Speaker 1: Why do we have the experience of being conscious? Can
Speaker 1: you build consciousness just by putting together lots of neurons
Speaker 1: in the right way, or might there be deeper principles
Speaker 1: at work. Could quantum physics have something to do with
Speaker 1: the brain and specifically with consciousness. Is it possible that
Speaker 1: consciousness is actually something that predates biology and there's a
Speaker 1: sense in which biology evolved to take.
Speaker 2: Advantage of it.
Speaker 1: And what are the right ways to make new theories
Speaker 1: in neuroscience when we don't know the answers.
Speaker 2: Welcome to Inner Cosmos with me David Eagelman.
Speaker 1: I'm a neuroscientist and author at Stanford and in these
Speaker 1: episodes we sail deeply into our three pound universe to
Speaker 1: uncover some of the most surprising aspects of our lives.
Speaker 1: Today's episode is about consciousness and quantum mechanics and the
Speaker 1: question of whether there could be even possibly.
Speaker 2: Any connection between them.
Speaker 1: So to get at this, I'll be talking today with
Speaker 1: Roger Penrose, mathematical physicist and polymath and winner of the
Speaker 1: twenty twenty Nobel Prize in Physics, and also Stuart Hammeroff,
Speaker 1: an anesthesiologist who has collaborated with Penrose for many years
Speaker 1: on a theory. Before we dive into those interviews, I
Speaker 1: want to set the table by saying that what we're
Speaker 1: going to talk about today are speculative ideas, and many
Speaker 1: neuroscientists don't even like to go near them.
Speaker 2: But the fact is that despite the thousands.
Speaker 1: Of neuroscience journals and textbooks and laboratories, there are still fundamental,
Speaker 1: basic questions that we don't know the answer to. And
Speaker 1: one of the most fundamental is the question of consciousness.
Speaker 1: Why does anything feel like something? In other words, imagine
Speaker 1: that you built a little toy out of pulleys and
Speaker 1: levers and switches.
Speaker 2: Would you say that it is conscious?
Speaker 1: Presumably you wouldn't now double your little toy in size
Speaker 1: with new levers and switches and pulleys. Is it conscious?
Speaker 2: Now?
Speaker 1: There's no particular it's theoretical reason to think. So now
Speaker 1: keep adding to it. Put on another pulley, in another lever,
Speaker 1: and another little door, and attach a wheel, and keep
Speaker 1: doing this until you fill a room and then a stadium.
Speaker 1: Do you have any reason to assume that it becomes
Speaker 1: conscious and has internal experience just because it's more and
Speaker 1: more complex. If you now remove a pulley, does it
Speaker 1: feel pain. And if you put a little molecular detector
Speaker 1: on it such that it can recognize molecules of different
Speaker 1: shit apes, does it have a different experience like displeasure
Speaker 1: for some shapes and pleasure for other shapes, And where
Speaker 1: is that happening. I certainly wouldn't think that your giant
Speaker 1: toy is conscious, or at least let me say that,
Speaker 1: I have no theoretical reason to believe that it suddenly
Speaker 1: experiences pain or hunger or longing or pleasure, because it's
Speaker 1: just pieces and parts. So this is a fundamental question
Speaker 1: about the brain. We look at your eighty six billion neurons,
Speaker 1: which are generally thought of, especially now in this era
Speaker 1: of AI, as being units that are popping either on
Speaker 1: or off one or zero. And so it's not clear
Speaker 1: to any of us in neuroscience why we have private
Speaker 1: subjective experience. And this is true whether you have eighty
Speaker 1: six neurons or eighty six billion or eighty six gajillion
Speaker 1: of them. Why do these little electrical signals and chemical
Speaker 1: releases give us the the experience of eating a lemon,
Speaker 1: or the pleasure of an orgasm, or the pain of
Speaker 1: stubbing your toe. Now, we don't know the answer. But
Speaker 1: here's a speculation that some people have put forward. Could consciousness,
Speaker 1: the most intimate, subjective, elusive feature of our existence, have
Speaker 1: something to do with quantum physics. Now, this is not
Speaker 1: a mainstream idea in neuroscience. You're not going to find
Speaker 1: it in the standard textbooks most cognitive scientists, if asked
Speaker 1: to explain consciousness, we'll talk about neurons and synapses and
Speaker 1: the emergent properties of complex systems. The language will be
Speaker 1: biological and electrochemical and computational. But a few scientists have
Speaker 1: suggested a hypothesis that there's something deeper going on, something
Speaker 1: much stranger, and that's what we're going to explore today.
Speaker 1: I'm not presenting an argument that auto mechanics does explain consciousness,
Speaker 1: but it's worth understanding why some serious minds are entertaining
Speaker 1: the hypothesis. So we'll begin with Roger Penrose, who is
Speaker 1: perhaps an unexpected figure in this conversation because he's not
Speaker 1: a neuroscientist. He's a mathematical physicist. He's done so many
Speaker 1: amazing things in his career. He worked with Stephen Hawking
Speaker 1: on black hole singularities, or he might know him for
Speaker 1: his geometrical shapes called Penrose tiles. And you certainly know
Speaker 1: him because in twenty twenty he won the Nobel Prize
Speaker 1: in physics for showing that black holes result naturally from
Speaker 1: Einstein's general theory of relativity. And by the way, he's
Speaker 1: also the one who mathematically described black holes in detail,
Speaker 1: including their singularity where all known laws of nature dissolve.
Speaker 2: But especially in.
Speaker 1: The nineteen eighties and nineties, Roger Penrose turned his attention
Speaker 1: toward the brain, not because he wanted to build a
Speaker 1: better theory about cognition, but because he had a concern
Speaker 1: about out algorithms. Penrose felt that consciousness just can't be
Speaker 1: explained by any rule based system. He pointed to an
Speaker 1: idea called Girdle's incompleteness theorem, which said, look, there are
Speaker 1: mathematical truths that we can see to be true, but
Speaker 1: they can't be proven within mathematics. In other words, there
Speaker 1: are many systems where we can see things to be true,
Speaker 1: but the system itself can't prove them. You need to
Speaker 1: somehow step outside of the system. Now, to Penrose, this
Speaker 1: was a sign that human understanding operates in a way
Speaker 1: that transcends computation. In other words, he said, brains aren't
Speaker 1: just computers, and if they're not just computers, then the
Speaker 1: mystery of consciousness might demand a different kind of physics.
