Making Sense - Sam Harris - #374 — Consciousness and the Physical World

00:00:00.000 Welcome to the Making Sense Podcast. This is Sam Harris. Just a note to say that if

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00:00:45.460 Today I'm speaking with Christoph Koch. Christoph is a neuroscientist at the Allen Institute

00:00:51.220 and at the Tiny Blue Dot Foundation. He's the former president of the Allen Institute for

00:00:56.520 Brain Science, and a former professor at Caltech. He's the author of five books. Most recently,

00:01:03.920 Then I Am Myself, the World, What Consciousness Is, and How to Expand It, which is the topic

00:01:10.300 of today's conversation. Christoph and I speak about his development as a neuroscientist,

00:01:15.900 his collaboration with Francis Crick, their studies of the visual system, change blindness,

00:01:21.960 and binocular rivalry, the significance of sleep and anesthesia for consciousness studies,

00:01:28.240 the limits of physicalism, non-locality, and other quantum mechanical phenomena, brains as

00:01:34.960 classical systems, the possibility of conscious AI, idealism and panpsychism, integrated information

00:01:43.440 theory, also known as IIT, what it means to say that something exists, the illusion of the self,

00:01:51.300 the possibility of brain bridging, that is connecting two human brains in a shared experience,

00:01:57.340 Christoph's recent experience with psychedelics, and other topics. Anyway, this is the deep end of

00:02:04.120 the pool with respect to the scientific understanding of consciousness, and I certainly enjoyed it.

00:02:09.160 And now I bring you Christoph Koch. I am here with Christoph Koch. Christoph, thanks for joining me.

00:02:21.900 Thanks, Sam, for having me.

00:02:23.580 So you've written a wonderful book. You've written several books, but your most recent is

00:02:28.320 Then I Am Myself, the World, What Consciousness Is, and How to Expand It. And I just really,

00:02:34.440 I want to follow the line you took in your book here, which traces the evolution of your thought as

00:02:41.940 a scientist focusing on the nature of consciousness. And I mean, you've had a very productive career as

00:02:48.900 a neuroscientist, and you had a very fruitful collaboration with Francis Crick, who we'll talk

00:02:55.700 about. But then you, you know, kind of late in your career, you took the first person side of

00:03:01.860 things with both hands and have had some experiences with psychedelics that have put pressure on your

00:03:09.740 ontology, one might say. So I would just love to talk about all of this. Perhaps you can start

00:03:15.420 somewhere near the beginning. How is it that you came to focus on consciousness? And you started out

00:03:22.620 more as a physicist, you know, that was the side of science you came in, I believe, as an undergraduate.

00:03:28.480 What led you to the study of consciousness? Well, so I did get a minor in philosophy in

00:03:35.240 Tübingen, which is a 550-year-old university in Germany. And I did grow up reading Schopenhauer

00:03:43.840 and Immanuel Kant. It was that sort of household. So I've always been interested in consciousness,

00:03:49.740 that voice inside the head, right? How is that voice compatible with everything else we know?

00:03:57.380 And I grew up reading physicists, including Ernst Mach and people like Schrödinger. And they all

00:04:04.760 wondered, they also had similar questions. And in fact, both Schrödinger and Ernst Mach were very

00:04:10.860 explicit. Before I can be a physicist, I am a conscious being that sees, that thinks, you know,

00:04:18.980 going back all the way to your René Descartes. And so before I can even read an oscilloscope or read

00:04:26.620 an instrument as a physicist, I depend on my conscious sensation. And so consciousness has to be at the

00:04:33.900 center of our explanation of everything in the world. And I was puzzled when I first came from

00:04:41.740 physics into neuroscience. So my PhD was in the 20th century in what we now would call computational

00:04:48.320 neuroscience. I was puzzled when I really went deep and became a full-time professional neuroscientist

00:04:54.480 that consciousness at the time was simply not discussed. It didn't figure in the index. You know,

00:05:00.280 if you got the standard textbook, you went index and a consciousness, nothing. That was simply

00:05:06.060 ignored. It was all about behavior and neurons, which is fine, which is what I dedicated most of

00:05:11.840 my life to. But ultimately, we also have to explain the puzzle at the heart of our existence,

00:05:16.840 the fact that I'm not just a behaving thing. I actually see, I hear, I dread, I fear, I dream,

00:05:22.900 I desire, I want, right? So how do all of these things get into the world?

00:05:28.840 And then I met Francis Crick. So I did my PhD in Germany, then went to do a postdoc at the

00:05:34.980 Artificial Intelligence Lab at MIT. And previously, I'd encountered Francis Crick, you know, who at the

00:05:41.480 time had shifted from molecular biology, where, you know, with Jim Watson, he decoded the molecular

00:05:48.520 code for life and deciphered the double helical shape of the DNA molecule. But then he shifted because

00:05:54.980 he was also interested in consciousness. And the two of us got together and then wrote roughly

00:06:01.120 20 papers over the next 14 years, where we really initiated sort of a modern empirical

00:06:07.500 program to discover the footprints of consciousness in the brain. And the argument was very simple,

00:06:14.960 never mind about all the philosophy, we aren't going to converge anytime soon. You know, are we a

00:06:20.000 physicalist, an idealist, a dualist, a panpsychist, whatever? Let's just focus, we all agree today,

00:06:25.920 it's not the heart, as most people thought, it's your brain, that's sort of the organ of consciousness.

