Is Reality Real? - Neuroscientist On Evidence We're Living In A Controlled Simulation | Anil Seth

Dr. Rangan Chatterjee 0:00 I thought we'd start off by talking about death. Because as I've done my research on you, Anil, one thing we have in common is that in 2013 both of our fathers died. So for both of us, it's around 10 years since we saw our dads, at least in this realm. And because of what you study, the brain, our subjective experiences of life, consciousness, I, I'm really fascinated how do you view death? And specifically back in 2013, how did you view your dad's death? And 10 years on, has your perspective changed or altered in any way?

Anil Seth 0:47 It's amazing that it's already 10 years. I don't know if you find that remarkable-

Dr. Rangan Chatterjee 0:51 Yeah

Anil Seth 0:51 ... as well. It's, it's, for me it will be next month. It was on the longest day of the year, so the summer solstice always has-

Dr. Rangan Chatterjee 0:58 Mm

Anil Seth 0:58 ... a, a rather poignant feeling for me now. I think about death quite a lot and, um, I don't think in general we really do. We try to hide it away and pretend that it's maybe never gonna happen to either us or, or those around us, but of course it does. And when my father died, I was already... I'd been studying consciousness and thinking about consciousness and neuroscience for, for a long time then. And one of the things that I think helped me through that time was the recognition that consciousness and self are processes. They're not things. So my father's personality wasn't a sort of essence that was then disappearing forever. It was a process that was, was coming to an end. And actually, the general anesthesia, that was something that helped me face the death of my father and deal with it. Because in general anesthesia, I think we come as close to death as we ever will before we actually die. Now, general anesthesia is, is actually quite different from sleep. In sleep, if you've been asleep for a while, you might be confused about exactly how long, but you always know some time has passed when you wake up. But under general anesthesia, it's different. You are gone. The ends are joined up. There's just oblivion in the middle, the kind of oblivion that was there for you before you were born, and I think the kind of obl- oblivion that's there after you die. And in that absence of anything, you know, there's no pain, there's no suffering, there's nothing at all. And I think at some level, maybe I didn't consciously recognize it at the time, but there's a certain reassurance in that, that there really is nothing to be frightened of in death because there's nothing at all. There's no pain, there's no suffering, there's no anything. Knowing that or believing that, because of course we can never 100% know these things. Believing that helped me come to terms with so when my dad died, he really was gone. That process had come to an end. Of course, he lives on. I, I still dream about him. I don't know if you do. I mean, it's with astonishing regularity-

Dr. Rangan Chatterjee 3:20 Mm

Anil Seth 3:20 ... he still crops up in my dreams. But having this view of consciousness as being a process that depends intimately on the brain and the body just forces you into this recognition that there is an end to it, but it's a relative... It, it's, it's natural. You know, it's a natural end. And we don't worry so much about all the time before we were born that we were not conscious, so why should we worry so much about all the time after, whether it's for our own death or for somebody else's?

Dr. Rangan Chatterjee 3:50 It's so interesting to hear that perspective. But I guess what I'm trying to really understand is, and I guess this speaks to the heart of your work about consciousness, is w- you know, what is it? You know, to be human presumably requires that we have an element of consciousness, or we have consciousness within us. Otherwise, you know, we'd just be a table or this microphone, you know?

Anil Seth 4:12 Or a meat robot that just moves around from one place-

Dr. Rangan Chatterjee 4:14 Yeah

Anil Seth 4:14 ... to another.

Dr. Rangan Chatterjee 4:15 So then how can it be that when we're asleep for an operation, are we still human at that point? I know we're alive. We're breathing, right? Our, our parameters are being controlled. But, but, you know, what, what... how do you describe it? What's the difference-

Anil Seth 4:30 I think-

Dr. Rangan Chatterjee 4:31 ... between that and death?

Anil Seth 4:32 Well, I think we are turned into objects. I think we're, we're reversibly transformed into biological objects under anesthesia.

Dr. Rangan Chatterjee 4:40 [laughs]

Anil Seth 4:40 When consciousness is gone. Consciousness really is just any kind of experience whatsoever. You know, it's the experience of the world around us and of being a self within it with all our emotions and plans and memories. Any kind of experience is consciousness. And when that's selectively turned off, then you just become an object. And in a way, that, that is similar to death, but it's not the same thing because your body, the processes of life that animate your body are still ongoing. And an- that's why anesthesia's such a remarkable-

Dr. Rangan Chatterjee 5:13 Mm

Anil Seth 5:13 ... invention, because it, it's able to selectively alter consciousness without killing you, frankly.

Dr. Rangan Chatterjee 5:21 Do, do we, do we fully understand-

Anil Seth 5:24 No. [laughs]

Dr. Rangan Chatterjee 5:24 ... anesthetic? I don't think we do.

Anil Seth 5:26 No. I think that's why often th- this metaphor is that, you know, you'll often hear when you're going for an operation that you'll go to sleep for a while and, and then you'll wake up. This might be a comforting thing to hear, but it's, it's not very true. And what's perhaps even more disquieting is that we don't know exactly how and why anesthetics work. We just know that they do work. They're very reliable. And if used properly, they're, they're very safe. I mean, that's not unlike many things in medicine, as, as you know as well. We, we know that they work. But the deep reasons how and why things work are often still a little bit mysterious.

Dr. Rangan Chatterjee 6:00 Yeah. I mean, I imagine that's potentially scary for some people to hear that we don't really know exactly how anesthetic works [laughs] given how many people willingly go through it. But then, you know, as you describe in your book, you know, we kind of do the same thing when we get on an A380. Aeroplane. You know, every time I've been on one of these double-decker jumbos planes-

Anil Seth 6:24 [laughs]

Dr. Rangan Chatterjee 6:24 ... I, I, I'm like, h- how, how does this work? How is there two floors on this aeroplane, and all these heavy bags? And I still can't get my head round it. And I'm a, you know, I'm a reasonably well-educated [laughs] person. I... But I still go, right? So I guess the wider point is we're, we're always doing stuff that we don't fully understand but we kinda know works.

Anil Seth 6:46 That's right. I think probably we know, in general, you know, as a society, a bit more about how A380s work, because we design them from scratch. And anesthetics work on our brains, and brains were evolved not designed, so there's a little bit more uncertainty there. But you're absolutely right. The important thing in these cases, frankly, is that they do work. And anesthetics really do work. And we do know something about how they work. If you look at what happens in the brain under anesthesia, you see that parts of the brain stop talking to each other in the ways they normally do in waking consciousness. So the brain kind of disintegrates into little functional islands. And as that happens, consciousness goes away. And I remember the last time I had general anesthesia, I tried to really pay attention to this process of, of losing consciousness. The anesthesiologist often asks you to count backwards from 10, or 100, or whatever it might be. And I never get past three numbers or something.

Dr. Rangan Chatterjee 7:45 [laughs]

Anil Seth 7:45 I never get past seven. And then I'm gone, and then I'm back.

Dr. Rangan Chatterjee 7:50 Do, do we have any, uh, I guess case reports of people remembering stuff when they were under? You know, do we have a... Because we have, you know, again, talking about death for a moment, we have lots of reports of near-death experiences, don't we?

Anil Seth 8:09 Yes, we do.

Dr. Rangan Chatterjee 8:09 Or people who went to the other side and then came back. So how do you see all these kind of different experiences, and then how do you relate that to your work and your study of consciousness?

Anil Seth 8:22 I think there is a way to understand how they might come about. But also holding a little bit of humility here, because we don't understand consciousness fully. And so this is all a little bit provisional. There are case reports of people remembering things while supposedly having been under general anesthesia. This could be for a number of reasons. It could be because actually maintaining the balance of anesthesia is, is quite tricky. I mean, that's why anesthesiologists have to be very good at their jobs. You don't want to give too much, because then it can become dangerous for the patient. So sometimes the threshold might slip a bit, and maybe they are slightly aware-

Dr. Rangan Chatterjee 9:01 Mm

Anil Seth 9:01 ... and able to remember things. That can happen. And then of course, coincidences can happen too. When you come around in the recovery room, it's a very confusing, dissociated, almost delirious state. And you might think you remember things, but they're really sort of confabulations or-

Dr. Rangan Chatterjee 9:19 Mm

Anil Seth 9:20 ... or hallucinated memories that sometimes might just match something that somebody said. So these things can all, all happen. If anesthesia's done right, then I think you, you don't have memories of what happened.

Dr. Rangan Chatterjee 9:33 Okay.

Anil Seth 9:34 And near-death experiences. This is another, I think, really interesting example. And what I'm keen to s- emphasize here is that these experiences can be incredibly meaningful for the people that have them. And just by trying to provide a, a more scientific naturalistic explanation doesn't, shouldn't drain these experiences of meaning for the people that have them. But-

Dr. Rangan Chatterjee 9:57 Does that mean you don't think they're real?

Anil Seth 9:59 [laughs] It depends what we mean by real. I think the experiences themselves are real. You know, they are real for the p- the people that have them. They have the experiences they say they have. But it doesn't mean their interpretations of these experiences is true. So for example, a common report from a near-death experience is seeing a tunnel of light, and then maybe some emergence into all-surrounding-

Dr. Rangan Chatterjee 10:26 Mm

Anil Seth 10:26 ... whiteness. This could be interpreted as the soul leaving the body and traveling somewhere. But a more prosaic explanation is that, well, that's what happens when your visual cortex starts shutting down. And it shuts down more on the periphery of our vision first than at the center of our vision. And in that case, these experiences, they still happen, but they happen because the brain really starts to do some quite strange things when it's close to death. This can also be very meaningful because it means for these people, for, for all of us, that what we experience is not directly a reflection of what's going on. It's the brain's interpretation of what's going on.

Dr. Rangan Chatterjee 11:11 Yeah. I mean, there's a, there's a much wider point there, isn't there? Which we're definitely gonna dive into. That what we're experiencing every day is a form of controlled hallucination, and that what we call reality are just hallucinations that we all agree on, right? We're definitely gonna dive into that. But if we, if we, if we look at that through the near-death experience that you just mentioned, yes, so that, that is a common report, um, this kind of white light. And many people will say that actually, you know... 'Cause I've read some of these, uh, experiences, and I, I found them really, really interesting. Especially the meaning that comes in on the other side, which is, you know, the angel said, "It's not your time," you know. "Go back. You've got more work to do," or whatever it might be. And people often, I guess you may argue because of the meaning they put onto that, they then go and live their lives in a very different, more intentional way than maybe beforehand. But I guess the, the bigger question for me is- Why does it matter? In the sense that you said about your dad's death, understanding that, that it is a process and that there's nothing to fear. Believing that has helped you, right? So if we follow that logic, to me, why does it matter what the science says about consciousness? Surely it's the belief people have around it that then determines how it plays out for them in their life.

Anil Seth 12:55 I think in many cases this is, this can be true. And, and the two things are not necessarily incompatible either.

Dr. Rangan Chatterjee 13:01 Yeah.

