Daniel and Kelly’s Extraordinary Universe - How do we know quantum mechanics is really random?

Episode Date: November 24, 2022

Daniel and Jorge wrestle with Bell's experiment and the philosophical consequences.See omnystudio.com/listener for privacy information.

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On the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. My boyfriend's professor is way too friendly, and now I'm seriously suspicious. Wait a minute, Sam. Maybe her boyfriend's just looking for extra credit. Well, Dakota, luckily, it's back to school week on the OK Storytime podcast, so we'll find out soon. This person writes, my boyfriend's been hanging out with his young professor a lot. He doesn't think it's a problem, but I don't trust her. Now he's insisting we get to know each other, but I just want her gone.

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Every case that is a cold case that has DNA. Right now in a backlog will be identified in our lifetime. On the new podcast, America's Crime Lab, every case has a story to tell, and the DNA holds the truth. He never thought he was going to get caught, and I just looked at my computer screen. I was just like, ah, gotcha. This technology's already solving so many cases. Listen to America's Crime Lab on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Hey Daniel, do you have a pretty good routine?

You mean like a dance routine or like 10 tight minutes of stand-up comedy? I mean like a schedule. Like do you have the same day planned every day or do you wing it every day? Yeah, I'm pretty into my schedules. It's the only way I can really stay on top of everything. Oh man, that is the opposite of what I do. I like to wake up every day not knowing what's going to happen. Well, I like to plan every day, but in the end, every day turns out totally different

because my well-laid plans get blown up by something that happens. See, so what's the point of making plans? I like to live in a superposition of organization and chaos. So you're both or neither? Depends on which day you collapse my wave function and on which day my schedule collapses. Sounds like you're the one who collapses at the end of the day though. That's how you know I'm a true quantum mechanic. Hi, I'm Jorge. I'm a cartoonist and the co-author of Frequently Asked Questions about the universe.

Hi, I'm Daniel. I'm a particle physicist and a professor at UC Irvine and I'm supposed to understand quantum mechanics. You're supposed to? I guess so because you're a physicist, right? That's right. It's my official job. Particles are definitely quantum objects and yet it's still something that everybody in the field struggles with. But didn't Richard Feynman famously said that nobody understands quantum mechanics? And if you do, then you don't really understand it? And he was one of the top five smartest physicists. So, yeah, everybody below him on the ranking can't understand it better than he does. Wait, the top four do?

I think there are a few people out there that might understand quantum mechanics better than Richard Feynman, yeah. Do you think it's maybe just a limitation of the human brain or is quantum mechanics just not understandable? I think we definitely can understand the mathematics of it, but sometimes translating that mathematics into intuition is really complicated. It's hard to understand things which are very unfamiliar to us, because in the end, physics is about trying to explain the unfamiliar in terms of the familiar, but sometimes we don't have a good intuitive analog to reach for. Sometimes we find something which really is very different from anything we've experienced before. That's why I don't believe in intuition either. Schedules and intuitions, I just leave him at home every day. But anyways,

Welcome to our podcast, Daniel and Jorge Explain the Universe, a production of IHeard Radio. In which we attempt to apply our intuition to understanding everything about the universe. For these little squishy brains that evolved on this one rock around one planet, it's an incredible task to try to understand everything that's out there, including phenomena that our ancestors never saw. Crazy black holes, incredibly dense neutron stars, tiny buzzing particles. Is it even possible to grok all of that, to import it somehow into our minds so we can play with it, manipulate it, and understand it. That's right, because it is a vast

and incredible universe, full of amazing things that run counter to our intuition sometimes and that are very difficult to understand. And so the only thing we can schedule on this podcast is the idea that we're going to talk about it and try to understand it and ask questions about it. Because on the podcast, we try to do something which may be impossible, which is to translate all of these ideas, which in the end are expressed mathematically into concepts that we can deliver into your brain just with chit chat and conversation. It's not always easy to know how to transform these ideas from their essential mathematical principles into an intuitive understanding, a stream of words which land in your ear and build in your mind a little model that

makes you go, ah, I get it. But that's what we're going for. Yeah, it's a pretty challenging problem if you think about it, right? Because we're trying to take the entire universe, which is at least four dimensions, maybe more. And we're trying to get it down to really one dimension, right? Because audio is just one, one degree of freedom, right? I suppose though, although in principle there are an infinite number of frequencies along which to convey information. But yeah, that's a good point. We're trying to like serialize the universe into a stream of information, which unpacks itself into your mind to give you a mental model of the universe that somehow works. I guess it would help if maybe we record in stereo.

Like, I could be on people's left ear, and you could be on people's right ear, and then we could maybe convey more information that way, like a little angel and devil standing on your shoulders. Or maybe we need two cartoonists and two physicists going simultaneously. Wait, how does that help? And we're all talking at the same time? Exactly. It'd be two-dimensional podcasting simultaneously.

I feel like you'd still collapse, right, under the amount of information. You're still collapsing the information down to one-dimensional audio. Yeah, I think probably it's best to stick with one dimension and do our best to project these crazy ideas down into a one dimensional audio stream. Yeah, it is a complex universe and sometimes it's a seemingly random universe. It's a huge universe and all kinds of things are happening in it. And it's not quite clear whether things are happening according to a plan or if they are just randomly occurring in the universe. Yeah, one of the most fundamental questions about the nature of the universe is whether you can predict what's going to happen in the future. based on the past.

Is the universe like a big clock where if you understood all of the rules and had enough information, you could tell exactly what was going to happen? Or fundamentally, is there something weird going on at the heart of the machine that is running the universe,

something different from anything we have ever experienced directly, something truly random. Well, I guess the universe sees pretty random, right? Like if I flip a coin, it's really hard to tell if it's going to be heads or tails, right?

It does, and we often use flipping a code. in or rolling a dice as an approximation for something random, but those are not actually random processes. Those are just very, very complicated processes, things which are hard to predict, but in principle possible to predict if you had enough information and enough computer processing power. What about whether we're going to explain something well or not? Isn't that also kind of random? Hey, sometimes what we talk about on the podcast feels a little random. You know, I'll prepare a whole outline and we'll never get past the first bit.

Wait, are you saying I'm the random filter here? I'm saying the Daniel Jorge interaction is a little unpredictable sometimes what we end of talking about in the best possible way. I love those episodes when you're like, hold on a second, slow down. What does that actually mean? And then we spend 45 minutes talking about the definition. We just need like a parallel podcast or something. Maybe we need the multi-worlds podcast where we take every possible branch and every

possible digression simultaneously. Well, this idea of whether the universe is random or not was something that sort of came up recently in the last 100 or 200 years, right? I mean, after Newton, people figured that the universe was pretty mechanical, pretty much like a machine where everything followed F equals MA, and you could predict what the path of a baseball or dropping a coin. What was going to happen? You could predict that. But then came quantum mechanics who said, well, maybe things are not that predictable. Yeah, and both of those really are revolutions in our understanding of how the universe was.