00:06:32.400 So which particular bits and pieces of the brain? Is it the spinal cord? Is it the cerebellum? Is it the

00:06:38.140 retina? Is it the thalamus? Is it the cortex? And do they, does this bit of the brain that sort of

00:06:45.780 analyze or is the substrate of consciousness, does it have to oscillate? Does it have to buzz at a particular

00:06:50.780 frequency? Which genes are involved? Which cell types are involved? Is there sort of a conscious mode and an

00:06:57.100 unconscious mode? These are all questions that we felt will have an answer. No matter what your

00:07:03.560 philosophical predilection is, there will be an answer of the sort. These neurons in this state, in that part of

00:07:10.440 the brain at this time, express the fact that I see or that I hear. And it's causal. In other words,

00:07:18.460 if I can activate those neurons, if I can put these neurons into this particular buzzing state, for

00:07:24.860 instance, then you should have a conscious experience. Conversely, if I can somehow interfere

00:07:30.720 with this neural mechanism by a drug, by a neurosurgeon's electrode, by some external magnetic device, then you

00:07:40.640 shouldn't have the experience. And so this is sort of the modern program to study the footprints of

00:07:46.560 consciousness now called the Neuronal Correlates of Consciousness or the NCC. In patients, in neurotypical

00:07:53.840 volunteers in animals like mice and monkeys and rats and other animals.

00:08:02.860 But when I read you now, I recognize that you are someone who always took the so-called hard

00:08:09.760 problem of consciousness seriously, which is to say you thought that it was a non-trivial mystery, that it

00:08:16.320 should be like anything at all to be associated with a certain pattern of neural firing. Whereas

00:08:22.720 in my memory of Francis Crick's approach to this, he wrote a book, The Astonishing Hypothesis, way back

00:08:31.520 when, I remember him being more of an arch materialist of the sort that one met quite directly in my

00:08:42.980 friend Dan Dennett or in the Churchlands, right? I mean, somebody who just simply tried to ram past

00:08:49.380 the hard problem with the declarative statement that, you know, the mind is simply what the brain

00:08:54.660 is doing, right? You're just a pack of neurons. And there is no, you know, it seems like there's

00:08:59.380 something left out of that. That's just a symptom of what a bad view we have of the brain's role in

00:09:06.900 producing subjectivity. But so how did, from what you just said, it sounds like you sort of tabled

00:09:14.420 your philosophical differences of intuition there and just decided to go look for the neural correlates

00:09:20.020 of consciousness. It must be somewhere in the brain. We agree about that, whether we agree about anything

00:09:24.180 else in philosophy. But was that an impediment to your collaboration with Crick at all? Or do I have

00:09:29.700 Crick wrong? No. No, you don't have them wrong. That was the starting point. That was the explicit

00:09:35.140 starting point that once we understand neurons and their vast complexity, you know, of an untamed

00:09:41.780 complexity that's incomprehensible for us. You know, humans, we deal with simple networks that are,

00:09:47.620 that are, you know, that we can understand, but we've never been faced with the vast complexity

00:09:52.820 that we find in evolved systems like biology, whether that's a brain of a simple creature like a

00:09:59.220 worm that has three or two neurons or the brain of a, of a, of a human that has on the order of 100

00:10:05.380 billion neurons. But he was also, Francis was very clear. He said, this hypothesis may not be true.

00:10:11.380 There might be other ways we have to think about it. And he was sympathetic. So, for instance,

00:10:17.300 very early on, we encountered Jerry Edelman, another Nobel laureate who would also move from Manhattan,

00:10:23.300 from the, you know, from the Rockefeller Institute to the, to the Scripps Institute in, in La Jolla.

00:10:28.660 And he worked with a person at the time, Giulio Tononi is now also a very well-known

00:10:34.340 consciousness researcher. And he explored the possibility that maybe it has to do with the

00:10:39.060 complexity. They wrote, for example, an early influential paper called consciousness and complexity,

00:10:44.340 arguing that complexity had to be, had to be involved, which is a little bit more than just saying,

00:10:49.940 it's just a bunch of neurons, you know, because the, the, the, the most widespread belief among

00:10:55.140 neuroscientists is, well, it's an emergent property, just like wetness emerges from water.