Speaker 1: So he wrote a very interesting book called The Emperor's
Speaker 1: New Mind, which asserted that the brain can't just be
Speaker 1: a computer. So in your Book's New Mind, which I
Speaker 1: read as a young person and really loved, so you
Speaker 1: argue that consciousness can't be explained by algorithms.
Speaker 2: So help us to understand that.
Speaker 3: But it really means, you see, an algorithm is just
Speaker 3: the sort of technical word for a computer program. I
Speaker 3: feel like maybe people use that term. It just means
Speaker 3: that you have a rule which is a computational rule.
Speaker 1: Right, And why what made you feel that consciousness can't
Speaker 1: be explained by algorithms?
Speaker 3: Well, it goes back to the Girdle the lecture that
Speaker 3: Stein gave about Girdles theorem. And I realized that you see,
Speaker 3: if you see mathematical proof, you could have a set
Speaker 3: of rules, axioms and rules of procedure. These are of
Speaker 3: a nature that you could put them on a computer.
Speaker 1: You think there are forms of human insight that fundamentally
Speaker 1: cannot be replicated by algorithms.
Speaker 2: Is that that's correct.
Speaker 3: Okay, yes, absolutely right.
Speaker 1: Okay, great, and so and so that made you think
Speaker 1: that maybe this mystery of consciousness needed to be taken
Speaker 1: seriously by physicists and mathematicians. So, yes, So how did
Speaker 1: you how did you start addressing this?
Speaker 3: I was trying to think about the laws of physics
Speaker 3: that we sort of understand, and some of them are
Speaker 3: very powerful. Well, even you turn in mechanics explains an
Speaker 3: awful lot and science general theory of relativity explains a
Speaker 3: lot more, and it's more difficult to apply things, but
Speaker 3: it's still computational. What about quantum mechanics?
Speaker 1: Now, before we go further, I just want to give
Speaker 1: a reminder about what quantum physics is. It's the branch
Speaker 1: of physics that describes the behavior of matter and energy
Speaker 1: at the smallest possible scales, at the level of atoms
Speaker 1: and subatomic particles, and down there the world behaves nothing
Speaker 1: like what we're used to. Particles can be in more
Speaker 1: than one place at once. This is what's known as superposition.
Speaker 1: Particles can become mysteriously linked across space in what's called entanglement.
Speaker 1: And the most bizarre feature of all is that the
Speaker 1: mere act of measuring a system seems to affect its outcome.
Speaker 1: This is what's called the observer effect. In our current
Speaker 1: understanding of quantum mechanics, the story is that until a
Speaker 1: particle is observed, its properties don't exist in a definite way.
Speaker 2: They exist only in probabilities.
Speaker 1: In other words, a quantum particle doesn't have a precise
Speaker 1: location until you look at it. Until that moment, it's
Speaker 1: smeared across a range of possibilities, and then those possibilities
Speaker 1: collapse to one outcome when you observe. Now, this isn't
Speaker 1: just a metaphor. This general idea has been tested and
Speaker 1: confirmed for over a century, and it's built into the
Speaker 1: fabric of our technology. Quantum mechanics is the science that
Speaker 1: allows the transistors in your cell phone, and the lasers
Speaker 1: at the grocery store scanners and the GPS in your car.
Speaker 1: Quantum mechanics is real, and it's very countereteitive, and it
Speaker 1: seems to tell us that at the heart of reality
Speaker 1: is a kind of indeterminacy, a fuzziness that only collapses
Speaker 1: into certainty when it's observed. So think of it roughly
Speaker 1: this way. You toss a coin in the air and
Speaker 1: while it's spinning. It's not heads or tails. It's sort
Speaker 1: of like it's both at once, but the instant you
Speaker 1: catch it and look, it becomes just one heads or tails.
Speaker 1: That moment of catching it is like the wave function collapsing.
Speaker 2: Now here's the thing. In quantum mechanics.
Speaker 1: There's no way to predict what the coin's going to be,
Speaker 1: heads or tails, and so that non computable strangeness, that's
Speaker 1: what Penrose was interested in. He wondered, what if that indeterminacy,
Speaker 1: that collapse of possibilities into one real outcome, wasn't just
Speaker 1: a physical process but also has to do with a
Speaker 1: mental one. In other words, what if the flicker of
Speaker 1: consciousness is related in some way to the collapse of
Speaker 1: the quantum wave function. So back to Penrose talking about
Speaker 1: his search for something non computable and getting interested in
Speaker 1: the collapse.
Speaker 3: What about quantum mechanics? Then I thought, wow, I was
Speaker 3: shruding no equation, that has no problem about putting that
Speaker 3: on there. Maybe lots of parameters involved, it's make it tricky. Well,
Speaker 3: that's a well determined determined It is a good question.
Speaker 3: Roading equation doesn't give you what happens in the world.
Speaker 3: Why doesn't it give you what happens. Schrodering himself was
Speaker 3: very keen on explaining these things and his well known cat.
Speaker 3: He was making this is an absurdity. To have a
Speaker 3: cat which is dead and alive at the same time
Speaker 3: is a nonsense. This is point of what he was
Speaker 3: trying to make. He was saying, this is an absurdity.
Speaker 3: His equation he was trying to say. He was saying,
Speaker 3: roughly speaking, my equation does not describe reality. There is
Speaker 3: something more. And this something more is what we tend
Speaker 3: to call the collapse of the wave function. You're a
Speaker 3: wave function drugs along and behaves according to the Schroding
Speaker 3: equation very reliably and honestly, and then from now time
Speaker 3: to time it says, whoops, I'm going to do something else,
Speaker 3: and then it becomes probabilistic, and it's all hidden in
Speaker 3: all sorts of man and manical schemes.
