What is more mysterious than consciousness? Where does our subjective experience come from? It's certainly a puzzle that has baffled philosophers for eons. But wait, what about quantum mechanics. That's a big puzzle too. Why can quantum objects maintain a superposition but classical objects, which are made from quantum objects, somehow cannot? And what's the difference between a quantum and
classical object? Also a major source of philosophical confusion. But hold on a second, what about the conflicts between quantum mechanics and gravity? How can we have two beautiful theories, both of which have been stress tested to an extraordinary level, but which clash in their basic description of the universe? Can they ever be harmonized? These three questions battle for supremacy in the world of philosophy and physics. Each one has been attacked from many sides, the greatest minds in
history struggling to make concrete progress. But what if we could solve not just one, not just two, but all three with one theory, one idea that explains consciousness, quantum measurements, and harmonizes quantum mechanics with gravity. Today we'll explore a controversial theory that claims to do just that and a little more. Welcome to Daniel and Kelly's extraordinarily ambitious universe.
Hello. I'm Kelly Winer Smith. I study parasites and space, and today we are talking about all of the topics that make Kelly's brain go ouch.
Hi. I'm Daniel. I'm a particle physicist, and I like to insert all of those topics into your brain. Not to make your brain go ouch, but to make your brain go oh.
Do you have a topic that makes your brain just like when you hear about it you immediately go ouch?
Chemistry?
Oh?
Yeah, of course, but that's a whole field. Is there like a particular topic in chemistry that makes you go ouch?
There's a topic in chemistry which overlaps with physics a little bit, which is statistical physics and thermodynamics, and it has the same issues for me as chemistry that there are lots of different scenarios with different assumptions which on need different formulas and it's hard to sort out when you do what. And it's the one class in grad school which I was terrified I was not going to pass.
Well, does that mean you got an yeah?
Something?
Oh?
Daniel, and the instructor for that was like a real old school Berkeley dude. He used to smoke cigars in his office at Berkeley, and like there's a strict no smoking policy, but he had strict ignored that no smoking policy policy.
Good to have tenure.
He was like a thousand years old when I got to Berkeley, And yeah, he taught like it.
Does he still persist.
I don't know. And actually I was supposed to meet him. I took my final and I turned it in and I was terrified about how it went, and he sent me a message saying, please come meet me, and I just didn't go because I was so terrified. But I ended up getting an AUS in the class, and so whatever happened happened. And I don't believe that he's any longer with us.
Oh all right, well you turned out pretty okay, So that's awesome.
As long as I focus on the particles and the tiny stuff and not like millions of buzzing things interacting, then yeah, it all makes sense to me. And my goal on this podcast is to make it all make sense to you, which is why we dig into complicated topics and we answer questions from listeners who want to understand and crazy theories about the universe.
Well, and one of the things that I love about being your co host is that the topics that usually make my brain go ouch definitely make my brain hurt less when you're explaining them to me, and so I have the best chance of understanding them on today's show. So let's go ahead. Today we're going to talk about does consciousness come from quantum processes in the brain.
That's right, it's a smoothie if all the heart is problems in the universe blended together with quantum gravity. And this is not a random topic that we have chosen. This is the subject of a theory by one of the smartest guys out there, Roger Penrose. He who won the Nobel Prize in physics for understanding black holes. So definitely a very smart dude. And he has this crazy theory about consciousness. And we got a question from a listener who asked us to explain it. Here's Scott's question.
Helloja, Daniel and Kelly. Roger Penrose and Stuart hammer Off have hypothesized that the rise of consciousness, the hard question in neuroscience, comes from the collapse of quantum superpositions inside microtubules in neurons. To me, this sounds like a perfect crossover of quantum physics and biology. So I'd love to hear your explanation of and take on the orchestrated objective reduction theory.
Thank you, all right, So my question to you, Daniel is this is this another case of a physicist jumping into like biology and thinking, oh, this is lesser because it's biology. So I'm just going to assume that I can do it without really doing any research.
It's not quite so bad, Okay. He started out just thinking about the physics, the quantum mechanics of it, and then was thinking a little bit about the philosophy of it. And there's a terrible track record there of physicists doing philosophy without really knowing what they're doing with panos He's a smart guy. He's thought a lot about quantum foundations, so what he says on that topic is not just nonsense. And then he paired up with a biologist, an anesthesiologist actually,
who helped him connected to the brain. And so not only are we going to be talking about consciousness and quantum mechanics and quantum gravity and quantum computing. We're also going to touch on anesthesiology.
Oh, we don't understand any of those things.
Amazing, so maybe they're all the same thing, right, This is the wonderful temptation. I see this from listeners all the time. They're like, you don't understand dark matter. You also don't understand antimatter. What if dot dot dark matter is antimatter? And I totally get that temptation, because there are times in the history of science when two things we didn't understand click together perfectly to make one beautiful thing we do understand. And so what a great moment
that would be. Dark matter is not anti matter, unfortunately, and the jury is still out on whether Penrose's theory of consciousness makes any sense.