Anil Seth 13:01 And one of the things that also helped me through my dad's death was, was ritual, which, you know, doesn't come from a scientific worldview. It came from his, his Hindu religion. And, um, ritual is really helpful at these times. It gives you a frame. It stops you thinking too much. It gives you things to do. And I found that a great comfort at the time.

Dr. Rangan Chatterjee 13:24 Can you share some of the rituals if you-

Anil Seth 13:25 I, I [laughs] I remember there was, there was a, there was a little, a little bottle of Ganga water, Ganga jal. Water from the River Ganges that he'd brought back on his last trip to India, which had been a couple of years before. And one of the first things you do in Hinduism when somebody dies is put a few drops of Ganga water in the mouth and on the eyes if I, if I remember, right?

Dr. Rangan Chatterjee 13:52 Mm.

Anil Seth 13:52 There were a lot of instructions like this, um, which I found just very helpful because at times like that you just want to be told what to do. You want to feel that you're doing the right thing. And ritual can do that for you. It can give you this, this architecture. You feel like you're participating in a social process and not something that's only happening to you.

Dr. Rangan Chatterjee 14:16 And if you reflect back on that as a, you know, globally respected neuroscientist. You know, I don't know if there's science on rituals, right? I'm, I'm, I'm sure there is. But the point I'm trying to make is, is that whether there's a scientific basis for rituals or not, I think we all kind of intuitively know how helpful they can be.

Anil Seth 14:42 Yeah.

Dr. Rangan Chatterjee 14:42 You know, after death it's useful to have a framework, this is what you do, instead of having to figure out and rationally explain, you know, oh, well, what's the point in this? Or should I really be doing that? It's like, I don't know. There's some- there's something, I don't know, this sort of feels as though it al- also relates to consciousness which is, yes, we can study it, and I know that's what you do. But we can also maybe feel that we're experiencing it and are happy to experience it and think about it without a kind of modern scientific explanation.

Anil Seth 15:22 Absolutely. So people have managed to deal with death for [laughs] many, many thousands of years without drawing on modern neuroscience. That, that's fine. That happens. It really probably applies selectively. I mean, for me, it's very, it was very important to try and align these different ways of understanding what was happening in my life, to be consistent between the scientific me and, and, and the more, you know, the son of my father. Sometimes beliefs can be in conflict with what science reveals. So it's not always comfortable, and I think being a scientist and trying to understand something like human consciousness and human psychology does mean you, you have to face the possibility that you will learn things about the mind and the brain-

Dr. Rangan Chatterjee 16:13 Mm

Anil Seth 16:13 ... which might conflict with some otherwise comforting beliefs. And then you've got some work to do, but I think that's work that's, that's always worth doing.

Dr. Rangan Chatterjee 16:22 Yeah.

Anil Seth 16:22 And I think that that's because I probably have this prior belief, even, even higher level belief, that understanding more about how things are will, in the long run, always enable me to, to live a better life, to, to manage better, to cope with adversity better. Now, that might be wrong. [laughs] That might be entirely wrong. Maybe it's better to just live a life of comfortable delusion.

Dr. Rangan Chatterjee 16:46 It probably depends, doesn't it, on who you are and how you choose to live. It, it's, it's so interesting to me that you're ... In, in, in some ways, I don't know if this is fully accurate or not, it seems as though what you found comforting about what you chose to believe about your dad's life and what death meant, in some ways as opposing to how I'm choosing to look at my dad's death now. Which is maybe in a less scientific way, a more maybe spiritual, more the beliefs I've absorbed from my culture growing up. Certainly my Indian culture, my family background, that, you know, in Hinduism the soul is eternal. Right? Uh, there, there's a belief in reincarnation. And I guess the way I've explained it recently is this idea that I still feel I have a relationship with my dad, it's just different now. I can't see Dad in the physical form. I can't go round. I can't, you know, pop in after work and see him having a cup of tea watching BBC News for the 12th time that day-

Anil Seth 18:03 [laughs]

Dr. Rangan Chatterjee 18:04 ... on repeat, right? I can't do that anymore.

Anil Seth 18:06 Yeah.

Dr. Rangan Chatterjee 18:06 But Dad... It's funny. 10 years on I feel that my dad is really playing quite a significant role in my life now, but he's not around. Like, the way I relate to him, the way I think about him, the things... You know, that picture there just behind you on the wall is- ... me and my dad

Anil Seth 18:25 I saw that when I came in. It's a lovely picture.

Dr. Rangan Chatterjee 18:28 Yeah. I mean-

Anil Seth 18:28 Yeah

Dr. Rangan Chatterjee 18:28 ... I can know that you've been, what, seven or eight back then. And so I don't know. I don't know what I'm trying to say. I guess all I'm trying to say is that we, we w- 'cause I think death is such a big thing, I agree that we don't talk about death enough. I think certainly in, in a lot of Western societies, we, we hide death. You mentioned culture. You know, I can still remember as a... What was it? Was it 1984 when the Indian Prime Minister Indira Gandhi died?

Anil Seth 18:52 Mm-hmm.

Dr. Rangan Chatterjee 18:53 I still have some sort of memory watching her funeral, maybe as a seven, eight-year-old kid on TV with my mom and dad. And I know how unreliable memory is, right? But this is the memory I think I have of watching her on a funeral pyre, her body alight, right? You're literally w- witnessing the body being burnt. Whereas we don't do that in Western culture. We hide the body. I, I c- I'm not... I don't want to speak in absolutes, but it's interesting, isn't it, how different cultures look at this?

Anil Seth 19:27 That's right. And my family, my dad's side of my family come from a, a place called Allahabad in Uttar Pradesh in Northern India, which is not far from Varanasi, where there are these public cremations on the banks of the river there. And I remember going there for the first time when I was probably 18, something like that, and seeing these things happen right there in front of me, and smelling them as well. I mean, you're right there. That was really rather shocking for me at the time. And yeah, it speaks to a totally different way of approaching death. There are many cultural variations. Um, there's, I think in, you know, in some cultures, in some Pacific Island cultures I think, people dig up the dead people every year and, and give them some food and drink and something to smoke, and then bury them again. I mean, there's, there's, there's very different kinds of rituals that happen. But just responding to one of the things you said as well about for you... Yes, you're right. In, in Hinduism, there's the soul. There's the Atman. It's, it's, um... has this, this context of being reincarnated or reincarnateable.

Dr. Rangan Chatterjee 20:32 Mm-hmm.

Anil Seth 20:34 Um, and the sense that for you, your, your father's still around. He's just not around-

Dr. Rangan Chatterjee 20:38 Mm

Anil Seth 20:38 ... in the physical sense. There's a sense for me, which, which this is the case as well, and this is because I think a human self, whether it's you or me, or your father or my father, we exist partly in the minds of others. Part of what it is to be a human self is the way I perceive other people perceiving me. It's as if my self is kind of refracted through the minds of my family and my friends and my social context. So I still also have a relationship with my father because he is literally, part of my brain-

Dr. Rangan Chatterjee 21:14 Mm

Anil Seth 21:14 ... is, is part of his self because part of his self was part of how he perceived me perceiving him. So, so the, the self is not this one unitary thing in this view. It... Part of it is distributed across-

Dr. Rangan Chatterjee 21:26 Yeah

Anil Seth 21:27 ... many. So in that sense, even though for him consciousness has gone, his self or the parts of his self that were distributed, they, they still exist. So, you know, I think we're familiar with this in Western cultures as well. There's this idea that we do live on in the memories of others-

Dr. Rangan Chatterjee 21:48 Mm-hmm

Anil Seth 21:48 ... in, in, in the works of art and science that we produce as well. It's not the immortality that, you know, some tech billionaire in Silicon Valley might aspire to, where they literally want to-

Dr. Rangan Chatterjee 21:58 Yeah

Anil Seth 21:58 ... keep existing as a subject of consciousness for a long time. But it's, it's a way of persisting.

Dr. Rangan Chatterjee 22:05 It's just so fascinating to reflect on these topics. Your perspective that we're basically living these controlled hallucinations, which we are gonna explain. I'm gonna-

Anil Seth 22:21 [laughs]

Dr. Rangan Chatterjee 22:22 Shortly, you can put, you know, why you believe that to be the case. But if we just take that for a moment and then apply it to death and apply it to what we've just been saying, could we make any case that death then is actually an illusion?

Anil Seth 22:46 I'm not sure we can. It, it... Of course, it depends what you think death is in the first place. I, I... For me, and again, I might be wrong about this, but witnessing the intimate dependency of consciousness, the ongoing flow of experience, witnessing the intimate dependency of this on the brain and the body, how changes in the brain are instantly reflected in changes in experience, how when the brain stops under anesthe- well, it doesn't stop under anesthesia, but how when, how when changes in the brain in anesthesia interrupt the flow of consciousness, it's very, very hard for me to reconcile that with the idea that consciousness for an individual persists when the brain stops entirely, which is medically when we say death happens.

Dr. Rangan Chatterjee 23:38 Yeah. That, that term's interesting, the flow of consciousness. I like that, the flow of consciousness. So if very simplistically speaking, consciousness is what makes us as humans different from a table, okay? Or one of the things that makes us different.

Anil Seth 24:00 One of the things, yeah.

Dr. Rangan Chatterjee 24:00 Right? I know because you've, you've... there's this article in Public about, um, your dad's death, and you, you say in the article your dad was lucky to have died in the way that he did, which I found really interesting. And it's funny, on a podcast I did last year, I was on someone else's podcast, and they asked me, I think, something like, "What moment in your life would you like to relive?" And the moment that came up for me was my dad's death because it was actually a very... It, it was a very powerful experience. Of course, the death of a parent is, but just a little bit of background. My dad was on kidney dialysis for 15 years.

Anil Seth 24:50 Hmm.

Dr. Rangan Chatterjee 24:50 So he had an autoimmune disease called lupus. Now, I think Dad died on a, was it Wednesday late? And I think at the weekend, Dad was in Manchester Royal Infirmary, and the head nurse of the dialysis unit had a chat with me and my mom and explained that, um, they didn't think it was a good idea to dialyze Dad anymore. And of course, I knew what that meant. It's like, well, dialysis is keeping Dad alive, and for a variety of reasons, they had decided, or certainly were consulting with us, but yes, had also decided that it wasn't appropriate to dialyze Dad anymore. And so I knew, again, I've not really thought about this in this way for a while, but I knew after all these years of chronic illness that, oh, Dad's gonna die at some point now. Now this is a, a reality that is coming.

Anil Seth 25:52 Whereas previously, his state of illness was something that seemed difficult but, but stable.

Dr. Rangan Chatterjee 25:57 Yeah.

Anil Seth 25:57 That was, that was him, and that was what he was going to be like.

Dr. Rangan Chatterjee 26:00 Yeah, exactly. Uh, yeah. And so, again, I was a very different person back then. I was 10 years younger. I saw the world very differently. Um, but on that final day, I remember at lunchtime, Dad was in a hospital bed. He wasn't very well, but somehow Dad became really alert, and his brother and, um, his family and me and my kids and my brother and his son, you know, were all there, and he hadn't eaten much for a few days, but he ate. He had like a full lunch.

