Why Current AI Cannot Be Conscious | Dr. Christof Koch

One in four patients currently being considered for life support withdrawal may actually be fully conscious, they just can't signal it. That single finding, from a landmark New England Journal of Medicine study, is the practical stakes behind one of the most philosophically rich conversations in this series. Dr. Christof Koch - former president of the Allen Institute for Brain Science, 25-year collaborator with Nobel laureate Francis Crick, and founder of the startup Intrinsic Powers - joins Craig Smith to discuss why the hard problem of consciousness remains unsolved, what integrated information theory predicts about which systems can and cannot be conscious, and why his own mystical experience three years ago shifted his view from physicalism toward idealism. The conversation is grounded throughout in empirical work: Koch explains how Intrinsic Powers uses brain complexity measurements - sending magnetic pulses into the brain and measuring the complexity of the electrical response - to detect consciousness in behaviorally unresponsive patients, providing clinical teams and families with one critical bit of information at the most consequential moment of their lives. The episode closes with Koch's most personal revelation: a mystical experience in which the boundary between self and world dissolved and he felt direct acquaintance with the idea that everything is ultimately mental, an experience he is careful to distinguish from supernatural claims, but which shifted his metaphysical view in ways he describes with unusual candor for a scientist of his standing. Subscribe to Eye on A. I. for weekly conversations with the people building and deploying the future of AI.

• 0:00Speaker 00

  I experimented with psychedelics when I was young, I'm 70 now, and it very much informed my view of the world, or view of reality, or view of civilizations, structures, and all of that. But could it simply be the suppression of the self and the resulting experience?

• 0:19Speaker 01

  It's just your brain. In the case of psychedelics, it's your brain on drugs, okay? So all it teaches us that brains can reach extraordinary states.

• 0:27Speaker 00

  If you have someone in a vegetative state, who's been declared in a vegetative state, and you use this device and detect that there is complex neural activity that suggests consciousness. If you pull the life support on that picture, do you see some spike in complexity that might correlate to their recognition of what's happening?

• 0:52Speaker 01

  We now know that a quarter of these patients, one out of four of these patients, is actually conscious. They're there, they're present, they're just not able to signal it. If you lose the cerebellum, it's not good for you. Cerebellum is there to do sensory-motor coordination, among others. But people never complain, that a lesion in the cerebellum never complain about loss of consciousness. It doesn't seem to relate to consciousness, because it's not very well-integrated. Everything is mental, everything is phenomenal, everything ultimately is consciousness.

• 1:22Speaker 01

  I'm a physicist, I got my PhD in theoretical physics, but I've studied for the past 40 years brains, I'm a neuroscientist. I was for 25 years a professor at Caltech, California Institute of Technology, where I had a lab studying the biophysics of the brain, but also cognitive neuroscience and the way people see and experience. And as you mentioned, I worked for 14 years with Francis Crick, the Nobel Prize-winning molecular biologist, who discovered, you know, co-discovered the double helical nature of the DNA, and then shifted, as he went from England to La Jolla in Southern California, shifted his interest from molecular biology to consciousness.

• 2:07Speaker 01

  I left Caltech 15 years ago to join the Paul Allen Institute. Paul Allen, the co-founder of Microsoft for Brain Science here in Seattle. I was chief scientist and then its president. I've stepped down from executive duties, I'm still employed at the Allen Institute, and I also run a foundation called the Tiny Blue Dot Foundation, based in Santa Monica, to study perception, what we call the perception box, and its therapeutic benefits for all people. So that's briefly my biography. Yeah, so a scientist, you are a physicalist.

• 2:50Speaker 01

  Well, it used to be known as materialist, until early the 20th century, an ancient metaphysical position. Democritus is one of the first pre-Socratic Greek thinker. He famously said, "All there is is atoms and the void." And today, this is called physicalism, that essentially asserts everything is physical. Put differently, everything is quantities, is numbers. Now, the devil's in the details. And what used to be called physical or material, if we go back to materialism, was very simple to understand on a classical physics.

• 3:32Speaker 01

  So on a classical physics, you take an object like this, you know, this is one of these things to, you know, train your muscles, and it has position and velocity and momentum. And anything that has a position and momentum, classical physics, on a classical physics, you can completely determine its course, its path, and its future. And if you knew the location and momentum of every particle in the universe, everything would be an open book. In principle, if you had a big enough computer, you can compute everything that happened in the past and everything that you expect to happen in the future. Now, of course, we know the world is not described by classical physics,

• 4:14Speaker 01

  because one of the two revolutionary theories of the 20th century is quantum mechanics. So now we have this underlying thing that cannot be directly observed, the wave function. And the wave function is interpreted to be, in a probabilistic way. And then, of course, to get from wave function to real things happening, you have so-called the collapse of the wave function, and you've got these weird paradoxes that are very paradoxical for us to understand, because we don't observe them at our level. Things like can be simultaneously in two states. So Schrödinger's cat experiment, where the cat is simultaneously dead and alive.

• 4:56Speaker 01

  And our intuition tells us, well, look, either you're dead or the cat's alive. It can be in both states. But under certain conditions, this is exactly what nature permits. More recently, although this goes back to another, to Erwin Schrödinger, he had predicted this property of quantum system called entanglement. What we mean, so if you have a system, a single quantum mechanical system, and this relates to consciousness already, a single quantum mechanical system, you can separate them over vast distances, but they're still one system. What do I mean by that? So let's say, you take a pair of entangled particles, one is spin up and the other is spin down.

• 5:41Speaker 01

  So because they're in a superposition, the system could be like this, is in a superposition of this state and this state. Okay, and you don't know which. And then you move them very far apart. Let's say a light here, such that you turn on a flashlight at one location, that light wouldn't get to the other location until a year later. So they're really, really, really far apart. Yet, what we know now to be true and purely beyond a doubt, that as soon as something interacts with that one system, let's say the system on my left, and knows that the spin is up, instantaneously, independent of the distance, the state of the other one is down.