I mean, before quantum mechanics, even just the idea that the universe was deterministic, that it was like clockwork, that the whole apparatus of reality was somehow following physical laws which you could uncover and understand and use to predict the future, this was a big idea, right? This flew in the face of lots of people's sort of spiritual sense that there was somebody out there unpredictable in control of the universe. To reduce it to a set of natural laws which governed it, that was a big step forward. And so then to pull the rug out from underneath that and say, actually, no, at the heart of all of it, there might be something unpredictable.

Some process which determines the outcome but isn't determined by the past is somehow fundamentally random. That was a crazy big new idea. Yeah, I guess it was a double sweeping of the rug, right? Because before Newton, I guess, and before these fundamental laws of the universe, people kind of thought the universe was random, right? It was random or at least at the whim of some gods or some deity that sort of randomly decided things. And then we thought it was all ordered and then we realized, wait, it is sort of random. Yeah, exactly. Though random in a very, very different way, right?

Quantum mechanical randomness, as we'll dig into, is not arbitrary or at the whims of some God, right? How do you know, Daniel? You know, we might be at the whims of the writers of the simulation. But whatever code they wrote is what determines how the universe seems to work. What if that code is at the whim of some other writers? Well, maybe it is, but they don't seem to have been changing the code recently. It seems like the code is pretty stable over the 14 billion years of the universe's history. So there haven't been any updates.

Well, it seems like we've done a double take here on the randomness of the universe. And the latest is that according to quantum mechanics, things are random. But is that really true? And so today on the podcast, we'll be tackling the question. How do we know quantum mechanics is random? really random, as opposed to just plain wacky or flaky, or at the whim of some quantum mechanical gods? Well, you know, quantum mechanics has probabilities in it, and you can talk about what

probabilities mean. Sometimes probability just means our lack of information, things we don't know, but in principle could predict, and sometimes probability means fundamentally random governed by a process outside of our control. If you're going to bet on the outcome of a roulette wheel spin, for example, you might think That's random. In principle, if you knew how the ball bounced and you spun it the same way twice, you should get exactly the same answer.

So it's not really random. The probabilities there just come from your lack of understanding. The question really is, is quantum mechanics the same way? Are there details which actually do determine the outcome of these experiments? We're just not aware of them? Or is the universe really actually at its core a random number generator? You're asking, is it really random or does it just seem random? Because something can seem random, right?

Like I can have a computer code that spits out random numbers, which will look pretty random to anyone, but actually they're sort of hard-coded on the computer, right? Exactly. Random number generators follow a sequence, right? Computers follow rules. They can't actually generate random numbers. They can only have pseudo-random number sequences

that sort of look random-ish. Right. And so we're asking the same question about the entire universe. Is the universe actually random at its core, or does it just seem random? and I guess we need to go to quantum mechanics to find the answer. And we've been talking around this topic in a few recent episodes, and listeners have responded and asked us to dig into the heart of the matter.

Yeah, and as usual, we were wondering how many people out there have thought about whether quantum mechanics really is random or not. So thanks to everybody who answers these questions for us. It gives us a great sense for what people know and what they're wondering about and what you might be thinking out there. And if you would like to lend your voice for a future episode, please don't be shy, write to us to questions at danielanthorhe.com. So think about it for a second.

Do you think quantum mechanics really is random? Here's what people had to say. Actually, I think that's what Einstein thought. He thought there was some hidden variables that controlled all the processes and we didn't know about that. And that's why we thought it was random. But I think there have been many experiments where they repeat the same thing over and over,

but in the same conditions. But there's a different result each time. and that's how we know that it is truly random. Is this a trick question? We do experiments thousands and thousands of times so that we can get probability curves that show randomness. But you would only know to a certain amount of certainty based on how many experiments you do.

You can't do an infinite number of experiments. So maybe we don't know that it's random, but it's just random enough for our purposes. Well, if it's not random, I guess scientists would have figured out how it's really working, and we would have really cool quantum computers by now. We may not know it as an absolute fact, but our models really suggest it is random through many experiments and theories. That model of randomness holds out really, really well, and that's about as good as we can get. If the model fits, we accept it. I'm a big fan of the idea that

there's a hidden variable that we don't understand, but at the same time, I realize that all the evidence says that it's really, really random. There's that whole thing where you send electrons through a slit experiment, one electron at a time, and they still interfere because, as I've heard you guys say, it's a field, not a point, but I don't really understand that. As a computer programmer, I know that quantum is the gold standard for truly random numbers, but I guess I really don't understand that at all. If you set up an experiment, well, so they call it an ensemble, if you set up multiple instances of that experiment and everything is the same, and you produce the electron, say

you, I don't know, fire it in a given direction. And then, well, since you know its position or the trajectory it's taking, if you then try to measure its momentum while it's moving, even though the experiments are set up in exactly the same way, you get different answers for the momentum. And it doesn't depend on how you set up the experiment, because the ensembles are exactly the same. And there is no, like, sort of external factor that you can change that somehow correlates with the measured momentum. And that's why we say quantum mechanics is random. Well, I guess you could set up the same experiment many, many times. And if you get different outcomes with a sort of random distribution,

you would know that it's very random. Otherwise, I have no idea. Interesting. I feel like some people don't want to know, kind of. It is really hard to accept this idea that the universe is so different from the one you experience. So I think a lot of people resist it. Yeah. And do you think quantum mechanics is random or maybe it was just discovered randomly?

It does seem like the history of science is a little bit random, you know, especially in the case of quantum mechanics. Because we had a few experiments that people had done and nobody really understood. And then Einstein and Planck came along and sort of put the pieces together years later. Makes you wonder if it could have happened sooner or maybe if it could have happened decades later. It's fun to think about alternative histories and what we might have discovered. Or not at all, right? Like what if Einstein had decided that he wanted to play soccer for a living? Maybe we wouldn't be having this conversation at all.

You usually can't say that about historical figures. But Einstein is one of those figures where if he hadn't come along at the moment he did, things would be super different. Things might be different. There are people who say that a lot of the precursors to his ideas came from other people, and so it was sort of inevitable for them to click together. You know, a lot of the math that underpins relativity was developed by other folks. Riemann, for example, developed the Riemannian manifold, which Einstein realized was a great way to describe the curvature of space. Other folks were working on similar ideas and may have brought it together even without Einstein, though it could have taken a few years or decades longer.

Well, Einstein did what he did. And here we are talking about quantum mechanics and randomness. And whether or not it is actually random at its core. And so I guess, Daniel, let's start with the basics here. Well, first of all, what do we mean by the word random? So by random, we really mean something which is not determined by the experimental setup. You build an experiment to shoot a ball or to flip a coin or to roll a dice or whatever. If it really is random, then you can do the same experiment twice and get different outcomes. Right. Like, for example, a computer random number generator is not really random because it uses a computer formula, right? Like that one works by taking a look at the current time, grabbing a bunch of different variables that are changing all the time. And then it processes those. And then it spits out what seems like a random number, but it's not really random. Because if you knew all the numbers that went into the random number generator, you could generate the exact same sequence, right? Yeah. And we do that all the time. You have random number seeds, for example. These are the parameters that control the random number generation. and if you give a computer the same seeds,

it will generate the same sequence of random numbers every time. So computer random number generators are deterministic. They can be predicted from their inputs and reproduced. You run the same random number generator with the same inputs, get exactly the same outputs. So that's deterministic. That's not random. But they are chaotic.

