Consciousness: Anil Seth on AI, Reality, Perception, and Psychedelics

What is consciousness? How do we perceive reality? Will AI become conscious? We discuss these questions and more with Dr. Anneil Seth, the author of Being You. [music] Dr. Seth, welcome to the show. I saw your talk at the Royal Society recently online and you dedicated the presentation to your mother. Uh you said when the end of consciousness comes there is nothing to be afraid of and I was wondering if you could talk about that dedication for a moment. Well she's she's been in rather poor health for for a long time and actually it was a quite a surreal evening giving this seminar at the Royal Society for this the Faraday Prize.

It was a very prestigious lecture but uh my mother had gone downhill healthwise over the last few days. Um, so she's recovered a bit now, but at the time it wasn't clear whether she was going to make it. In fact, we didn't think she was. So, it reminded me of this. One of the things I think about when I think about consciousness is the existential implications and how we think about the beginning of life and and the end of life. And and there's a a Julian Barnes novel which has the title Nothing to Be Frightened of. And it's all about mortality and our attitudes to mortality. And so I basically in my book too I've used that phrase uh because I think it has this beautiful double meaning that the absence of any kind of consciousness is can be simultaneously both terrifying.

We can be very frightened of nothing but of course there's the other interpretation that if there's nothing well you know there's no pain there's no suffering. We don't worry too much about the vast expanse of time before we were each born. So why should we worry too much about the vast expanse of time after we die when we won't be around to experience anything. It's a very very challenging concept to keep in mind. I mean people can spend their whole lives struggling with the idea of not existing and it's something we mentally very hard if not impossible to fully grasp because the act of grasping anything thinking anything uh means implies being aware being conscious and the closest I think most people come to is something like general anesthesia where we are totally gone we're not just asleep you know it's as close to the oblivion of death that I think for many of us we will ever encounter.

And so in your estimation, what is death? Well, I think we need a little bit of humility here. I I can't be 100% sure what happens when we die. No one lives to tell the tale, but it seems likely based on what we know about the brain and the brain's relationship to having any kind of experience is that when the brain stops, we stop. Over history, the notion of death has changed quite a bit. There's both in how we think about it from our cultural traditions of of religion in terms of things like you know the afterlife and hell and heaven or some or the bo or other things. Uh but also medically you know the point of death has changed from when somebody stops breathing to when their heart is stopped to now when their brain stops.

I mean that's clinically when death is established. But even that is now becoming a bit more of a gray area than it used to be. You know when exactly do we say that the brain has stopped to a point that it cannot be resuscitated and advances in medicine are wonderful but they tend to have this side effect of complicating these clear lines that we might otherwise have drawn. Well let's start with the most basic question. What is consciousness? It is a basic question. It's of course a very tricky question. I mean it's one of those words that I think we all used in different ways and we certainly encountered it being used in different ways.

For some people consciousness refers to something at the level of society. You know do we have a collective consciousness and awareness of our impact on the rest of the planet um [snorts] as a human society? I'm not referring to that sense of consciousness, at least not in in the work that I do in in my lab and in my writing. Consciousness in this sense has a very relatively precise meaning. It is what goes away under general anesthesia. And as we've just discussed at death too, that's the ultimate loss of consciousness. Uh the philosopher Thomas Nagel puts it like this. He says for a conscious organism there is something it is like to be that organism.

It feels like something to be me or to be you or to be many other different kinds of animal probably. But for a table or a chair or or a laptop computer, there's nothing it is like to be that for the thing itself. And they're just complicated objects. And I like this definition because it's it's very liberal in the sense of it avoids the tendencies or the what we might tend to do is associate consciousness with other things like intelligence or language or explicit awareness of myself as an individual. Yeah. All of these things might be associated with human consciousness. But consciousness itself I think is much more basic.

It's just any kind of experiencing at all. Pain, pleasure, red, green, any of these things. Whenever there is experience, there is consciousness. Now, you talk about the brain as a prediction machine and that reality is a controlled hallucination that stems from this prediction machine. Can you tell us what you mean by that? Two things. They're two separate claims there in a sense. This this first idea of the brain as a prediction machine is a hypothesis about a fundamental principle of operation of the brain in the body um that I think is very useful for understanding how we work and how consciousness manifests in ours and in other systems too.

We'll explain a bit more about that in a second. The other thing you said though that reality is a controlled hallucination is not quite what I say and the distinction is important. You know I [snorts] think reality exists. It's real. Reality is real. It doesn't depend on our minds. Um however the way in which we experience reality that is a kind of construction. That is what I think of as a controlled hallucination. So you know we never see things or hear things as they really are. The way in which we encounter objective reality is is always a kind of construction that is very tightly geared to objective reality.

Evolution is made very sure of that. [snorts] Um so there's no sort of slipping into nihilism or relativism or any of these things or idealism when we say that reality doesn't exist. Now the way I understand all this is through this concept of the brain is a prediction machine. And this can mean prediction of the present not necessarily prediction of the future. [snorts] And the way to understand it I think is to imagine being a brain. You imagine you are your brain. You're trapped inside the skull trying to figure out what's going on out there in the world. And from the brain's perspective all it's got access to are these electrical signals.

maybe a few chemicals swishing about things that are just very indirectly related to how things are. Um they didn't come with labels on these electrical signals all these chemicals. So from the perspective of the brain figuring out what's going on has to be a process of inference of best guessing of the brain figuring out what is the most likely state of the world in the body given this barrage of unlabeled ambiguous signals. and the brain's prior expectations or beliefs or models about the way the world in the body is. And so the claim here is that the brain is always making predictions about what's out there in the world or or in here in the body and using sensory signals to update these predictions.