00:11:00.900 You don't get, if you have two H2O molecules, they're not wet, but if you got, you know,

00:11:05.700 10 to the 23, like a, a liter of, of, uh, H2O molecules, then it gets wet. And similar,

00:11:12.980 if you have a few neurons, they're not conscious, but you got a hundred billion of them,

00:11:16.900 then somehow they're conscious. But then we also, Francis and I realize that's inadequate

00:11:21.540 because you have some structures like the cerebellum. Okay. So you have this little brain

00:11:26.740 tucked underneath your big brain, right? At the back of your head, it contains in fact,

00:11:31.380 80%, four to five neurons in your head are in the cerebellum. You can lose these neurons. Let's say

00:11:37.300 due to a stroke or due to a tumor, you will be impaired. You can't do fast speed typing on your

00:11:42.900 phone anymore. You can't play violin or piano anymore. You have a few other issues like that,

00:11:48.180 but basically you, you stagger about, you look like you're always drunk, but basically all these

00:11:54.420 people, these patients who have lost part or whole of their cerebellum, they see, they hear, they dread,

00:12:01.060 they fear, they imagine, they, their consciousness is essentially to first order unchanged. And so that

00:12:07.780 tells you that it can just be the number of neurons. It has to do with, at least with the way they're

00:12:12.900 organized. Same thing with the spinal cord, right? You can be quadriplegic. You've just lost all your

00:12:18.100 spinal cord, 200 million neurons, right? So you can't move. But again, your consciousness hasn't really

00:12:23.620 changed that dramatically. So it, it, it can't just be the number of neurons. It has to be the way they

00:12:29.700 organize. And Francis, the hope was similar to what he had accomplished in molecular biology,

00:12:36.260 that if we look at the right neural mechanism in the right way, then suddenly it'll become apparent,

00:12:42.500 just like it was apparent when you look at the double helical structure of DNA, that that's a

00:12:46.740 natural way to copy genetic information. But we, we, we, of course, we didn't find such a simple

00:12:53.620 explanation and he always was open to the possibility that other ways of conceiving of it may be necessary

00:13:00.820 to finally understand it. Hmm. Well, I, I should say that anyone who has seen me try to type on my phone

00:13:07.220 will wonder whether I have lost my cerebellum in some, some terrific accident. Uh, it's, uh,

00:13:13.140 Well, you know, a few number of people, and, and, you know, a few people are born without a

00:13:17.700 cerebellum altogether, you know, so-called agenesis of the cerebellum. Well, I can confirm I do have one,

00:13:24.180 having been, having done my fair share of, uh, MRI experiments. Oh, there you go. But, um, actually,

00:13:30.020 I don't know if you're aware of it. You and I once met, you, you, when I was doing my PhD at the

00:13:34.580 Brain Mapping Center at UCLA, you came and did a seminar in Mark Cohen's lab, so. Yes, a long time

00:13:41.700 ago with Mark. Yes. Yeah. I don't think our paths have crossed since, but. No, no. Okay. So now how has

00:13:47.380 your, you know, your, your evolution as a, um, a neuroscientist in, in trying to understand

00:13:54.420 consciousness as an emergent property of brain activity, you know, I remember the work you did

00:14:00.180 with you, you and, and Crick were, were focusing on the visual system if, if memory serves and you

00:14:06.900 were, you were looking at, um, things like bistable percepts and, and change blindness and

00:14:13.220 binocular rivalry. Right. Right. Binocular rivalry. That's, that's a fascinating phenomenon. Maybe you

00:14:18.980 could describe that and, and, and why that seemed like such a promising avenue, because it's, it's,

00:14:24.500 it's a, to experience it is, um, striking. Both binocular rivalry and, and change blindness are

00:14:30.420 quite wonderful to experience as a subject in an experiment. Yeah. So the general philosophy here in

00:14:35.460 these experiments is, is to create conditions where in, on the one hand, you're looking at the stimulus and

00:14:41.940 see it. And then when the same stimulus is present, you may not see it, or you may see it differently.

00:14:47.940 In other words, in the two conditions, you're always looking at the same thing, but sometimes you see

00:14:53.060 it one way and sometimes you see it the other way. So in change blindness, you know, you, you have an image

00:14:58.900 like there's a famous image of soldiers, UN soldiers boarding a plane. And then you see an image that's

00:15:06.340 slightly changed, uh, with a blank in between where, for example, the photographer has removed

00:15:12.180 using Photoshop has removed the engine of the airplane. And you go back and forth between the

00:15:17.620 original image, a blank image and the changed image and blank original image, blank changed image.

00:15:25.540 And you may be staring at this for 10 or 20 or 30 seconds and your, your eye move about, but you

00:15:32.260 don't see the actual change until, you know, suddenly you get, ah, of course it's the engine

00:15:38.180 that's changed. And then of course you cannot not see it. So there you have a situation where for 10

00:15:42.980 or 20 seconds, you're looking at the same thing, but you're simply not seeing what's in front of

00:15:47.380 your eyes. So you can track down where are the mechanisms in your brain that respond only to the

00:15:52.660 retinal input compared to where are the neurons that respond when, when you actually see it.