They are hard to predict. They're designed to be complicated the way, for example, a dye is designed to be unpredictable. It has all these sharp edges which balance. Unpredictably against surfaces and makes it really tricky to know if a two or a four is going to land upright. It's very sensitive to exactly how you throw it, which makes it hard to predict and appear random, but not actually be random. Right, because a dye with sharp edges, sort of like if you stand it on one corner, I guess, it might fall to the right or it might fall to the left or it might bounce to the right or left,

just like a coin. If you stand it up on its side, it could maybe flip or land either way. Yeah. Imagine trying to learn, for example, how to flip a coin so that it always comes up heads. In principle, you could. You could learn how to spin it at just the right frequency and toss it at the air, just the right velocity, so it has a certain number of flips before it lands on your hand and it's always going to come up heads. That would be a great skill, right? But it's so hard to do because it's so sensitive to all of those details, you'd have to be a master coin flipper to be able to do that. Same with a dive. If somebody knew how to roll sevens every single time, they would be. would make zillions of dollars at casinos every day, right? The whole game of craps is built on the assumption that nobody can really control what happens to the die, even though they give them to you. They let you roll them, right? And so the whole assumption there is that you can't reproduce

the same toss over and over again. So why they don't let you into casinos anymore? It may they stop you at the door for us. They're like, are you Antonian physicists or a quantum mechanics? If you say quantum physicists, they'll let you in. They'll let you in, exactly, because you've given up and you've allowed the randomness to enter your life. All right. So that's the kind of the difference between random and not random. Random you can't predict given the initial conditions. And not random, you can't predict it.

Even if it is really hard, if you can't predict it, then it's possible that you can predict it. And so it's not random. And everything in your everyday experience is not random. Whether you hit a green light or whether you trip on the steps or whether that bird poops on your shoulder or whatever, these things can seem random, but they're really just complex. They're actually just chaotic. Even the weather, right, the weather is not fundamentally quantum mechanically random. It's just difficult to predict because it's so complicated. So in our

experience, everything that seems random is actually just deterministic and complicated. Or at least, I think you mean it's mostly deterministic and chaotic, right? I mean, it's just saying that Newtonian dynamics dominate our everyday lives, but there is still a little bit of a quantum at its heart, right, at the microscopic level, right? Like as the coin hits the, the table, there is some sort of maybe quantum interaction there that could determine whether it flips to the right or to the left. Well, we do know that microscopically, everything we experience is made of quantum objects. And so if quantum mechanics is random, then you know, you might ask why aren't things made of quantum objects also random? The answer is that that randomness

mostly averages out. And so if an electron is going to like quantum mechanically fluctuate to the left, somewhere there's an electron quantum mechanically fluctuating to the right. So when you have in big enough groups of quantum objects, these things tend to wash out. It's very difficult to actually pinpoint quantum mechanical impacts on everyday macroscopic classical objects. Otherwise, we would have discovered quantum mechanics sooner. It would have been more obvious if there were quantum mechanical impacts on our everyday life. Right, but you just sounded a little bit absolute. But then you said it mostly washes out, right? Not completely, right? There is still a little bit of tiny, a little bit of maybe quantum randomness in our everyday life.

too. Yeah, there's a little bit there, right? In the end, these things are averages. So there are probabilities you could in principle disappear and quantum tunnel to the other side of your house, right? It's not impossible. That's why you should never say things absolutely. Also, this is not something that we 100% understand, right? How do quantum mechanical objects when they're all tiny is a huge frothing mass of them? How do they come together to make the classical picture that we understand? That boundary is kind of fuzzy and not super well understood. So there might be places where quantum effects really do have sort of like cascading consequences which lead to macroscopic effects like the heart of the human brain. Are there quantum effects inside your neurons which

change the decisions that you make? We don't really understand that in enough detail to be absolutist about it. Right. But I think what you're saying then is that in our everyday lives, things are mostly deterministic because all the quantum mechanics sort of mostly washes off, although there's still a little bit of room there for things to be random. But they're not as random as they are at the microscopic level. If you're looking at like one electron, that has a huge randomness factor, whether it goes right or left. Exactly. We think that at the microscopic level, quantum mechanics might be really truly random.

Although there are a lot of different interpretations for these weird experiments that we're going to dig into, these Bell's experiment with entangled particles. Right. So even at the macroscopic level, you can ask the question if an electron is, actually, actually random or whether it just seems random, right? That's the question we're asking today. That's the one at the heart of the matter. If the tiniest little bits in the universe can be predicted if you have not all the information,

or if the universe is like rolling a truly random dye every time an electron has to decide where it's going to go. All right. Well, let's dig into whether or not the universe is random at the microscopic level or not and how we could maybe tell the difference using a famous experiment. At first, let's take a quick break. December 29th, 1975, LaGuardia Airport. The holiday rush.

Parents hauling luggage, kids gripping their new Christmas toys. Then, at 6.33 p.m., everything changed. There's been a bombing at the TWA terminal. Apparently, the explosion. Actually impelled metal glass. The injured were being loaded into ambulances, just a chaotic, chaotic scene. In its wake, a new kind of enemy emerged,

and it was here to stay. Terrorism. Law and order, criminal justice system is back. In season two, we're turning our focus to a threat that hides in plain sight. That's harder to predict and even harder to stop. Listen to the new season of the new season Season of Law and Order Criminal Justice System on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts.

My boyfriend's professor is way too friendly, and now I'm seriously suspicious. Wait a minute, Sam, maybe her boyfriend's just looking for extra credit. Well, Dakota, it's back to school week on the OK Storytime podcast, so we'll find out soon. This person writes, my boyfriend has been hanging out with his young professor a lot. He doesn't think it's a problem, but I don't trust her. Now he's insisting we get to know each other, but I just want her gone. Now, hold up. Isn't that against school policy?

That sounds totally inappropriate. Well, according to this person, this is her boyfriend's former professor, and they're the same age. It's even more likely that they're cheating. He insists there's nothing between them. I mean, do you believe him? Well, he's certainly trying to get this person to believe him because he now wants them both to meet. So, do we find out if this person's boyfriend really cheated with his professor or not? To hear the explosive finale, listen to the OK Storytime podcast on the Iheart radio app,

podcast or wherever you get your podcast. I'm Dr. Joy Harden-Bradford, and in session 421 of therapy for black girls, I sit down with Dr. Ophia and Billy Shaka to explore how our hair connects to our identity, mental health, and the ways we heal. Because I think hair is a complex language system, right, in terms of it can tell how old you are, your marital status, where you're from, you're a spiritual belief. But I think with social media, there's like a hyperfixation and observation of our hair. Right, that this is sometimes the first thing someone sees when we make a post or a reel is how our hair is styled.