So when we experience something, when we perceive something, it's not really a readout of the sensory input, though that's what you'll that's the impression you get on reading textbooks in neuroscience. And and maybe that's how things seem to us. It seems as though the world just pours itself into our minds, but actually it's the other way around. The brain is always making these predictions in an inside out or top down direction that are constantly being refined and calibrated by sensory signals. And my claim is what we experience well that's the predict that's the top down predictions. We actively construct the worlds that we experience.

We don't just passively register them. Perception then the brain's interpretation of reality as it exists. that perception is the bridge between reality and then the way we experience it. Would that be accurate? Yeah, I think it's it's a very good way of putting it. I mean, perception itself can be divorced a little bit from this bigger challenge of understanding consciousness. Perception can be thought of as how any system makes sense of sensory data to figure out some useful inter interpretation of it. So we can build artificial intelligence systems that could be said to perceive their worlds because they're not just directly reflecting sensory inputs.

They're making some interpretation of it. And then consciousness is this yet further aspect that for humans and I think probably not for machines but for humans sometimes this process is accompanied by a by a conscious experience. Now our brains aren't just doing complicated information processing. when we open our eyes and look around, we have a visual experience of the world or the or the body or you know not just in a visual experience, an auditory experience, an emotional experience. So yes, in this sense the mechanisms of perception do indeed provide a bridge from you know objectively what's going on in the world and the body and subjectively what's happening in our experience of that.

Well, along those lines, you said color is where the brain and the universe meet. Could you expand on that idea a little bit? I think color is a good place to start to unpack some of these ideas. I mean, colors are very, very important aspects of our lives. I mean, you're wearing this vibrant red [clears throat] jacket. At least it looks red on my my screen. Um, this uncharacteristically blue sky outside my window in in England. But what is color? Color's been debated in philosophy and science for hundreds of years. But and there's still a lot of discussion, but there are a few things we can say that shed light on on these ideas of perception.

Color is not really out there in the world as color. It's not that objects are literally blue or red. They just reflect electromagnetic radiation in different ways. Now, there's this whole spectrum of radiation going from radio waves with very long wavelengths to X-rays and gamma rays with very short wavelengths. None of these things are actually colored. It's just different wavelengths of energy. And there's a very small part of that spectrum, the so-called visible spectrum, uh, which is a thin slice of this objective reality. And then within that thin slice, the cells in our eyes are sensitive to roughly only three different wavelengths.

We call them red, green, and blue, but they're not red, green, and blue. They're just three different energies. [snorts] Out of combinations of these uh wavelengths, our brain creates a universe of colors. You know, many more than three. You know, we experience thousands, [snorts] perhaps hundreds of thousands, perhaps millions of distinct colors. So color in our experience is simultaneously less than what's really there because it's based on a very tiny subset of this wide spectrum of electromagnetic radiation. But it's also more than what's there because we experience this vast repertoire of colors.

And it's a useful thing for the brain to kind of construct because what colors help us do is keep track of surfaces as lighting conditions change. And so this very useful way for the brain to kind of pass reality because it just presents objects in visual experience. We have experiences of objects with different colors. They look different from each other and and they they have a continuity as the ambient light changes. Um but without brains there would not be colors. So in this sense color is different from many other things. The philosopher John Lock talked about this a lot. Colors really do require a brain to exist.

Otherwise there's just electromagnetic radiation. Um but other things that we might experience like how heavy something is or how solid something is. I mean those properties exist independently of a mind and a brain. Not if I am not looking at a wall and I walk into it, I'll still stop. It'll I'll still hit the wall and fall over. It doesn't just stop being solid because my brain isn't perceiving it. Uh but the experience of looking or touching a solid object now that is a construction. The way solid objects feel to us is a construction. But yeah, color. No, I think I don't think it was my quote.

I think I probably like most things borrowed it from somewhere else. But the color being where the brain and the universe meet I think just emphasizes this kind of humbling perspective that such [snorts] an important part of our daily lives is this collaboration between the brain and the world. It's not just to be taken for granted. We actively generate it every moment of every day. There was a discussion of that in your book being you the new science of consciousness which is an amazing book by the way. highly recommend it to anyone listening to this conversation if you're interested in these topics.

Um, you talked about a walking meditation in which you're trying to keep that front of mind uh the relationship between brain and colors. And I found that's a very useful way to just be in awe of everything around us and how much is going on in terms of perception and color. And I just wanted you to just touch on that a little bit about how you exercise that walking meditation cuz I think that's a really useful exercise for anybody that's interested in consciousness. [snorts] I'm anything but a diligent meditator. I've kind of dabbled [clears throat] in meditation but dabbling in meditation is not the generally it's not generally the best way to um to practice it but I do think that years of studying and thinking about consciousness is in a way a form of meditation and the two things meet a little bit more in this idea that you just mentioned and it's something I find myself doing um without really thinking about it as as a meditative practice quite frequently walking around or just sitting outside in in nature or even in the house and just reminding myself and this becomes for me a bit of an automatic mental habit that what I'm experiencing even though it seems to be objectively the way it is and my brain is just open to the world as it is.