• 6:24Speaker 01

  Now, Einstein famously called this, 1935, spooky action at a distance. Because what mechanism allows the information, this state, to propagate across vast distances? And now there even weird thing called quantum contextuality that people are testing. We know this to be true, because now we have an industry called quantum computer industry that exploits some of these weird superposition. But what that means, that we don't know anymore what it means exactly to be physical. And some people in the foundation of physics, in fact, are now arguing that there may not be absolute facts.

• 7:04Speaker 01

  In the sense that, I'm a biker, I don't own a car, I have several bikes. My bike, at rest, has a particular mass. It weighs like, I don't know, 25 kilo or whatever. But quantum mechanics would say, until and unless something interacts with that bicycle, it doesn't have, probably speaking, a mass. It's not that you don't know the mass, that's just an epistemic limitation. We, you know, I don't know more things in the world. No, it's that it simply doesn't make sense to talk about it like it has a specific mass, until, depending on the reading, either something observes it or otherwise interacts with it.

• 7:47Speaker 01

  Now, again, this is not my grandfather's materialism anymore. So that's been one persistent challenge. And in fact, some physicists in foundational physics are now bringing in consciousness. They might, they are beginning to argue that consciousness, in a sense, has to be built into, at the rock bottom, the rock bottom description of our reality. So that's the markation line between physicalist and non-physicalist is very, very difficult to define. And so people say, "Well, it's a future physics." Well, okay, but the future physics, you know, that's like waiting for, you know, waiting for the rapture. Yeah, maybe in future we'll have a physics, and maybe that includes consciousness, all I know.

• 8:32Speaker 01

  So it's difficult to pin down physicalism. The other challenge with physicalism has always been, what the philosopher David Chalmers calls a hard problem, to explain why is it that three pounds of brain matter like this? And in principle, it's just like another piece of matter like this. Okay, this is hard matter, or semi-hard matter. This is, you know, soft matter, squishy matter. But in principle, it constituted out of atoms and molecules and electrons and all of that, interacting by the laws of quantum mechanics. Nothing special here. Yet, this thing can love and hate. Well, where does that come from? And even if you track it down, even if you carry out the program that Francis Crick and I initiated in the early 1990s,

• 9:17Speaker 01

  of identifying for any one experience, what are the exact neurons, in what state do they have to be, do they have to involve microtubules or superposition, or whatever you want to come up with? Why is it that this particular mechanism, you know, it's a mechanism like any other mechanism, like a fancy Swiss clock, why is it that this mechanism can feel pain, or feel pleasure, or feel boredom? I mean, it's a complete non-secular, right? On the one hand, you have the laws of physics. On the other hand, you have experiences, pain, pleasure, boredom, anger. You know they're linked, you know, just a single hit on the head will tell you, yeah, if the brain is, if you hurt the brain, you're gonna, you know, you're gonna seriously interfere with consciousness.

• 10:02Speaker 01

  But why should they be linked? There's nothing in the laws of science that tells us matter can love and hate. So that's, those are the two, the two challenges. And I mean, they've been around for several decades now.

• 10:17Speaker 00

  The neural correlates, exactly what was lighting up at the time that you were feeling or experiencing certain phenomena? And at what point did you decide that that wasn't going to be enough? I mean, I guess you knew that wasn't going to be enough, but you, you thought it was useful in the absence of some other empirical experiment that you...

• 10:43Speaker 01

  Well, A, if, assuming we had the, and of course, I lost a famous bet against David Chalmers.

• 10:49Speaker 00

  Yeah.

• 10:50Speaker 01

  Because we had not discovered them after 25 years, but he agrees with me, they will be discovered. This isn't discovering the footprints of consciousness in the brain. It's another way to think about them. That, that is a perfectly feasible project, and that will be immensely useful. Because once I know what the footprints are, I can look for them. For instance, there are many patients that are behavioral unresponsive. They used to be called vegetative state. We know now, we now know that 25% of these people are actually conscious, called covert conscious. They're fully conscious, or they may be fully conscious, we simply don't know, but we can't communicate, they can't communicate that to the outside. So they're like a stranded astronaut, okay? Well, if I have the NCC, I can just look, are they present in this patient?

• 11:35Speaker 01

  I can decide, for example, most people, most experts who concern themselves would assume that a third trimester fetus probably is conscious. Well, if I have the NCC, I can say, well, are they there? Or when do they occur? Are they present already in the second trimester? Or maybe only in the third trimester? What about here? Are the dog, Bernice's mountain dog, what about dogs? You know, and I can, so this is an empirical program, tracking the footprints of consciousness. There will be immensely practical importance to determine consciousness, to measure it, to maybe quantify it in, in normal people, in people with various diseases, disorders,

• 12:18Speaker 01

  psychiatric disorders, animals, et cetera. So it's useful, but of course, it does not explain why this particular, these particular thing in this configuration gives rise to red and slightly different to orange, or to an orgasm, or to toothache, right? So there are two ways to look at that. So one for the longest, you have to start rather, so most people who think about consciousness and make theories of consciousness, they take the brain and try to squeeze the juice of consciousness out of it. You know, they're trying to turn the waters of the brain into the wine of consciousness, to adopt a biblical metaphor.

• 13:01Speaker 01

  And they say, well, it has to be this thing. It has to be a global workspace, or broadcast of information, or leia five neurons, or NMDA receptors, or microtubule likes to hammer off, you know, or whatever. Well, again, why this and not that? Why microtubule, not other, some, some other cellular organism? You know, ultimately, it's very difficult to go beyond that question. So there's one theory that's unique, really, that's called integrated information theory.

• 13:34Speaker 00

  Yeah.