Anil Seth 26:32 Hmm.

Dr. Rangan Chatterjee 26:32 Uh, I think my mom was feeding him and, and then I can't remember, you know, everyone said their goodbyes. People left, and then me and my mom stayed. I was on the right-hand side of Dad's bed holding his right hand. Mom was on the left-hand side holding his left hand. And over a period of hours, probably for 10, 11 hours, bit by bit, the life force within him starts to extinguish, right? So bit by bit you would see the heart rate changing-

Anil Seth 27:01 Mm-hmm

Dr. Rangan Chatterjee 27:01 ... blood pressure starting to go down. Dad was al- in the corner just looking up at the top right of the walls for hours. And what's really interesting is that when I think about your work, Anil, and this study of consciousness, is what happens? At what moment does consciousness leave my dad's body, right? At what moment is... You know, he's not responding for hours. He's not saying anything, right? But yes, his, his pulse is there. His blood pressure's there. So there is something beating within him. And so I, I really find this fascinating. At what point? Because what was also interesting, 'cause when Dad was officially medically dead, I called my brother who, uh, you know, he, he was struggling with a... He'd, he'd just broken a bone in his leg. He'd had an accident, so he couldn't be there. I called him. He got a cab into the hospital. And I remember for a few hours, it was in the middle of the night, me and my mom and my brother were in this cubicle in Manchester Royal Infirmary, in this hospital room. My dad was lying there dead. But it was such a wonderful few hours. We were just chatting, me and Mom and my brother, and Dad could've just been asleep.

Anil Seth 28:19 Mm-hmm.

Dr. Rangan Chatterjee 28:21 Right? It was a really powerful moment where it was like, wow, we were just chatting away about the good times and things, almost ignoring the fact that Dad's dead. We knew he was. So I'm sorry that was a bit long-winded. I, I, I guess I'm really trying to understand, 'cause I've loved diving into your book over the last few days to really try and get my head around this quite complex topic of consciousness.

Anil Seth 28:43 Mm-hmm.

Dr. Rangan Chatterjee 28:43 Right? How would you, how would you reflect that back to me? When do you think consciousness leaves someone's body?

Anil Seth 28:55 I think it leaves someone's body when the brain finally stops or maybe slightly before then. It's very hard to know from the outside, isn't it? And my dad, one of the ways he was lucky was that he, he died at home. I still remember the parallel moment to me from the doctor saying they were no longer going to dialyze your dad was we went... My dad had heart failure. We went into the John Radcliffe Hospital in Oxford. This is about three weeks before he died, and, and the doctor there said, "Really there's, there's nothing more that we can do." But he wasn't... He didn't need to stay in hospital.

Dr. Rangan Chatterjee 29:31 Mm-hmm.

Anil Seth 29:32 But driving home from that hospital was one of the memories that seared into my mind now, recognizing at this point that, well, that was the last time we'll do that drive. Everything was suddenly-

Dr. Rangan Chatterjee 29:44 Mm

Anil Seth 29:44 ... the last time. And that imbues things with such a sense of meaning and significance. And my f- my dad sat down on the sofa when we got home, and I still remember, he just said, "Oh, well, cycle of life." Very, very... I don't know what he was feeling inside, but he seemed calm and, and resigned. And then the next three weeks, he, he, as you said, he gradually, gradually slipped away. It was very hard to know when the moment was. I actually missed it because it was... He was at home for three weeks, and my mother was there. I happened to have popped out for a walk around the village, and my mom called me and said, "I think he's gone." And when I got back, there was a definite change. Um, exactly when it happens is very, very hard to know, but I do think it's when, when the brain stops, which is why, you know, the moment clinically, as you know, the moment where we define death has changed over decades or centuries of medical practice from, you know, when breathing stops to when the heart stops to now really when the brain stops.

Dr. Rangan Chatterjee 30:50 Hmm. How does that play into these near-death experiences, do you think? Do you think the brain's still... But by that definition then they're... Are we saying that they're not actually dead?

Anil Seth 31:03 Right. Right, right.

Dr. Rangan Chatterjee 31:04 [laughs]

Anil Seth 31:05 Exactly. And just as you were describing about your dad, that on his last day he sat up and he started eating a lot-

Dr. Rangan Chatterjee 31:12 Yeah

Anil Seth 31:12 ... and maybe was more alert than he had been previously. There's some evidence. Now, it's very hard to study this in the lab, 'cause you don't... You can't [laughs] really get the ethics to do this very easily, and of course you can't time these things. There've been a few studies with, with animals, with mice and rats and things. What you tend to see is there is this burst of activity in the brain as death approaches, a kind of last hurrah of brain activity.

Dr. Rangan Chatterjee 31:38 Mm-hmm.

Anil Seth 31:39 And the experiential flip side of that may well be what a near-death experience is.

Dr. Rangan Chatterjee 31:45 Yeah. I mean, my belief is, and I use that word intentionally, my belief is that Dad on some level knew that this is it, these are the final hours now. And so because everyone was around-

Anil Seth 32:01 Mm-hmm

Dr. Rangan Chatterjee 32:01 ... something internal caused him to wake up, engage, enjoy his last meal before signing off. And again, I have no proof of that. But then going back to that question, you know, is death an illusion? Well, I guess it depends on your definition of death. Because, you know, by the older definition of death, or one definition of death, the near-death experience where someone goes to the, the other side and then comes back would argue that, yes, it is an illusion. But it depends when you define that point, doesn't it?

Anil Seth 32:37 Right. Right. And illusion is alway- it's a very tricky word.

Dr. Rangan Chatterjee 32:39 [laughs]

Anil Seth 32:39 When people say the self is an illusion or free will is an illusion, it's like, with respect to what?

Dr. Rangan Chatterjee 32:44 Yeah.

Anil Seth 32:44 You know, it assumes that there is, you know, a definable ground truth that we're, we're not perceiving accurately.

Dr. Rangan Chatterjee 32:52 When does consciousness start, then? If we don't know when it... I guess [laughs] it's also gonna be an unknown, but, you know, is it when the sperm meets the egg? Is it... You know, how... Again, I, I, I ask the question knowing there's probably no firm answer. It's more to generate the conversation about it, you know. It's interesting to imagine, isn't it?

Anil Seth 33:13 It is. And there is frankly not much known about this because it's also very hard to, to study. There's this-

Dr. Rangan Chatterjee 33:20 So why have you chosen to study such a difficult topic?

Anil Seth 33:23 [laughs] Well, I... Because I tend to study in, in people in the time between being born and dying, when it's, when it's [laughs] slightly easier. When it's pretty unambiguous what's going on. But just, you know, in the moment of, of birth, we, we tend to, you know, assume for cultural or religious reasons that there's some point at which awareness starts. Whether it's at birth or whether it's before birth, or even, you know, there's a possibility that it might be after a baby is born.

Dr. Rangan Chatterjee 33:50 Mm.

Anil Seth 33:51 That there might be this period where they're not really experiencing anything. It... Very, very difficult to tell. Um, but what we do know is consciousness develops in stages. It's not like suddenly the lights are on and you have consciousness in this sort of mini version of a, of a human adult. William James, who was one of the originators of psychology as a science in the late 19th century, speculated about the conscious experience of a newborn baby. He called it a blooming and buzzing confusion. For us as adults, it's kind of clear what's a visual experience and what's an auditory experience. We hear things, we see things. Sometimes what we hear affects what we see, and sometimes what we see affects what we hear. But our ways of encountering the world are relatively segregated. But the idea is that doesn't come at the beginning. That's something we develop, we learn to do, in part. And so the world of a newborn might be this undifferentiated mass of sensory impressions, this, this blooming and buzzing confusion, as James put it in, I think, a delightful phrase. So I think these, for me, these are the, in a way, the more interesting questions about this semi-arbitrary moment-

Dr. Rangan Chatterjee 35:08 Yeah

Anil Seth 35:08 ... when it starts and, and when it finishes. It's more what is it like and how does it change?

Dr. Rangan Chatterjee 35:15 Let's move on to these controlled hallucinations. Um, a- and if people have not seen your TED Talk, I highly, highly recommend it. I don't know how you got so much brilliant information into just, what, 17 or 18 minutes. It, it, it really is very, very good. And it throws up a lot of questions for people. Uh, I enjoyed watching it with my son this morning-

Anil Seth 35:37 [laughs]

Dr. Rangan Chatterjee 35:37 ... for the, what, third or fourth time in the last few days. Uh, he really enjoyed it as well. And, um, I guess this idea that we're living controlled hallucinations. I wonder if you could backtrack a little bit and explain what do you mean by, by that? Because people could hear that, Anil, and go, "What are you saying? You're saying that basically life is just a simulation? You know? What... Is it, is it not real?" And I don't think you're quite saying that.

Anil Seth 36:04 I'm, I'm not saying that.

Dr. Rangan Chatterjee 36:05 [laughs]

Anil Seth 36:06 It's very hard to find the right words to describe these concepts that are coming out of neuroscience and philosophy. No metaphor is perfect. And in this idea of our experience being a controlled hallucination, the control is extremely important. But let me try and unpack what this concept means in its essence. And I'll do that by just asking... Le- let's just reflect for a moment on what happens when we open our eyes in the morning. We wake up, we open our eyes, and it seems as though the world is just out there with all its colors and shapes and smells and so on, and it just pours itself into our minds through the transparent windows of our eyes and our ears and our nose. As if we're just passive recipients of this objective reality. This might be how things seem, but it's not how things are. The idea, and, and it's not, it's not a new idea. It goes back in philosophy hundreds of years-

Dr. Rangan Chatterjee 37:07 Mm-hmm

Anil Seth 37:07 ... to Immanuel Kant and, and back to Plato in some ways, and in psychology and neuroscience at least 100, 150 years. The idea is the brain doesn't read out the world. It kind of writes the world. What we experience is the brain's best guess. It's the ba- brain's... What we experience is the brain's prediction of what's out there in the world or, or in here in the body. There's this essential indirectness between what we experience and what's really there. I think the easiest example for this is color, and color is such an important part of our daily lives.

Dr. Rangan Chatterjee 37:44 Mm-hmm.

Anil Seth 37:44 It imbues our lives with beauty and meaning. But what are colors? We know from physics that there are no colors, so to speak, out there in the world objectively. There's electromagnetic radiation. It goes all the way from radio waves at one end to X-rays and gamma rays at the other.

Dr. Rangan Chatterjee 38:06 Mm-hmm.

Anil Seth 38:06 And our eyes, the cells in our eyes only respond to three of these wavelengths, which aren't colored, right? They're just wavelengths of, of energy. Yet out of those three wavelengths, the brain generates this infinite palette of beautiful color. So what we experience when we experience color is simultaneously less than what's really there, 'cause it's just sampling this thin slice of reality, but it's also more than what's there because out of that thin slice of reality, the brain conjures millions of different colors. So it doesn't make sense to say that, you know, is our perception of color, is it accurate? Well, that's, that's an ill-formed question because color isn't there in the world anyway. Evolution has developed our brains to experience color because it's useful, not because it exists.