It's not true that the colors, the shapes, the sounds that I'm hearing, they are all constructions of the brain that are reigned in by objective reality. They're not literally out there. And you're absolutely right that if you do this, and I find if you do this, it stops you taking consciousness for granted. And that I think can be very it can be very rewarding. and to some extent empowering experience. It certainly imbuss most of the time for me a sense of wonder and a bit of a sense of gratitude for for this process to exist. I mean perhaps being conscious of something was evolutionarily optional.

Maybe other forms of life on other planets could have evolved to behave and survive and reproduce without consciousness being part of their story at all. I think it's unlikely, but but who knows? Along those lines of color, you talk about uh is it Adelman? Adelman. How do you pronounce the checkerboard? Adelman. Oh. Oh, no. That's Aden. Sorry. There's there's very similar names. My old boss was called Gerald Adelman, but there's a very um well-known visual illusion called Aden's checkerboard. Different people, different things. There we go. Okay. Aden's checkerboard. What can we learn from Aden's checkerboard?

[snorts] Well, I think it's like many visual illusions. You often first see these things and they just give you this sense of, wow, that's weird. You know, that's that's not that doesn't seem right. What trick is my visual system or what trick is my brain playing on me? But I think the real value of these things is that it's not a trick. Your bl brain is not playing any kind of trick on you. Visual illusions are windows into how the brain works all of the time. Um so just to describe for for anyone listening what Adon's checkerboard is, it's [snorts] an image that shows us how deeply our brains predictions about the world shape what we experience.

So basically you see a checkerboard which has kind of light gray and dark gray squares um arranged as like a chess board you might see and there's a a little column a round cylindrical shape that's um at one end of the the checkerboard casting a shadow and the shadow is falling over the checkerboards. And what we seem to see is just this checkerboard with a shadow um passing down along di the diagonal of the checkerboard. But if we focus on the individual patches, then something strange is revealed, which is that two squares on the checkerboard, you can find two that look very different shades of gray.

Like the one under shadow looks much darker than the one not under shadow. But if you take all that context away and all you're looking at are these two squares, they turn out to be exactly the same shade of gray. Exactly the same. It doesn't matter how often you do this, it just works. It works as strongly as it did. I've seen this thousands of times. And so what's happening here? It's very surprising because the squares are so obviously the same shade and they look so obviously different when you've got the context. It's because context gives the brain an expectation about the scene and what and perception what it's trying to do is not just reflect sensory signals directly like yes this this is you know this patch of our visual field has this much uh you know value on the grayscale is trying to figure out what's going on and the best explanation for what's going on is that there is a checkerboard and checkerboards in checkerboards the colors alternate uh but some of it's under shadow.

So that's what we experience. We don't experience the contextfree properties of of light. Then the key realization is well this isn't just a weird quirk happening here. This is happening all the time. All of our experiences whether we realize that they're constructions or not they all are. It's just becomes obvious in certain situations. Yeah. I think it's an interesting idea that all of our experiences influence this prediction machine well beyond vision. The brain is making predictions about everything in our conscious experience all the time. [snorts] And that is going to influence everyone else differently in terms of their prediction machine, so to speak, is wired specifically to them a little bit differently, which is going to change how they perceive a conversation, how they perceive uh words and ideas.

And [snorts] it seems useful in terms of a way to create a little more empathy and understanding um especially when in when disagreeing with other people. No, [snorts] I think you're yeah I I very much agree. There are three ways to think about this idea of prediction machines very very briefly worth distinguishing. I mean one is very mechanistic. It's a claim about what the neural circuitry in our brains are actually doing. You know, actually throwing these predictions and updating them in a in a particular way that still stands as a hypothesis, right? I mean, we're one of the things I'm trying to do in my lab and many other labs, too, is trying to nail down these details and figure out exactly what's going on.

Is it really true that the brain is doing this? Um, I think there's a lot of evidence for it, but it's still, you know, it's still a hypothesis. The second thing which becomes much clearer is that whatever's going on under the hood, there is this deep effect of the brain's expectations about what we experience. The Adelson's checkerboard, many other examples, it's very very clear that what we experience is not a direct reflection of what's there. Expectations, context, and so on deeply shape it. However, it's actually working under the hood. And then the third thing is an implication which as you said and it's something I've become very interested in lately is that given that these expectations that the brain has that we might not even know our brain has cuz by the way we didn't really you don't need to know that your brain knows stuff about shadows.

It just does and then we don't need to know that our brain knows that. given that that is actually happening in some way, it's very likely happening in slightly or or even substantially different ways for different people. And I like to think of this in terms of the concept of perceptual diversity that just as we differ on the outside in terms of skin color and height and body shape and so on, we also differ on the inside. And and these differences don't have to be dramatic differences. differences that, you know, we might be tempted to label with this or that condition. Um, now we're used to the term neurodeiversity now as well, but that's got a lot of connotations typically about, you know, autism or ADHD or some other condition.