• 13:35Speaker 01

  That takes a different tack. It's a consciousness first account. So it really starts where Rene Descartes started. The, the only thing I'm absolutely certain of is that I'm conscious. Because even in doubting it, I reassert it. And consciousness furthermore, is the only way I encounter the world. If I'm a scientist, I still depend on, I have to read papers or books, that's visual consciousness. I have to look at a, you know, an oscilloscope, again, I interact, I have to listen to a Geiger counter, that's auditory consciousness. So the only way I interact with the world, including my own body, is through my conscious experience.

• 14:17Speaker 01

  So if you think about it, the only thing I have direct acquaintance with, I have direct knowledge of, is conscious experience. And so any theory has to start with, with, any theory of consciousness, which is different from a theory of the neural correlates, a physical substrate of consciousness, any theory of consciousness has to start with consciousness. And, and then sort of go from there to say, well, which system is conscious and what are they conscious of? And, and this theory, integrated information theory, the main architect of that theory is an Italian-born American psychiatrist and neuroscientist, Giulio Tononi at the University of Wisconsin-Madison, is a, is a theory that does that.

• 15:02Speaker 01

  Now, it's a scientific theory, it may well be wrong.

• 15:06Speaker 00

  Yeah. Well, let me ask, first of all, I'm fascinated by, you have a startup, right? That's, that's working on an instrument or instruments that would be able to detect consciousness in, in people who are otherwise considered brain-dead. How, how far along have you gone in that? Have you abandoned that, or?

• 15:33Speaker 01

  Oh, no, no, no, no. So as I said, it's just independent what you believe about the metaphysics of consciousness. There's no question that, that we have now tools. So this was developed over the last 20 years, techniques to query the brain, essentially you do it, you hit the brain using magnetic pulses, and then you're, you're sounding, you're, you're listening to the echoes using EEG, electrical brainwaves, right? So you send in a pulse of energy, you essentially, you know, it's like taking a bell and hitting it with a hammer and then listening to it. And a conscious brain, whether that person is awake, like you or I, or in a, in a REM

• 16:16Speaker 01

  sleep where the person is experiencing, or on a high-dose psychedelic where they may be immobile but highly conscious, the complexity of this brainwave, so you can compute the how complex it is, called Lempel's Ziff's complexity. And if, in conscious people, it's always above a threshold. In unconscious people, whether they're regular people, regular folk, but they're anesthetized, or they're truly in a very deep coma where it's unambiguous that there, that there is no activity, the brain complexity is very low. In the simplest case, your EEG is flatlined. I mean, that's extreme case of very low complexity. And so we've developed this tool now, and started this company that you mentioned, called

• 17:01Speaker 01

  Intrinsic Powers. We were working with people at MGH, at Harvard, and in, in, in Madison, and in, in Columbia, trying to put this into the workflow. Because what happens today is if you or I have a car accident, or hemorrhage, or cardiac arrest, and you're alive, you know, someone calls 9/11, you get into the ICU, you're on life support now, on ventilator, you might be there, you know, unresponsive, eyes open. So these people were called vegetative states, but as I said, are now called behavioral unresponsive. And if you remain in this state for three, or four, or five days, then the, the clinical

• 17:46Speaker 01

  team will initiate discussion with the family and says, is this what they would have wanted? And here, in the developed world, between 70 and 90% of the time, family and doctors decide no, and they pull support. But we now know that a quarter of these patients, it was a very large paper last year published in the New England Journal of Medicine, roughly quarter percent, depending on the demographics and all of that, one out of four of these patients is actually conscious. They're there, they're present. They're just not able to signal it. And so we want to know that, because then I can give, this device can give the clinical team and the family one additional bit, in fact, literally, it's one bit.

• 18:30Speaker 01

  Are they there, or are they not there? And that can then help further inform, you know, what the doctor and, and what the family wants to do with, with that information. So that's a, so I like it a lot, because while A, we help people, and B, it demonstrates that this very airy, ephemeral topic of consciousness, you know, it's been around with us for the last 3,000 years, seems very airy-fairy, right? But this, if you're ever called upon this, to make this, this call for a loved one, right? This is the most consequential decision you can make. It's very existential. Are they there, or are they not there? And should we pull, then, you know, should we pull the plug or not?

• 19:11Speaker 01

  And so this is where the, this, this abstract mind-body problem hits the, you know, the rubber hits the road.

• 19:18Speaker 00

  Yeah. And let me just, I don't want to get lost on that, but have, how far have these experiments gone? If you have someone in a vegetative state, who's been declared in a vegetative state, and you use this device and detect that, that there is complex neural activity that suggests consciousness, if you pull the life support on that patient, do you see some spike in complexity that might correlate to their recognition of what's happening?

• 20:00Speaker 00

  Or, or do you see any, any change in that complexity?

• 20:04Speaker 01

  No, because, I mean, the, the technique is, so it takes an hour, an hour and a half to establish. And then, of course, you know, you'll have to make this, you make this information available to the doctors, and ultimately to the, to the team. And then it takes, you know, a lot of back and forth, and it's, it's complicated, Craig, because... It's a very complicated question and we cannot help. So there are three, when you get that call, there are three things you want to know. Are they alive first? Are they there? And then lastly, are they going to recover? And you know, right now, we can't, we can't say that very well, whether or not.

• 20:49Speaker 01

  The fact that they're conscious is encouraging, even though they can, they may not be able to respond. Right? So it's, it's a very difficult decision to make. Do you think, I mean, imagine yourself, if you're, if you're in this situation, unable to communicate and it's unclear, depends of course on your age. If you're 20, it's much better than if you're, you know, 60 or 70. What would you like? Do you want to be forever in this, in this state where you can communicate? But you're conscious? And then, you know, now your brother or your sibling, or I mean, or your parent or your child has to make this decision.

• 21:31Speaker 01

  So it's a very complicated decision environment. And because at this point, we can't tell you, yes, he's there and 95% chance he's going to recover. I can tell you that.

• 21:42Speaker 00

  Yeah. So was that work concurrent with your work with Crick?