Speaker 1: So you mean is that classical computation can't explain consciousness,
Speaker 1: and so the question is then what can? And this
Speaker 1: is where you make the fascinating proposal that quantum mechanics,
Speaker 1: and specifically the collapse of the wave function, might be
Speaker 1: involved in consciousness.
Speaker 3: See people say sometimes I'm just not say, well, here's
Speaker 3: the problem, and here's a problem. So they're the same thing.
Speaker 3: It's not that it's that we need something which is
Speaker 3: not a computable part of physics. What is it in
Speaker 3: the physics that we know it would not be possible
Speaker 3: to put on a computer. Well, you see, if the
Speaker 3: collapse of the wave function is purely random, then you
Speaker 3: could put it on a computer source off. And it's
Speaker 3: not perhaps really random, it's something very subtle, and you
Speaker 3: need that for the collapse of the wave function. And
Speaker 3: the story has developed in other ways beyond what I had.
Speaker 3: Then you see, this was the beginning of the story,
Speaker 3: and you're asking me about the beginning. The beginning was
Speaker 3: the story. It was a little bit in the sense
Speaker 3: that I didn't know really much about what to do.
Speaker 3: I could see that in according to my new point,
Speaker 3: the collapse of the wave function had to be a
Speaker 3: major part of the physics which is responsible for evoking consciousness.
Speaker 1: So to summarize where we are, Roger felt certain that
Speaker 1: consciousness couldn't be explained just by classical computation. Again, most
Speaker 1: of quantum mechanics you can easily model on a computer,
Speaker 1: like the evolution of the Schrodinger wave function, but there's
Speaker 1: something very weird about the collapse. That's the part you
Speaker 1: can't compute. So Roger felt he was onto something interesting there.
Speaker 1: So he sat down and wrote The Emperor's New Mind,
Speaker 1: and the title, as you might guess, was a reference
Speaker 1: to the story of the Emperor's New Clothes. The idea
Speaker 1: being that everyone is assuming we can explain consciousness by
Speaker 1: putting together enough neurons, but in fact, in his view,
Speaker 1: the burr is naked consciousness possibly can't be explained by
Speaker 1: just a bunch of neurons. So I asked Roger what
Speaker 1: happened just after he published the book In nineteen eighty nine,
Speaker 1: I wrote.
Speaker 3: My book Them Prisoner Mind and hoping some young people
Speaker 3: might be stimulating, and only got old retired people. I
Speaker 3: thought I'd done lo It was sort of a fairly
Speaker 3: reasonable job as an ignoramus, but not too bad at
Speaker 3: a job of trying to learn the main features of neurophysiology.
Speaker 1: So Roger started studying up on the brain, really as
Speaker 1: a side gig to his mathematical physics career. But the
Speaker 1: more he looked at it, he thought that maybe the
Speaker 1: macro level at which we were able to study.
Speaker 2: The brain wasn't really revealing its secrets.
Speaker 3: And I would say that it has a genuine, deep purpose,
Speaker 3: and that purpose is not clearly revealed in the structures.
Speaker 3: But it's not something which is obviously like a computer.
Speaker 3: Something else going on. But I didn't know what was
Speaker 3: going on. I had no real idea by the time
Speaker 3: I got to the end of my own presuming but
Speaker 3: I just I might. I could have stopped writing in
Speaker 3: this point, and I said, well, that's I've written so
Speaker 3: much so far.
Speaker 2: I better go on.
Speaker 3: And so I'm more or less sort of some idea
Speaker 3: which I didn't really believe. I tried to think of
Speaker 3: something that might be non computable, you see.
Speaker 2: So that's where things were for Rogers' idea.
Speaker 1: He suspected there must be some kind of quantum effects
Speaker 1: in the brain, but he didn't know where to look.
Speaker 1: But at the same time, in America, there was a
Speaker 1: young antesthesiologist named Stuart Hammeroff who was interested in consciousness.
Speaker 4: And I got interested in consciousness, and I went to
Speaker 4: med school and was interested in neurology, neurosurgery, psychiatry. But
Speaker 4: I didn't like those lifestyles, particularly what they got to do.
Speaker 4: They didn't actually get to do the surgency, but the
Speaker 4: neurologists in particularly didn't have much to do. And I
Speaker 4: took a research elective over summer in a cancer lab
Speaker 4: and studied my toasters. I figured just try something different,
Speaker 4: and so we uh studying cell division. And as you know,
Speaker 4: the cell divide, the chromosomes are separated by these spindles,
Speaker 4: which are microtubules.
Speaker 2: That's Stuart hammer Off.
Speaker 1: And while everyone in that lab was interested in the chromosomes,
Speaker 1: where the genes are, he found himself interested in the microtubules. Now,
Speaker 1: what are microtubules. The starting point here is that all
Speaker 1: the cells in the brain, like neurons and glial cells,
Speaker 1: are not empty. Inside every single brain cell is a
Speaker 1: bustling inner world. You've got all kinds of structures that
Speaker 1: help the cell keep its shape and transport materials around.
Speaker 1: And among these structures are microtubules, which are tiny hollow tubes.
Speaker 1: They're part of the cells skeleton. Sometimes people think of
Speaker 1: these like the tracks that guide packages through a warehouse.
Speaker 1: Now these are very very tiny. Each microtubule is about
Speaker 1: twenty five nanometers in diameter, which means you can line
Speaker 1: up four thousand of them across the width of a
Speaker 1: single human hair, and they're long too, so they stretch
Speaker 1: like tiny straws all through the interior of the neuron.
Speaker 1: Now what's amazing is these are constantly assembling and disassembling themselves,
Speaker 1: almost like living legos, and this adjusts the internal architecture
Speaker 1: of the cell in real time. So Stuart got interested
Speaker 1: in these microtubules and wondered if they were more than
Speaker 1: just railroad tracks.
Speaker 2: Back to Stuart Well.