00:15:58.900 A separate case is this binocular rivalry. So there you, you have two different images,

00:16:03.860 let's say phase one and phase two. Let's say you're projecting phase one into one eye to make

00:16:09.060 it concrete. We can think about, for instance, you have an image that you can do this. And we did it

00:16:14.660 20 years ago with the two presidents at the time. You can imagine on, on your left image, you have Biden

00:16:20.660 on the right, in your right eye, you project the image of Donald Trump. Now, if you don't do things

00:16:26.500 correctly, you can see sort of a juxtaposition of, of the both of the two. But if you do things

00:16:32.020 correctly for a while, you will only see President Biden and then one or two seconds or three seconds,

00:16:40.900 and then Biden will fade and Trump will come in. And then Trump will stay for several seconds,

00:16:46.260 and then Biden will come in. It's sort of this never ending dance.

00:16:49.780 So just to clarify for listeners who haven't, who may not be able to visualize this, you have

00:16:56.180 one image projected to one eye and, and a different image to the other eye. And your conscious

00:17:02.980 experience tends to, if it's set up correctly, is you're, you're, you're simply seeing one of the

00:17:07.140 images and then it just randomly shifts to the other image. And it's something over which you can't

00:17:13.780 control, you can't control the shift. And what's interesting about this experimentally is that

00:17:18.820 the inputs to your nervous system are completely stable. I mean, all you have are these,

00:17:23.300 these two inputs to, you know, one to each eye and nothing is changing. And yet at the level of your

00:17:28.500 conscious, you know, phenomenology, there is this very bizarre shifting back and forth between

00:17:35.140 seeing one image and then seeing the other and then seeing one image and then seeing the other.

00:17:39.060 And it's, um, this was a wholesale change in the contents of visual consciousness. And yet there's

00:17:44.420 zero change happening at the level of the bottom of your nervous system from the, you know, the

00:17:50.340 retina onward. That's correct. Yeah, that's correct. So something is changing. They're sort of this

00:17:54.820 bi-stable. It's like the nervous system wants to see what's in the left eye. And then it wants to

00:18:00.100 sort of check what's on the right eye and it goes back and forth. And this can go on for, you know,

00:18:05.380 many minutes. So now you can, in principle, you can do what you used to do. You can put

00:18:10.740 people in a magnet or you can put people in a magnet like we've done at the time at UCLA with,

00:18:16.660 with Itzhak Fried on the wall. These are neurosurgical patients

00:18:20.660 that for other reasons, because the doctor has to know where they, where the elliptic seizure

00:18:24.980 originates, you put electrode into the, into the brain. You can see the same thing, or you can do it in a,

00:18:29.940 in a monkey, where you can attack throughout the monkey's visual system. Where are the,

00:18:34.980 the first stages of the neurons that actually respond to what you see? Not just what the left

00:18:40.100 eye quote sees or what the input received by the right eye, but what the animal sees or what the

00:18:45.700 person sees that tend, that typically tends to be a higher up in the, in the visual hierarchy.

00:18:51.060 And you can ask, where are those neurons? Are they of a particular type? Are they of a particular layer?

00:18:56.580 And then of course, what happens if I, if I can begin to manipulate those neurons, which at the

00:19:01.540 time was, wasn't really possible, but today you can do using fancy optogenetics. So this was one

00:19:07.860 of a number of ideas that we exploited to track, or that people exploit to track the, the neural

00:19:15.140 footprints of consciousness, in this case, visual consciousness throughout the brain. And people

00:19:19.460 continue to do that in all sorts of different ways. Is there a problem here conceptually because you're,

00:19:25.620 so you're, you're obviously conscious all the while there's a, there's a distinction we could

00:19:31.860 make between consciousness itself. I mean, the fact that it's like something to be you to use Nagel's

00:19:38.260 definition, which of which I've always been a fan and the, any, any specific contents of consciousness,

00:19:45.540 right? So you're like there, you're really interrogating specific contents, you know, and, and,

00:19:50.580 but one could argue that, I mean, you could completely lose, you know, a perception of

00:19:55.140 the visual field as well, and, and yet be just as conscious, right? I mean, now you're no longer

00:19:58.900 conscious of vision, but you're, you're conscious in other sensory channels and of just, you know,

00:20:04.020 awareness itself, one might argue. Do you?

00:20:06.820 It's a different way. It's a different way to study. So, so the other way to study is you point

00:20:11.380 out is the distinction between consciousness too cool and not being conscious. I like in sleep,

00:20:18.820 or in anesthesia. So you can take a subject, normal subject, hears, sees, et cetera, then you anesthetize

00:20:25.140 them and you can see what changes. And then as they wake up, it's called LOC loss of consciousness.

00:20:30.820 And then you can see what happens when they, when they come out of anesthesia and each you're

00:20:36.500 looking at different things that, you know, they're not similar and that different concerns

00:20:42.100 you have to have. So for instance, when you go to sleep or when you are anesthetized, all sorts of

00:20:46.980 other things as well as change as well. For instance, you don't have memory anymore. You can't move

00:20:52.100 anymore, right? Because you become paralyzed in deep sleep or in anesthesia, you also become paralyzed,

00:20:57.940 but it's much more dramatic compared to looking at something. And I'm, as you point out, I'm still

00:21:02.340 conscious. It's just the content of consciousness changes. So they're just different experimental

00:21:07.860 techniques to track different things. In one case, you're specifically tracking the content of my visual

00:21:13.060 consciousness. In the other case, you're tracking the, the entire physical substrate of being

00:21:18.260 consciousness in the legal sense. It feels like something to be me.