• 21:51Speaker 01

  Yeah, so this was primarily done, so we, you know, it's why this work on patients sort of widely published then over the last 20 years by, by Giulio Tononi and then an Italian neuroscientist neurologist, Marcello Massimini. Yeah, and that went on at the same time as we, as we, you know, tried to push this empirical program in people and in, in lab animals to study the footprints of consciousness in, in the brain. A purely empirical program that by the way, does not depend on whether you're a physicalist or dualist or a panpsychist or, you know, an, an idealist. It's just, we just want to know the, the footprints of consciousness, how to study them,

• 22:36Speaker 01

  how to measure them, detect them, that we could then use for, for diagnostic and prognostic purposes.

• 22:43Speaker 00

  What point did you decide that, that you were never going to close that gap between correlation and causality and, and switch to a form of panpsychism? I mean, was it, I guess, was it a moment or is it, was it?

• 23:03Speaker 01

  Well, first of all, I don't, I've never abandoned the hope that we can get a theory that explains, I mean, a theory like integrated information theory. And you know, panpsychism, suddenly the way I think about it is in the sense that it may well be possible, A, that every member, every evolved organism, including simple, singles, simple cells, individual cells, a mobile, may feel like something, it's a bit, see, okay? And integrated information theory in principle, because the vast complexity of the 10,000s of different proteins present even in a single cell is such, no computers ever managed to simulate that.

• 23:47Speaker 01

  But of all this vast complexity, mehrere, some very, very simple proto-feeling of being alive versus not being alive. That's entirely possible. I don't know how to empirically test it right now, but it's, it's entirely, it's entirely possible. What happened to me is slightly different. I had two extraordinary experiences that I described in my last book, Then I Am Myself, The World. One of which was sort of a near-death experience in the first week of the, of the pandemic, where Christoph was gone, the world was gone, everything was gone, except this light,

• 24:28Speaker 01

  this very bright light, some people describe it as a tunnel, and a feeling of, of terror and ecstasy, just those three things, terror, ecstasy, a bright light. There was no space, all of space had convulsed itself into this single, this single point, this singularity. There was no time, passage of time, that's always with us, collapsed, that moment, this experience didn't last too long or too short, it simply was. It was probably under 10 minutes by the clock. And there was no self, there was no Christoph, there was nothing there, you know, the usual distinction between observer and observed, knower and knowing, apprehender and apprehended. All of that was gone.

• 25:09Speaker 01

  And so it, it's what some Buddhists often call a non-dual experience.

• 25:15Speaker 00

  Yep.

• 25:16Speaker 01

  It wasn't particularly pleasant. I mean, as I said, it was terror and ecstasy.

• 25:21Speaker 00

  Yeah, but not, not, it wasn't the result of a psychedelic experience.

• 25:26Speaker 01

  It was something I, yeah, I prefer not to, to talk about it.

• 25:31Speaker 00

  Sure, yeah.

• 25:33Speaker 01

  But what, what it taught me is two things, that A, the sense of self, you know, we all have a sense of self, explicit or implicit. Some people have it weaker, they constantly belittle themselves, you know, they, they constantly think, oh my God, everyone hates me. And other people like our president have a, let's just call it a highly exaggerated sense of, of self. And it's always, we all live in this gravitational field of planet ego. It's always about me, me, me, explicitly, implicitly. But then, just like an astronaut on a special condition can become weightless and floating out of space, so under certain conditions, including psychedelics of course, you can totally lose that self.

• 26:17Speaker 01

  And what you realize then, that self-consciousness is just a subset of all possible experiences. The fact that I know I'm me, I know what I had for breakfast, I know I'm going to die one day, all of that is, is, is consciousness, but you can also, if you don't have that, like in that state, whatever remains is clearly highly conscious. And then it took away the, and the fear of death, you know, the, which is not uncommon. But then I had a second experience, but it didn't change fundamentally my metaphysics, the way I think about the world.

• 26:53Speaker 01

  That happened several years later, three years ago, when I had a mystical experience, where again, you lose a sense of self, you lose where you are and what you are, and you feel, I mean, it's very strange to put it in words, you feel you become one with everything, you merge with the universe. And, and I mean, the title of this book, Then I Am Myself, The World, comes from this, it's a translation from the German, selbst dann bin ich die Welt, which is what Tristan in Isolde, in Richard Wagner, in a pornous opera, sing, when they, they have this mystical

• 27:37Speaker 01

  experience where they become one, the two, the lovers become one, but they also become one with the universe. So they, that's what they sing, then I, under the most rapturous music composed in the Western canon, they become one, whatever remains become ones with everything. And that is, you know, profoundly transformative, because, you know, once I came out of it, I don't know how long it lasted, probably under an hour, is just, I mean, you now have direct acquaintance, I had direct acquaintance with what I felt was like, what, what is

• 28:19Speaker 01

  truly underlying everything is mental, that I realized, oh my God, everything is mental, everything is phenomenal, everything ultimately is consciousness. And this material universe in which we exist ultimately is a manifestation of something mental. So this is known as idealism, right? The belief that, you know, you know, most of Western mind-body metaphysics revolves around these two poles, the physical and the mental. And, you know, since the Greeks, most people say, well, the only pole that really exists, it's the physical, and everything else has to somehow emerge out of that in ways we don't understand. Or some people say, no, it's both. So that's your classical dualism. Most people are probably in this country, probably dualist, right?

• 29:03Speaker 01

  There's clearly the brain and, and matter and all of that, but then there is my soul, you know, and that's separate. And then of course, and then there are idealists, well, then there are also panpsychists, like, like Joffrey interviewed, and then there are also idealists, like Arthur Schopenhauer, probably the best-known 18th century, early 19th century German philosopher, and then modern idealists like Bernardo Castro, who says what ultimately exists is mental, the mental follows laws, it's not supernatural, so it doesn't imply existence of a God or God or hierarchies of God, any, anything like that. It is, finally, what exists, what truly exists, is something, it may be very primitive,

• 29:46Speaker 01

  it may be evolving under some sort of instinctual law or something, and that gives rise itself to, and to the material. And that's, to me, that's exactly what it felt like when I had this experience.