Speaker 4: Micro teams are found in all cells, including neurons, which
Speaker 4: are full of them, and they are like the skeleton
Speaker 4: and the scaffolding on the cell, but they're also the
Speaker 4: nervous system of the cell. They organize things, and their
Speaker 4: structure I learned back then is a lattice kind of
Speaker 4: like a computer lattice, where you have individual units proteins
Speaker 4: called turbulence that I thought back then can be in
Speaker 4: two states, like flexing like a peanut open and closed,
Speaker 4: and that would be like a bit at one or zero.
Speaker 1: So Hammerff is looking carefully at these and he proposed
Speaker 1: that microtubules might be doing something beyond structural work, that
Speaker 1: instead of just looking at the microtubule as a roadway,
Speaker 1: you might think about the details of the microtubules and
Speaker 1: ask whether this could be a structure that was a
Speaker 1: lot more interesting than it first appeared. So he started
Speaker 1: modeling tubulens, the little bricks of microtubules, and came to
Speaker 1: the conclusion that you could store something like ten to
Speaker 1: the sixteenth bits of information in a single neuron using microtubules.
Speaker 1: And this was essentially the number that people were talking
Speaker 1: about for the storage capacity of the entire brain.
Speaker 2: Now, his colleagues were skeptical. They didn't want to hear it.
Speaker 2: Tell me to get lost.
Speaker 4: So except then one day, fateful day, this guy said
Speaker 4: to me, Okay, why is that asked? Let's say you're right,
Speaker 4: how would that explain consciousness? How would that explain love, feelings, pinkness, joy,
Speaker 4: blah blah blah. Essentially the hard problem five years before
Speaker 4: Dave announces. But you knew the problem, I said, WHOA,
Speaker 4: you're right, I have no idea. I was a reductionist nudgeon,
Speaker 4: and I was ashamed of myself.
Speaker 1: Actually, so we actually just want to say, I want
Speaker 1: to make sure everyone's following. So the hard problem of
Speaker 1: consciousness is you've got all this physical stuff happening in
Speaker 1: the brain, why does it feel like anything.
Speaker 2: Why do we have experience? That's the hard problem.
Speaker 1: Okay, Right, so you were looking at these microtubules which
Speaker 1: are made up of these tubulin peanut shaped proteins, and
Speaker 1: you're saying, hey, there's something really interesting here. But it
Speaker 1: didn't solve the hard problem.
Speaker 2: Right.
Speaker 4: So I was just saying, more computation, more information processing.
Speaker 4: So and the guy had a beautiful point, and I
Speaker 4: was kind of stunned. And he said, you should read
Speaker 4: this book by Roger Penrose called The Emperor's New Mind.
Speaker 4: I said, I've kind of heard of that guy. So
Speaker 4: I bought the book. I read it, and I was
Speaker 4: kind of blown away. I mean, it's an amazing book.
Speaker 4: The first half is about why consciousness is not a computation.
Speaker 4: He used something called Girdle's theorem from mathematics, which said
Speaker 4: a mathematical theorem cannot prove itself. You need somebody or
Speaker 4: something outside the system, like a mathematician, to say yeah,
Speaker 4: it's true or not. And he extrapolated and said it's
Speaker 4: like understanding, you know, to understand something, you need to
Speaker 4: be outside the system, very similar to John Searle's Chinese
Speaker 4: room argument. You know, the guy has the Chinese symbols.
Speaker 4: He looks them up and he translates, but he doesn't
Speaker 4: understand Chinese.
Speaker 2: So that's the sense just doing computer operations, right.
Speaker 4: And so that was the difference and Roger. So the
Speaker 4: second half of the book was Roger's solution, which had
Speaker 4: something to do with quantum physics and collapse of the
Speaker 4: wave function, the measurement problem in quantum Kinnis, which was
Speaker 4: a whole other mystery. But he said, the solution to
Speaker 4: that mystery is the same as is for consciousness. But
Speaker 4: Roger didn't have a biological structure that could be at
Speaker 4: the quantum level. And he said in the book, I
Speaker 4: don't know what it is. Maybe somebody does. So I
Speaker 4: read the book and I said, holy crap, he needs microtubules.
Speaker 4: I've been studying for twenty years.
Speaker 2: So Stuart wrote Roger a letter.
Speaker 3: But then Stuart Haerrov read my book and wrote back
Speaker 3: to me said, evidently you don't know about microtubules. He
Speaker 3: was absolutely right. If I'd known about microtubules, that's it.
Speaker 3: Here's a much better bet. For various reasons, they are
Speaker 3: probably because they're too See. It seemed to me that
Speaker 3: there is a much better chance you could isolate quantum effection.
Speaker 1: So they met up in England and Roger was very
Speaker 1: taken by the geometry of these microtubules. Tell us what
Speaker 1: is special about microtubules?
Speaker 3: Well, what's special about microtubules? There's several things which excited
Speaker 3: me about them. Some of them are sort of peripheral,
Speaker 3: but not so stupid. Maybe they are two to begin with,
Speaker 3: and that struck me as much better chance preserve coherence.
Speaker 3: You see, if you're going to have the collapse of
Speaker 3: the wave function, you've got to have a well defined
Speaker 3: wave function which isn't collapsed by the environment. You see,
Speaker 3: normally what happens is that the environment collapses that and
Speaker 3: that's no use to anybody this standard, As I say,
Speaker 3: Ladi von Neumann arguments, do you say that the collapse
Speaker 3: occurs because the environment gets involved? You have no control
Speaker 3: over the environment and so therefore it behaves randomly in someone.
Speaker 1: In other words, he's pointing out that the environment normally
Speaker 1: collapses the wave function very rapidly. But he appreciated the
Speaker 1: possibility that microtubules might serve as a wave guide, which
Speaker 1: means there's something about the particular structure of these long,
Speaker 1: thin straws that keeps the wave function uncollapsed for a
Speaker 1: longer time. A.