00:21:22.260 Yeah. The, the problem you always run into there, which you just alluded to is that it's hard to

00:21:28.580 differentiate and perhaps in principle, it could be impossible to differentiate a true cessation of

00:21:34.660 consciousness from merely a loss of memory, right? So I, you know, I, I've, I disagree.

00:21:40.660 Yeah. Well, it was, yeah. So let's, let's talk about that. I mean, I think it's, it's harder to make

00:21:44.180 this case for, for general anesthesia, given what we think about just the, the underlying state of the

00:21:50.180 brain. But for deep sleep, it's often, I've often felt that we're too quick to allege that it

00:21:58.740 interrupts conscious experience because many people, I count myself among them, at least believe,

00:22:06.340 imagine that they've had an experience of, of dreamless sleep. Now, whether that's, you know,

00:22:13.780 stage four delta sleep or not, I don't know, but there's a very common experience of being asleep and

00:22:18.660 dreaming and, and there's something that it's like to be doing that, but there's a more esoteric

00:22:23.080 experience that people have had of being asleep and experiencing just a, I mean, it's very much like

00:22:30.260 a, a meditative, you know, samadhi-like experience. I mean, it's just, you know, a vast experience of,

00:22:36.280 of contentless consciousness while asleep, right? And that's, that's certainly reported in,

00:22:42.300 among yogis who claim to, to have been able to train that. So, so I, I just think, you know,

00:22:48.360 that's the, the fact that most of us, most of the time don't remember a thing about what it was like

00:22:55.920 to be deeply asleep could be just analogous to, to most of us not remembering our dreams. You know,

00:23:02.020 I mean, I, you know, I presume I dream every night, but at this point in my life, I rarely remember

00:23:05.980 anything from my period of, of sleep. Well, so there is one technique at least that tries to get,

00:23:12.380 I can think of two techniques to try to get at that. One is to put you in a magnet or probably

00:23:18.320 more plausibly to put EG electrode on you as you sleep. And people have done this. I'm thinking of

00:23:24.300 one study by Siclari et al from the Tononi lab, in fact, where they did exactly that. They had high

00:23:30.260 density EG on these irregular people, but they're trained people, trained observers. So they've done

00:23:35.820 this for a while now and you randomly wake them up, right? So randomly I look at your EG and I wake

00:23:43.140 you up now and I ask you, you know, tell me, did anything, was anything in your mind just the moment

00:23:51.640 before you woke up? And I look at the 10 seconds before I wake you up and then I can correlate. And

00:23:57.460 of course, what they found, which is, if you can go back to the original report back in 53,

00:24:02.760 defining REM and non-REM sleep, it is true. 30% of the time, even in deep sleep, people do report

00:24:10.340 dreamlike experiences. Okay. So even in deep sleep, you can have dreamlike experiences. However,

00:24:17.960 they're typically not this sort of elaborate narrative structure. You know, they're more sort of episode,

00:24:23.160 oh, I just saw a face, or I just had this feeling of dread, something bad was

00:24:27.460 going to happen. And conversely, in REM sleep, only about 80% of the time do people actually

00:24:33.940 report, you know, have dream reports. So that's one way to get around this fact that most people

00:24:39.380 forget most of the dream. You wake them up spontaneously during the night and you ask them,

00:24:44.460 do you remember anything over the last 10 seconds? Now, of course, it's also possible

00:24:47.980 that if they have lost shorter memory as well, then of course, yes, then of course you wouldn't know

00:24:54.060 it all. But most people can report that they had experience, dream experiences, or that they

00:24:59.180 didn't have dream experiences. And here, by the way, so you can, again, track, people have used

00:25:04.340 this technique to track the footprints. It is true when you have dream experiences, it's typically

00:25:09.860 particular part of the back of the brain, the posterior hot zone that are activated in the

00:25:15.080 preceding 10 or 15 seconds by EG criteria.

00:25:18.740 But when you're talking the posterior hot zone, you're not talking about visual cortex, you're

00:25:23.220 talking about precuneus and...

00:25:25.420 Yeah, exactly. Precuneus, posterior cingulate, sort of parietal areas in some higher order

00:25:32.280 temporal area. So behind the central fissure that goes across the brain in the back.

00:25:38.900 So, let's step back for a moment and review some of the underlying philosophical controversy

00:25:47.860 because there are many ways in which people think about what is here. And I want us to

00:25:55.580 get to integrated information theory, IIT, which I believe you still are a supporter of

00:26:03.100 and contributor to. I don't know if it fully captures your current view of things. But

00:26:08.140 we'll get there. But I mean, you express in the book a similar astonishment and frustration

00:26:14.120 that I've always felt with the eliminative materialists of the Dan Dennett and especially

00:26:20.520 Paul and Patricia Churchland sort, who just simply say that consciousness itself is an illusion.