All right, well, speaking of making any sense, let's see if this question makes any sense to our extraordinaries. Because you went ahead and ask them, does consciousness come from quantum processes in the brain. Let's hear what they had to say.
The choices I make are not deterministic. Therefore, I'm in favor of a quantum explanation of consciousness.
Jeez, I believe so I'm speaking for ignorance here, but consciousness I believe doesn't come from the quantum processes that embedded in the brain. Perhaps it has something to do with the virtual particle popping in that I resistance.
My first reaction is no, we can't even agree on what consciousness is. But since it's biology, I'd have to say, we don't really know.
Everything comes from quantum processes, but consciousness. Who knows how.
I think that quantum processes are at a different scale neurological processes.
Perhaps that's how we achieve official general intelligence through the use of quantum computing.
Well, I think at the end of the day, everything comes from quantum processes, but I'd still say yes.
And neurons definitely rely on quantum processes. I will say yes because of the electricity in our brain, which I believe comes from the Sun, which gave rise to life on Earth.
I don't think so.
The amount of entanglement juice needed to power the flux capacitor and the brain would be too much for this task. I don't think so. I think consciousness comes from feedback loops. I suspect that Daniel's answer is no because the brain is too wet of an environment. The mush insider our skulls is quantum, and quantum consciousness comes from that. Quantum mechanics is inherently tied to chemistry, and the way that the brain works is all based on chemistry.
So I'd say, yeah, definitely, I do not know, but that's a great theory.
Now, no one respects the extraordinaries more than me. But I'm going to go ahead and say that a lot of these answers made no sense it all.
I mean, the question is kind of bonkers, ye, but I do love the flux capacitor answer like nice reference.
Yeah, yep.
And the person who sent back their file with the title quonsciousness, I can't believe that's not a word, Like, that's an awesome word, counsciousness.
It should be a word. Yes, now it is.
And let me clarify something which was brought up by a few of the listeners, like what does it mean to be quantum?
Right?
Quantum processes? In a sense, everything is quantum because we're all made from quantum objects. Right, I'm made out of particles. Those particles are quantum, So in that sense, I'm quantum, and my whole process relies on being quantum. All of biology is quantum because biology is just big chemistry, and chemistry is just big physics. So in that sense, it's a silly question because the answer is always yes, it's quantum,
but that's not really what we mean. Sometimes when you zoom out from quantum processes, the quantumness of it all average out, like when you have a baseball and you throw it across the field. Yes, it's made out of ten to the twenty nine quantum objects, obeying the Shrotiner equation. But you don't need to know quantum mechanics to describe it because all of the interesting quantumness averages out, and
you can just use classical physics. And so what we're asking here today is not are we made out of quantum objects? The answer to that is obviously yes. The question is is it crucial that we're made out of quantum objects? Is the quantumness of those objects somehow propagate up to our consciousness and our experience and our free will in an important way?
Okay, so we've set that groundwork. But now all right, I'm going to read our question one more time. Yes, here is our question. Our question is does consciousness come from quantum processes in the brain?
Right?
Okay, So first let's unpack the word consciousness. And we actually have a whole episode with doctor Megan Peters where we talked about consciousness, what it means, what we understand about it. You can go check that out, but we're gonna summarize it here a little bit. So, Daniel, for starters, what is the hard problem of consciousness?
Yeah, exactly. So in order to understand Penrose's theory, we have to figure out first what it's solving. And there's multiple problems it's solving. The first one is consciousness, and so the hard problem of consciousness is essentially saying, why do I have an experience? Why is it something there's like to be me right? Like, I feel like I'm in my body and it's not just that photons hit
my eyeball and send a message to my brain. I experience red, and red is like there's something reddish about red in a way that like I can't describe to you completely. This is famous thought experiment about a woman who lives only in a room filled with black and white objects. Could you describe read to her in a way that when she leaves the room she could identify red from blue in any way other than showing her
something red right. It tries to probe why there is an experience of being you, Why a complex series of things in your brain emerges somehow to you having a first person experience, Because as far as I know, a rock doesn't have a first person experience, a car doesn't have a first person experience, an ant probably doesn't, you know, my AI probably doesn't. But where does that happen? How does that happen? That's the question of consciousness.
And I remember we had an interesting discussion with Megan about you know, should we be worried about whether or not AI does some octopus have a first person experience? And how would we even try to measure that exactly?
And measuring it is crucial because so many times in science we begin by measuring something and then trying to explain it. We want to understand why electron goes left and right. Well, we make some measurements, and then the nature those measurements are what we're trying to predict. And the fact that in quantum mechanics those measurements are fuzzy is a whole issue. In mechanics we'll talk about in a minute, But in consciousness, like can I measure that.
All I know is that I'm conscious. You tell me that you're conscious, but I can't measure your consciousness at all. And in philosophy they have this famous thought experiment called philosophical zombie that says, for example, is it possible to have another version of Kelly who acts exactly the same way, claims to be conscious, acts as if she.