You talk about the important role hairstylist play in our community, the pressure to always look put together, and how breaking up with perfection can actually free us. Plus, if you're someone who gets anxious about flying, don't miss Session 418 with Dr. Angela Neil Barnett, where we dive into managing flight anxiety. Listen to therapy for black girls on the IHeart Radio app, Apple Podcast, or wherever you get your podcast. The OGs of Uncensored Motherhood are back and badder than ever.

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many women protect predatory men. And then me too happened. And then everybody else want to get pissed off because the white said it was okay. Problem. My oldest daughter, her first day in ninth grade, and I called to ask how I was going. She was like, oh, dad, all they were doing was talking about your thing in class. I ruined my baby's first day of high school.

And slumflower. What turns me on is when a man sends me money. Like, I feel the moisture between my legs when a man sends me money. I'm like, oh my God, it's go time. You actually sent it? Listen to the Good Mom's Bad Choices podcast every Wednesday on the Black Effect Podcast Network. the iHeartRadio app, Apple Podcasts, or wherever you go to find your podcast. All right, we're asking the question whether the universe really is random and whether or not Daniel can plan his day with any certainty at all.

Or is it all a futile exercise? You just give up like I do. Just embrace the chaos. Yeah, no, embrace the randomness. it's different than kale well you should embrace both I guess just let whatever happens happen yeah so there's a famous way to tell whether or not electrons and things at the microscopic level are

truly random or whether or not they just seem random right and this is the idea of bell's experiment and it goes actually back to Einstein again Einstein though he had some of the foundational ideas that led us to develop quantum mechanics he was fundamentally uncomfortable with the idea that the universe was truly random. He thought that perhaps

there were just details there that we were not understanding that when things seemed random, it was just because there was missing information that we didn't have that was actually controlling the outcome of the experiments. So he and a couple of buddies of his came up with a thought experiment

because he was like champion of thought experiments to demonstrate how weird it would be if quantum mechanics was really random. Yeah, and I think it also goes back to this picture of one electron, right? Like if you shoot an electron, towards a magnet, it has kind of a random equal probability of swerving to the right as it does swerving to the left, right? And that's kind of the fundamental random experiment that people

picture when they picture quantum mechanics, right? It's like it has a half a probability to go right, have a probability to go left, and it's totally randomly. There's no way you could maybe predict whether it was going to go right or left. Yeah. And just to clarify, electrons always go the same direction when they hit like a big macroscopic magnet because magnetic fields turn electrons in a way that we understand it. But electrons also have another quantum mechanical component, the spin, which affects their little magnetic field. And so that can affect whether they go like left or right when they hit like a weird magnetic field. And so you're right. Quantum mechanics says there's an equal probability for it to be spin up or spin down, which mean that it goes left or it goes right.

And it says that that's not actually determined until somebody measures it, that both possibilities are live simultaneously until you actually measure it. Whereas the other view says, No, no, no, no. There's some detail that determines whether it's spin up or spin down, whether it's going to go left or right, and it goes left or it goes right the whole time until you look at it. Right. That's the idea of the hidden variable, right? Like maybe the electron at its core knows whether it's spinning up or spinning down. It's just that we don't know. And so that's why you call it a hidden variable. And so the question is, does the electron actually know if it's spinning up or down or does even the electron not know what's going to happen until somebody comes in and asks it or pokes it? Yeah. And you might imagine it's impossible to. tell the difference. Like, how can you know if it's actually determined but you're just not aware of it or if it's chosen at the time you poke it? Because before that, nobody's poking it. So how can

you tell? So Einstein's big idea was to add another electron, which say, well, what if you have two of these things and you know something about the pair of them? You know that they have to have opposite spins. Maybe they come from the same source so they're constrained somehow. There's a connection between them so that if one of them is spin up, the other one has to be spin down. This is the idea of quantum entanglement. And it's not so hard to understand the general idea. Say, for example, you have two bags, one with a red ball, one with a blue ball in it. And you and your friend each take one bag, but you don't know which is which. And you travel like 10 miles apart. Now you look at the bag and you say, oh, I have the blue ball. That means my friend has the red ball. Or if your friend

has the blue ball, it means you have the red ball. Because you know there's only one blue ball, then you know something about what's happening with the other particle. So that's the idea of entanglement, connecting these two electrons together. Right, because when you separate the balls in the bags, you take one this way and take the other one that way, they have something that ties their history together, right? Some sort of constraint that says if one is blue, the other one's red, and if this one is red,

the yellow one has to be blue, right? It's something that ties their histories together. Exactly. And Einstein's point was, if things really aren't determined until you look, that means something really weird. That means that the electrons, which are now five miles apart from each other, if you measure one of them and it determines to be spin up,

if you're saying that they really weren't determined until you're measured, that means that the other electron now 10 miles apart instantaneously goes from undetermined to spin down without anybody even looking at it. So this was Einstein's complaint that if quantum mechanics really was random, then it was somehow non-local. It's somehow instantaneous collapse of the distant electron, the other one, the one you weren't even looking at.

Right. Yeah, you mentioned the idea of local. because that's kind of a big part of it, right? Like, if I take one of the balls and I go to New Mexico and you stay in Los Angeles and I open my ball and I see that it's red, then I know that your ball is blue, but you don't know that I opened my bag and found a red ball, right? To you, it's still a totally unpredictable what's in your bag. Unless I go and I call you or I send you an email saying, hey, my ball was a certain color, then you would know what color your ball is.

Exactly. But according to quantum mechanics, it is at that. that point determined. Once you've measured yours to be red, then mine is blue. So Einstein's big point here was to say, this is ridiculous. This idea that quantum mechanics is random, that there aren't details determining which one is spin up and which one is spin down, requires them to somehow conspire across great distances faster than the speed of light. So he said, obviously, this can't be true. But it turned out that it is true. I feel like you were leading me to that, but I don't really know. That's what Einstein wanted everybody to think.

But again, you can ask the question, how can you know? Maybe quantum mechanics really is just weird that way, and it doesn't sit well at Einstein's brain, doesn't mean it isn't reality. Is there some way we can enhance this experiment so we can tell the difference? We can tell if it really is random and decided at the last minute before you measure it, or if it's all somehow decided in advance, using information we just don't have access to, some sort of weird hidden details about these particles that determine which one is spin up or spin down. So that was the great challenge. is there a way to come up with an experiment to tell the difference?

Right. You're saying that as soon as I open my bag in New Mexico and I see that my ball is red, suddenly your ball goes from being a quantum mechanical object that could be anything to a non-quant mechanical object which can only be blue. That's the weird thing that kind of freaked Einstein out. It's like as soon as I open my bag in New Mexico, somehow your bag in Los Angeles starts being quantum mechanical instantaneously. Yeah, so people were chewing on this problem.