Dr. Rangan Chatterjee 38:59 Yeah. Okay, I, I love this, right? I, I absolutely love this. So couple of years ago, we were on holiday somewhere, my wife, myself, and my kids, and I remember looking at the sea. And I think one of the key things I want to teach my kids is that everything in life is just perspective, right? And I think this really speaks to your work. Um, it's just perspective, right? And you have a perspective, but other people have... may have a different perspective. I'm always talking to them about the things they get taught and say, "Okay, could, could there be another explanation for that? What's an alternate viewpoint on that?" I think it's a... I'd like to believe it's a really great way to interact with the world. Gets us out of our little tribes where we think that things are only one way. And we looked at the sea and I said, "What color is the sea?" And because we do this quite a lot, ultimately the conclusion was, well, the sea appears to be blue to us, but we don't know what color a dog sees. Or maybe we do, but to my knowledge, we don't know. What does a dog see when it sees the sea? What does a dolphin see when it sees the sea? Does it see it as pink? Does it see it as green? Does it not even have a color, right? So when you start looking at things like that, is it then accurate to say not that the sea is blue, I perceive that sea as blue?

Anil Seth 40:31 Yes. I think that's much more correct to say. The artist Cezanne said this years ago too. He said, "Color is where the brain and the universe meet."

Dr. Rangan Chatterjee 40:40 [laughs]

Anil Seth 40:41 Very nice way to put it.

Dr. Rangan Chatterjee 40:42 Beautiful.

Anil Seth 40:43 And yet the s- the, the color of the sea, the color of anything is not existing in the thing itself. It's what the philosopher, um, John Locke called, it's a secondary quality. It requires a mind to exist as well. Not everything is like that, right? Solidity. If you, if you think about a car coming down the road and it's a particular color, that color only exists in the interaction of the physical object that's the car and the brain that's looking at it. And because we all have different brains, it's not only a dog will have a different experience. You and I might have a slightly different experience. We just probably won't realize it.

Dr. Rangan Chatterjee 41:22 Hmm.

Anil Seth 41:23 But the, the car still has solidity. That's not dependent on the brain. If you go and jump in front of it, it's gonna do some damage. But the way we experience it, that's always a construction. So I think this is, this is a key part of this idea of controlled hallucination. I'm not saying that nothing exists, the mind just makes up reality. No, reality is there and reality can bite, but the way we encounter reality is always a construction. We never see things as they really are. You know, we, we see them... I'm drawing another quote here, stealing a quote from the novelist Anaïs Nin. "We see things not as they are. We see them as we are." But that doesn't mean they're not real. They're, they're perfectly real, and that's why we can get around in the world. We can behave.

Dr. Rangan Chatterjee 42:10 Yeah.

Anil Seth 42:10 That's why when people are hallucinating in an uncontrolled way, maybe through psychosis, maybe through chemicals, maybe through other things, they're less able to behave-

Dr. Rangan Chatterjee 42:20 Yeah

Anil Seth 42:20 ... in the world because now their hallucinations lose their grip on reality.

Dr. Rangan Chatterjee 42:27 Not only do we all see the world differently, we all perceive the world differently. Even within ourself, there's multiple versions of us that can see the same thing in different ways. So an example would be an email, right? And I, you know, I'm not a neuroscientist, so please do give me your perspective on this. But one thing I think a lot about, and I would say for a good two or three years now, is that- We all see the world through the state of our nervous system. So you can read an email at 4:00 PM on a Friday if you've had a fraught week, and you're tense, and your stress is up, and you don't feel you've got enough time to finish what you need to before the weekend. So because you're stressed, your whole system has changed. You're no longer, uh, having your peripheral vision. You've now got tunnel focus trying to get things done, right? You can interpret the words in that email as a threat. Whereas let's say after a relaxing weekend, uh, where you've chilled out on a Sunday, spent time with family, gone for a walk in nature, had a good s- night's sleep on Sunday night, on a Monday morning when you're in a nice... let's say you're in a calm state, that same email with the same words, you can infer a different meaning. You can perceive it differently. So it's not only we all see the world differently, we... There are, there are, there are multiple versions of us within ourselves that can also perceive things differently.

Anil Seth 44:00 That's a really good point. I, I really like that, and I think it's absolutely true. And I think it, it speaks to this fundamental subjectivity of how the brain creates our experience. So we, again, w- we see things as we are, and we change. We change over time, and I... what you [laughs] the example of the email really, really hits home because I've had exactly that experience. We also have it when we're talking to friends or partners, where if we're stressed about something at work, we interpret what somebody says in a very different way-

Dr. Rangan Chatterjee 44:31 Yeah

Anil Seth 44:31 ... than, than if we're relaxed. And of course-

Dr. Rangan Chatterjee 44:32 Interpret being the key word.

Anil Seth 44:33 Be- being the absolute-

Dr. Rangan Chatterjee 44:34 Interpret.

Anil Seth 44:34 Yeah, the truth is not necessarily in, you know, in the sounds that we hear. It's in the meaning that, that we make from them. And what I think is, you know, fascin- it's actually one of the, the things that I think has... you know, can help each of us. When we recognize that it's really that way all the way through our experience, even color is an interpretation, and it becomes easier to catch yourself in the act of interpreting things.

Dr. Rangan Chatterjee 45:01 What, what was the, the example I think you referred to in your book? W- was it this blue and white dress?

Anil Seth 45:06 That's right.

Dr. Rangan Chatterjee 45:06 This... C- can you just explain it?

Anil Seth 45:07 Yeah.

Dr. Rangan Chatterjee 45:07 'Cause I think most people will probably get it. And, and on the video version, we'll, we'll, we'll maybe find an image and cut it in so people can see it.

Anil Seth 45:16 If people were anywhere near the internet in 2015-

Dr. Rangan Chatterjee 45:19 [laughs]

Anil Seth 45:19 ... it would've been very hard to avoid this particular meme. So this was a photo, a badly exposed photo of a, of a dress, and it suddenly tore around social media because there was this violent disagreement. Some people said, "Well, it's a... That dress is clearly white and gold." And then some other people said, "What are you talking about? It's clearly a blue and black dress, absolutely, no question."

Dr. Rangan Chatterjee 45:41 Hold on. Bl- white and gold and blue and black-

Anil Seth 45:44 Very different

Dr. Rangan Chatterjee 45:45 ... are very, very different.

Anil Seth 45:46 Very different. And this is why it, it kind of took off, and various celebrities w- weighing in, and of course, then it went completely nuts. And I remember I'd just been teaching a class on, um, consciousness, as it happens, and I'd recently published a book on visual illusions as well. And my phone was going off the hook, and emails were coming in. What is going on with this dress? I'd never heard of it until that morning either. First I'd seen it, and I looked at it and I thought, "Well, that's clearly a blue and black dress." And I took it around my lab, and the first five people said, "It's a blue and black dress." The sixth person said, "It's white and gold." And I thought, "Oh, hold on, it's... There is something here." And I didn't know what it was at first, um, but of course I agreed to try and explain it [laughs] about an hour later. Um, and what, what's happening here is that the colors that we perceive depend not only on the light reflected from the thing itself but on the context. So this is another general thing about interpretation. When we interpret something, we interpret in a way that's hugely dependent on the context in which we're in. This could be an emotional context, like you said, the difference between a stressful Friday afternoon and a, and a peaceful Sunday evening. But in the case of the dress, the context was the ambient light, the surrounding light. Our brains do something very clever, which is basically control for what the ambient light is. So if you take a piece of... We've got some pieces of white paper on the table here. If we take them from inside this studio out into the garden, they'll still look white, but the light reflected from the paper into your eyes has changed massively. Inside, the illumination is, is relatively yellowish.

Dr. Rangan Chatterjee 47:30 This is why paint in a paint shop can look very different-

Anil Seth 47:33 Yeah

Dr. Rangan Chatterjee 47:33 ... from when the paint is put on the wall in your house.

Anil Seth 47:36 So yeah. If there's one lesson to take home from this, is you always need to take a sample of the paint home. Never trust what it looks like in the shop. [laughs]

Dr. Rangan Chatterjee 47:42 Yeah. This is, this good neuroscientific research on how to, how to decorate your house.

Anil Seth 47:46 That's right.

Dr. Rangan Chatterjee 47:46 You know I like it.

Anil Seth 47:47 That's right. I'm still terrible at choosing colors.

Dr. Rangan Chatterjee 47:48 [laughs]

Anil Seth 47:48 But if we take this paper outside, it'll still look white even though the ambient light has changed massively 'cause the brain controls for it. It's called color constancy. What we didn't know, and really, ps- people in psychology haven't studied this, is that this process can vary a little bit between people. And this particular photo of a dress hit a sweet spot where for some people, their brains assumed that the ambient light was relatively yellowish, that it was an indoor scene, in which case their brains inferred that the dress was blue and black. But for other people, their brains assumed that the ambient light was more bluish, like an outdoor light.

Dr. Rangan Chatterjee 48:28 Yeah.

Anil Seth 48:28 And their brains inferred that the dress was white and gold.

Dr. Rangan Chatterjee 48:32 On- once someone has... Is it possible that someone who sees it as, let's say, blue, can they also in a different setting, do we know if they can also see it as white and gold-

Anil Seth 48:49 Yeah

Dr. Rangan Chatterjee 48:49 ... once they've been tuned into this is what it can look like?

Anil Seth 48:52 I think so. If you change the context enough, you can flip it. It's not easy. I, I find it very difficult to flip my perception from one interpretation to the other. There's these other illusions, things like Necker cubes, which are these, like-

Dr. Rangan Chatterjee 49:05 Yeah

Anil Seth 49:06 ... cubes ma- you just have the outline lines. And you can either see it as if it's from below or from above. You can never see it both ways at once, and your experience can sometimes flip between the two. Same thing, same thing with the dress, but it's, it's much harder. What was just fascinating about the dress is that it really, it perplexed people because it, it challenged this assumption that most of us have most of the time, that we see things as they are. And we have this common phrase, like, "I'll, I'll believe it when I see it." And by just this one simple example showing that, hold on, it's the same image, yet two people can have a radically different experience of the same thing, usefully undercuts that-

Dr. Rangan Chatterjee 49:48 Yeah

Anil Seth 49:48 ... that idea.

Dr. Rangan Chatterjee 49:49 Well, what you're speaking to here through, through this example of the dress, it's like wait a minute, you see the world the way you see it, right? Not everyone sees it the same way. Yet, you know, I don't know, what did it teach you about humans? Um, I don't really remember this back in 2015, right? And not, certainly not clearly. Was there a really divisive dialogue? Were people quite, um, I guess demeaning to other people who saw it differently, saying, "You're blind," you know? You, what are you... You know? What, what was going on there? And there's a, there's a little mini example here where when my wife and I started dating, I can remember, um, at my mate's wedding we went to [laughs] she wore this really nice dress. Um, now I think I saw it as orange, she saw it as red, and we would have this kind of back and forth for, for months over what color it was. And both of us were, you know, maybe at that time in our relationship both keen to assert that this is this color.