Speaker 3: Their tubes. B. They have a very symmetrical structure of
Speaker 3: the tubulence, and they combined together in this particular structure,
Speaker 3: which I found fascinating because it has, for example, symmetries
Speaker 3: in three different directions. One is along the axis, one
Speaker 3: is twisting one way, and the other is twisting the
Speaker 3: other way. So it just struck me what's funny about
Speaker 3: these microtubules. You have these microtubules which have one direction
Speaker 3: along the tube, and that seems mirror what you get
Speaker 3: in these tubes, that they become super conductive. So this
Speaker 3: suggested to me that maybe there is some quantum super
Speaker 3: conductive effect along the tubes, which is quite different from
Speaker 3: nerve transmission, which is absolutely a quantum effect.
Speaker 2: So the idea is you've.
Speaker 1: Got these microtubules which are inside all the neurons and
Speaker 1: these conservative waves guides. One of the criticisms that people
Speaker 1: have had about quantum mechanics in the brain is they say, look,
Speaker 1: it's too warm and noisy in there.
Speaker 2: What do you say in response to that.
Speaker 3: Well, that's a general comment you might expect that applies
Speaker 3: if it hasn't gone some very very specific structure, and
Speaker 3: the market tube was I thought, much better chance of
Speaker 3: that sort of thing. I mean, they're doing a pretty trick,
Speaker 3: pretty good trick, you see. If they actually are preserving
Speaker 3: coherence along the tubes, this is a neat trick that
Speaker 3: nature allegedly. I'm saying that to say that's my viewpoint,
Speaker 3: must actually have succeeded and making this trick. I'm The
Speaker 3: general comment is warm and messy, sure as a whole,
Speaker 3: but there are structures when this warm and messy thing.
Speaker 3: You don't need the whole thing to be structured in
Speaker 3: this way. You just need certain elements in this complicated structure,
Speaker 3: which as a whole may be warm and messy and
Speaker 3: all sorts of things. But there are things, the claim goes,
Speaker 3: which can preserve quantum coherence. And the idea is that
Speaker 3: maybe microtubules do. And when I heard about them from Stuart,
Speaker 3: I thought that was a much better case than anything
Speaker 3: I'd seen before.
Speaker 1: So hammer Off and Penrose got interested in this possible
Speaker 1: relationship between microtubules and quantum mechanics. But what does any
Speaker 1: of this have to do with consciousness? Back to my
Speaker 1: interview with Stewart in quantum Mechanics, things can be in
Speaker 1: different positions. The wave function predicts how that moves along nicely.
Speaker 1: But what happened as you get a collapse of the
Speaker 1: wave function, which tells you, hey, let's say the particle
Speaker 1: is over here, over here, and the idea was the
Speaker 1: collapse that moment when that happened, there's some consciousness in
Speaker 1: the universe.
Speaker 2: That's what he predicted. That's what he predicted.
Speaker 4: People are saying conscious comes to the outside and causes
Speaker 4: the collapse, but that puts consciousness outside science. It's a
Speaker 4: dualist position. And actually one of the charmers takes now,
Speaker 4: but it goes back to Vignaer and von Norman and
Speaker 4: Boord early part of the twentieth century and then and
Speaker 4: others had didn't want collapse to deal with it or consciousness,
Speaker 4: so they just said many worlds, it's easier to think
Speaker 4: about the consciousness. And Roger came up with a solution, says,
Speaker 4: the separations are unstable and will collapse and give consciousness
Speaker 4: and due to an objective threshold given by the indeterminacy
Speaker 4: principle one equation.
Speaker 1: Okay, and so who is experiencing the consciousness or the
Speaker 1: quality of when there's a collapse of the wave function.
Speaker 4: The collapse itself is who's is who, what is experiencing.
Speaker 4: I don't think it is controversial. I don't think there
Speaker 4: needs to be a separate self. Other people disagree with
Speaker 4: me on that, but I think if you have a
Speaker 4: sequence of experiences and memory, you have a self. You
Speaker 4: know who you are, you know when you wake up
Speaker 4: the morning, the same person moment to moment. So I
Speaker 4: don't think there's any separate entity as the self. I
Speaker 4: think just I think you have a sequence of experiences,
Speaker 4: complex experiences. I should go back and say when, when
Speaker 4: when the objective reduction that's his name for objector threshold,
Speaker 4: quantum state reduction, objector reduction, or or when that occurs
Speaker 4: in the environment and in the chair anywhere other than
Speaker 4: in particular arrangements. It's the experience is random, fleeting, disconnected.
Speaker 4: It comes and it goes. It's apparently happening all around us.
Speaker 4: We never noticed. It's like and that was proto conscious,
Speaker 4: so that they call that proto conscious, and I liken
Speaker 4: that too. If you go to the symphony and the
Speaker 4: musicians are tuning their instruments before and you hear all
Speaker 4: this to me noise to train the musicians different. But
Speaker 4: to me, it's like uh uh, you know, it's it's
Speaker 4: noise and then they start to play and it's Broms
Speaker 4: or Beethoven or whatever, and uh. And that's what the
Speaker 4: brain does, that's what the micro tubuas do. Orchestrates the
Speaker 4: objective reduction. Hence the theory is orchestrated objective reduction.
Speaker 1: Okay, so when there's the collapse of the wave function,
Speaker 1: there's a little bit of consciousness. But if you build
Speaker 1: a device in the right way where you've got all
Speaker 1: these microtubules that are guiding this, that are orchestrating this
Speaker 1: whole thing, then you get something like our contry and
Speaker 1: they have to they.
Speaker 2: Have to be entangled.
Speaker 4: So the superposition states become part of one one much
Speaker 4: more complicated state. So when you when we're collapsing our
Speaker 4: conscious moments, now there's a lot of richness in it.
Speaker 4: I see you, you see me, I see this stuff
Speaker 4: behind you, et cetera, et cetera. And so and there's sound,
Speaker 4: there's different senses. It's all orchestrated. I would say integrated,
Speaker 4: but that's a different theory. It's more orchestrated.