• 30:03Speaker 00

  Yeah. And, and the, I mean, I, not to get into why I'm interested in this, but you know, I was, I experimented with psychedelics when I was young, I'm 70 now, and it, it very much informed my view of the world or view of reality or view of.

• 30:32Speaker 00

  You know, the civilizations, structures and all of that.

• 30:37Speaker 01

  How is that?

• 30:39Speaker 00

  What's that?

• 30:40Speaker 01

  I mean, how is that? In what way?

• 30:43Speaker 00

  Well, just in the way that you're describing, the breakdown of a sense of self and and understanding.

• 30:53Speaker 00

  Not a logical understanding, but the feeling that everything in the universe is all one thing. And so you're all made of the same stuff.

• 31:07Speaker 01

  Yes.

• 31:09Speaker 00

  And so what interests me about reading about your research, you identify in the quick work, or maybe it happened after the quick work, the areas of the brain responsible for the sense of self, for the experience of the self. And could it be that psychedelics in that self organizes perception in a way that you can operate in the world, manipulate the world? But if you remove that sense of self, which you have a physical correlate, then you're without that structure and that gives you the feeling of oneness.

• 31:54Speaker 00

  But could it simply be the suppression of the self and the resulting experience? Yeah, rather than, you know, go ahead.

• 32:07Speaker 01

  Yes. So physicalists would say, okay, great, great that you had this experience. Congratulations. But it's ultimately it's just your brain. In the case of psychedelics, yeah, so it's your brain on drugs. Okay, so all it teaches us that brains can reach extraordinary states. Now, if we just stay with that for a moment, what is still extraordinary are the fact that many of these experiences can be very transformative and almost always in a positive way. You know, we know this going back from psychedelics, going back to the research at John Hopkins, where people that have stage four cancer, that, you know, where medicine is given up, we can't really do anything anymore, they're terrified of dying.

• 32:50Speaker 01

  They get a high dose psychedelics and then they totally transform themselves. It doesn't cure them of the cancer, they will still die, but they're now willing, they have this completely transformed psyche. And we know, for instance, you know, there are hundreds of clinical trials, both here and abroad, doing psychedelics for, you know, treatment-resistant depression, major depressive disorder, generalizing, the PTSD, et cetera, et cetera. And we know through these questionnaires, MEQ 30, the mystical experience questionnaire, that the extent to which people have a mystical experience in these trials directly correlates to the extent that they derive therapeutic benefit.

• 33:31Speaker 01

  So in other words, it's quite likely when that patient who's depressed has a mystical experience, in this case induced by psychedelic, no matter the underlying metaphysics, will help them. And they will, they might fall out of, they might not even score as a depressed anymore. You know, not immediately afterwards, you know, this is not an instantaneous effect. But then you think about it, you know, you cannot help. I mean, you must probably still, Craig, think back about your experience, right? That you had 50 years ago. So because you constantly think about it and you talk with other people about it, you read about it, maybe you have a therapist and you talk to them about it. And slowly it changes your entire life and your attitude, your motivation.

• 34:14Speaker 01

  So independent of the metaphysics, the fact that an experience that typically lasts under an hour, that's, you know, you can't really control very well, right? Can have this transformative experience itself is, I mean, you know, nothing short of miraculous. It's even more challenging to think about when you have near-death experiences. So near-death experiences are very similar in character to this mystical experience. People have showed that. And these, of course, typically occur in a highly traumatic circumstances. So for instance, you have an in-hospital cardiac arrest, right? Or you're near drowning or on the battlefield or a car accident where you bleed out.

• 34:55Speaker 01

  So these are, you know, by all of our knowledge, they should be causing massive trauma. But instead, people radiate this equanimity and they're content. They say it's the most meaningful experience I've ever had in my life. It totally changed my attitude to my loved ones. So no matter what the underlying metaphysical implication is, for first, they're very, they're among the most meaningful and profound experiences that we know of, period. Yeah. Independent of what you think about it. Yes, but then there are these two obvious interpretations. One is, okay, ultimately it's just your brain, nothing else, move, nothing else to see, move on, move on, nothing to see. Or you can say, no, what happened in those circumstances?

• 35:38Speaker 01

  And that's the road I'm trying to, I'm going down. Somehow your own, you, so usually we have this boundary between my consciousness and your consciousness, I don't experience you directly. Right?

• 35:53Speaker 00

  Yep.

• 35:54Speaker 01

  To find out how you feel, I have to ask Craig, how do you feel? And you can be with your partner, your wife or your spouse, your bodies can physically penetrate, but you still don't know what she is or he is thinking. Ultimately, all you have is their words and their gestures, right? It's always indirect. So we live in a world where we each have our own planets, if we want, our own bubbles. But under certain circumstances, this boundary becomes dissociative or becomes sort of dissociates, you know, dissolves and suddenly you can, you now become part of this greater reality. That's my, that's my interpretation.

• 36:36Speaker 01

  And the question is, is this comparable with some currents in modern physics? Where, you know, given these weird quantum effects and entanglement, contextuality, et cetera, and the fact that even you can't even define whether things exist without them interacting and being observed. Well, to what extent are these, are this interpretation comparable with some of these foundational physics? But I don't know. I'm talking, I'm talking a lot to these physicists. I organized a workshop on this topic, et cetera, to see, can they be reconciled?

• 37:12Speaker 00

  Yep, yep. So, I mean, there's the physicalist view. And what I'm hearing is that in your correlate work, your work on the correlate subconsciousness, what neurons in the brain fire to correlate with certain mental states, that you just cannot close that gap between the physical and the experience. And so you offload it to, it's a fundamental property and these complex neural.

• 37:56Speaker 01

  Mechanisms.

