we talked about quantum mechanics and the measurement problem.

1:13:50 of quantum theory. Don't worry about it. Yeah, and that's how bad a communicator he was. even though he was kind of wrong about the foundations of quantum mechanics? So I say that, you know, science leads us to not believe in God. And maybe like, actually, we could maybe understand this if we just tried. It's not ineffably mysterious. That's it? Yeah, I guess, but still, that's stunning when you hear that it's somewhere around 100.

1:17:52 That's how we get to get new blood in there. We turned it on in 2008 and then it exploded. but in some sense we learned give rise to that, we've known since the 70s. is very valuable and tangible stuff. Well, not just that. I wanted to make progress, right? So So it's just so hard to make progress under these circumstances. And what was the motivation behind starting your podcast?

1:20:34 I'll tell you, the motivation was when I wrote my previous book, The Big Picture. I could literally just email a Nobel Prize-winning biologist and say, could I drop by and talk to you for an hour? So yeah, this podcasting thing, I mean, I'm not telling you this. Okay. That was the other motivation behind starting my own podcast I should dedicate myself to a week of my time to reading this book. And hearing people talk about it in an informal

1:23:52 their imagination. So people want to talk about, you know, monetary policy and things like that. So I can always say like, hmm, that's an interesting idea. you know, I've always noticed this about And suddenly, when I started having a blog and I would spout off and people would say responsible and want to get things right Like when I talked to Seth MacFarlane, it was interesting.

1:26:37 about it what is the point it's like much like me in physics like the kind of physics i do That's a good move. or reading their mentions, That's the secret. Twitter is for linking, not for thinking. It's not supposed to. i'm sure you've had snarky articles written about you it's it's weird it's like well that i wouldn't with friends i mean it wasn't there was no grand ideas when this thing got started it was just

1:30:11 podcast studio around so if i like going to boston in a few weeks i'm going to try to get like 10 Okay.