00:26:28.440 It seems to me, it's always seemed to me to be absolutely obvious that consciousness is the

00:26:33.400 one thing about which you cannot say that. Because any illusion is as much a demonstration

00:26:38.780 of consciousness as any veridical perception of anything, right? I mean, it's the one thing.

00:26:43.300 The fact that something seems to be happening is the one thing we can be sure of, even if we're

00:26:47.500 totally confused about everything.

00:26:49.880 René Descartes. I couldn't agree more. It's the one thing I cannot doubt, because in doubting,

00:26:55.160 I affirm it. And if I call it an illusion, well, then everything is an illusion and the word becomes

00:27:00.420 meaningless. Yes. So I think this is the biggest feeling by far of physicalism, right? So physicalism,

00:27:07.220 you know, it's a metaphysical idea that the only thing that exists is physical. Let's come, you know,

00:27:12.840 I think we have to discuss what is meant by that. But sort of most people have an intuition,

00:27:16.860 you know, it's matter and energy, right? Good old materialism. And then the challenge is,

00:27:23.040 well, if you believe that, fine. But then how, how does, how do feelings emerge? And, you know,

00:27:29.640 because we have been not able, you know, philosophy has been utterly unable or science has been utterly

00:27:35.180 unable to explain how any sort of feelings, it feels like something to be me emerges out of

00:27:41.100 atoms and the void. That's the biggest challenge that physicalism has utterly failed to me, number one.

00:27:48.440 Yeah. Which is to say, so again, I've spoken about the hard problem of consciousness,

00:27:53.040 a lot on my podcast and over at Waking Up in the app. And I've interviewed Chalmers and

00:28:00.300 Anil Seth. And I mean, we've covered this ground before, but the thing to recognize is that the fact

00:28:06.380 that there is this explanatory gap, the fact that our intuitions that seem to anchor every other type

00:28:16.080 of scientific explanation, you know, the wetness of water, the brittleness of, you know, any higher

00:28:22.320 level material, all of those physicalist reductions run through. And yet with the hard problem, with the

00:28:30.060 fact that the lights are on subjectively, something seems to be left out. The fact that there's,

00:28:35.840 that we have this, where this intuitive impasse doesn't suggest or much less prove that it isn't

00:28:44.980 simply so, right? That it isn't just, we just may, you know, we just may be in a bad position to think

00:28:50.380 about how consciousness emerges. And it may always seem like a miracle, even if we had, even if we had

00:28:56.760 the answer in hand and it just was whatever, 40 hertz oscillations in thalamocortical loops,

00:29:02.760 which I think was once a pet thesis of yours. Yes. If that's just the answer, if God told us

00:29:08.160 that's, that is how it happens. Well, it may always just seem like a brute fact that doesn't

00:29:14.280 actually explain anything. You're entirely right. My dog doesn't understand general, you know,

00:29:20.800 general relativity or the stock market or election. My dog is a perfectly intelligent member of a species

00:29:27.720 that survived for millions of years, but certain things are cognitive beyond it. And maybe this is

00:29:33.940 also beyond us. But now that the additional evidence, right, for, for physicalism being

00:29:39.380 inadequate, namely at the bottom, at the rock bottom of physicalism is how do we define the

00:29:46.180 physical? And if you listen to anything in the science, in, in quantum mechanics of the last 30

00:29:52.160 years, like we all know, it's deeply troubling and it's very difficult to define what is the physical.

00:29:59.060 And the fact that physical includes such bizarre things as two particles that are entangled that

00:30:03.740 are at opposite ends of the universe. If one, you know, if you observe one and determine its state

00:30:09.320 instantaneous, you know, instantaneous, the state of the other one is determined, right?

00:30:15.040 You're talking about non-locality.

00:30:16.500 Non-locality. So what sort of, I mean, what sort of physicalism is that if things are entangled

00:30:22.100 across the universe, right? That's, that's certainly not my grandfather's. That's certainly

00:30:26.540 not Democritus, you know, atoms in the void. And then, you know, now turns out that the entire

00:30:32.180 school of physics, you know, that does what's called contextuality or called first person physics,

00:30:38.460 right? Where it is, where they accept as a, as a, as a, as a fact, as an observational,

00:30:43.580 as an empirical fact that what exists really depends on what you measure. And if you have

00:30:49.560 different measurement protocols, different things, sort of, you measure different things

00:30:54.300 that weren't there before. So the mere act of observing, you know, it's a participatory universe,

00:31:00.180 the mere act of observing creates reality. Well, how does that sit with standard sort of physicalism,

00:31:06.760 right?