• 37:58Speaker 00

  Yeah. Somehow can capture that fundamental property. And, but I guess my one question off that, do we know yet? Or at least, broad brush, which parts of the brain consciousness depends on?

• 38:21Speaker 01

  Well, okay, so it depends on many things. It depends on your heart. You know, if your heart doesn't beat, you will faint within 10 seconds approximately. So we know that. It depends on mechanism in the brainstem. And we know small strokes in the brainstem can render you dead or in coma, where you're totally unresponsive. But as far as we can tell, you know, given what, that we can see these complex scenes that I see right now, given that I can hear and, you know, be conscious of so many different things. That is the property of the automus layer of the brain, the cortex, you know, which is really,

• 39:01Speaker 01

  it's a sheet like this, you know, like a cloth, like two to three millimeters. So like a pizza, 12 to 14 inch pizza, that thickness. And you have two of them, they're highly, you know, highly convolved and convoluted and they're crammed into my left and my right hemisphere. In particular, it seems to be the back, the back part of that structure that seems to give rise to seeing and hearing and touching and wanting, which are the modalities that we understand best. But that's on a both, again, that's independent of whether you're a physicalist or an idealist. Because we can, I think it's clear, the evidence shows that if you don't have these parts of the brain,

• 39:46Speaker 01

  you're going to be in severe trouble or we can predict. I mean, Oliver Sacks wrote about this 30 years ago. Depending on which part of cortex are gone, you will have specific deficits, like you are unable to see your face. Although, you know, you can perfectly well see the eyes and the nose and the hair, but you don't, you don't have that conscious experience of a face anymore because he lost the neurons that convey that. So in that sense, there are footprints and you can track them and you can identify them. The question, are they the, do they give rise to consciousness? Or, you know, what is the nature of the substrate or do you need a substrate at all?

• 40:27Speaker 00

  Yeah, yeah. And that's why I was so interested in Penrose and Hemeroff's theory. Because they were trying to pinpoint a mechanism in the neurons of the brain that would channel or in which there would be some quantum effect. And then you could offload consciousness to, to.

• 40:57Speaker 00

  To the quantum realm. How do you feel about that, about the microtubules?

• 41:05Speaker 01

  Well, leaving aside the microtubules, I think that's extremely speculative. Roger Penrose is the first to admit that. Let's take the more general question. What do we know about quantum mechanics and consciousness? Well, we can even ask the empirical question. Is there any evidence that large-scale microscopic quantum events are relevant to biology? Let's put it that, okay? So clearly, the creatures like me and you and dogs and trees are subject to the same laws of quantum mechanics, just like anything else, right? But of course, they operate unlike if you go, for example, to quantum computers like Google makes them. They operate at 27 milli Kelvin.

• 41:50Speaker 01

  Okay, so zero degree milli Kelvin is absolute zero, no more molecular motion. We live at roughly, you know, 270, we live at 300 degrees Celsius. It's 300 degrees above that, right? So this is unimaginable cold, it's vastly colder than outer space, because outer space is 40 degrees Kelvin, right? The background radiation. So you need extremely isolated environments, extreme vacuum to eliminate all this motion, the jostling of the molecules and the atoms that would eliminate these quantum mechanical effects. Given that biology on this planet evolved in what physicists would call a warm and wet environment, you know, with lots of water.

• 42:31Speaker 00

  Yep.

• 42:32Speaker 01

  The vast majority of people, of biologists and physicists argue, okay, biology, quantum mechanics simply isn't relevant for biology in general. Yeah, there are some special effects, like maybe where light meets the photons in your photoreceptors. But by and large, all these large-scale, in particular like superposition and collapse thing, those things don't matter. So I have a collaboration with a bunch of people where we try very hard to show empirically that there are these, that there are quantum effects, that things like nuclear spin do matter for biology. And there's some tantalizing evidence that we can go into, but it gets very technical,

• 43:14Speaker 01

  about such hypothesis. But so far, the verdict is still, there's so far not a believable, reproducible experiment that shows microscopic quantum mechanical effects in biology at room temperature.

• 43:34Speaker 00

  I see, yeah. Although it must be there, I mean, to manipulate quantum states, yeah, you need to supercool them. But that doesn't mean that quantum effects stop happening at room temperature.

• 43:50Speaker 01

  Well, except that you're right, but then they would immediately, within 10 to the minus 9 seconds, wash out, because, you know, everything is constantly vibrating.

• 44:00Speaker 00

  Yeah.

• 44:00Speaker 01

  You know, and so the way you operate quantum computers, you're in this incredible static environment where there's almost no more molecular motion and you can freeze it, and then you get this superposition. Given that, you know, our brains are in this state, any superimposed or entangled state would immediately, within, you know, a nanosecond disappear. So that's the challenge. Is there now other special protected environments? I mean, evolution is very clever and evolution had a lot of time to select things. And anything not, this is also Stu Hamerhoff's argument, I agree with that.

• 44:39Speaker 01

  Anything not ruled out by the laws of physics can in principle be exploited by biology in general and by neurobiology in particular. But right now, we simply don't have any positive evidence for that. We and other people are trying, but so far it's still nothing too convincing.

• 44:59Speaker 00

  Yeah, one thing that fascinated me in one of your talks, you talked about that under psychedelics, the, is it the complexity or the electrical impulses slow down in the brain? Where you would expect it to do the opposite.

• 45:26Speaker 01

  Well, there's actually some evidence that the complexity slightly increases. This perturbation complexity there, or Lempel's if actually under magic mushrooms increases in the brain. But on the other hand, you know, if you think back your own experience, you know, noise, for example, you know, if you just look at, well, you and I are old enough that we still remember television when they weren't off air, right? When there was just speck of noise, right? Well, that's highly complex, that's very complex, but it's not very meaningful. But the fact is, our experiences on a psychedelic can be incredibly meaningful, right? As I said, as we said before, they can be the most meaningful of your life.