Um, whereas what I'm focusing on these days is the differences that we just might not otherwise notice. uh because there might be relatively small because we use language to the papers over these differences if we both say yeah you wearing a red jacket I mean we can agree but maybe we're having different experiences of red and finally of course we we just seem to see things as they are and because it seems to me that reality is just the way it is and I my brain doesn't have much to do with it that's another bias against us recognizing how distinctive our inner worlds might be and by fleshing out that idea and one of the projects that I'm very deeply involved in excited about the moment is a project called the perception census we've been running which has surveyed about 40,000 people each of whom has done between one or maybe several hours of experiments for us um all trying to get at different ways of [snorts] the uniqueness of individual experience and so this project.

We're still analyzing the data, but my hope is it's going to paint a picture of how different our inner worlds are. Scientifically, I think that's fascinating, but there's also this cultural significance that I think you hinted at that when we realize that we might live in perceptual echo chambers to some extent. um then that can cultivate within us a bit of humility about our own ways of seeing and perhaps our own beliefs about the world and society too. If we can literally experience the same situation visually in different ways, I think if we build really in better recognition of that, then that can be very helpful in cultivating humility, empathy, and platforms for communication and understanding.

That's a bit idealistic. I realize how it sounds, but I don't think it's nonsense. I think there's some plausibility to it. I would agree with that. And I like a little idealism. We [snorts] may not ever achieve uh perfect empathy and humility, but if we can if we can just move the needle a little bit, that's good for everybody. Let's switch gears a little bit to talk about emotions because I thought one of the most fascinating portions of the book was talking about how we experience an emotional state and assume that that emotional state drives bodily responses. We feel scared and so adrenaline's going to surge, cortisol [snorts] levels are going to go up, my palms are going to be sweaty.

But you describe a situation in which [snorts] the body has a response and then the brain is guessing at which emotional state should match that bodily state. It's reading the sweaty palms and the cortisol and the adrenaline going, "Oh, uh, this person is scared." Can you talk about that in a little more detail? Yeah, I'd love to. I mean, it's an it's an old idea again. A lot of these ideas about the brain as a prediction machine actually go way back. It's just that they're they're getting themselves on a much more solid footing with the tools of modern neuroscience and psychology. William James who was one of the founders of psychology along with a German psychologist called Carl Langanger independently they proposed this basic idea that we don't cry because we're afraid we're afraid because we cry the arrow of causality is reversed.

So it seems to us that we might be in a situation. Let's say we we encounter um I don't know someone's running at us with a with a knife and and we we see the situation. The visual experience of that situation causes us to feel fear and the experience of fear sets in train all these bodily responses [snorts] cortisol adrenaline so that we can either fight or or flee. Um again this might be how things seem but the proposal from James and Langanger is that it's the kind of the other way around so that we register our brains register the threats that automatically triggers the body to move towards this state of higher physiological arousal cortisol adrenaline the rest of it and it's the brain perceiving the body being in that state in the context of this person with a knife rapidly approaching would infers what's going on as fear is now the the relevant experience to have.

So the experience of fear doesn't cause the body to be in a particular state. It reflects the body being in that state in the context of the wider situation. And so thinking of things this way, it emphasizes a continuity. So that emotion is not really completely distinct from visual perception or or other kinds of experience. We can think of it as really resulting from the same kind of process where the brain is still making predictions. But now the predictions instead of being about the causes of visual signals or auditory signals, the brain's predictions are now about sensory information coming from the interior of the body in the context of the world.

You know, sensory signals from from the rest of the world. Uh so I like this way of thinking because it just it's very parsimmonious. It suggests there's one core process happening. The brain is making predictions but depending on the the target and function of those predictions, we have different kinds of experiences. An emotion or a visual experience or perhaps an experience of our body as being an object in the world or an experience of an action as being freely willed. But they're all kinds of constructions. And I think recognizing emotions in this way can also be um quite liberating and quite freeing because it can stop us falling into the trap of raifying our emotions.

And if we feel anxious or um angry or whatever it might be, if it's an aversive emotion, opens a little bit of space where we can recognize that that emotion is not a direct reflection of reality as it is, but it's a construction and it may partly depend on the context. Um, and it's a state of the what we're perceiving mainly as a state of the body. doesn't mean the emotion isn't appropriate and it certainly doesn't mean the emotions go away but it's very analogist to say how we we're talking about color you know when we understand more about color it's not that we stop perceiving colors no I still experience colors all over the place but there's another perspective on them now which is enriching it's sort of color is is a collaboration between my brain body and the world and the same goes for emotion I think it opens that space where we have a little morelex flexibility in how we respond to that emotion and that will also change how the emotion feels.

There there are sort of emotional equivalents of this Adelson's checkerboard. Um the same rush of adrenaline or cortisol can give rise to different emotional experiences depending on the context depending on what the brain thinks is responsible for the surge of cortisol and emotion. Is it a scary situation or is it an exciting situation? Depending on the context, we'll have different experiences, but the body is in the same state or a very similar state. Yeah, it made me think of of numerous things. Um, one that athletes uh high performing athletes a lot of the time in a situation that makes them feel nervous when there's a lot of pressure.