Speaker 1: Now, what would that get us to have entanglement across
Speaker 1: different regions of the brain. Well, one example Stewart turns
Speaker 1: to is what's called the binding problem. The binding problem
Speaker 1: is a long recognized mystery that different regions of the
Speaker 1: brain encode very different types of information like.
Speaker 2: Movement here, and colors here.
Speaker 1: And face recognition and sound and touch, and yet you
Speaker 1: enjoy a totally unified experience. For example, let's hey watching
Speaker 1: a basketball player race down the court dribbling the ball.
Speaker 1: Different areas of your brain are processing the shape and
Speaker 1: the movement and the sound of the ball hitting the court,
Speaker 1: but you perceive the whole thing as one guy racing
Speaker 1: down the court. The colors and the motions and the
Speaker 1: sounds don't separate off from one another. So how are
Speaker 1: these distinct features processed in total different brain regions integrated
Speaker 1: into one seamless perception. This remains a central mystery in neuroscience.
Speaker 1: So how might their theory address.
Speaker 4: That spatial temporal binding? You know, you see something moving
Speaker 4: through the sky and its shape, color, motion, meaning or
Speaker 4: processed at different places at different times in the visual
Speaker 4: cortex and cortex in general. And yet we see one object,
Speaker 4: we see a yellow kite fluttering instead of yellow kite
Speaker 4: fluttering move. We see one thing instantaneously, so it's it's
Speaker 4: integrated or orchestrated in time, and also in different regions
Speaker 4: of the brain. So I think the brain needs entanglement
Speaker 4: one way or the other.
Speaker 1: So, in other words, neuroscience traditionally just thinks about neurons,
Speaker 1: and those are in some sense quite slow.
Speaker 2: But maybe Hammers.
Speaker 1: Suggests there are much faster processes. They're binding things together.
Speaker 4: It's more like music. It's more like resonance harmonics, interference beats.
Speaker 4: In fact, to get from the very fast and very
Speaker 4: slow interference beat, it's probably what does it. So I
Speaker 4: think the brain is more a quantum orchestra than a computer.
Speaker 2: Got it.
Speaker 1: And so essentially all our technologies are just measuring what
Speaker 1: neurons are doing. Like you dunk electrode in and you
Speaker 1: see the spike head of the neuron.
Speaker 4: And so they're only listening to the base and percussion
Speaker 4: of the symphony. They're missing the flutes and the piccolos
Speaker 4: and everything else. And what makes you think this The
Speaker 4: other theories don't work. All the other theories are based
Speaker 4: on a neuron firing is a bit or a neuron
Speaker 4: is essentially a one or a zero. And if you
Speaker 4: look at a single cell organism like a paramesium, it
Speaker 4: swims around, It finds food, it finds the mate, it
Speaker 4: has sex, it can learn. If you suck it into
Speaker 4: a capillary tube, it gets out faster and faster each
Speaker 4: It's one cell, and it does all that with its microtubules,
Speaker 4: whether it's silly and it's internal microtubules. So if a
Speaker 4: paramesium can do that, and are you serious and thinking
Speaker 4: that a neuron is a one or a zero and
Speaker 4: that's it, it's an insult in neurons.
Speaker 1: So together, Penrose and Hammeroff worked on their idea of
Speaker 1: entanglement going on.
Speaker 2: Across the brain.
Speaker 1: And the hypothesis is that these deep tubes humming away
Speaker 1: deep inside the brain's machinery, these orchestrate when and what collapses.
Speaker 1: So they call this orchestrated objective reduction. Give me the
Speaker 1: idea of orchestrated objective reduction?
Speaker 2: What does that.
Speaker 1: Mean and how does that explain consciousness potentially?
Speaker 3: Okay, think of as I used to play ping pong
Speaker 3: when I was at school, for instance. You see, as
Speaker 3: I never achieved any great skill with this, but I
Speaker 3: can understand there's just a game where you have to
Speaker 3: act very quickly, and the way if I flick the
Speaker 3: ball into the right hand corner as opposed to the
Speaker 3: left hand corner, it's because I think by looking at
Speaker 3: my opponent that he's not expecting it for me to
Speaker 3: flick it into the left hand corner, and so I
Speaker 3: do that flick into that corner because I think from
Speaker 3: what I've just gained it's very small fraction of a second,
Speaker 3: much less than half a second. I estimated that this
Speaker 3: is a good thing to do, so I think that
Speaker 3: was a conscious choice. Now, what is the current view
Speaker 3: amongst I believe, and I get this from Stewart. The
Speaker 3: current view amongst neurophysiologists is that these actions are not conscious,
Speaker 3: they're much too quick. But Stewart's view and mine is
Speaker 3: it is conscious, but it can only occur because of
Speaker 3: the following mechanism. The argument would be that you could
Speaker 3: preserve quantum coherence at a big level that is sufficiently
Speaker 3: isolated from the outside world that in this layer you
Speaker 3: could preserve a lot of quantum coherence, so that this
Speaker 3: would mean that the action of flicking the ball this
Speaker 3: way rather than that way, and this choice is it
Speaker 3: made conscious consciously. The current view is there's no time,
Speaker 3: that the consciousness come about, much too late for this.
Speaker 3: But our view is no, there is time because the
Speaker 3: choice of which action to take can be a conscious one.
Speaker 3: The action taking involves a lot of nerve transmissions and
Speaker 3: making your this way rather than that way, and all
Speaker 3: these things. I think of a tennis player deciding to
Speaker 3: go cross court rather than the bat down the line,
Speaker 3: and that involves different muscle muscle actions. Now those different
Speaker 3: muscle actions can be in superposition, kept in superposition, so
Speaker 3: which one of them is truck It can be done
Speaker 3: very quickly and those then the actions take place and
Speaker 3: the person that's what has decided to be done. So
Speaker 3: although the conscious action to move all those particular muscles
Speaker 3: like this, and that's not conscious, what's consciousness. I'm going
Speaker 3: to flick the ball to the right rather to the left.