And one other very smart guy who might understand quantum mechanics better than Richard Feynman, he came up with a really ingenious idea for how to tell the difference, for how to know if quantum mechanics was doing this at the last minute, if it was really was left undecided and truly randomly collapsed at the last moment, or if he was determined by some information we just didn't have access to. He actually came up with a way to test that, to build an experiment which would tell you what the universe was doing. Well, what's the alternative then? in the case of the two balls, the one in New Mexico and the one in Los Angeles. Like, if Einstein is right, then what actually happened to the balls?

You actually knew which one was red and blew the whole time? Yeah, if Einstein's right, then one was red and one was blue the whole time. We don't have access to the information. We didn't know that until we opened it up, but it actually was red the whole time. And if quantum mechanics is right, then it wasn't red. It was a possibility of being red and a possibility of being blue. Right. In the quantum mechanical view, both were possibilities.

until I opened mine in New Mexico and in which case both became non-possibilities. Exactly. And if Einstein was right, you get what he calls realism. He says the universe is a certain way. Even if you aren't looking at it, there is a fact of the matter. And the ball is blue or is red, regardless of whether we know it or not. That's what Einstein believed. But the typical description of quantum mechanics says that it really is undetermined and there's a random process that chooses it at the last moment just before you measure it or as you measure it. or the act of you measuring it collapses it and forces the universe to access its true random number generator. And I think what I mean Einstein's point is that it's hard to tell the difference between those two scenarios, whether they were red and blue the whole time or whether they decided only when I opened mine in New Mexico because there's no way to tell a difference with just that simple experiment.

So you need to sort of do an experiment 2.0 that maybe messes with that to see if actually things were random or not. Yeah, exactly. And that was Bell's big idea. Bell came up with a way to test this. And at first blush, it feels impossible, right? Like, how could you tell whether it's undetermined when you don't look without looking? And by looking, you collapse it. So it seems sort of like a paradox, like impossible to probe.

Bell's big idea was taking advantage of another aspect of quantum mechanics that didn't exist in the hidden variables picture. And that's the fact that it matters along which direction you're measuring the spin. So we're talking about a quantum mechanical property of these electrons. It's called spin. and it can be spin up or spin down, but it can be spin up or spin down along some direction, right? If you have like an axis you're defining as X, you can say, is my electron spin up or spin down along this axis?

You can also measure it along Y or measured along Z. Fascinating thing quantum mechanically is that these things are connected. In quantum mechanics, you can't know the spin in X and in Y and in Z simultaneously. They're all weirdly entangled by the Heisenberg uncertainty principle. The same way that you can't know the position and momentum of an object at the same time. Those two pieces of information are weirdly connected together. So Bell came up with this experiment where people in different locations might use different axes. They might be measuring the spin in different directions.

And quantum mechanics would make a different prediction for the correlations between those measurements than the hidden variable theory would. Yeah, let me maybe go back a little bit on this idea of spin because this is one I think is going to be hard to explain over audio. I think maybe a way to picture it is that, you know, instead of a red and a blue ball that we put in those hidden bags, instead of draw an arrow on our balls, like an arrow pointing up or an arrow pointing down, right? Or I guess the arrow could be pointing in any direction, really, in the ball, right? It could be pointing up, down, left, right, diagonal, diagonal down, diagonal up.

So it can be pointing in any of those directions. But one thing about quantum mechanics is that you can't ask whether it's pointing up and down and left and right at the same time. That's a weird thing about quantum mechanics, right? The weird thing about quantum mechanics there is that it matters the order in which you do it. Just like if you measure position, you get a number and then you measure momentum, then your position measurement is no longer valid. Once you measure momentum, you scramble the position. In the same way, here, if you measure the spin along one axis, you look to see if the arrow is pointing up or down according to your imaginary Z axis, and then you do it along Y or X, it scrambles the first measurement.

So you can't know the spin in all three. directions simultaneously for a quantum object the way you can for a ball right a ball you can just look at it and say oh it's kind of up in z and kind of down in x and kind of whatever you can just know it's determined it's possible these are sort of like orthogonal directions in the hidden variable theory in quantum mechanics they're weirdly connected to each other there's like less information available there's like shared information between x y and z in the spin measurements right let's maybe explain it like let's say I point an arrow on the face of my ball and it can be up down left right the diagonal or whatever. Maybe you can picture it as like the hour hand in a clock. So it can be pointing up at 12 o'clock or down at 6 o'clock or right at 3 o'clock or left at 9 o'clock or it could be pointing at 1 o'clock, 4 o'clock, 8 o'clock, 10 o'clock. And you can only sort of ask one thing at a time, whether it's generally pointing up or down or down, whether it's generally pointing up or down. So like if it's actually pointing at 2 o'clock, I can ask, well, is it pointing up or down? And you would say, well, it's at 2 o'clock. So it's pointing up.

Or I can ask, is it pointing left or right? And you would say, well, it's pointing right because it's pointing at 2 o'clock. But I can't ask both of them at the same time to really figure out what the hour was. Like once you ask whether it's up or down, the whole thing collapses and that's it. I can't know anything else about it. Yeah. Once you make a measurement, all your previous measurements are now irrelevant. So you can't like zero in on the exact details.

Right. Like you would maybe set your hour clock at a point in your clock, right? And then I would ask you, is it up or down? and you would say up. And now I can't ask you whether it was right or left because that would tell me exactly where the hand was kind of, right? Remember that there might not be any where it really was. In the theory of local realism, there is a true position, a total reality, and the clock

really is pointed in just one direction. But in the quantum theory without hidden variables, measuring it along one direction, scrambles it in the other directions. So they're not just not known. They are not determined. And that's really the issue we want to address, the question we want to answer. Can we tell if those measurements are undetermined or unknown? And the fact that in quantum mechanics, you can't know more than one direction of spin at once is the crucial concept in Bell's theory because it changes how measurements in different directions are correlated, measurements along different axes.