They talk about a version of reframing that nervousness as excitement because they know that will enhance performance and physiologically those two states are very similar and so as long as they're aware of it they're able to reframe that differently. Um, [snorts] it also made me think about uh dating and how the you have these common tropes of uh a a date to a scary movie or a date to an amusement park where you go on a roller coaster together. And you talk about in the book how being frightened is an aroused state and can often be uh tied into sexual attraction. And I I found that really interesting.

So, if you wanted to just just give us a few more details on on that idea. Yeah, I think I I honestly I don't know how much hard evidence there is for that. It's a little bit of a you know hard uh experiment to do, but there were some experiments back in the 1970s that tried to do exactly something like this when when ethical guidelines on experiments were perhaps well definitely more lax than they are now. And there's a famous experiment um done in in Canada by Dutton and Aaron were the two psychologists. And they had uh students walk over either a very rickety bridge high above a a gorge with a raging torrent and a rocky floor, very scary.

Um or over a bridge which was fairly boring, very sturdy, you know, very low over the water. So, a high arousal versus a low arousal inducer. Um, and then at the end of the bridge, they would get grilled by an attractive uh female with a clipboard. The students were all male and I guess this was the time where it was kind of an assumption of general heterosexuality, whatever. And um the quirk in the experiment was so so the the girl with a questionnaire would ask various questions but at the end of it would say and if you've got any uh further questions here's my number. Um and she was of course a stoogge for for the whole experiment.

And what was really in question was whether the people who went over the rickety bridge would misinterpret the physiological arousal caused by the bridge as uh attraction um some kind of sexual chemistry, romantic chemistry with the girl. And so the hypothesis was people who went over the scary bridge would make more calls um following up and maybe asking asking the girl out. And that's what they reported. Now, I mean, it's a it's it's a fun experiment to talk about. It's, you know, ethically dubious in in various obvious ways, and it's very hard to replicate because um can't really do that anymore.

[snorts] Uh but I think it's a yeah, it's it's at least consistent with what you're [snorts] what you're saying about dating, you know, on the other example um about athletes, you know. So, I'm I'm no athlete, but I also find this reframing useful in in some context. Like, I've been trying to be more disciplined about cold water immersion over the last couple of years. And, you know, trying to jump in the sea here in Brighton um when the water is very cold. It's still very cold in in May because it takes a long time to warm up or even just taking a cold shower every morning. And you know, when you start doing this, it's very emotionally unpleasant.

you know, you feel you don't want to do it and then it just feels like ah when you're in the cold water it's a horrible experience but then you know after a while there's a reframing that becomes possible which is you you realize that actually you're not going to die. Um, and so instead of these emotions which are all bound up with one's expectations about what cold water is going to be like and you just pay attention to some of the raw sensations like oh this is the experience of my body getting cold then the whole experience changes not just your interpretation of it. So I think this is important.

It's not I'm not saying that you can have an experience but you think about it differently. Know the context can change the experience. So for me now most of the time anyway getting into cold water just feels different even though you know it still feels cold. It's not that it feels warmer. It just is stripped away of some of the the optional I think interpretations [clears throat] of it that it's going to be very unpleasant. that is going to induce, you know, problems and going to panic and so on. And now it just feels cold and that's fine or fineish. Sometimes it just still feels pretty unpleasant, but it's much less so than it was.

I started this morning off since I'm in the uh Pacific time zone. I started this morning off with a cold plunge. I have a plunge at the house. And this is how I think about cold plunging. It's easier to act your way into a new way of thinking than think your way into a new way of acting. And I find that that cold plunge changes the bodily state and you can't help but to be alert, aware, uh ready to go um afterwards. And and I think that that ties into what we're talking about here with these bodily states drive our emotional state. Um and cold plunging is a great way to get there. Absolutely. I mean, sometimes you've just got to not think, right?

You've just got to not think and do. Um, so, you know, that's that's the strategy for things like this. If you think about it too much in advance, you your motivation for doing it just seems to get less. And if you just automate it, it's like, no, I'm just going to do this and give myself no choice. I mean, I think that's that's the way that you can then begin to bed in that that habit. You can change a habit and then it becomes like, oh, now it's beginning to feel different. it becomes easier to do and you you you can think about it and think okay now I'm going to do it but but the first few times yeah you have to turn off the the chatter if you like and just say no um I'm going to not think about it I'm just going to not give myself any agency or free will and uh and just go go ahead and there's actually an aspect of the predictive brain that plays into this another way that the brain can um uh can sort of do this ants between prediction, perceptual top down predictions and bottom up sensory signals is one way we've been talking about is the brain basically updates its predictions.

But the other thing of course is we can act, you know, we can act in the world and change the data. We can change the sensory signals. Um, and so there's actually a theory of not just perception but also of action in here. action becomes a self-fulfilling prediction about the movement and position of our bodies. So jumping into a cold plunge is like when you you know you really focus on self-fulfilling some predictions about the movement of the body um in a way that's becomes somewhat decoupled from the larger context. Now what can psychedelics teach us about consciousness? What a great deal. And as a side note here, I thought it was very brave of you to talk about your own experiences in the book.