Anil Seth 50:52 [laughs]

Dr. Rangan Chatterjee 50:52 This is this color, right?

Anil Seth 50:53 You didn't immediately agree with her? I thought that's what you'd done. You-

Dr. Rangan Chatterjee 50:55 No, I didn't. I didn't. [laughs] We, neither of us did. We were, we were pretty sure that the way we were seeing it was the way it was.

Anil Seth 51:01 Okay.

Dr. Rangan Chatterjee 51:01 But actually, it kind of speaks to this wider point, doesn't it? That all we're ever seeing is our own perception.

Anil Seth 51:09 It's... That's correct. And I think it's, it's not what... I mean, the thing with the dress is that it came and it went. It was a social media meme and then it kind of vanished a little bit. One of the things we're doing now, one of the projects that I've been running in the lab for the last couple of years is this, uh, thing called the Perception Census. And it's still going on, actually.

Dr. Rangan Chatterjee 51:27 Mm.

Anil Seth 51:27 And it's trying to understand these individual differences in, in how we perceive things. Not just in color, but in other aspects of vision. In the flow of time, in music, in sound, in emotion. We don't know very much about this kind of hidden landscape of inner diversity, uh, that characterizes all of us. And I think this is partly because, as you say, we... It's very hard to recognize that there could be this inner diversity, 'cause it seems as though we just see things as they are. And partly also because the dress was exceptional, that the difference was so big-

Dr. Rangan Chatterjee 52:04 So clear

Anil Seth 52:04 ... that it immediately showed up in our language and, and behavior. Not in a particularly vitriolic way, actually. More in a, in a confused way. Um, but man- many of the differences in how we encounter the world and experience might not be that dramatic. You know, if we both look... You know, the example of your wife's dress. Maybe you're different, maybe it's, it's just at the fringe where you're going to use a different word, and if the differences in your experience had been a bit less, you'd both have said it was, it was reddish or something like that.

Dr. Rangan Chatterjee 52:33 Mm.

Anil Seth 52:33 So with this Perception Census we're trying to get a picture, build a picture of how just as we all differ on the outside in terms of skin color and height and body shape and so on, we all differ on the inside too. And knowing this, I think, is vitally important. It's, it's an important scientific challenge. Let's see what's out there. It's a bit of a voyage of discovery. But it's also, I think, socially important for exactly the reason you were hinting at.

Dr. Rangan Chatterjee 53:00 Socially.

Anil Seth 53:00 That one of the things that the dress episode suggested to me was the importance in general for people recognizing that they have a point of view. That's what we see when we see the dress. Like, it's, it's not as it is. It's I'm seeing it through my point of view. And recognizing that we actually have a point of view is, is important.

Dr. Rangan Chatterjee 53:26 Yeah. I mean, Anil, I, I honestly think that the implications of this are, are truly quite profound. Because what I hear as the, or one of the conclusions of what you're talking about and what you're researching, I just see a more compassionate world. I see less tribalism, more forgiveness, more understanding, more empathy once we recognize that not everyone sees things the way that we see them.

Anil Seth 54:01 That's the hope. I mean, that's a very idealistic hope, but-

Dr. Rangan Chatterjee 54:03 No, I'm-

Anil Seth 54:03 But you, you know, if it checks out

Dr. Rangan Chatterjee 54:04 ... I'm an idealist, mate. I believe it's possible. I mean-

Anil Seth 54:07 Well, I hope so. I mean, y- b- but to your point, you look at something like political disagreements, right? Uh, people are so embedded in their political and social media echo chambers that they find it very, very difficult to not even understand another's perspective, but even recognize that other perspectives exist. And so here is something where I think the science of consciousness, of perception can be very useful. Because when you realize that you literally can see the world differently from other people and nobody sees it as it is, idealistically, optimistically maybe, this can cultivate a sense of humility about the way-

Dr. Rangan Chatterjee 54:47 Mm

Anil Seth 54:47 ... we perceptually encounter things. And then that provides a platform-

Dr. Rangan Chatterjee 54:52 Yeah

Anil Seth 54:52 ... for cultivating a bit of humility about what we believe. And it's not, it's not saying that our beliefs are arbitrary and that they bear no relation to the truth. It's, it's just saying that they are interpretations. There's a point of view happening here. And if we can cultivate a bit of humility about our own- ... perceptual interpretations, if you like perceptual beliefs about the world. Maybe we can also cultivate a bit of humility about our other beliefs, and that of course provides a platform for better communication, empathy-

Dr. Rangan Chatterjee 55:22 Yeah

Anil Seth 55:23 ... and so on.

Dr. Rangan Chatterjee 55:25 One of the examples I have used in the past to try and explain this to people, not from a neuroscientific point of view, but just from, just, just from the idea of trying to understand, well, what is truth? Right? What, what actually, what actually is going on? And I, the, the example I often use is let's imagine there's a romantic couple, okay? For ease of explaining, let's call it husband and wife, right? Husband and wife are having a heated disagreement around the kitchen table. Okay? I think most people would probably be able to relate to that. They would've had an experience like that at some point. What happened? What was the truth of what happened? Well, I think the truth of what happened kind of depends on who you ask. Like the husband will have their perspective on what just happened in that five or 10-minute heated disagreement. But if you walk round to the other side of the table, the, the partner, the wife, let's say, may have a completely different perspective on the same situation. So actually, what was the truth? What actually happened? Well, it kind of depends on which side of the table you're sitting on. I think that's quite helpful for people to really understand perspective. And then I, I read this study once about, um, these football fans, and maybe you're familiar with it, especially 'cause you're doing work on, uh, perspective, right? That... I'm trying to re- recall it all now, but it was, it was basically two sets of football fans on opposing teams were shown the recording of an incident in the game. I think, um, you know, someone tackled someone, right? So this wasn't in the midst of the game. This was afterwards when people were feeling calm, I think, at least. But they're looking at this, and how you reported that incident depended hugely on which team you supported, right? So again, what is reality? Right? Something happened, a foul or, you know, there was, there was contact between two footballers and something happened to a ball. But whether you deem that a foul or whether you deem that a great tackle kind of depended on which side you sat on.

Anil Seth 57:55 Yep.

Dr. Rangan Chatterjee 57:55 I mean, so what, what, what does this speak to?

Anil Seth 57:58 Uh, so I think there's two things. Firstly, it's important to recognize that something did happen. In both examples, maybe a glass broke in the kitchen, and in this case, yeah, a ball was kicked in a particular way or s- or somebody's foot hit somebody else's leg. So something happened. But beyond that ground truth, then things can start to differ in very dramatic ways through the biases that we have. And I think the really important thing here is that it's very hard sometimes to know that we have these biases, that we have these interpretive processes that are creating the world for us. We see through them. We don't realize that we have them. And when you take the piece of white paper outside, you're not aware that your brain is doing all this stuff in the background to take the context into account so that we still see it as white. We are subjectively blind to all this. So there's a need to... I think it's very helpful to the extent we can recognize that all our perceptions are, are creations, are, are constructions, but not totally arbitrary ones. You know, that helps us put a higher level of context on top of it.

Dr. Rangan Chatterjee 59:09 It-

Anil Seth 59:09 We can get a bit of distance

Dr. Rangan Chatterjee 59:11 ...

Dr. Rangan Chatterjee 59:11 is this where practices like meditation and mindfulness can be so helpful? Is this one of the reasons why they can be so helpful? Because it helps us develop that distance, that psychological distance. It helps us realize that we can observe these multiple interpretations. I don't know what, what's your... You know, given how long you've spent studying the brain and consciousness, w- how do you see meditation and mindfulness and their potential benefits? To make sure you're taking action after watching this video, I've created a free breathing guide that's gonna help you reduce stress, calm your mind, and boost your energy. In this guide, I share with you six really simple breathing practices that work immediately. Even just one minute a day will start to make a big difference. To receive your free guide, all you have to do is click on the link in the description box below.

Anil Seth 1:00:14 Extremely complimentary. I, I meditate a bit. I don't know about you. I've tried to meditate more diligently, but I've never really been able to muster the discipline. It's not easy to meditate. Um-

Dr. Rangan Chatterjee 1:00:26 Especially if you have a fixed idea of what meditation is-

Anil Seth 1:00:29 Right

Dr. Rangan Chatterjee 1:00:29 ... or should be. I think that's-

Anil Seth 1:00:31 Yeah

Dr. Rangan Chatterjee 1:00:31 ... often one of the, um-

Anil Seth 1:00:32 Exactly

Dr. Rangan Chatterjee 1:00:32 ... obstacles to meditation for people.

Anil Seth 1:00:33 Yeah. It's, it's... Yeah, you should not even think of a meditative state as something you should try to achieve-

Dr. Rangan Chatterjee 1:00:38 Exactly

Anil Seth 1:00:38 ... which is what makes it even harder, in my, in my view. But I, I have been on a, a couple of retreats, and I'm very interested in it, and I've some experience, and I've talked to a lot of people who've meditated a lot. And I think this, the, the parallel, the complementarity does lie in opening this little gap, this very useful gap between how things seem and how they are. In meditation, one of the standard ways to engage in meditation is just to let your thoughts, experiences, emotions, moods just pass by, like clouds breezing acro- across the sky. To just witness their passing and not buy into them in the way that we often do. We have a thought and it leads to another thought and another thought and we start ruminating. Meditation just makes you realize that thoughts are just thoughts. Thoughts come and they go. Our perceptual experiences, they come and they go. They pass. And, and that's... And they are... You know, I think deeper into meditation you also get some recognition that our thoughts, our emotions... Because emotions are just forms of perception too. They're just the way the brain makes sense of what's happening in the body. All of these things are constructions, creative acts. I know a former-

Dr. Rangan Chatterjee 1:01:57 Mm

Anil Seth 1:01:57 ... guest of yours, Ruben, talked about this in, in these kinds of words, that everything that makes us human is a kind of creative act.

Dr. Rangan Chatterjee 1:02:03 Yeah.

Anil Seth 1:02:03 It's not a passive registration of just something that's there. And meditation can make that pretty clear as, as well. We train our attention so that we don't get wrapped up in these habits of thinking, habits of perceiving, habits of behaving. But can step outside of these habits just for a little while. And if you do that enough, then I think you can recognize the grip they have on you in your everyday life too. So studying neuroscience for this long, I don't think it's equivalent to spending 10,000 hours in a, in a Himalayan cave somewhere-

Dr. Rangan Chatterjee 1:02:37 Mm

Anil Seth 1:02:37 ... really meditating. But I think the place you get to is somewhat similar. Another aspect of meditative practice is to realize that the experience of self is also changing. The self is not this fixed thing, but it's a bundle of different-

Dr. Rangan Chatterjee 1:02:52 Mm

Anil Seth 1:02:52 ... kinds of experiences and perceptions. And that's very, very complimentary to, to the neu- to the perspective-

Dr. Rangan Chatterjee 1:03:00 Yeah

Anil Seth 1:03:00 ... that I'm trying to talk about here too.