Was, But isn't It's Kelly pre coffee, That's what it is.
Is there something about consciousness which can be measured from the outside or is it purely an internal, interior thing. And if it's purely internal, an interior like I think it is, then it's by construction not measurable, which means it might be outside the bounds of science, it might be purely in the realm of philosophy. And I don't mean that in a negative way at all. It's just that science can only answer questions about things that we can predict and on, and so things that we can't
are philosophical questions, which doesn't mean they're less valid. Sometimes it means they're bigger picture questions, but it does limit us in how we probe them and understand them.
Well, So now I'm particularly interested in how a physicist is going to address this question of consciousness if it's a thing we can't even really measure.
Yeah, and this connects also not just to consciousness, but also to free will, right, like this feeling we have of being inside our heads and sort of driving our bodies. I decide to have coffee, I decide not to have coffee. I decide what to talk about on this podcast. You know, where's the room for that in our physical understanding of the universe. Is it just part of the physical systems that we are made out of that we sort of draw a dotted line around and say, this is the
decision making part. This is me making a decision. Or is there something separate, non physical, which is like driving the system but is not made of the phys bits and bobs. And so it's this experience not just of
having an experience, but having agency that's important. And so a few years ago a philosopher named David Chalmers identified this as the hard problem of consciousness, to separate it from the easy problem of consciousness, which is like, you know, how does the brain work and all the mechanisms inside
it and the optic nerve and all that stuff. He says, quote, even when we have explained the performance of all the cognitive and behavioral functions in the vicinity of experience perceptual discrimination, categorization, internal access, verbal report, there may still remain a further unanswered question. Why is the performance of these functions accompanied by experience? Essentially, why is it like anything.
To be you?
I love that the easy problem is a problem we like still haven't really figured out, and then the hard problem is a problem that we aren't actually sure we'll ever figure out. So they're both kind of hard problems, but is just even harder?
I know, and I saw yesterday on Twitter somebody said, quote, the hard problem of consciousness was invented by philosophers to sell more philosophy. Yeah, kind of true. True anyway, of course, there's a bunch of different ideas about the hard problem of consciousness, of various schools of thought, so let's survey them quickly. One of them is called physicalism, which says there is no hard problem, consciousness just emerges. And this
is like Daniel Dennett's theory. He says that it's a bit of an illusion, like there is no moment when you're aware. Your brain is just like weaving together a story about what happened, and your sense of being aware is actually your memory of the immediate past. That there is no like moment of awareness. That's just you're remembering something you didn't actually experience, and you think of that as experience.
Does that suggest that you don't actually have consciousness, you just have like a thing happening in your brain.
Yeah, exactly. And it's weird to read a book about how you're not actually reading a book, you know, or like, who is the you in this version who's not experiencing consciousness but is having it explained to them how they're not conscious. It's very confusing.
It's hard to think about these problems and disconnect like not wanting an answer to be the answer from how you feel about these things. Like my first thought is, well I don't want it to be that, but of course that doesn't make it wrong. But anyway, I haven't Maybe I should read Consciousness Explained by Dennett.
Critics of that book like to call it consciousness Explained Away.
Oh all right, what other theories do we have?
Another one is called emergentism, and that says that consciousness emerges, but it rejects the sort of reductionist approach that says, you know, everything has to be explained in terms of the microscopic that you need to like understand how this comes out of the little bits, and Bobs says it emerges on its own, that it's not reducible to some lower level description. This is what philosophers called strong emergence. Says that not everything comes out of the smallest bits,
that there can be fundamental laws at different scales. So like, it's not that F equals M is some average of all the quantum processes. There's a new set of laws at the classical level than there are at the quantum mechanical level, and maybe there's a new set of laws that deal with how complicated neurons interact with each other. And consciousness emerges from that, not from the smallest bits. Right, it can't be reduced to that it's something new and
that comes out at this scale. It's a very weird kind of idea for those of us who are physicists who like to think of the universe as determined by what's happening on the microscopic level.
Okay, but it's still not saying that like it's spiritual or you know, magical in any sense. It's just there's physical okay, physics happening at the quantum level and physics happening at the classy level, and something about what's happening at both of those levels is giving you consciousness.
That's right, it's happening at its own level, and it's not just bubbling up from below. It's its own thing. But it's still physical.
Okay.
Then you get to dualism, and that says, yeah, it's not physical at all. There are two kinds of things in the universe. There's physical stuff which can't think and have an experience, and then there's non physical stuff. Consciousness is non material. It's non physical. And you know this isn't talking about a soul necessarily, but this is like Descartes, you know, the spirit and the body, these things are separate, and you know, it just says that it does not
have to follow the same rules. And that's why you can't explain it using physical theories because it's not a physical thing.
Okay. Does this make pronouncements upon like do octopus have consciousness? Or can you ask questions like that?
Under this theory you can ask questions like that, and under variant of this theory occupy do have consciousness because they can have this non physical stuff to them which attributes them consciousness.
So yeah, okay, cool, all right, what else do we have?