Uh because usually someone who's a serious academic, they they hide that part of their lives or they shy away from sharing that. And I I appreciated that you talked about that openly. And would just love to hear more about that. Well, that's funny you should you put it like that because I was I was um I remembering a conversation between um a philosopher who you know who I respect greatly guy called Thomas Metsinger who's a philosopher of mind and I think he was talking to Sam Harris who asked him something similar and and his response was um well you know there are serious consciousness scientists and there are non-serious consciousness scientists and he sort of left it at that but but I you know I think that For me it it sort of felt that I was learning a lot about you know [clears throat] psychedelics from the third person but there was it was important to register that knowledge with the first person experience itself.

Um but what what can we learn? Well, you know, on the on one level an awful lot. I mean, one of the amazing things about psychedelics from a perspective of a consciousness researcher is that you have this relatively small change, you know, small intervention. You give a particular pharmacological compound. We know roughly where it binds to in the brain, its mech, you know, where where it ends up, the parts of the brain where there are more receptors. Um and then there is this massive change in conscious experience. So it's experimentally it's a very interesting intervention and it reveals in a sense how constructed our experiences are because many things can change in psychedelics you know in in different psychedelics course have different effects but for instance a common effect is ego dissolution.

our experience of being a well-defined self that's separate from the world and separate from other selves can can go away you know to some extent or even in some cases perhaps entirely. What do we learn from that? Well, I think we learn that the experience of being a self is not something to take for granted. It's something that the brain is actively constructing all the time. So psychedelics for me reveal what is you know this this surprising range of experiences that we can have and for me reveals how essential and how deeply our brain is implicated in constructing all of the experiences we have.

Now there are other ways that people interpret psychedelic experiences which I find less uh useful to think about which is that the content of a psychedelic experience instead of revealing the range and possibility and what we should not take for granted as revealing core insights into the way reality really is. Um and that's different. So if you take a psychedelic experience literally as sort of throwing off our filters and saying that this is real, this is more real than everyday experience, then I think you got it the wrong way round. Um it's for me it's shedding lights on how much is constructed.

It's not giving us a sort of unique unfiltered access to reality as it really is. You know, like one another example I think helps clarify this that people can often report out of body experiences. You know, they see themselves from somewhere that's out external to their body or perhaps floating off in in the air or in space. What should we learn from that? I mean, this might be from psychedelics. It might be from, you know, other situations, too. People can have these experiences in operating theaters or just with brain stimulation or many other reasons. Well, one interpretation is that your consciousness has in fact left your body and gone fly flying around.

Um, that would be to take the experience literally. That's really probably not true. You know, they're very hard to explain that. And of course, you know, how well how would you see anything without eyes? It just doesn't make sense in in in many different ways. Um but if you take the experience of an out-of- body experience not literally but seriously what it's telling us I think is that the very experience of a first person perspective is not to be taken for granted. The brain is always constructing it and sometimes under some situations it constructs it in a very strange way where the brain is saying no experience is coming from a perspective which is not in the body.

I think that's the right way to experience and it's completely different because in the second case we're still saying acknowledging that the brain is where consciousness is happening but the content of consciousness now we realize um something we might have taken for granted that well of course we will see the world from where their brain is because that's where the brain is but no the brain is figuring out what the best location for the first person is and it might not always be in the brain But it's going to depend and just to finish draw a loop on it's going to depend a lot I think on your on your prior beliefs about nature of consciousness like if you if you are partial to something like pansychism that consciousness is everywhere and part of everything then you might be more likely to interpret a psychedelic experience differently from if you are someone like me who is more of a materialist that I think consciousness is a property of biological brain-like systems.

Um, so there's going to be a lot of variety as well. And I also just wanted to emphasize that this is all separate from the value, the personal value that someone might take from it. So you know, somebody might after a psychedelic experience interpret it in a different way to how I would as as like an insight that consciousness suffuses the universe. And yeah, that would be a different conclusion than I would reach, but it still might be personally very beneficial for them. Um, and that's a whole other of course aspect of psychedelics, its potential for therapeutic deployment, for clinical use, for for enhancement of well-being.

And here I think there is a lot of potential, but I think the data is a bit mixed. And you know we need to be a little careful from the pendulum swinging from one extreme where psychedelics were illegal and and neglected by the mainstream medical scientific establishment to the other extreme where you know now there's there's huge enthusiasm and excitement and a lot of money into psychedelic startups and so on. I think there is a lot of potential but I also think there's no silver bullet. Speaking of consciousness arising from biological systems, [snorts] can AI become conscious in your estimation?

In my estimation, I think it's extremely unlikely. I am a little bit more um I'm a bit of an outlier I think among many colleagues of mine in neuroscience, but especially in when you hear people more deeply in the tech world. I think as a general belief that AI is on the road to consciousness. I think that's largely mistaken and I think this is true for several reasons. Firstly, there's just this background assumption that's very common in many corridors of academia and tech that consciousness is some kind of computation. You get the computations right, consciousness will happen. Um but for me this is a massive assumption like why should we think that uh you the metaphor of the brain as a computer has been very useful but ultimately it's just a metaphor and the more you look at things like brains the less like a computer they seem.

Um in a computer you've got this hard distinction between the hardware and the software. In a brain, you've got nothing like that between the mind wear and and the wet wear of a brain. Um, in a brain, it's very very hard to strip out what it does from what it is, but computers tend to work because they make that distinction very sharp. Um, so even if consciousness is a kind of computation, it might not be the kind of computation that can be done in things other than brains. But I think even more deeply, it's probably not a form of computation anyway. Um, you know, brains are very complex systems, but they're not necessarily kinds of biological computers.