00:31:06.980 Let me bring in my, my, put on my arch materialist hat, which I, which I rarely wear, but what,

00:31:13.600 what about the claim that however strange quantum mechanics may be, and, and I guess there's two

00:31:20.920 things to acknowledge here. One is that there, there are very strange versions of it that seem

00:31:25.760 to move consciousness and the observer out of the, out of any part of the, the significant picture

00:31:32.320 and give us something super determinism or, or, or, or, um, you know, many worlds theory,

00:31:37.960 right? Where like, you know, the, the universe is splitting, you know, at every, at every possible

00:31:42.900 choice point of which I think.

00:31:44.740 But how do we know this is exactly. So in fact, I've just written a paper with Hartmut Neven who runs

00:31:50.160 quantum Google AI lab. It may be precisely consciousness that's responsible for, at the moment you create a

00:31:59.440 superposition, there are two or a multitude of different multiverses that split off. So how do

00:32:07.340 we know that conscience isn't in fact responsible for that splitting off?

00:32:11.700 Well, I'm going to, I'm going to have you fight with David Deutsch about that, but leaving that aside,

00:32:16.080 what, what about the claim that at the scale of brains and even at the scale of neurons, kind of the

00:32:23.540 wet and hot mess of, of goo that is in our heads, quantum mechanics, you know, it is a perfectly

00:32:29.940 classical view of physics is good enough because everything, you know, everything decoheres and

00:32:36.260 there's just, you know, it's, it's at the scale of brains, none of that highfalutin physics need apply.

00:32:42.640 Yeah. In short, brains are warm and wet. So this is the argument I've always made in all my previous

00:32:47.340 books. The brain is warm and wet. So if you look at Google's quantum computers, they operate at 23

00:32:55.180 milli Kelvin. So that's about a thousand times colder than the temperature of out of space,

00:33:01.180 right? Which is the temperature of background radiation, a couple of degrees of Kelvin. And

00:33:05.580 of course, a hundred thousand times colder than right now, what you and I experienced here on the,

00:33:10.940 on the West coast, right? So, and my belief has always been, yeah, it's wet. The brain, as you said,

00:33:16.460 it's warm and wet. And so it's irrelevant. But now we learned over the last 10 years, well,

00:33:21.660 they can find entanglement in all sorts of soft metal system in some gas. There was a paper recently

00:33:27.340 out of Barcelona, I think that measured it in, in gas, that's sort of minus 50 Celsius. So people are

00:33:36.220 now, as they're looking, as we better understand in this, what some people call the second revolution

00:33:41.340 in quantum mechanics, it may not be true that it's only in these very extremely cold systems that

00:33:48.460 entanglement and superposition may occur even in what physicists think of soft matter, i.e., you know,

00:33:55.340 brains or bodies. This is an empirical question. In fact, together with some biologists and with this

00:34:03.180 previous mention, Hubwood-Naven, we're now doing some experiments in, in organoids and in flies to

00:34:10.780 exactly test it. There's this interesting phenomena that's xenon. So xenon is a rare gas and it acts as

00:34:17.740 an anesthetic. This is well known. In fact, it's a pretty good anesthetic, except it's expensive. But

00:34:23.020 there's this one paper many years ago in mice that claimed there's this differential isotope effect of

00:34:31.340 anesthetic potency. In other words, different isotopes of xenon. So 129, 131, 132, they all have

00:34:42.140 the same. So chemically, they're all the same. They all have eight outer electrons. So none of them

00:34:48.060 interact. They're called Nobel gases because they're so noble, they don't interact with anyone. Okay.

00:34:53.820 So only what differs is the nucleus inside, right? They have an additional one neutron or two neutrons or

00:34:59.500 three neutrons. And so their, their nuclear spin differs. Some of them have nuclear spin zero.

00:35:04.300 Some of them have nuclear spin one half. And it turns out those that have nuclear spin one half have

00:35:09.580 a different anesthetic potency in mice. Now they haven't been done in people yet, in mice than the

00:35:16.300 ones with spin zero. Now, if this is, so this has to be replicated, right? Two out of three experiments in

00:35:21.980 biology can't be replicated. So we have to repeat this. So which is what we're doing in flies and in

00:35:27.500 in cerebral organoids and in primary cultures, with Ken Cosek, who's a professor at UCSB,

00:35:34.140 if this is replicated, then it would seem to indicate that something as subtle as nuclear spin

00:35:41.180 actually makes a difference at room temperature in these organisms. So the great thing about science,

00:35:50.300 it would be weird. And that's a great thing about science, right? If you construct a part,

00:35:54.860 if you ask in nature the right question and you do, you know, you listen carefully,

00:36:00.300 you can get an answer, even if the answer may be extremely unexpected. So that would be cool. We'll see.