• 46:10Speaker 01

  So it can't quite be that, well, okay, it just sort of throws in some more noise, some more complexity. So I think we're still very early on in terms of the neuroscience of psychedelic, despite what press announcement keep on promising. We're still in very, very early days. We still don't understand what they do to the brain.

• 46:32Speaker 00

  Yeah, let me ask again, going back to integrated information theory. That's, is there a correlate to that in the brain? That you have all these different structures of the brain that are cooperating but operating independently? And, but they're integrated and that that's necessary for consciousness? Is that, am I?

• 47:02Speaker 01

  Yeah, in fact, that's why, so for instance, if you ask me where are most of the neurons? 80% of your neurons are here in the back, in a little brain called the cerebellum. Okay, that's where 80%. This cortex has roughly 16 billion, this in the back is 69 billion of the 80, and all the rest is only 1 billion. But it turns out they're not very integrated. They're organized in two-dimensional slabs and they have primarily feed forward loops. So, you know, like in a deep, in an LLM, where one stage excites the next stage, excites the next stage, it has massive feedback, which I think is precisely why the cereb, if you lose the cerebellum, it's not good for you.

• 47:46Speaker 01

  You know, when you go to the doctor to do these sorts of tests, right? That's when, that's when you test for cerebellar function. You look like you're drunk, you know, you tumble about, you're speech, you're slurred, et cetera. So the cerebellum is there to do sensory motor coordination, among others. But, but people never complained, that a lesion in the cerebellum never complain about loss of consciousness. So it doesn't seem to do empirically. It doesn't seem to relate to consciousness, because it's not very well-integrated. And this is really what cortex does, because of its very dense connectivity, that feedback and excitatory is more world connectivity, rich hubs, et cetera, et cetera.

• 48:27Speaker 01

  That's why I think cortex is the substrate that in us gives rise to this very high degree of, particularly in adults, in normal, typical adults, gives rise to people like you and I, who are very conscious.

• 48:44Speaker 00

  Yeah, the, you know, when I was younger and paying more attention to this than I have been in the last 30 years, because I have a different career. The split brain, I did a lot of reading about the split brain.

• 49:02Speaker 01

  Yep.

• 49:03Speaker 00

  Experiments, and to me, naively, at that age, that settled it for me. Well, that's the end of dualism, that, you know, you split the brain, you have two consciousnesses more or less opaque to each other.

• 49:21Speaker 01

  Yes.

• 49:22Speaker 00

  How do you reconcile that with the idea that consciousness is a fundamental property that?

• 49:35Speaker 01

  It's still, well, I mean, so in general, it's a question, leaving aside for a moment split brains. I don't right now access your conscience, I don't access this universal consciousness, mine at large, as Huxley said, right? Assuming it exists. Why is that? Well, because typically, in order for me to survive, I need to, you know, evolutionary, I need to worry about me and my genes and my kids, right? Well, that doesn't work if I feel I'm one with everything. Evolutionary, I mean, that's a wonderful feeling, but that doesn't give rise to competition that you need, right? Because I need to struggle, my genes need to survive to make it into the next generation. So there are lots of reasons why my consciousness is isolated from this universal consciousness.

• 50:19Speaker 01

  Schopenhau's beautiful metaphor, these ripples or this wave, you take a ocean, think of it like mine at large, or universal consciousness, it's this gigantic ocean, and there's this little Eddie. This Eddie has existed for 69 years, and you know, maybe, you know, God willing, it'll exist for another 10 or 20 years, but ultimately, this Eddie will merge, will become, you know, will of course disintegrate, will lose its identity, its egoic consciousness will be gone forevermore, and it returns to the ocean. And so that's also why you and I, you know, you're an Eddie and I'm an Eddie, and we don't have access directly to each other, but under certain conditions, this mystically explained

• 51:01Speaker 01

  somehow, possibly when the brain's activity is turned very, very, very low due to psychedelics, because we know psychedelic depress a lot of activity, you might be able to access this sort of more universal, but usually you do not. And so now we come to split brain, what's, I grant you, so these were done at Caltech, by Roger Sperry, you got the Nobel Prize for them. You take a brain, you cut it along the midline here, the corpus callosum, 200 million fibers, and then you have two consciousness, this one speaks, this one can sing and hum, but it's also conscious. And although, as you said, they're opaque, although they sit, the brain sits, you know, one centimeter away from the other, they don't know about each other, they may as well be

• 51:45Speaker 01

  at the dark side of the moon, and there are all sorts of conflicts that you can see in the clinic that arise because of that. So each one has its own dissociative boundary that dissociates it from its neighbor, just, you know, just one, you know, a tiny, tiny gap away, but that's the experience of all of our life. I'm isolated from you and from any other conscious. It's only under special circumstance that we can lose this dissociative boundary and access everything else. So the split brain wouldn't really make that more challenging than just to explain in general, how is it if mine is truly universal, why don't I access it all the time?

• 52:26Speaker 00

  Yeah, yeah. So, so you split the substrate and it channels two separate.

• 52:38Speaker 01

  Well, now you have, because now you have two smaller brains, effectively, that's what you're having.

• 52:43Speaker 00

  Yeah.

• 52:44Speaker 01

  You have two smaller cortices, you can't do it in, you know, you can't quarter, you can't do it indefinitely, you can only bisect it in this way. Yeah, you have two independent, you have two independent, related experience that we know very little about it is conjoint twins, right? There are some, it's a very rare concept, that like Siamese twins, but that twins are connected at the level of a brain, there's one case I know in here north of us, in British Columbia, where they share part of their brain. And it may be under those circumstances that, particularly during sleep, when the boundaries

• 53:27Speaker 01

  may be down, they may be able to access each other, it's a rather strange case. And the other case may be multiple personality disorder, you know, DID, identity dissociation disorder, where there may live various personalities inside one brain, where they have managed to build, typically, to deal with massive emotional, sexual or physical trauma, they, these people deal with that by having these multiple personalities, and we know they can have different memories, they can have even different immune states, they can have different memories for infections, et cetera. So there you have a case where you have, where the brain had to adapt to traumatic circumstances, did dissociate.