And this is the exact idea at the heart of Bell's experiment. Bell says, let's take our balls and let's pick three directions in advance. And the people who are doing these measurements, they're going to pick one of these three directions to make their measurement. As you say, it's like picking two o'clock or nine o'clock or six o'clock on the clock, right, to make your measurement to ask whether the arrow is up or down. They're going to pick one of those. And if things really are determined, then the direction they pick doesn't matter, doesn't

change the state of the ball at all. So it's a very simple relationship between whether or not they're likely to see the same answer. You know, if they both pick 12 o'clock, they're going to see the same answer. One of them picks 12 and the other one picks 2 o'clock, they're almost always going to see the same answer, this kind of stuff. And so you can say, if things aren't messed up in that wave, measuring in one direction doesn't measure the other directions, then we understand exactly how often people should get the same answer. But in the quantum mechanics version, if these things are scrambled, if measuring in one direction messes up measurements in the other directions, you get a different

relationship that people with the two balls or the two electrons get the same answer sort of more often than you would expect if things really are determined by hidden variables. These correlations between the different directions quantum mechanically come into play and sort of mess up the otherwise perfect picture. Right. I think you're saying that like in our original experiment where we had the two balls in Los Angeles and I took one of the balls to New Mexico, now we're going to introduce something new to Einstein's experiment in order to test this quantum randomness. And that is to put people in between Los Angeles and New Mexico.

and have them ask questions about the ball on the way as it's traveling from Los Angeles to New Mexico, right? And somehow that's going to tell you whether or not things are actually random or not. You measure each ball one time because once you've measured it, there's no more entanglement with the other ball going in the other direction. And you don't necessarily measure each ball along the same spin axis. Each ball gets measured along one of three directions. You can make the three directions like a Mercedes symbol if you want. Both balls might get measured along the same. direction, in which case one is up and one down, that happens a third of the time. But two-thirds

of the time, you don't choose the same axes. And bells inequalities all about how often both balls get measured spin up or spin down along the random axis that's chosen. For a hidden variable model, you get the same answer from both balls less than two-thirds of the time. And so when you compare the answers for one ball and the other ball, it just depends on like what angle the ball actually was at. Right. Maybe let's step people through that example in our, scenario here of LA versus New Mexico. So let's say that things are not quantum mechanical and you actually drew on your ball, you know, an arrow pointing at one o'clock, right? Now, the first person is going to ask, is it generally pointing in the 12 o'clock direction? And you would say yes.

And when it arrives in New Mexico, it's still going to be pointing at one o'clock like you drew it, right? Exactly. You also have to have people asking the same questions of the other ball and then comparing the answers. That's the key to the experiment. Okay. Now, that's what that's going to happen if if the universe is not random if it has hidden variables if you actually drew the arrow on the ball before putting it into the bag. But now let's paint the quantum mechanical version

where it's something, it's not really drawn on the ball, it's just something. It just has the probability of being something, right? Yeah, so as a probability in any random direction, and the only thing we know is that whatever direction it's in the other ball going to the other city is pointing the other way.

And so in the quantum mechanical version, you can really only ask one question. You can measure it along one direction. You can say, is it pointing towards 2 o'clock or is it pointing towards 11 o'clock? Once you've done that, you sort of messed it up. You can't really get any more information about the ball. So you can make one measurement about your ball. And your friend going the other direction can make one measurement about their ball.

If you pick these three directions in advance, then you can predict how often they will get the same answer. Like if both people say 2 o'clock, then you know they're going to get opposite answers, right? Because one ball is going to be up with respect to 2 o'clock. the other one's going to be down. But if one person uses 2 o'clock and the other person uses 11 a.m., then they might get different answers. And quantum mechanics tells you

how likely they are to get different answers. Well, let's step people through it. What happens if it is a quantum mechanical ball that goes through and gets the question? So the first person says, is it generally pointing towards 12 o'clock? And then that will sort of collapse the ball a little bit, right? I think that's what you're saying.

Is that now the ball cannot be pointing downwards? If I say yes, if you say yes, then the ball cannot be pointing downwards so that if the next person says, hey, is it pointing three o'clock? They can't tell you, right? Well, what happens is you've destroyed the entanglement. So you can make the measurement,

but it's no longer constrained to be the opposite of what the other ball is. And the whole idea is that these things need to be entangled. Once you've made a measurement, then the entanglement is broken. You can only use up the entanglement sort of one time. That's why you can only really make one interesting measurement. You can make as many measurements as you like,

but they're not really as interesting because you're no longer measuring an entangled system. Right. Once you interact with something, you break the entanglement. But wait, is that really a good analogy of Bell's theorem that somebody along the way asks if it's pointing towards 12 o'clock? Sort of if you would take one more step. Bell's experiment says, pick three directions in advance. Everybody decides in those three directions. Then when you actually make your measurement, you pick one of those three directions randomly.

So, you know, Jorge in New Mexico is going to pick the two o'clock direction. And Daniel in L.A. is maybe he's going to pick the two o'clock direction. Maybe he's going to pick the 11 o'clock. There's a random element there. If we pick the same directions, we're going to get answers exactly opposite each other, of course. If we don't pick the same directions, then we might get the same answers. We might not. And that's the part that's predicted by quantum mechanics.

Oh, I see. You don't ask it the three times when it's going from L.A. to New Mexico. You ask it one time, like one of the three people ask their question. That's what you're saying. And the person who gets to ask the question is decided at random. Exactly. And in the hidden variables version, you can very easily. calculate what are the chances that the one ball is going to give you the same answer as the other ball.

And it's all determined. And so you can just do the calculations. You get a very crisp number of prediction. But quantum mechanics adds more connections between these balls because it says measurements in one direction are connected to measurements in another direction, which doesn't exist for the hidden variables versions. So it means you have more likely in the quantum mechanics to get the same answer as the other person. Bell's experiment is not a one off thing. You can't say from one experiment, oh, definitely it was random. It's a statistical calculation. across many iterations of this experiment, you get a correlation between these things

which should be impossible in the hidden variables version. Your measurements agree more often than if all the details were specified in advance. And it's because of that quantum mechanical connection between measuring in different directions. All right, well, let's dig into this a little bit more because I feel like maybe you're sort of waving your hand and saying there's a lot of complex math here

that we can understand on the podcast. But I wonder if there are sort of intuitive ways for us to figure out why they would give you different results if there was a hidden variable or not. Let's try to dig into that. But first, let's take another quick break. December 29th, 1975, LaGuardia Airport. The holiday rush, parents hauling luggage, kids gripping their new Christmas toys.

Then, at 6.33 p.m., everything changed. There's been a bombing at the TWA terminal. Apparently, the explosion actually impelled metal, glass. The injured were being loaded into ambulances, just a chaotic, chaotic scene. In its wake, a new kind of enemy emerged, and it was here to stay. Terrorism. Law and order, criminal justice system is back. In season two, we're turning our focus to a threat that hides in plain sight.

that's harder to predict and even harder to stop. Listen to the new season of Law and Order Criminal Justice System on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. My boyfriend's professor is way too friendly, and now I'm seriously suspicious. Wait a minute, Sam. Maybe her boyfriend's just looking for extra credit. Well, Dakota, it's back to school week on the OK Storytime podcast, so we'll find out soon. This person writes, my boyfriend has been hanging.

he out with his young professor a lot. He doesn't think it's a problem, but I don't trust her. Now, he's insisting we get to know each other, but I just want her gone. Now, hold up. Isn't that against school policy? That sounds totally inappropriate. Well, according to this person, this is her boyfriend's

former professor, and they're the same age. And it's even more likely that they're cheating. He insists there's nothing between them. I mean, do you believe him? Well, he's certainly trying to get this person to believe him because he now wants them both to meet. So, do we find out if this person's boyfriend really cheated with his professor or not?