00:36:06.060 Yeah. Yeah. Well, yeah. Keep me apprised of that because that would, uh, that would shake some

00:36:11.900 assumptions I have working on the background here. Me too. So let's talk about, again,

00:36:17.980 I want us to get to IIT, but how would you characterize the, the most common ontology of

00:36:27.500 mind in neuroscience and the sciences of mind generally now? I think, I think in your book,

00:36:32.940 you talk about it as you described it as computational functionalism. It's certainly

00:36:37.420 the, the view of, uh, that is causing people to imagine that developments in AI have some

00:36:45.020 future implication for how we understand, uh, minds in their totality and that we may build

00:36:51.100 conscious machines. We may be able to upload ourselves into the matrix. All of this seems to

00:36:56.140 suppose that, that mind, you know, we already know this is true of intelligence. I mean,

00:37:00.700 it's clearly intelligence on some level as a matter of information processing, but the underlying thesis

00:37:04.620 seems to be that consciousness itself is an emergent property of information processing and

00:37:10.140 therefore really by definition is, is substrate independent. Is that an accurate view of what you

00:37:15.420 think most people think in, in the sciences of mind at the moment? Yeah. Based on some version of

00:37:21.180 functionalism, i.e. that, and everything has a function. Clearly that's true for intelligence.

00:37:26.620 Consciousness also has a function, you know, enable planning or, you know, long-term planning,

00:37:30.940 short-term planning, summary of the current situation that's ongoing in my body, whatever

00:37:37.100 it may be, it has a fun one or more function. And once you replicate those functions, in particular

00:37:41.980 on a Turing machine, right, this is called Turing unit, Turing functionality or, or computational

00:37:47.180 functionalism, then that machine will have all of the properties, including consciousness. So that's a deep

00:37:53.260 belief, particularly in the tech industry and among computational neuroscientists. And now, of course,

00:37:58.300 with LLMs, it's present to the, to the level of the general public that people assume, yeah,

00:38:04.940 these things sooner or later will be sent in, will be conscious. Right. Here, here is what I predict

00:38:11.100 is going to happen. And, um, it worries me on some level. I think, I think we will probably

00:38:17.020 build, you know, humanoid robots that fully pass the Turing test, you know, and, and, and better

00:38:24.060 because they'll, they'll be superhuman and in, in virtually every respect. And once we get out of

00:38:29.900 the uncanny valley with them, they'll certainly seem conscious to us because we'll build them to

00:38:34.300 seem conscious to us. And they'll talk about their experience and their, and their emotions,

00:38:38.860 et cetera. They'll certainly be very attentive to our emotions and, and better judges of that than

00:38:43.660 probably any person we've met. And we will just, you know, effortlessly slide into this sense of

00:38:49.740 being in relationship to these entities. And we will still not understand the neural basis of

00:38:55.820 consciousness or the computational basis of consciousness or any, or any other basis of

00:38:59.900 consciousness. And we'll be in the presence of these artifacts, which seem conscious to us. And we'll

00:39:05.980 simply just lose sight of whether it's an interesting problem to wonder whether or not they are conscious.

00:39:11.020 We will helplessly perceive them to be conscious because they will, they will seem that way.

00:39:16.140 Do you, can you imagine that we're going to stumble into that sort of Westworldian future,

00:39:21.820 where it's just, you're not going to be able to, you're certainly not going to be able to mistreat

00:39:26.060 these robots because you'll feel like a psychopath because you'll be, you know, only a psychopath could

00:39:30.300 want to mistreat something that is so perfectly seeming to be a locus of experience. It just seems like

00:39:37.900 the problem may evaporate for most people. I mean, obviously, some people will still hold on to it

00:39:41.820 and wonder whether these, these machines are conscious because obviously it'll be very important

00:39:46.620 ethically to understand whether we have built machines that can suffer. You know, if the lights

00:39:51.340 are on over there and, you know, we're basically murdering our robots every time we turn them off,

00:39:57.260 that will be an interesting problem to have created for ourselves. But I just think if, if the robots,

00:40:02.620 if we're out of the uncanny valley before we actually understand how consciousness is integrated

00:40:10.060 with the physics of things, we just might lose sight of the problem.

00:40:13.740 For a short time, for a short period, this may happen, yes. But I don't think it's stable. I don't

00:40:21.100 think it's a stable, it's a stable situation inherently. Because these intelligences will evolve

00:40:28.620 evolve at a, at a timescale that simply not matched the timescale that human society or human as

00:40:35.020 individuals, it's evolved. And so they rapidly will surpass us. And of course, if we believe

00:40:40.780 they're conscious and they, as you point out, they have all the moral attendant responsibilities and

00:40:46.060 right, it'll further dehumanize us and will further dehumanize nature and will become less and less

00:40:52.300 relevant. Because, you know, we're building these other guys, they are our successor. It's,

00:40:56.460 it's obviously the next step beyond human humanity. They're smarter than us. They're more robust than

00:41:01.580 us. Ultimately, they're more aggressive than us because we'll build them for warfare. You can see

00:41:06.460 that already, you know, happened beginning to happen in Ukraine and Russia. And where does this leave

00:41:13.660 homo sapiens sapiens? Yeah, but for most part, for most people, this problem will, will go away because

00:41:20.380 of course they're conscious. How can you not? You can talk to them. People will have intimate

00:41:24.540 relationships already now, right? You can talk to these companies or make these more.

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Making Sense - Sam Harris - July 09, 2024

#374 — Consciousness and the Physical World

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