And then my favorite kind of crazy theory is called pan psychism, and this says everything is conscious. Electrons have a little bit of consciousness, and two electrons have a little bit more, and ten of the twenty nine electrons have quite a bit, and all the stuff that makes you up together makes your complicated consciousness. So the whole universe is aware. And this is kind of cool because it doesn't draw a dotted line between us and the universe.
It says, you know, we are the part of the universe that is maybe most aware because we have these complicated things going on inside of us. There's arrangements of the stuff we're made out of. It makes us more aware. But we're all aware and that's kind of cool, I guess. But it's also pretty out there to say that electrons have a first person experience, that there's something it's like to be an electron.
So it's not just how much mass or how many particles you are made of. It's also about the arrangement those particles, and somehow humans are at the best arrangement of particles for consciousness. Is that right?
Yeah, exactly. So then Penrose comes in and Penrose is deeply influenced by Girdle's theorem. Girdle is a mathematician about one hundred years ago, and he was around when David Hilbert was trying to find the axioms of mathematics, like what are the fundamental underlying rules of all of mathematics from which you can derive any bit of math? Which was a cool program, but then Godel showed that it
is actually impossible. Godele's famous theorem, the incompleteness theorem says that there's no consistent set of axioms that are capable of proving all true things about arithmetic.
For example, What a downer this guy is.
I know, it's kind of mind boggling, but it means that you can have like a system of math with a consistent set of axioms. But there are things that are true that you can't prove. Okay, right, facts that are true that there's just no algorithmic way to show that they are true. So there's like no procedure you can find.
But you can be sure that they're true.
Yeah, you can't prove it, but they exist.
Okay.
One example of this is the halting problem. So like, can you given an arbitrary computer with a program and an input, can you tell whether that program will run forever like spinning beach ball of death or it will ever stop? Because computers can get stuck in loops. Right, And so it turns out this is a non computable problem, like, not only can we not solve it, it's not solvable
in principle. Okay, so Penrose said, that's pretty cool. Godal is showing that there are things that we can't understand, but we can understand Godle's theorem.
Hmm.
Okay, all right, So.
We can understand this theorem about how some things can't be proven. That means that our understanding is non computable. Right, Some things are non computable, like the halting problem, But our understanding of the halting problem means that our understanding the process we use to understand things can handle non computability. Because we can understand noncomputability, this is sort of meta. Therefore, consciousness itself is non computable, non simulatable.
So isn't wouldn't our understanding of Girdle's theorem be computable because we understand his theorem.
We understand his theorem, but it's a theorem about noncomputability, right, And so you're right, and like scholars on Goodle are like deeply unimpressed with this leap of logic. Okay, so you're right to be skeptical because in principle Godle's theorem itself can be proven right, and it exists in a larger set of axioms, and so understanding it doesn't mean that our brains have to be non computable in some way. But this is Pedrose's argument, and he says, therefore, our
minds are rooted in non computable physical law. There's some part of physical law that's non computable, and our minds are using that non computable element of it to work because we can understand noncomputability. Therefore our minds must be non computable. And I agree with you that that step
is suspect, But that's his argument. So now he's thinking about consciousness, and he's looking for something in the universe which is non computable, which is physical, which he can then use to establish as a basis for consciousness.
Okay, So pretend you were explaining this to someone and you were going to skip Gotle's theorem and you were just going to say, here is a piece of information you need to know. How would you explain that? Like, I think I'm getting tripped up on the non computable thing, just like, give me a sentence that bottom lines. Penrose believes that our brains are.
Penrose believes that our brains operate on some principles which can't be computed. That there's no algorithm to go from what you're feeling and thinking now to what you're feeling and thinking in a second. Okay, that there's no computer program you could write to predict it because it relies on some physical process which is non computable.
Okay. Does that relate to any of the theories that we were just talking about.
No, No, it's very different from any of these theories. It's its own personal theory of consciousness. But it does connect to his theories of the foundation of quantum mechanics, which we'll talk about after the break.
All right, So Penrose has decided that our brain is not like a computer. Yeah, and now we are talking about the next step of this complicated process. Daniel, where are we going next?
So Penrose says, our brains are not like a computer. Look out in the universe to find some physical thing which seems like not a computer, and maybe we can use that as the basis of our theory of consciousness.
All right. So his target here is quantum mechanics, because quantum mechanics is very weird, and computers are like deterministic, right, they operate under basic rules of algebra and logic, and so you can always predict what they're going to do, whereas quantum mechanics is fuzzier and weirder and we don't quite understand it and how one thing gets chosen. And so it sounds like maybe a promising area to find some non computable physical law that you could use as
your basis of consciousness. All right. So let's remind ourselves what is the other really hard philosophical problem out there right now, not just consciousness. Put that in a box. Let's talk about the measurement problem in quantum mechanics, the other major thing that everybody else struggles with. And this is a question of how the universe decides what we see when we measure or quantum object. Because remember The cool thing about quantum objects is they can be in
a superposition. You have an electron, you put it through a machine, it can either go left or right before you measure it. It's in a superposition of left and right. It's not that it's gone left and you don't know it, or that it's gone right and you don't know it, or even that it's somehow done both right. You see that in popular science all the time. Instead, it's in a superposition of both of those states. And that's something that quantum objects can do. They can have a superposition.