To hear the explosive finale, listen to the OK Storytime podcast on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. I'm Dr. Joy Harden Bradford. And in session 421 of Therapy for Black Girls, I sit down with Dr. Ophia and Billy Shaka to explore how our hair connects to our identity, mental health, and the ways we heal. Because I think hair is a complex language system, right, in terms of it can tell how old you are, your marital status, where you're from, your spiritual belief. But I think with social media, there's like a hyper fixation and observation of our hair, right? That this is sometimes the first thing someone sees when we make a post or a reel is how our hair is styled. You talk about the important role hairstylists play in our community, the pressure to always look put together, and how breaking up with perfection can actually free us.

Plus, if you're someone who gets anxious about flying, don't miss session 418 with Dr. Angela Neil Barnett, where we dive into managing flight anxiety. Listen to therapy for black girls on the IHeartRadio app, Apple Podcasts, or wherever you get your podcast. All right, we're talking about Bell's experiments, which, if it's true, confirms whether or not quantum mechanics really is random, or we just think it's random, which would also confirm whether the universe is random. And that's a pretty big deal, right?

If the universe is random, then it's totally unpredictable. If the universe is not random, then everything that happens is kind of predetermined. Yeah, although to this day, there are very strenuous philosophical arguments about what the results of Bell's experiment really mean. Is it actually ruling out local hidden variables? And one person who argued very strongly that these experiments don't rule out hidden variables was Bell. Bell was persuaded not that the universe was random but just that the universe was non-local that it was somehow coordinating the results of these experiments

across space and time in a way that we didn't understand. Well, we had this experiment set up where we had some balls and we drew arrows on them or had them quantum mechanically drawn on the balls and then we sent them to New Mexico and had people asking questions along the way. But it seems sort of like you're saying that really to understand how Bell's experiment works, we sort of really need to dig into the math because that's where the differences between a random universe and a non-random universe really are. Like if it's really random, then the math says that you should get one type of result from this experiment.

And if it's not random, then the math has you should get another kind of result. Yeah, it does come down to the math. And there are lots of times in quantum mechanics where things don't make intuitive sense to us, but the math is pretty clear. And it tells you exactly what's going to happen. And this is one of those scenarios where you're like, well, that would be really weird if that were true. The quantum mechanic predicts it to happen. And then you go and you do it in the experiment and it does.

Like people have done these experiments starting in the 70s and up to fairly recently more and more sophisticated versions of them. And the numbers they get agree with quantum mechanics. They disagree with the local hidden variables picture of the universe. And what you want is to like have a deep understanding of why that is. What is it about quantum mechanics that makes it have a different prediction? So this experiment predicts something different for quantum mechanics and the hidden variables theory.

And that's tricky. I mean, it's very clear if you just look at the math like you write. out the probabilities, you do the calculation, the number comes out a certain value. But we don't all think mathematically, and so you want sometimes an intuitive understanding. And I think the most intuitive understanding I have of it at least is that quantum mechanics ties up these different measurements. If you're thinking about measurements in one direction, how they're connected to measurements in other directions, then sort of in the hidden variables version, everything is clean and crisp and they don't mess up each other. Whereas in the quantum mechanical version, you make a

measurement in one direction, it's more connected to measurements in other directions. That's what gives you these enhanced mathematical probabilities. All right. Well, I think maybe the next question then should be have people actually done this experiment. I mean, we sort of talked about it and we know that if it comes out one way, it sort of proves quantum mechanics is random or not. And have people actually done this experiment?

They have. The first test was in 1972, originally done with photons. You can do this kind of experiment with any sort of quantum object where you can create entanglement, where you create a connection between these two things so that they have to like follow some overall constraint. want to spin up or want to spin down. In the case of photons, they're not to spin one half particles. They don't spin up or down.

They have three different states, including like a circuits or polarization. But fundamentally, the idea is the same. And so the first test confirmed Bell's experiment in 1972. That was just a few years after his original paper. It's actually a funny story about that because Bell chose to publish his theorem in a really cheap journal that didn't charge him to publish it. And it meant that very few people actually read the paper when it first came out. It was such a cheap journal that if Bell wanted copies of his own paper, the journal would even charge him for his own copies.

Usually if you write a paper, you get like a certain number of free copies. So he published it in this cheap, obscure journal, which meant that not many people saw it. But one guy did, and he was really intrigued, and he set up the first experiment in the 70s to test this idea. And it involves kind of pairing up electrons or pairing up photons. And so maybe just to paint us a picture, you know, you sort of run this a bunch of times, right? not just once and then you can tell if the universe is random or not, you have to run it like a hundred times. And if at the end you get, you know, a certain number of times

them both being spin up or spin down, it means that the universe is random. But if at the end you get that there's both spin up or spin down, it's a different percentage, then you know that the universe is maybe not random, right? That's kind of what we're looking at. Yeah, you prepare these particles. You send them off in different directions.

Then you have some process to randomly choose the axis along which you're going to measure the spin. Remember, you have to have three different possibilities and you have to randomly choose which one. Uh-oh. How did they do it? Did they flip a coin? I don't remember the details of the first experiment, but they've become more and more elaborate as time goes on. They use things like telescopes pointed to distant stars and like the flickering of that star helps determine which one you pick. They've been really, really careful about how to determine these things. Sometimes they're linked to cosmic rays, which people think might be fundamentally random? Is there a muon hitting my detector right now? So they do a lot of work to try to make

sure these things are random. Remember in our episode about super determinism, this was the heart of the matter. People were worried about whether that choice really was random or whether it just appeared to be random, whether the whole universe had been built to conspire to make these things look random when really they weren't. Wait, wait, wait. I think you're telling me that this experiment that humans have devised to test whether the universe is random or not depends on us. doing something random. That's a little bit funny, isn't it? Mm-hmm, absolutely.

And people have been digging into these apparent loopholes in Bell's experiment, and that's one of them. Like, how do we know that the way we constructed the experiment is actually random? Another one is, how do you know these two things actually aren't communicating in some way? The first experiment wasn't that big. You know, the photons, they didn't send them very far apart. And so they've been making these experiments more and more elaborate, trying to make them more actually random in the way they choose the axes

and making the particles further and further apart. So there's no way to transmit information from one to the other unless you do it faster than the speed of light. So they've been slowly working to try to close these loopholes. And every time somebody does one of these experiments, somebody goes, oh, wait, but what if, have you checked? How do you really know in one of the core foundational loopholes that people are trying to close is this one about the randomness?

So they come up with these more and more elaborate systems to try to ensure that the construction of the experiment itself is actually random. Right, because if the experiment depends on you doing something random, if you're not really random doing it, then the whole experiment sort of falls apart a little bit, right? Yeah, absolutely. That's the basis of super determinism to say, no, things really are determined.