• 54:12Speaker 01

  Because typically, they don't coexist, right? These different personalities, they go over time, but they don't exist at the same point in time. So the question is, is that more like what happens in everyday? I don't know, there are lots of interesting questions and lots of research you could do.

• 54:30Speaker 00

  Yeah, and I want to go, just end on artificial intelligence and the current complex, large language models. Jeff Hinton, who I've had several times on the podcast, is speaking, and he has for a long time, as soon as LLMs came out, I talked to him, and he believed that there was understanding, he was saying at that time, now he's using the term consciousness. Why could a complex set of artificial neurons not have experience?

• 55:14Speaker 00

  And I know that you don't believe that they can.

• 55:17Speaker 01

  Well, in principle, yes, of course they can, that, once again, the brain is just a regular piece of matter, and, you know, silicon is another piece of matter, so a priori, there's nothing, it's not that this is supernatural somehow, right, a special property that the other one doesn't have, in fact, where you to build what's called a neuromorphic computer. So computer, okay, so that, that computer, if it truly has our sort of constitution, like my brain or your brain, it would be conscious. But IIT sort of, it's not a functional theory, so functional theory, the majority of scientific theories of consciousness are functional, says, well, the brain, consciousness has a

• 56:01Speaker 01

  certain number of functions, whatever they are, and once you reproduce these functions, even in a universal Turing machines, then all the properties will come with it, including consciousness. Yeah, so sooner or later, you know, on topic, either will be conscious or it's already conscious, you know, Claude, and you can argue, well, maybe not quite, because there's still this one missing gadget, you know, whatever. But at least according to IIT, within IIT, you can formally show, using formally mathematics and models of von Neumann digital machines that have very low connectivity, they're essentially much more like a series of feed-forward networks.

• 56:40Speaker 00

  Yeah.

• 56:41Speaker 01

  They're not, they don't have this heavily interconnected character that cortex has, so you can formally show that you can have two networks, you can have a model of a brain and an LLM or something like an LLM or von Neumann machine simulating an LLM, although functionally, they have the exact same transformation from input to output. One will have a lot of causal power, will feel like something, the other one will not feel like something, because experience, according to IIT, has to do with the structure, the causal powers inherent in a mechanism, and that really depends on the way it's wired together, you have to look under the hood. According to IIT, you can't just do it like a Turing-like test, like ask it a bunch of

• 57:26Speaker 01

  questions, and if it gives me the right answer, then I can say check mark. No, I have to open the hood and look at the underlying hardware. But of course, you could argue, it's immaterial, because many people already today, right, there are millions of people who have them as their friends, as their girlfriends, you know, use them as therapists, so practically speaking, people seem to behave like they're conscious.

• 57:50Speaker 00

  There's something about, you say that, that what counts in a computer is the transistors opening and closing gates, I think that was you, not the pattern.

• 58:03Speaker 01

  IIT is a causal theory, it's really concerned with causal powers, and you have to look at the causal power of the actual machine, which means you have to go to the CPU sitting in the cloud and analyze the flow of, sort of the causal flow of, you know, electrons going down, you know, going in the valence band, and the copper wire going on the gate of a transistor opening that, et cetera. It's not, let me give you a really good metaphor. Today, we can perfectly well simulate Einstein's equation of general relativity that described the central sun at the center of our galaxies in Sagittarius A star, okay?

• 58:45Speaker 01

  It weighs 3 million solar masses, it has 3 million solar masses, and so it bends spacetime around it, so nothing can escape, i.e. it's a black hole, and you can simulate this. But funnily enough, when you turn on the simulation, you don't have to be afraid that it's going to suck you into, that spacetime is going to distort around the computer doing, carrying out the simulation. Well, why not? Or people say, that's a stupid question, it's just a simulation. Well, so this was consciousness, yes, today, LLMs, like in this interview I did with Cassian, he perfectly seemed to be a very smart, very eloquent person, but that's a simulation,

• 59:28Speaker 01

  and simulation, you have, this is the difference between simulating something and actually physically making a difference to yourself, it doesn't have the causal power that the human brain has, and that, according to IIT, makes all the difference.

• 59:41Speaker 00

  Yeah, and just, I mean, but what bothers me about, about that separation of the patterns and the information that the gates are processing, I mean, if you look at the gates, it's just a mechanism, but if you look at the pattern, that's, that's a meta layer, it's, it's, it's being executed by the transistors and their gates, but the pattern itself, I mean, it's, there's, James Gleick has a wonderful book, The Information, I don't know if you've read

• 1:00:20Speaker 00

  it, but that everything comes down to a code, to information.

• 1:00:27Speaker 01

  No, but the code is in your head, the code, when we talk, like you and I, we are two conscious creatures, and so the coding metaphor makes, makes sense, there's no one to read them inside the machine, so this code metaphor, yeah, to you and I, it might be a code, because we're conscious creatures, we can look down at it, but the question is, does the machine by itself, is it meaningful? No, and all it does, it just takes whatever it gets, and then predicts the next thing, and the next thing, and the next thing, and does it amazingly well, I grant all of that, it's clearly passed the Turing test, but that doesn't mean it feels like anything.

• 1:01:03Speaker 00

  Yeah. Okay, well, I've taken up more than an hour of your time, where are you going next? You're working on the quantum.

• 1:01:11Speaker 01

  Yeah, we're doing experiments on, yeah, that's one thing, I'm just really interested in it. I always thought the chances are very small, and I still think the chances are very small, but the great thing about science and nature is, if you ask the right scientific question to nature, you will get the right answer. You will get an answer, and the, you know, this is what we claim, what, it can tell us about nature, so that's the great thing. You have to design the right experiment to test this, but then you will get an answer one way, so we will know, sooner or later, whether it's going to be on my watch or not, who knows?

• 1:01:50Speaker 00

  Okay.