Dr. Rangan Chatterjee 1:03:02 I, I definitely want to get onto the self shortly because the, the way you write about it, the changeable nature of the self, it's, it's... Again, it's very provocative I think for people. But it's very, very helpful, especially when we think about the rising rates of mental health problems and things like depression where people often feel stuck. They feel stuck. They, they, they often feel... And, and again, I understand that everyone has a different experience of this. Often feel that actually they're stuck a certain way. The, the, the way they think is reality, and that's all there is. So, you know, I'm always trying to think about practicalities. I al- I feel al- already in this conversation this idea that there are multiple perspectives hopefully is gonna help people realize next time I'm arguing with someone, next time I'm strongly attached and fighting about something, maybe I can take a step back and go, "Maybe that person sees the world and experiences the world differently from me." I, I, I think that's a pretty profound take-home for people. Th- this idea that meditation and mindfulness can help us just wedge in a little bit of distance to go, "Oh, wow, these things are changeable", I think that's very, very practical. Sorry, go on.

Anil Seth 1:04:25 Yeah. No. I, I'm just... I, I just agree. I mean, there's some sort of ideas that meditation is, is just sort of having an empty mind, and I think that's, that's wrong. And I think meditation, indeed, it, it, it doesn't mean you stop thinking, you stop perceiving. It just changes the relationship-

Dr. Rangan Chatterjee 1:04:40 Yeah

Anil Seth 1:04:41 ... that you have with yourself and your perceptions and your thoughts. And it's a very, very powerful thing to do.

Dr. Rangan Chatterjee 1:04:47 Ha- have you at all studied or are you familiar with the science, the neuroscience of what happens to the brain when someone is meditating?

Anil Seth 1:04:55 There's a lot of work on this. It's not work we actually do in my group. But it's, it's still ongoing. The two kinds of studies that tend to be done are studies on people who are beginning to meditate. So we might follow them over 8 or 12 weeks of meditation to see what changes. Um, or studies of people who've already accumulated, you know, years and decades-

Dr. Rangan Chatterjee 1:05:19 Mm

Anil Seth 1:05:19 ... of experience meditating. Of course, you don't then know what they were like to begin with. It's, it's hard to draw conclusions besides the fact that you do see differences. There are differences in the brain in the meditative state.

Dr. Rangan Chatterjee 1:05:33 Mm.

Anil Seth 1:05:33 And it seems likely that these differences accumulate over time. So after a lot of meditation, it's not only that your brain is in a different state during meditation, but that it's... meditation has, has changed your brain over time too.

Dr. Rangan Chatterjee 1:05:46 Mm.

Anil Seth 1:05:47 Exactly how, how it is, I think, you know, that's still... The, the-

Dr. Rangan Chatterjee 1:05:51 Yeah

Anil Seth 1:05:51 ... details are still to be worked out. But in a sense it doesn't much matter. Everything changes your brain. Breakfast changes your brain. Breakfast over time certainly changes your brain. But it's, it's more the direct... It works... Of course it works through the brain, but I think the right level or the helpful level to think about meditation is how it changes your experience and why that can be-

Dr. Rangan Chatterjee 1:06:16 Mm

Anil Seth 1:06:16 ... can be valuable. Of c- as you say as well, is very valuable for dealing with mental health issues. One of the things that happens in conditions like depression is that there's, um, there's a very dysfunctional sort of realism that you bring to your experience of yourself and the world, and things seem terrible. They seem unsalvageable.

Dr. Rangan Chatterjee 1:06:40 Mm.

Anil Seth 1:06:42 And of course that's an interpretation. And it's very hard from the depths of depression to recognize that this is an interpretation of events. It doesn't mean that everything is fine.

Dr. Rangan Chatterjee 1:06:54 No.

Anil Seth 1:06:54 You know, thing- there may well be d- of course depression often triggered by things that are objectively very challenging, very, very difficult.

Dr. Rangan Chatterjee 1:07:01 Mm.

Anil Seth 1:07:01 And are not solved just by meditating for a bit-

Dr. Rangan Chatterjee 1:07:04 Yeah

Anil Seth 1:07:04 ... or just by thinking differently. This is not a panacea. But it can be helpful just to break that cycle where things seem to be a particular way, you believe them to be a particular way, and therefore you, you behave and respond in a particular way, which can become self-entrenching-

Dr. Rangan Chatterjee 1:07:21 Yeah

Dr. Rangan Chatterjee 1:07:25 Staying on the subject of controlled hallucinations, right? And that we're not really seeing, I guess talking visually, what's there. It's an interpretation of that. It's how we put it together. You mentioned the conversation I had with Rick Rubin. A- and I wanna just follow that thread a little bit because one of the things I remember talking to Rick about, uh, for those people who've not heard, Rick Rubin is a, a legendary record producer. And a few months ago we had a quite wonderful conversation about health, happiness, the creative process. So many things, right? But one of the things I think we touched upon on the mics was this idea that, let's say Rick has been working with a band on an album for a period of months, let's say. It's always a good idea to get someone fresh to hear it towards the end. Because if you're, if you've been hearing it for two or three months, you're going to... This goes, this, I guess, speaks to this idea that you talk a lot about, that the brain is a predictive organ, right? That you're often not hearing it... Well, you're not hearing it as if someone was coming in fresh and hearing it. So someone coming in fresh is always gonna pick up stuff that you may not be picking up, right? When I think about editing books myself, like it's always helpful towards the end getting somebody fresh, and it's amazing what they pick up. And you think... Or even typos.

Anil Seth 1:09:02 Exactly. I was thinking that. And it-

Dr. Rangan Chatterjee 1:09:04 Typos. You're like, "I've read that. There's no typos in that." And then somebody-

Anil Seth 1:09:06 Yeah

Dr. Rangan Chatterjee 1:09:06 ... goes, "Have you seen that?" I'm like, "How, how did that go so... " And I think in your TED Talk you beautifully show various examples of the brain as a predictive organ. You used voice. I wonder if you have any of those files to hand. Is, uh, this-

Anil Seth 1:09:21 Yeah

Dr. Rangan Chatterjee 1:09:21 ... is this a good thing to use to, to explain?

Anil Seth 1:09:23 I, I think it's a great thing. But by the way, I mean, I was so s- I listened to your conversation with Rick Rubin, and I didn't expect there to be such a close resonance with the perspective that, that I've been developing as well. And I, I mean, I just, I have to read this, this quote. I mean, I, I went out to read his, his brilliant book, and there are some passages which are just, you know, more beautifully than I could write, put some of the same ideas. He said, "The outside universe we perceive doesn't exist as such. Through a series of electrical and chemical reactions, we generate a reality internally. We create forests and oceans, warmth and cold. We read words, hear voices, and form interpretations. Then in an instant, we produce a response. All this in a world of our own creation." I mean, I... It's, uh, it's exactly-

Dr. Rangan Chatterjee 1:10:10 It's the same

Anil Seth 1:10:11 ... it's the same. And, but what he's emphasizing, and what I didn't usually emphasize, is the creative aspect of it. Yes, it, it's, it's implicit in this view of the brain as a, as a prediction machine. As an active, interpretive organ that, that generates. I mean, there, there is something essentially creative about that. And what I loved about that conversation with Rick is you, he, he sort of links the thread all the way from this basic level of how our brains create our experiences of the world to, of course, the kind of creativity that he embodies as a, as an artist. And, and we're all artists in his view. And-

Dr. Rangan Chatterjee 1:10:48 Yeah

Anil Seth 1:10:48 ... one of our other artistic heroes, Brian Gibson, who said this too, and, and, and he's, in using this technique we've also been working on in the lab of stroboscopic light to give people interesting visual experiences. The original thing he did in the 1950s was, was really designed to make people aware of the power of the, their own brains and minds to create their experience. And underline that this means that, you know, we are all artists. We are all-

Dr. Rangan Chatterjee 1:11:16 Mm

Anil Seth 1:11:16 ... creative expressions of what's happening within our brains and bodies.

Dr. Rangan Chatterjee 1:11:21 A- and you, you, to give you credit, the, the beautiful phrase that you use in the TED Talk, and I think in the book, "We don't passively perceive the world, we actively generate it." I mean, that is thought-provoking. That we are actively generating our experience of the world. And I guess a lot of spiritual philosophers would argue, and I know the Indian philosopher Sadhguru, for example, who I've been watching some of his talks recently, especially his chat with David Eagleman on consciousness. I, uh, in preparation for our conversation, I, I saw parts of it. And, you know, he would argue that... Or his perspective is that that's what makes us human. That actually we can actively generate our experience. We're not compulsively reacting to what's going on around us. We're actually in charge, if we know how to harness that, I guess.

Anil Seth 1:12:18 Right. Because I don't think this process is limited to humans, of course.

Dr. Rangan Chatterjee 1:12:21 Right.

Anil Seth 1:12:21 So other animals too. We, we share very similar brains. It's always an interesting question.

Dr. Rangan Chatterjee 1:12:26 Mm.

Anil Seth 1:12:26 What really makes us different and distinctive? Is it something in the brain? Is it something in culture? But this is a very, very deeply evolutionary conserved principle, I think, of how many organisms perceive the world. And it gets back to what you were saying earlier about the dog looking at the sea. What experience is the dog having? It's also creating its experience. It's also a cr- [laughs] highly creative dog. But what it will come up with is gonna be quite different, and it's gonna be different partly in terms of the sensory receptors in its eyes. Maybe it's sensitive to different wavelengths. But the bulk of it will depend on how the dog brain interprets the signals that it, that it gets. So it's not just humans-

Dr. Rangan Chatterjee 1:13:10 Yeah

Anil Seth 1:13:10 ... that are great. But maybe we uniquely have the ability to recognize this process as unfolding. And as you say then, harness it, guide it, take advantage of it in some ways. But let me, let me try to find an example.

Dr. Rangan Chatterjee 1:13:25 Yeah, yeah, yeah. Go for it.

Anil Seth 1:13:26 This is a phenomenon called sine wave speech. So it really sh- shows how our- ... brains' interpretations can change what we consciously experience even for the same objective sound that we might hear. So I'm going to play one sound first.

Dr. Rangan Chatterjee 1:13:44 Okay.

Anil Seth 1:13:45 Here it is. I think Brexit is a really terrible idea.

Dr. Rangan Chatterjee 1:13:51 Okay. I, so to me, that sounds like a jumbled mess. I have no idea-

Anil Seth 1:13:58 No idea what's going on?

Dr. Rangan Chatterjee 1:13:58 No idea what that was.

Anil Seth 1:13:59 Okay. So have a listen to this. I think Brexit is a really terrible idea.