They cannot be settled into one particular outcome. But then when we measure something, we put a detector to say did it go left or did it go right? Then the universe picks one. The superposition collapses into either left or either right. Okay. And how this happens and why it happens is the question of quantum measurement, because this seems to happen when we measure quantum object with a classical detector, Like I have a big detector in my lab and it's made of big physical things, and you
know I'm moveing around. It's a size and scale of me. It's not the kind of thing that can be in superposition. I can't be in a superposition. You can't be in a superposition. It makes a definitive measurement a left or a right. It doesn't come back and say lefty and right y at the same time. Right. It measures left or right. And when a classical object like that measures the quantum object, the quantum object collapses into either left
or right. Superposition is gone. The super weird bit is that that doesn't happen if we interact our quantum object with another quantum object, like say I shoot in another electron, and I can entangle them together, and now they can be like one is left and one is right, and or one is right and one is left. They can maintain their superpositions even though they interact. But when they
interact with the classical detector, boom collapse happens. And that's super weird because what's the classical detector made out of? Well quantum objects, So why does interacting with the classical detector have to collapse the superposition? When you interact with the first first quantum object, that's the very tip of the detector, that should just be like interacting with another quantum object, you should stay in a superposition and then
in the next particle, and then the next particle. At what point is your classical object, which is made of quantum objects, no longer capable of being in a superposition? Why does that happen? That's the measurement problem in quantum mechanics. How and when and why you go from superposition to collapse.
That was a really good explanation. I don't think you've given that particular explanation on the show before, and excellent. So what's the best answer we have for that, Daniel?
We have a bunch of weird answers. The most common answer is nonsensical. This is the Copenhagen theory, and it says, look, there's two kinds of things in the universe, this quantum stuff, which can mean superposition, and this classical stuff, which cannot be in superposition. And then you ask, well, what's the difference between classical and quantum stuff? And they say, I don't know. They say, well, where's the line between quantum and classical stuff? And they say undefined. So it's not
really an answer, right. It just says, let's just say that there is classical stuff and there is quantum stuff. So it's one of these like answers only by definition that doesn't really satisfy anybody.
It's just like throwing their hands up in the air and being like, oh, I don't know, I quit yeah.
Yeah. And it's weird because it's, on one hand, the most common explanation and the one you see in like quantum textbooks and in popular science, but in philosophy of physics, people like it's incoherent. It's not even a theory, like it doesn't even explain it, it doesn't even try. But you know, it allows you to move forward and like calculate stuff without worrying about it. So if you don't really care about the answer, you can just sort of accept that and move on.
It does sound impressive, The Copenhagen interpretation does sound It sounds impressive.
Wonderful, wonderful Copenhagen.
Yes. But then the good news is, now that you've listened to this podcast, the next time someone says the Copenhagen interpretation, you can go the Copenhagen interpretation, and now you get to sound snotty.
So another famous interpretation is the Many World's interpretation, and this says there is no collapse. What happens is that the universe branches. There's a version where the universe goes left and a version when the universe goes right. We happen to be in one of them and not the other one. But there is no real collapse. And this is a beautiful theory because collapse is weird, like collapse
doesn't exist in the equations of quantum mechanics. The equations suggest everything just keeps evolving and maintaining the wave function, and so this is in some sense the most natural interpretation of quantum mechanics. Sean Carroll is a big advocate for this and talks about it very eloquently. He was on our podcast to talk about that. It was a lot of fun and essentially in that scenario, you become part of the system, like you make our measurement. Now
you are in one branch or the wave function. The superposition still exists, the electron can still be left or right, but you are in the right branch, which is why you're measuring right, and there's another version of you in the left branch, and that version of you is measuring
the left. This is often misunderstood is like the whole universe is duplicated, like we make a copy and create more electrons, but instead just think of it as like the superposition of possibilities just keeps flowing man right, and now you're part of the system instead of looking at it from the outside.
So, but how does that answer the question about like you're this big classical object that's making the measurement, and as you're moving from one electron to another in the classical object, how do you go from being an electron to being a classical object?
Like there are no classical objects. Everything is quantum whoa, And every time you interact you become entangled with the system.
That is a lot for my brain to handle.
Okay, Another really fun idea is called Bomian mechanics, and this says, forget all this random stuff. Quantum mechanics is not actually random. It's deterministic. It's controlled by some global pilot wave. And this has an end run around Bell's experiments, which if you member proved that there's no local hidden variables controlling quantum mechanics, that truly is random. By saying oh there's no local hidden variables, there can be global
hidden variables and that's the pilot wave. It's this like weird thing that sits on top of the universe and decides where particles go, and so there's no randomness at all. It's just all determined by this pilot wave that we can't see or measure that's deciding and it makes it look like it's random, but it really isn't.