Speaker 3: And so that is a whole lot of different motions
Speaker 3: which are all together in superposition. So this is the
Speaker 3: idea that this collection of motions and that collection's motions
Speaker 3: and which ones are activated are all there together, and
Speaker 3: which one is activated is a conscious choice. And that
Speaker 3: conscious choice, as it is at a quantum level choice
Speaker 3: in these very specific cells that you get the coherent
Speaker 3: superposition of different actions. So it could be this it's
Speaker 3: under control all this one or this one, and they're
Speaker 3: all there in quantum superposiniess. So the choice you make
Speaker 3: as to which one is controlled is a quantum choice.
Speaker 1: And presumably when when the waveform collapses, that's when you
Speaker 1: become conscious of something.
Speaker 2: That's that's the idea. Yes, that's what it is.
Speaker 3: Consciousness is to do with the actual collapse.
Speaker 1: One intriguing thing is that this proposal seems to blur
Speaker 1: the line between physics and philosophy in an interesting way. So,
Speaker 1: if consciousness arises through quantum processes, does that suggest that
Speaker 1: consciousness is not just a feature of brains, but a
Speaker 1: more fundamental property of the universe.
Speaker 2: How do you see this?
Speaker 3: Yes, but you see, But it might be you've got
Speaker 3: to get it organized in a very subtle way in
Speaker 3: order to reveal. You see, the collapse part of it
Speaker 3: might be easy to reveal, but the way in which
Speaker 3: it's not quite random and quite random, probably in a
Speaker 3: very sophisticated way.
Speaker 1: Does this hypothesis have implications for free will?
Speaker 2: That's a very good question.
Speaker 3: You see, I'm even quite recently sort of changed my
Speaker 3: view on this question. I often thought it's a sort
Speaker 3: of meaningless question in a way. I mean, does it
Speaker 3: mean that a quantum effect is brought into play because
Speaker 3: quantum thing is not deterministic? And does the fact that
Speaker 3: it's not deterministic mean free will? Not normally because it's random?
Speaker 3: And if it's random, that's not free will. I mean
Speaker 3: you're just tossing a toy. It's not random because it's
Speaker 3: got to be doing something. I mean, randomness isn't beneficial.
Speaker 2: In a way.
Speaker 3: You see, you could make it random, but that's not
Speaker 3: the point free will. You could say that, you see,
Speaker 3: people often say that free will could be there if
Speaker 3: it's not deterministic, but it doesn't know you any good
Speaker 3: if it's just right. So the view I have is
Speaker 3: more or less this. It's not even money. It's a
Speaker 3: very recent view, I think. But the view is more this.
Speaker 3: There is something rtrachursal about it. What free will really
Speaker 3: means and what I'm arguing for here. It's not that
Speaker 3: you can do anything you like, and you can act
Speaker 3: randomly if you like. You're doing what you think is
Speaker 3: the right thing to do, so you have the free
Speaker 3: will to do what you think is the right thing
Speaker 3: to do, and it doesn't necessarily be righteousness center virtuous.
Speaker 3: It means, in your judgment, the correct thing to do.
Speaker 3: Whether it's correct, desper for or beneficial less or for
Speaker 3: the goodest, the whole, or whatever, that's not the point.
Speaker 3: The point is that you are doing it because you
Speaker 3: think it's the right thing to do. Now that means
Speaker 3: you're understanding it.
Speaker 1: What kind of experimental result would excite you most in
Speaker 1: the coming years.
Speaker 3: I think if you're looking at things plausible within current technology,
Speaker 3: maybe some convincing kind of quantum coherence within microtubules.
Speaker 2: I want to ask you about AI.
Speaker 1: We've seen such incredible progress in classical AI systems, but
Speaker 1: given your view that consciousness involves non computable processes, do
Speaker 1: you think that AI is conscious, could be conscious or
Speaker 1: is it just an impressive simulation.
Speaker 3: No, in one word, it's not conscious, and it's not
Speaker 3: going to be conscious by having more and more and
Speaker 3: more elements in your computers.
Speaker 1: So could a quantum computer in the future. Could a
Speaker 1: quantum computer be conscious if it were designed with the
Speaker 1: right architecture or is something else still missing?
Speaker 3: You have to be careful about what you mean by
Speaker 3: a quantum computer, because I don't think quantum computer in
Speaker 3: the sense that people use that term does actively role
Speaker 3: using the collapse of the wave function as part of
Speaker 3: the mechanism in quotes, because it's not really a mechanism.
Speaker 2: That's right, Yeah, okay, got it.
Speaker 1: So the kind of quantum computers that for example, Google
Speaker 1: is working on now, because presumably it doesn't involve the
Speaker 1: collapse of the wave function, you think it wouldn't be
Speaker 1: conscious as such.
Speaker 2: Yes, that's right, Okay, great.
Speaker 1: I asked Stuart the same question about whether contemporary AI
Speaker 1: could be conscious.
Speaker 4: Not with the kind of computers we am now, not
Speaker 4: with a silicon based And you know, our friend Dave Chalmer's,
Speaker 4: after decades of the heart problem, recently came out and said,
Speaker 4: well AI consciousness is inevitable and throwing the heart problem
Speaker 4: under the bus.
Speaker 2: Totally interesting, and then backing up and.
Speaker 4: When I questioned him about it, he said, well, what's
Speaker 4: the fundament there's no fundamental difference between silicon and carbon.
Speaker 2: I said, wrong answer today. First of all, it's not carbon.
Speaker 4: It's organic carbon, which means aromatic rings, which means quantum.
Speaker 4: So that and there's a huge difference between organic carbon
Speaker 4: and silicon. Silicon can't do that. So and this organic
Speaker 4: carbon aromatic hydrocarbons have been in the universe right from
Speaker 4: the start.
Speaker 2: So let's summarize.