Dr. Rangan Chatterjee 1:14:08 Okay. Crystal clear. I can hear that. Okay.

Anil Seth 1:14:10 Crystal clear. Right. Now we'll go back and we'll play the same sound that I played first, the exact same sound that you couldn't make head or tail of. Have a listen. I think Brexit is a really terrible idea.

Dr. Rangan Chatterjee 1:14:23 Yeah. I think Brexit is a really terrible idea. I mean, okay, so how do you explain that?

Anil Seth 1:14:32 This is a phenomenon called sine wave speech. It's been well studied in psychology for a long time. What you do is you take a spoken phrase, in this case, "I think Brexit is a terrible idea." [laughs] I recorded this in, in 2016 in preparation for the, for the TED Talk. You take that phrase, and then you treat it. You basically chop off all the high and low frequencies, and it becomes really hard to understand. Actually, if you do it enough, it becomes incomprehensible, as I think you found it. So you play that. People have no idea what it is. It sounds like noisy whistles. And then you play the original sound, and it's very clear. Now, what this is doing is it's giving the brain, if you like, a perspective, an interpretation on the basic sound-

Dr. Rangan Chatterjee 1:15:19 Mm

Anil Seth 1:15:19 ... that's common to both, so that when you next hear the treated sound, the noisy whistle sound, your brain has an additional expectation about what's going on. It has a prediction about what, not the sound is, but what the sound means, and that causes us to hear it in a very, very different way.

Dr. Rangan Chatterjee 1:15:41 It's almost priming the brain.

Anil Seth 1:15:44 It's priming the brain. It's giving it, it's giving it a frame. It's giving it a perspective on-

Dr. Rangan Chatterjee 1:15:49 Yeah

Anil Seth 1:15:49 ... what the sound is.

Dr. Rangan Chatterjee 1:15:50 How, how does this differ from when you go to the car showroom, for example, and see some red cars? Let's say you're thinking of buying a car, and there's a red car that you particularly like. And then the next day and the following week, when you're out on the roads or you s- you see red cars everywhere, and you think, "Oh, wow, there's loads of red cars," you know, in, uh, on the, on the roads at the moment. Whereas the reality is, is that... Well, the probable reality is that it's the same type of cars, but your brain has been primed now to look for red cars. Is this similar or is it different? 'Cause I think that... Is that meant to be the reticular activate, activating system?

Anil Seth 1:16:36 No, I don't think so. No.

Dr. Rangan Chatterjee 1:16:37 No.

Anil Seth 1:16:37 No. I think, um, I think they're slightly different examples. So in the, in the car example, what may be happening is that you're more, you're just paying attention to these things. Red cars have become suddenly a lot more salient 'cause you just spent a lot of money on one. And, um, so then you, your brain will start to notice more red cars.

Dr. Rangan Chatterjee 1:17:00 So is this predictive processing in the same way? Like, to, to me, I'm, I... what I hear as a non-neuroscientist is there's all kinds of signals and noises in the environment all the time, right? We, we can't... If we took everything in that was out there, we'd, we'd literally be frazzled and won't be able to operate. So our brain is constantly trying to make our life easy and simpler, and it's feeding us consciously the information that it thinks we need to interact with the world. And so that's the kind of broad lens through which I look at these examples. I get that maybe, um, you know, physiologically and biochemically they may work in different ways, but that's kind of my overarching way of looking at it. H- how would you explain it?

Anil Seth 1:17:48 That broad picture is, is basically right. I think there's just a couple of differences. I think they're important differences actually, so it's worth dwelling on a little bit. And I'm glad you mentioned the car example because it does highlight these differences. So yes, in general, you're absolutely right. Our brains sample just a tiny amount of the information that's actually available there to us, and this is another aspect of perception that's quite difficult for us to recognize. You know, we only see in detail a very small proportion of the whole of our visual field, of the entirety of our visual experience. Yet it seems as though we see quite a lot, you know, all the way out to the edges and the tops and the bottoms of our visual experience. The brain is kind of creating the rest. Um, and we move our eyes a lot, and we move our attention a lot too. We can focus in one direction or we can suddenly pay attention to something that may be happening-

Dr. Rangan Chatterjee 1:18:43 Mm

Anil Seth 1:18:43 ... out of the corner of our eyes. This is one way in which the brain is actively engaged in probing its environment. It's not just passively sitting there, this control of attention. That's one way in which the world can seem different, if we pay attention to different things. And that's slightly different from these examples of, of sine wave speech because they don't really depend on attention-

Dr. Rangan Chatterjee 1:19:09 Mm

Anil Seth 1:19:09 ... so much. It's really changing the brain's template for something. You know, what the brain thinks is the cause of the sensory information-

Dr. Rangan Chatterjee 1:19:19 Mm

Anil Seth 1:19:19 ... that it gets. The two processes are very interrelated. You know, what we pay attention to has a bigger impact on our-

Dr. Rangan Chatterjee 1:19:28 Mm-hmm

Anil Seth 1:19:28 ... perceptual experience. It's like turning the volume up on some sensory information. And if we do that, then our brain's predictions are likely to change more than if we don't pay attention. In fact, there's a, there's a phenomenon called inattentional blindness, which is if you don't pay attention to something and you're not expecting it to change, then you don't experience the change at all.

Dr. Rangan Chatterjee 1:19:52 Wow.

Anil Seth 1:19:53 Even if it's perfectly visible to you, even if you're staring straight at it. Now, I once used, I once used this phenomenon to try and get out of a parking ticket in, in San Diego when I was living there. There was a no left turn sign which had recently been put up where I used to drive to the beach and, and turn left and go surfing, and I'd made this turn hundreds of times over the years I was living in, in California. And so when the sign appeared, even though it was directly visible to me right there in front of my car, I claimed to the traffic court that I literally did not see it because of this phenomenon of inattentional blindness. Something had changed. My brain was not expecting that change, so there was no way that I could have-

Dr. Rangan Chatterjee 1:20:36 And how did that go?

Anil Seth 1:20:37 ... actually seen it. It didn't go very well. [laughs] I did get a letter.

Dr. Rangan Chatterjee 1:20:39 But it's a great point, isn't it? It's a great... There is a... Although it's a funny story, right? Actually, it's quite possible that some people simply will not see it. It's there, but they're not seeing it. Now, this then, I mean, this then gets really either empowering or really quite confusing for people. As in, if we're all creating our own experiences of the world, you could go to an extreme and go, "We're all just playing our own internal computer game," right? So what, what does it mean for us? Like, how do we put all of this together, Anil, and try and then interact with the world?

Anil Seth 1:21:22 I think it's by recognizing that yes, our perceptual experiences of the world are individual, are distinctive in ways we're trying to measure with this-

Dr. Rangan Chatterjee 1:21:31 Mm-hmm

Anil Seth 1:21:31 ... Perception Census Study, which people can... Actually, by the way, pe- it's still open, so we'd love to get-

Dr. Rangan Chatterjee 1:21:36 So how, how do people-

Anil Seth 1:21:36 ... more data on this

Dr. Rangan Chatterjee 1:21:37 ... go onto it?

Anil Seth 1:21:37 If they just look at my website, anilseth.com.

Dr. Rangan Chatterjee 1:21:41 anilseth.com.

Anil Seth 1:21:42 You'll find it straightaway. We've got already 25,000 people from 100 countries.

Dr. Rangan Chatterjee 1:21:46 And what, what... And if people are interested, what happens? They go onto your website. They go on the link.

Anil Seth 1:21:50 Yeah.

Dr. Rangan Chatterjee 1:21:50 And, and what do they get? Asked a series of questions?

Anil Seth 1:21:52 It's, it's just some questions, but there's also little interactive visual illusions-

Dr. Rangan Chatterjee 1:21:57 Oh

Anil Seth 1:21:57 ... um, that people can play with.

Dr. Rangan Chatterjee 1:21:59 Sounds great.

Anil Seth 1:21:59 We designed, we designed it to be actually fun and not just, um, not just useful. So people-

Dr. Rangan Chatterjee 1:22:04 Is it open for a few more months?

Anil Seth 1:22:05 It's open for at least until the end of September 2023. And-

Dr. Rangan Chatterjee 1:22:09 Great

Anil Seth 1:22:10 ... there's many different sections. It sort of... What, what will happen as well, each section takes about half an hour and maybe on different topics, and at the end of it, you'll learn something about that aspect of perception and about your own way of perceiving and how it might relate to others. And of course, you- people will get the warm glow of helping advance the science of all this.

Dr. Rangan Chatterjee 1:22:30 I, I'm gonna do it. I'm in. I'm in. I'm interested. Okay, so back to what, what we can take from this.

Anil Seth 1:22:37 What we can take from it then is that indeed we each create our own experience in an individually distinctive way. We have different brains.

Dr. Rangan Chatterjee 1:22:46 Mm.

Anil Seth 1:22:46 We have different bodies. We will inhabit a unique subjective world. But that it isn't arbitrary. You know, there is a real world. Evolution has designed our brains to make pretty damn sure that most of the time we see the world in ways that it's useful for our survival, for our behavior, for our daily activities. So there's always this balance. W- what we don't want to do is, is fall into a kind of solipsism or something and say, like, "The way I see things has got n- has, has got nothing to do with the way anybody else sees things." No. We... There, there's a lot of overlap. But recognizing that we have a perspective, that we have a point of view, that there is this indirectness, and that this applies not only to the world, but to the self too.

Dr. Rangan Chatterjee 1:23:37 Mm.

Anil Seth 1:23:38 Think that's a very useful message to constantly just... I mean, what I do often, [laughs] I don't know if this is generally helpful for people, but, but to try and alternate that a bit. So when I just walk around the world, it's a bit like a kind of walking meditation in some ways. I will just occasionally stop and just reflect on this for a bit. Just think about the colors that I'm seeing and just think about, "Where are these colors?" You know, "Are they out there? They seem to be out there, but where are they?"

Dr. Rangan Chatterjee 1:24:04 Mm-hmm.

Anil Seth 1:24:05 They're in the interaction between the world and my brain. And recognizing that I think really can be very helpful.

Dr. Rangan Chatterjee 1:24:14 Yeah.

Anil Seth 1:24:14 It really does introduce this space between how things seem and how they are in a way that allows us to, to better communicate with others because we can recognize that they have their own kind of creative act of perception too.

Dr. Rangan Chatterjee 1:24:30 Yeah. You know, one thing I've started doing over the past few months, I don't even think I've told my wife that I'm doing this, but I sometimes, um, when I'm gonna see her after a, let's say a day's work or when I'm interacting with her, have this internal mantra, start from zero, which is this idea that... And I think this speaks to your work, a- and I'm sure you'll give me your perspective shortly, but this idea that often when we're interacting with people, we're so conditioned by our previous interactions that it can color positively or negatively the present experience. And I think many people in, you know, social interactions will realize that a lot of the time they're not reacting to what is actually happening. It's what they think is happening based on what has previously happened.