Is there any way to test this.
There's no way to test these two theories. They make exactly the same predictions for all experiments, so they're just interpretations. They're just ways of saying what's happening behind the scenes invisibly, and because it's the invisible part we're talking about, and that's the only place they differ, we can't come up
with experiments to differentiate between these two. Okay, But the crucial thing for our conversation about Penrose is that in the Copenhagen interpretation, where you have this like weird moment where we go from superposition to collapse, that collapse is what interested Penro right, because it sounds on the surface of it like, hmm, maybe this is something that can help us establish consciousness because it's something weird that's happening here.
But the hurdle immediately is that collapse in the Copenhagen theory is random, okay, but it's computable in the sense that you can't tell exactly what's gonna happen, but you can predict the probabilities. And so Penrose is looking for something that's not random and not computable, so he can't use this Copenhagen collapse theory. So he comes up with his own theory of the measurement problem, his own theory
of collapse. It's called objective reduction. He comes up with a theory that has a collapse of the wave function, but the collapse is not random, but it is non computable. So he's come up with his own theory, not Copenhagen, not many Worlds, not Bowman, his own explanation for collapse that provides a not random, non computable mechan for the collapse, which is what he's going to need later for his theory of consciousness.
Does this do a better job of explaining quantum mechanics or is this just like motivated by a desire to explain consciousness and so he's creating a whole new world.
It sort of does a better job in that it's more ambitious. Not only is he going to try to solve the measurement problem, huge outstanding puzzle in philosophy, in order to set him up to solve the question of consciousness, another huge outstanding puzzle in philosophy. He's going to do it by trying to simultaneously solve the quantum gravity puzzle. Wow, which physicists have been banging their head against the wall
for for one hundred years. Right, He's like, oh, maybe I can go for a home run here, Let's go for the trifecta a hat trick. Yes exactly.
I think that's you get three things in a row with the hat trick. That's what we want.
Yeah, well he's going to go for four in a minute.
Oh okay, let's take a break and we'll let Penrose do his hat trick, and then he can do his hat trick plus one, because I don't know enough about sports to know what happens when you get four points and we're back, and so let's go ahead and talk about how Penrose solves the quantum mechanics problem in a non computable way. Did I say the science words in the right order? There?
You totally dead, Yes, you science stick correctly. So we have this problem in physics, which is that we have two wonderful theories. We have quantum mechanics, which explains particles and randomness and has been tested like ten decimal places
and is totally correct, and it's amazing and beautiful. And we also have gravity, and we have a theory of general relativity, which tells us a story about space and time, and it's been tested to ten decimal places and is totally correct, and that's wonderful, except that the two theories are fundamentally at odds with each other, and we do
not know how to bring them together. And most of the time that's not a problem because things are either gravitational, like the way the Earth moves around the Sun or the way black holes form, or they're quantum mechanical, like the way electrons interact in a system, or what happens when you smash protons at the large Hadron collider. You can ignore one, and you can choose one and ignore the other. But there are sometimes in the universe when both are at play, like what's it the heart of
a black hole? Or what was it like in the early universe. In those regimes, we don't know how to operate. We can't make predictions for example, before the earliest moment in the universe, because we don't have a theory of quantum gravity, and we can't tell you what's inside a black hole because we don't know how to do gravity for tiny particles. Okay, so major stumbling block for particle physics and for cosmology. And one of the issues is that when you try to do gravity for particles, you
get stuck, and you get stuck like this. Well, if particles can have probabilities of being in different locations, like is the electron left or is the electron right, then that location determines where space is curved right. Then that means that like space can have different curvatures. So if the electron could be left and could be right, it means that space could be bent over here or it could be bent over there. And so now you have like this weird thing where the curvature of space isn't
known because you don't know where the masses are. The masses only have a probability of being in certain places. So either you have like the probability of different curvatures or space has probabilities built into it, And so nobody knows how to tackle that problem.
I'm so glad biology has everything figured out.
So Penrose says, all right, well, what have each of those superpositions, those different possible arrangements of men which caused their own different space time curvatures. What are those different possibilities? That's what causes the collapse. So think of like one arrangement of particles having one set of curvature, and another possible arrangement of the same state, right, quantum mechanical superposition
having a different arrangement. And if those two arrangements of space time, which cause different curvatures, get different enough, then something becomes unstable in the universe and collapses. Okay, So when the gravitational difference between two quantum branches exceed some threshold, then the wave function collapses from superposition into one option.
So now instead of just talking about electrons, we're talking about groups of particles.
It could also just be one electron, because in principle electron has mass and it should curve space time, okay, And the question is does it curve space time over here or over there? And Penrose is saying if the difference between those two things gets big enough enough particles in there, then it collapses and there's a threshold there, and it doesn't rely on observation or on interaction, but the bigger the tension between the two gravitational possibilities, and
whenever it gets above some threshold, it collapses. And so this is his theory called objective reduction. So we're not yet a consciousness. This is just Penrose's theory of why things collapse. And along the way he's going to try to reconcile quantum mechanics and gravity. So he's saying that it's this tension between the different gravitational results of two elements of the superposition that causes them to collapse down to one.