Um, so I think AI is certainly on the path to convincing us that it's conscious and can simulate conscious systems. We can model it. I mean, we can simulate the brain on a computer, but we can simulate anything on a computer. That's what computers are good at. And you know, if we have a simulation of a weather system, we don't get confused about the fact that it's not wet or windy inside the weather forecasting computer. We know it's just a simulation. But for, you know, computer models of the brain like we see in AI, we might start to get confused and think, oh, it's not just a simulation. It's actually the thing itself.

But I think there are many reasons to doubt that. And there are many reasons why we make why we're tempted to make those kinds of attributions. I mean, we're very anthropocentric, anthropomorphic creatures. We see the world through the lens of being human and we project human qualities into things on sometimes rather flimsy evidence. So, language is a very very powerful lever in this in this domain. When things speak to us, we tend to project things like understanding consciousness into them. The current wave of language models has been very powerful here. But I really think the tendency to attribute consciousness to these kinds of AI, it tells us more about our human psychological biases than it does about what's likely to be happening in these systems.

So, I see a lot of obstacles to AI being conscious, but I see large challenges for us anyway when we're surrounded by systems that give us the, you know, impenetrable impression of being conscious even though we might at some level think that they aren't. Yeah. Especially when [snorts] a lot of the interfaces that are being created by new companies now are seem designed to make those large language models seem more like a person uh like a friend that you're talking to. That will get that will get tricky for people to parse out what they're dealing with there. It's already getting tricky. I mean there's already cases of people, you know, behaving in ways that are, you know, not good for them on the basis of interacting with language models and and believing that the language models really care about them.

And there are questions here for, you know, the the people developing these kinds of things. There's this sort of assumption that AI, you know, especially among the more evangelistic segments of AI and tech, that the goal is to develop systems that are hum humanlike. But it's not clear that that's what we should want. a mentor of mine who sadly died a few weeks ago, the philosopher Daniel Dennett said many years ago but kept saying again, I think for very good reasons that we should um you know we should remember always remember that we should treat AI as tools rather than colleagues and and always remember the difference and that has important implications for how we design AI.

Maybe we don't want to design AI to be as similar to us in all possible ways. You know, maybe we design systems that complement rather than replace us. And for me, that's a, you know, a path towards you getting more of the positives from this new technology and avoiding some of the potential negatives. Now I did want to ask because earlier you mentioned different frameworks for thinking about psychedelics or different frameworks for thinking about consciousness. Where does your framework for consciousness diverge from Donald Hoffman's framework for consciousness? Uh because I I spoke to him and and really enjoyed our conversation.

Uh but he has a much different way of looking at all of this. Talking about consciousness basically giving rise to an interconnected consciousness uh giving rise to space and time which is a much different way to approach all of this than a materialist perspective which is that consciousness arises from biological properties individually. uh if I'm if I'm summarizing that correctly and if I'm not please let me know. Yeah, I mean more or less I think my perspective is bi is that there's something special about biological systems but I don't know that for sure and the claim in materialism more broadly is doesn't [clears throat] um it's not restricted to biological systems.

It says consciousness is a property of matter of some form. So Donald and I have had many conversations. I always enjoy talking to him too. I always learn something. Um and we agree up to a point, you know, we agree that the the world that we experience is not the world as it is. You know, it's a kind of construction. Um and the relationship or the way in which we encounter the world is something evolution has tuned to be useful, not to be accurate. And so those are two large points of consensus. The first point of disagreement I think is he's he's very fond of this kind of user interface um metaphor where the world that we experience is some kind of interface that's useful for the self as the user.

Um now I don't like that way of thinking because I think the self is part of the construction too. There's no self that's perched inside the brain kind of reading out perceptions and figuring out what to do. That's a kind of inner homunculus view that that I I think is unhelpful. But I think the more fundamental place we diverge is what can be said about the nature of reality on the basis of thinking this way. Now Don takes it all the way that the level of indirectness is such that for him it makes sense to say that reality is fundamentally constituted by conscious agents of some form or another.

And you know I don't want to pretend I can accurately summarize his his view on this. Um but he goes to this to it you know that far and says okay that fundamental claims about the nature of reality and and space and time you know are also aspects of construction. So I just I suppose I'm a little more conservative than than Don on this. You know I think in a sense more radical that the self is part of the construction. It's not the user in the interface. I think that's you bit unhelpful. Um [clears throat] but I don't see any re any license in thinking this way that that that means we can say anything about the ultimate nature of reality.

Now I do think that things like the way we experience time and space are also to some extent constructions. Emanuel K said this said as much um hundreds of years ago. uh but he also said Kant had said that well there's this numinan there's this nature of reality and we never have direct access to it but it is there and I guess I'm a sort of some you minor descendant of that way of thinking that there is objective reality but the way we experience it is a construction and I just don't think we're licensed to say that the nature of reality is made of conscious agents or otherwise you know I still find materialism to be a good working assumption.