It's just that even how you're choosing the apparently random element of this experiment is not random. That itself is determined by things that happened before. All right, so then people have been doing this experiment for 50 years and they've been trying harder and harder to make it more and more pure and exact and foolproof and what's the overall result that they've been getting they've been getting that the universe is really random at the quantum level they've been getting a result that says that there are no local hidden variables right that says that there's no information that's being

passed along with these particles that somehow determines whether the ball is red or blue or you know what direction is pointed at there's no information with the particles wait i feel like maybe you're using um sort of lawyer speak here absolutely i am right right Like I asked whether the universe is random or not, and you said there are no local hidden variables, which is not a yes or no answer. It's not a yes or no answer. So what are the lawyerly nuances here? Yeah, because it's possible that there are global hidden variables, that there's something controlling everything that happens in the universe that determines the outcome of this experiment. Bell's experiment only rules out local hidden variables, not global hidden variables.

What's the difference? Well, local hidden variables would mean the information is being passed along with. the electron, something about the electron itself in the environment of the electron determines whether it goes spin up or spin down. Something global would be coordinating across space time faster than the speed of light. So for example, there is an interpretation of quantum mechanics called Bohemian mechanics where quantum mechanics is not random, but there's this pilot wave, this thing which controls the whole universe and arranges for these things, coordinates and says, oh, if this one over here spin up, I'm going to go make this one B spin down. And so it's

like coordinating globally faster than the speed of light. Wait, so a local hidden variable is when the ball you put in the bag has a little pocket inside of it that knows whether it was spinning up or down. That's local hidden variable. And the Bell's experiment proves that there is no such pocket inside of the electron or the ball. But there might be a global hidden variable, meaning like there's a giant universe-sized pocket out there hiding information and coordinating information between here and Alpha Centauri kind of, right? Exactly. And that seems really weird. So the more common interpretation is, oh, quantum mechanics is really just random. If you don't like non-locality, if you don't like things being coordinated across the universe, then the more common interpretation is, well, things are just really random. But it's important to remember that that's one possible interpretation of Bell's experiment. There are other ones which involve non-local hidden variables. So it doesn't actually put a nail in the coffin of hidden variables completely, just local hidden variables.

Wait, you're saying that like a global hidden variable, like the whole universe is coordinated somehow magically, is this looks the same as a totally random universe. Yes, we cannot tell the difference. Nobody's come up with a way to distinguish between that view, which is Bohemian mechanics, which actually Bell himself was a huge proponent of, and sort of Copenhagen view where these things are not determined, and then they collapse when you make this measurement. I guess then the next question is, if there is a giant universe-size, in pocket variable, you know, thing coordinating everything is that random or not?

In that theory, it's not random. It's deterministic. In that theory, everything that happens is determined by the initial conditions. There's no randomness in it. I feel like this confirms something I sort of come to believe for a long time, which is that there's really no difference between a totally random universe and a universe run by an all-powerful god. Well, we can't tell the difference. Philosophical. it's a very different statement about what's out there, what's real, what's happening in the universe. But it really goes to the heart of the question of like what that means. What does it

mean for things to be happening if we can't know the difference? If these particles really are undetermined or if they were determined the whole time by some crazy pilot function, which is controlling the fate of the universe, what really is the difference to us? If we can't ever devise an experiment to tell the difference, then is there really a difference? I don't know. It's a really interesting question in philosophy, which is one reason why philosophers still have jobs. Because people are confused. It sounds like we need to start a new religion called pilotism, maybe. Pilotism, or how would you call it? Global hidden variableism. It's not a religion. It's a totally respectable philosophy of quantum mechanics. And it's not very mainstream because for a long time,

people thought that Bell's experiment ruled it out. And there was actually a proof by Von Neumann that suggested that no hidden variables were allowed, but there was a mistake in it. So it's a sort of a historical accident that Bohemian mechanics was sort of cast aside for many years, even though Bell himself was a proponent of it and people thought that his experiments ruled out all hidden variables. And now Bowman mechanics is sort of like an afterthought. People don't get taught it in school. It's not mentioned very often, even though it's totally consistent with our understanding of the universe. It's just maybe even stranger than a random universe. Well, it's interesting to think that maybe we'll never find out, right?

Like, it's possible that it's impossible to tell the difference between a, you know, all-powerful God or pilot function or pilot wave and a totally random unpredictable universe. It's possible. Or maybe we just need next century's John Bell to come up with an even more clever idea for an experiment that can somehow tell the difference. I mean, I remember learning about this experiment as an undergrad in quantum mechanics and thinking, how could you possibly construct an experiment to tell the difference? It's impossible. And then reading his experiment going, oh, wow, that's clever. I never would have thought of that. So it might just mean that we need another generation of clever scientists. Maybe somebody out there listening has actually understood our description of Bell's experiment

and thought, hmm, what if you added this feature to it? What if you did that? What have you changed it in this way to come up with a new experiment that might tell us the difference? Well, what's the probability of that? Somewhere between zero and one. As long as it's not zero, I guess. We just got to keep doing it and eventually somebody will come up with the answer, right? That's how statistics works.

That's right. If we do an infinite number of podcasts, we will eventually inspire the physical theory of the universe. Yeah, yeah. We'll eventually get to take credit for understanding the universe. Exactly. Monkeys on typewriters and cartoonists and physicists on podcasts. Well, we're making pretty good progress, right? We've got a couple hundred episodes under our belt.

Yeah, something north of 400. Yeah, so now we just need, what, infinity minus 400 more? Exactly. Let me do the calculation. That's infinity. But getting closer. All right, well, we hope you enjoyed that. Attempt at trying to explain Bell's theorem, which is pretty complicated.

It's pretty complicated, even if you have the math and the diagrams in front of you. So thanks for bearing with us and this attempt to translate into a one-dimensional form for your audio stream. Hope you enjoyed it. Yeah, and please join my new church of Pilot Waveism. Where Jorge is the God. Are you accepting donations? There you go. That's right. I am the Pilot Wave. Thanks for joining us. See you next time.

Thanks for listening. And remember that Daniel and Jorge Explain the Universe is a production of IHeart Radio. For more podcasts from IHeartRadio, visit the IHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows. Ah, come on, why is this taking so long? This thing is ancient.

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powered by Intel Core Ultra processors, so you can work, create, and boost productivity all on one device. December 29th, 1975, LaGuardia Airport. The holiday rush, parents hauling luggage, kids gripping their new Christmas toys. Then, everything changed. There's been a bombing at the TWA. terminal, just a chaotic, chaotic scene.

In its wake, a new kind of enemy emerged, terrorism. Listen to the new season of Law and Order Criminal Justice System on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. My boyfriend's professor is way too friendly, and now I'm seriously suspicious. Wait a minute, Sam. Maybe her boyfriend's just looking for extra credit. Well, Dakota, luckily, it's back to school week on the OK Storytime podcast, so we'll find out soon. This person writes, my boyfriend's been hanging out with his young professor a lot. He doesn't think it's a problem, but I don't trust her.

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