So then what does Penrose's idea do with the fact that we know that when you observe something, you get a collapse.
Yeah, so Penrose is saying, well, when you observe with a quantum object, you're adding a bunch of stuff to the system that goes above the threshold because now you have like enough gravity in there to get above the threshold. Your big classical detector, which has you know, a big piece of material on it, has so much gravity in it that it can't be in two states at once
without those two things collapsing. So that's why classical things can't be in a superposition because they exceed this threshold, which is very very small. It's like plank scale threshold. And so only really tiny stuff can be in a superposition because bigger stuff exceeds this threshold. And this is a cool idea. Nobody's proven it. Nobody knows whether this is true. We can't test it at all. And like many theories in quantum gravity, we can't test them because
we can't probe this stuff. We can't go inside a black hole, we can't visit the early universe. For Penrose, the cool thing about this is now, the collapse is not random, but it's also not algorithmic, okay, it's non computable. It's determined by something he calls, you know, the platonic truth of the universe, and so you know why it goes into left or right, why collapses into one or
the others? Not random, but it's non computable, okay. And so he's tried to solve this measurement problem along the way come up with a proposal for quantum gravity unification.
And what he ended up with is a explanation for quantum mechanics and the measurement problem, which says that the collapse is not random but also non computable, and that's what he thinks consciousness is, right, and so he thinks that maybe this kind of experience, having these micro states collapse using his objective reduction theory is a fundamental building block of consciousness because remember he was looking for something in the physical universe which is not random but also
non computable. And you know that's not enough. It's not like saying, hey, consciousness has these two characteristics, and this thing I just came up with also has those two characteristics. Therefore they're the same thing. Like not everything that's big and red is a fire truck. Right, Having two things in common doesn't mean that they're identical, but it's sort of a hint in the right direction.
Okay, right, because right now that would say that rocks have consciousness because they have these features, right.
Yeah, exactly. And so now we come to the biological side of this. There's a guy, an nisc theologist named Stuart Hammeroff, and he's been thinking about anesthetics and consciousness, as aniseciologists will do, and he read about Penrose's theory of objective reduction, and he went to chat with Penrose, and he said, I have an idea for where this quantum stuff is happening. And so there's these things inside neurons that are protein scaffolds. They're called microtubules, and they're
really tiny little things. They're like fifty micrometers long, they're really thin, they're like twenty five nanometers thin, and you know they're involved in like maintaining the structure of the cell and they form a cytoskeleton. And so these things are inside your neurons and they're really really small, and he thought maybe these things support quantum superpositions, like they can be in two different states, like you know this twist or that twist, and because they're so small, they
can be in a superposition of different states. And he has this idea that anesthetics work by binding two microtubules to turn off your consciousness. He thinks microtubules are quantum objects in that you know they can be in this superposition and that their collapse is where the moment of consciousness comes from. That when these quantum tubules become unstable and they collapse in this non random, non computable way,
that's the moment of consciousness. So Hammer Off and Penrose came together to make this theory called orchestrated objective reduction theory. So member Penrose came up with objective reduction, which explains
how things collapse quantum mechanically. This orchestrated objective reduction theory says, Okay, it's microtubules in your neurons that are collapsing, and the neural processes in those neurons orchestrate the build up of these superpositions which then become unstable and they collapse, and every time they collapse, that's a little bit of the conscious experience. And so this orchestration is like the physical
basis for intentional control. It's not like, you know, you are outside the universe and you're determining it in some spiritual way. But they can like affect the way that the collapse happens and in that way impact the decisions you're making. So hammer Off, the anesthesiologist helps by proposing like exactly where this quantum process might be happening in the brain, which is non computable and non random in the way that Penrose wanted.
All right, so first, I think I'm constrained by the metaphor that I always use when I think about microtubules, which is, I think of them as like the studs and joists of like yourselves. You know, they give your it the structure. So this idea that they're like in a superposition is foreign to me. So the idea is that they're like twisted and they untwist. Is that that's true, question mark.
It's about the confirmational states. I don't think it has to be twists necessarily, okay, But these things are not firm, right, They can wiggle a little bit, okay, and so you know, they have a possibility to wiggle this way, wiggle that way, or stretch this way or stretch that way. Here, we're definitely at the very edge of my biological knowledge.
Yeah. Yeah, I'm not a microtubule person unfortunately.
And so and these are also not the things that give Jedis the force in Star Wars, right, those are the Midi Chlorians.
Oh, I wasn't seeing where you were going there. Thank you for walking me the rest of the way. Okay. So you get consciousness in like little drips and drops every time these superpositions collapse.