I don't know if it's true, but we certainly haven't exhausted thinking of things this way. And it matters because if you if you adopt that perspective just as a working assumption, you tend to do experiments that shed light on the phenomenon. You know, it's a good assumption in the sense that it generates interesting testable predictions about how the brain works and how it shapes our our reality. And if you start talking about conscious agents as the fundamental nature of reality, I'm yet to be convinced it's a use. It leads to many useful um experiments. Um it's not to say it's wrong. It just I I think it detaches itself from the power of the scientific method has always relied on this balance of thinking creatively and and being skeptical about the story that's told about things but also remaining in this kind of space of adjacency, the adjacent possible where where you you iterate and and you test something, you come up with new ideas, you test something else, but you still want to more or less in the domains of testability.

Maybe not for everything but but at least for some things. So yeah, we we end up differing I think a lot about our claims about reality but in practice in how we understand the brain as a prediction machine perhaps not so much. Yeah, I think there is a lot of overlap um between your thinking on this with his and I for one am glad both of you are doing the work you're doing uh because I think it's provocative and interesting and coming at it from two [clears throat] different perspectives and anyone that is interested in consciousness and what it's like to be to really think and examine what it's like to be a conscious agent would benefit from studying your work and his and going from there.

There is this par there is an overlap with me and Dom. But you know there are also many other theories of consciousness that are very different you know [clears throat] in in other ways too. They might be more similar to my way of thinking in the sense that they share a basic materialist foundation but then they'll differ greatly in what they think the mechanisms of consciousness are. There's this global workspace idea championed by Bernie Bars and Stand Hane. consciousness is to do with global broadcast of information in the brain. There's the really challenging integrated information theory of consciousness which is probably the most ambitious theory out there and it has implications that consciousness is much more widespread than we might think but it it takes a very different perspective again and and many others too and um I think this is an exciting time in the field because we we have a number of theories now uh that explain different things that make different assumptions But but there's an effort to try and compare them to try and test them against each other.

And you know, I've seen over the last 10 or 20 years these things develop substantially. And I think the next period of time is is going to be really exciting because these theories and the experimental methods we have now are getting to the point where we can meaningfully compare contrasting ideas about the nature of consciousness. And of course, that's where science really takes off. when you can start uh you know comparing and disambiguating different theories one as that process moves forward do you think slowly but surely this great mystery in science of where consciousness arises do you think that is solvable I think it's dissolvable I think what we what's most likely to happen is that as progress is made then there won't be one a where we you know wake up to the news that scientists have solved the problem of consciousness and you know here it is and um partly because we don't even know what a solution would look like.

I think much more likely is something that happened previously with our understanding of life wasn't that one day somebody discovered the secret of life. I mean you could argue that Watson and Crick discovered and and Rosalyn Franklin discovered the structure of DNA but that's not this that's not solving the problem of life. The problem of life had been largely solved before then that we collectively realized that it wasn't a single magic thing that it was you know many different processes that particular systems living systems tend to do and our nature of the problem changed just as much as our grasps on the solutions to the problems of life.

[snorts] And so I think consciousness is likely to follow that trajectory rather than the Eureka kind of trajectory. Um that as we understand more we won't solve the problem as it seems to us now but we the nature of the questions we ask will change and so the problem of consciousness will gradually seem less of a problem than it does and this is already happening. I mean this is what does keep me going if if I was relying on there to be a single Eureka solution you know in a race to find it you know I think that would be for me anyway a bit demotivating what what I enjoy about the field is that even without fully solving the problem what we're discovering is both interesting and useful and we've talked about this when we talked about perception you know it's useful in society to know about these things but the nature of the problem is also changing you know I think about consciousness in a different way now than I did 10 years, 20 years ago.

And so that is an optimistic take, but you know, we need we need to be a bit optimistic otherwise you wouldn't do anything. But I also think it's reasonably likely and there is a world where yeah, we have a much more satisfying understanding of consciousness even if at the end of the day there's still a little bit of mystery that remains. And Dr. Dr. Seth, if anybody wants to learn more about your work, there's the book of course, Being You, A New Science of Consciousness. Where else can they go to learn more about what you're doing? Oh, thank you for mentioning uh the book. That's that's definitely the place to start.

Um, then that's a couple of years old now, but it's still very current. Um, but for the latest stuff, I have a website anilsth.com. [snorts] Uh, so that's reasonably up to date, so you can find out more about research in my group and podcasts like these will be posted there. Um, and I'm still for my sins somewhat on Twitter or X where you can follow me on Anil Kes, so with a K in the middle for my middle name. Anilath was already taken. So, those would be the places to find out more. Great. Well, thank you so much for coming in today. I know you have places to be, people to talk to. Um, and I and I want to respect your time, but honestly, I could talk to you all day.

I just think you have a fascinating mind. And one of my favorite things about the book uh was some of the little the little bird walks that you take in the chapters um that just reveal how you process [snorts] the world and think about things. Um and I I personally hope there's another book out there in the future. Um because I think uh everybody would benefit from a little more uh Dr. Seth out there in the world. [snorts] That's very nice of you to say so. Um yeah, I'm sure there'll be another book. It's I haven't started writing it yet, but you know, I think these things these things take time.

Thanks a lot. It's been a great uh really enjoyed talking to you. I appreciate your time, too. So, thank you very much, Nick. Okay, everybody. Until next time, ask questions, don't accept [music] the status quo, and be curious. [singing] [music] [music]