Speaker 1: According to this idea from Penrose and hammer Off, the
Speaker 1: brain isn't just a network of firing neurons. It's also
Speaker 1: a kind of quantum computer. Inside every single brain cell
Speaker 1: is a whole world of microtubules, these tiny cylindrical structures
Speaker 1: that are so small they've traditionally been ignored. But maybe
Speaker 1: they suggest these structures are doing more than organizing the
Speaker 1: cell's interior. Maybe these microtubules are hosting quantum processes. Maybe
Speaker 1: they're sustaining delicate quantum states long enough to do something
Speaker 1: meaningful and entangling across cells, and that the collapse of
Speaker 1: these states might correspond to moments of conscious experience. Now,
Speaker 1: I just want to repeat one point. You might be thinking, Wait,
Speaker 1: doesn't quantum physics get washed out in warm, wet environments
Speaker 1: like the brain. That's a reasonable objection. In fact, it's
Speaker 1: one of the main reasons that many scientists have been
Speaker 1: skeptical of the orchestrated objective reduction theory. Quantum coherence usually
Speaker 1: does not last long in messy biological environments.
Speaker 2: It's fragile.
Speaker 1: But on the other hand, that skepticism has been challenged
Speaker 1: in recent years by findings in other parts of biology.
Speaker 1: Quantum effects have now been observed in photosynthesis, in bird navigation,
Speaker 1: in the sense of smell. Somehow, living systems might be
Speaker 1: more hospitable to quantum phenomenon than we thought. And if
Speaker 1: that's the case, then maybe, just maybe, the brain has
Speaker 1: found a way to leverage quantum effects, not just for computation,
Speaker 1: for consciousness itself. Now, Penrose and Hamros's theory and others
Speaker 1: like it remain highly speculative. Neuroscience continues to make great
Speaker 1: progress without invoking quantum mechanics artificial neural networks, which are
Speaker 1: entirely classical in their architecture. These have achieved unbelievable feats
Speaker 1: like the modern blossoming of AI. But so far as
Speaker 1: we know, artificial neural networks like CHATCHPT are not conscious,
Speaker 1: and so the idea here is that we need to
Speaker 1: think not just bigger, but perhaps also sub microscopically smaller.
Speaker 1: So we've just heard from two thinkers who aren't afraid
Speaker 1: to step beyond the comfortable borders of their fields. To
Speaker 1: probe around in areas that most scientists won't touch. What
Speaker 1: I find so compelling isn't the certainty of the theory.
Speaker 1: It's the audacity of the question. It's the willingness to say, look,
Speaker 1: perhaps our current tools aren't enough. Maybe consciousness isn't just
Speaker 1: a clever computation, but something much stranger. Maybe the deepest
Speaker 1: puzzles in neuroscience can't be solved without rethinking everything from
Speaker 1: the ground up. There's a long history of big leaps
Speaker 1: in science, beginning with questions that sounded naive or mystical.
Speaker 1: There was a time when most of the ideas we
Speaker 1: take for granted today were ridiculous. So I want to
Speaker 1: return to one last thought from Roger. What advice would
Speaker 1: you give to young scientists who are drawn to the big,
Speaker 1: risky questions about consciousness but are afraid to step too
Speaker 1: far outside conventional boundaries.
Speaker 3: To try and do the following. You will have some
Speaker 3: specialist view that you see in order to make progress,
Speaker 3: you have to dig deeply in a certain area and
Speaker 3: understand that area as well as you can and better
Speaker 3: than most other people. But you also, at the same
Speaker 3: time should keep a broad outlook of what's going on
Speaker 3: in the outside world and pick up maybe if you
Speaker 3: see something which might connect with what you're doing.
Speaker 1: There are plenty of critics of this idea who point
Speaker 1: out reasonably that there's not enough experimental evidence to take
Speaker 1: this idea with the requisite seriousness yet. But it's okay
Speaker 1: to explore the speculative as long as we keep one
Speaker 1: foot planted in the empirical. It's a key to making
Speaker 1: progress in science is balancing skepticism with curiosity and openness.
Speaker 1: All of us in neuroscience like to believe that we're
Speaker 1: close to cracking the puzzle of consciousness, but the fact
Speaker 1: is we're probably just at the foot of the mountain,
Speaker 1: and it's always possible, just like in any field, that
Speaker 1: we're not even asking the right questions.
Speaker 2: Yet.
Speaker 1: What if we've been looking at the hardware in an
Speaker 1: incomplete way and missing the best tricks of physics. The
Speaker 1: fact is that the central mystery of neuroscience, for which
Speaker 1: no one has a good answer, is the hard problem
Speaker 1: of consciousness. Why if we have an organ that goes
Speaker 1: around and collects information than a camera or a microphone,
Speaker 1: why does it feel like something, presumably in a way
Speaker 1: that your iPhone does not When it makes recording. Why
Speaker 1: do we have private, subjective experience of the world. Quantum
Speaker 1: mechanics may or may not provide the answer. Maybe we're
Speaker 1: all just shooting in the dark until we discover a
Speaker 1: new field and one hundred years from now called Schwanton mechanics.
Speaker 1: But whatever the case turns out to be, it seems
Speaker 1: likely to me that the neuroscience textbooks used by our
Speaker 1: great great grandchildren will have very different stories than we
Speaker 1: do today, and future centuries will look back on our
Speaker 1: scientific frameworks with the quaintness that we look back on
Speaker 1: ideas of flagiston or spontaneous generation, or that the Earth
Speaker 1: was at the center of the universe.
Speaker 2: But the only way we're going to.
Speaker 1: Get there is to keep digging deeper and asking, by
Speaker 1: not falling for the assumption that we've got it all
Speaker 1: figured out with our stand in textbook models, but by
Speaker 1: continuing to propose and put to the test brave new hypotheses.
Speaker 1: Go to Eagleman dot com slash podcast for more information
Speaker 1: and to find further reading.
Speaker 2: Check out my newsletter on substack and be a part
Speaker 2: of the online chats there.
Speaker 1: You can watch the videos of Inner Cosmos on YouTube,
Speaker 1: where you can leave.
Speaker 2: Comments until next time.
Speaker 1: I'm David Eagleman and this is inner Cosmos.