Yeah, okay, that's the idea. And so you know, we've tried to explain consciousness by saying, it's the collapse of this dates of these microtubules in your brain, which is non computable yet not random, and happen when this superpositions get big enough that they go above this quantum gravity threshold that Penrose has postulated. That's a big idea. So these microtubules are basically in these quantum states, and the
collapse of those states is your experience. There's a lot of like big leaps here that is just sort of dot dot dotting over. Even if this is all true, and microtubules are in quantum super positions and that collapse is non computable and non random, I don't see how that connects to consciousness. Like we thought that link was kind of weak earlier saying that we can understand the theory of noncomputability, therefore our thinking itself is non computable.
That seems kind of weak. And even if you accept that, just because our thinking is non computable and there's something non computable happening inside our brains doesn't mean again that it's the fire truck. Right, There's no clear thing connecting one to the other. But you know, Hameroff's argument is these things are connected to consciousness, because anesthetics bind to these things to turn off your consciousness. Right, So there's
our fourth element of the hat trick. We're also going to explain the mystery of anesthetics.
But when we did the episode on general anesthetics and I was interviewing an anesthesiologist, she said that when you inject noble gases, which don't react to anything, into people, you get a similar effect to knock people out, and they're probably not binding to the microtubules, right, And so we don't understand what's happening with anesthetics at that level. I thought, Yeah.
So we've tried to present the best case we can for this. Now it's time to you know, hook at some of its weaknesses. Hey, we've handed at a few of those already, and the point you made is a great one. But more broadly, people think that microtubules are anyway just too noisy to make any sort of coherent quantum superpositions, Like they're big. You know, these things are
not individual particles. They are micrometers long. And Max tech Mark's response to this theory is, quote, the brain is about as quantum coherent as a cup of warm, wet oatmeal, Like the idea that these things could maintain a superposition, which requires being isolated from the rest of the environment in order to maintain that superposition until the moment you
want to collapse. Right, seems hard to do because they're already big and connected with each other, and so to have them individually collapsing, they need to be isolated so they can maintain that superposition, and that seems pretty tough. The big concern here, though, is that this is a lot of speculation, and you know, a lot of it could be right, but most of it can't really be tested.
Like we can't test the theory of quantum gravity, we can't test quantum mechanical interpretations, we can't test these questions about consciousness. It's also beyond our ability to probe. So it's sort of like saying, hey, these four things that we can't really ever test. What if there's one coherent explanation? Yeah, man, past the banana peels. That sounds cool, but what are we gonna do with that?
Right?
Yeah, that doesn't mean it's not a good exercise, you know, to think about and ponder and use to like generate new novel ideas and stuff.
But absolutely, Yeah, so I did talk to my friend who's a neuroscientist. She does research on fruit flies and stuff like this, and I asked her, like, do you think neurons are random or deterministic? Like if you feed a neuron the same input twice, are you going to get the same answer or does it depend on the quantum nature of the things that neurons made out of? And she was like, neurons are totally deterministic, Like there's
noise reduction stuff that's happening in there. You tweak a neuron the same way twice, you're gonna get the same answer. And you know, she latches onto neurons in the lab and does this, so she knows a lot about neurons. So already it seems hard to build consciousness out of neurons if those neurons already have the quantumness averaged out, the neurons essentially already being classical, they're like the baseball's
more than they're like electrons. I mean, I guess Penrod's argument is that this goes deeper than neurons, but I'm skeptical of that as well. But you know, these are not hard criticisms because there isn't really anything you can concretely attack in this theory. Because there are no experiments that you can do. You can just argue about the ideas well.
I think that we have all earned ourselves some self care this evening. So get in a bubble bath with a bath bomb. Go have a bottle of whisk not a bottle of whiskey. I mean a glass of whiskey, not the whole bottle. Make good choices, friends. This was There was a lot going on in this episode, but we learned a lot and you got us through it, Daniel, in a really gentle way.
All right, Well, let's send this back to Scott and see if his bubble bath and his glass of whiskey have put him in a place where he goes ouch or mmm, I get it now. Thank you very much for sending in your question, Scott. Let's hear what Scott has to say.
Hello, Daniel and Kelly, thanks so much for responding to my question about Penrose and Hammeroff's orchestrated objective reduction theory of consciousness. Kelly well captured my experience when she said that was a lot for my brain, which is fairly typical when I listen to you guys, not exactly ouch,
but not totally I get it now either. But whether or not my consciousness arises from the collapse of quantum superpositions in the microtubules and the neurons in my brain, it does love being challenged and stretched and exploring new ideas, which I think is actually a form of self care. I feel like I have at least some new understandings of theories of quantum superposition and theories of consciousness, as
well as the challenge of testing those theories. I appreciate them putting forward this idea to expand our thinking around the hard question, and I also appreciate the skepticism that Daniel brings to the idea. So thanks again for answering my question, or at least trying your very best to do that.
Mallow Well, Daniel's explanations today made me go hmmm, not ouch today, So thank you for that great explanation of a super interesting.
Theory, all right, and thank you very much E Briddy for being curious about the universe and for wanting to understand these ideas on the cutting edge. Please please share your curiosity with us, send us your questions and lend us your ears.
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