Anil Seth 1:25:33 Th- that's absolutely right. Yeah. It's a bit like that speech example-

Dr. Rangan Chatterjee 1:25:37 Yeah

Anil Seth 1:25:37 ... that, you know, what we're reacting to is, is what we think is being said.

Dr. Rangan Chatterjee 1:25:41 Exa- exactly. So th- this whole start from zero idea that I'm playing around with is this idea- Can I show up and interact with my wife as if this is the very first time I've met her? Which of course is impossible to a certain degree because, you know, I've been married for over 15 years now, right? So it's not the first time. But there's something really liberating and enjoyable about trying to interact in that way. I, I'm really enjoying it. I feel it, it gives a different kind of experience. Although I haven't told her that's what I'm doing sometimes. I think when she hears this [laughs] because she's the producer of the show, um, I'm interested in her perspective. I'll, you know, maybe tell you next time we talk. But I d- I do actually do that sometimes, and I think it's a really nice and beautiful way to try and interact with people. But w- would you say it's going against what our brain is there to do? Our brain is a predictive organ, so how does an exercise like that, do you feel, help us? Or, or, or is it pointless?

Anil Seth 1:26:49 No, I think, well, you'll have to ask your wife about whether she's found it helpful as well. But that would be a fascinating thing actually to know, whether, whether it seems different from her perspective without her having known that you're engaging in this exercise. It sounds potentially extremely valuable because it does strip away some of the preconceptions-

Dr. Rangan Chatterjee 1:27:08 Yeah

Anil Seth 1:27:08 ... we bring to our interactions. And yes, the brain has evolved as a prediction machine, but that doesn't mean it's always gonna do the right thing in every specific situation, you know?

Dr. Rangan Chatterjee 1:27:20 Mm.

Anil Seth 1:27:20 The brain has evolved in general to do the right sort of things at the right sort of times. Um, but of course this can mean very different things in different-

Dr. Rangan Chatterjee 1:27:29 And of course it's evolved for safety-

Anil Seth 1:27:31 Yeah

Dr. Rangan Chatterjee 1:27:31 ... not harmony, right? So it's, it's there to predict things to keep us safe. But in a lot of relationships, of course not all relationships, but in many relationships the issue isn't safety, it's harmony, right? So maybe what the brain has been evolutionary wired to do is working against harmonious relationships some of the time. I think we could make that case.

Anil Seth 1:27:55 I think you could. I think one of the things that really screams out to us when we think about the vast tracts of time over which our bodies and brains have evolved is that the environments in which they were evolving are very, very different from the world we live in now.

Dr. Rangan Chatterjee 1:28:11 Yeah.

Anil Seth 1:28:11 Very different. Think about things like how we, how we deal with climate change. We can't... Even though we know it's a problem, it's very hard to experience it as being the problem-

Dr. Rangan Chatterjee 1:28:24 Mm

Anil Seth 1:28:24 ... until we start to see storms happening and, and immediate catastrophes happening in places. We didn't evolve in a world where it was necessary to perceive things changing over that kind of timescale.

Dr. Rangan Chatterjee 1:28:37 Mm.

Anil Seth 1:28:37 Even though geologically it's incredibly fast, you know, psychologically it's, it's so-

Dr. Rangan Chatterjee 1:28:42 Yeah

Anil Seth 1:28:42 ... slow as to not be salient at all. And that applies as much to social circumstances as well. Probably the social circumstances that our ancestors existed in were very different. Now people make all kinds of claims based on this. There's a whole discipline of evolutionary psychology. Which is just, it's interesting, but sometimes it's a little bit weak I think because it's, it's, it's a lot of speculation. Um, but I think the truth is fundamental, that indeed, you know, our brains did not evolve to deal with the world in which we live. So then it can be very important in the world in which we live to notice the habits that our brain gets us into, and to challenge them-

Dr. Rangan Chatterjee 1:29:22 Yeah

Anil Seth 1:29:23 ... when we can.

Dr. Rangan Chatterjee 1:29:26 A couple of times in this conversation, the phrase the self has come up, and I know in Being You, you have spent, you know, a lot of time trying to unpick what is the self. As you see it now in 2023, if someone says to you, "Anil, what is the self?" what do you say?

Anil Seth 1:29:50 I would say the self is not the thing that does the experiencing, like the mini me behind my eyes sitting somewhere in, in my brain. The self is a kind of perception too. The self is a set of perceptual predictions. The self is a creative act.

Dr. Rangan Chatterjee 1:30:09 So who we are is a series of perceptions and predictions.

Anil Seth 1:30:16 Right.

Dr. Rangan Chatterjee 1:30:16 So that means then the self is changeable.

Anil Seth 1:30:19 It's always changing. It's relatively tempting to think that the self is this essence that, that is the recipient of this perceptual information that comes from the world and that decides what to do next and then does it in this sort of cycle of we sense things, we think things, and, and we act in the world. But what I think is much closer to the truth is that experiences of the world and of the self are both based on exactly the same principles of the brain making predictions about what's going on and updating these predictions, testing them against the world. The relevant part of the world when it comes to the self is largely the body. So the body... If you think about, if you think about things... One thing I find helpful is to think about things from the perspective of your brain.

Dr. Rangan Chatterjee 1:31:13 Okay.

Anil Seth 1:31:13 And just try and imagine that you are a brain. You know, you're locked inside this bony vault of a skull, and the purpose of the brain is to try to, at a first approximation, figure out what's going on.

Dr. Rangan Chatterjee 1:31:24 Okay.

Anil Seth 1:31:25 When it comes to the world, we've already told the story. The brain doesn't have direct access to what's actually there. It has to make predictions and update these predictions based on the sensory information it gets, and that's what we perceive. You know, we actively generate the world that we experience. We don't just passively perceive it. But then the body too. You know, the brain- ... is, is somewhat cut off from the body. It doesn't have direct access to what shape the body is, where it is in space, or even what it's doing on the inside. Gets a lot of sensory information. You can see the body. We can touch things. When it comes to the interior of the body, things like heart rate and blood pressure, there's a lot of, there's a lot of nerves that carry information about the internal state-

Dr. Rangan Chatterjee 1:32:12 Mm

Anil Seth 1:32:12 ... of the body to the brain. And the brain has to undergo the same process. It can't just read out the state of the body. It has to infer it. It has expectations about what's going on, and it, it perceives the state of the body as, again, a kind of internally creative act now.

Dr. Rangan Chatterjee 1:32:29 But you can train it, can't you? Like, you can train it in the sense that you're right about interoception, that perception of our internal state, I guess. Is that, is that an accurate definition?

Anil Seth 1:32:39 Yeah. It's the perception of the body from within. And we don't norm- we tend to think of perception as this, like the five senses-

Dr. Rangan Chatterjee 1:32:44 Mm

Anil Seth 1:32:44 ... right? Hearing, touching, tasting, smelling, seeing. But there's a whole... There are many other senses. You know, we sense our body position. We sense our body movement. We have a sense of balance. And then we have all these senses that tell the brain about what's going on inside the body. And that's all interoception.

Dr. Rangan Chatterjee 1:33:05 And I think interoception is something that can be trained. You know, you, you hear stories of yogis who've spent years, you know, putting their attention on their internal state, being able to actually feel their gut contracting, right? To, to many of us, we would say, "That's ridiculous. You can't do that." But the more you understand, or certainly the more I learn about the brain and how adaptable our bodies and brains are to what we're doing, you think, well, yeah, it's very believable to me that that would be the case if you spend a lot of time training yourself for that. And I, and I kind of feel that many of us are... I, I would, I would, I would think that many of us are more disconnected than we have ever been from our internal state because of the way many of us live now with all this tech, all this distraction, all this external stuff. You know, if you get up first thing in the morning and go straight onto your phone and are constantly consuming all the time other stuff, you're, you're not putting attention inwards. And I think it's a big problem for health, for happiness, for our wellbeing. You know, I, I've said for many years that the most important practice I do on a daily basis for my own health and happiness is a practice of solitude. There's many things I do within that solitude. But of course, we've already touched on meditation and mindfulness. And I do have concerns with trackers potentially in this kind of like, you know, now getting to the point where some people need a sleep tracker to tell them how they feel. Of course, not everyone uses them like that. But I think this, this internal perception of ourselves, I think is really, really important. Um, a- an- any comments on that?

Anil Seth 1:34:58 Definitely. I think it's... I think I agree with everything you said there. Um, and there is a lack of attention in, uh, modern culture to this. And there's this sort of dominant cultural narrative that the, you know, the brain is maybe primarily a thinking thing. And the body is, is just something that needs to be kept healthy in order to stay alive longer. And this idea also that the brain is a kind of computer, you know? And, and maybe the mind is the software running on the, on the wetware of the brain.

Dr. Rangan Chatterjee 1:35:29 What do you think about that?

Anil Seth 1:35:30 I think, I think it's wrong. You know, I think computers are extraordinary and powerful. But we've always used a dominant technology as a metaphor for how the brain works. Before computers, it was something like, um, telephone exchanges. And before that, it was something like networks of pipes. So we've always reached to technology. N- now it's changing, and maybe we think of the brain as a little bit more like the internet, a big cloud of information processing. But all of these things are inadequate. The brain is its own thing. It has its own reality. And if we think of it as a kind of computer, then the body fades a little bit into the background because for a computer, it doesn't much matter so long as it's light enough to carry it around, and its screen is big enough, and so on.

Dr. Rangan Chatterjee 1:36:15 Mm.

Anil Seth 1:36:16 It doesn't have an interiority in the same way that, that bodies do. So when we learn to pay attention to our bodies... I, I totally agree, by the way. I don't think you need to be a, a yogi for thousands of years. I think we can all learn to pay attention to what's going on in our bodies a little bit more. Meditation is, again, a way of doing this. You know, one of the, one of the conduits to meditative practice is to really pay attention to the breath and to notice what's happening in your body as you breathe. And then when you move on from there, one of the ways I think it can be very useful for, for mental health is the relationship between the body and the emotions-

Dr. Rangan Chatterjee 1:36:57 Yeah

Anil Seth 1:36:57 ... that we feel. You know, it's easy to feel an emotion and look for its cause out there in the world or in somebody else. But if we pay attention to what's happening when we feel an emotion, we pay attention to what's happening inside our bodies, it becomes clear that a large part of any emotional response is, is our brain's interpretation of-

Dr. Rangan Chatterjee 1:37:21 Yeah

Anil Seth 1:37:21 ... what's happening in the body. You know, when I feel anxiety, I, I try to, you know, with more or less success depending, really notice what's happening in the body. And you can feel it. It's like, wow, my, my arms, my hands, and my feet feel different. Anxiety for me tends to appear in the extremities of my body. And when you realize that, and then you... It can help dissolve the negativity of these emotions 'cause you realize-

Dr. Rangan Chatterjee 1:37:45 Yeah

Anil Seth 1:37:45 ... that they're just constructions. They... Maybe they're not ... uh, an, a- an objectively valid reaction to what's going on in the world. That's something that's happening in my body, and if you allow that to change, the body can change.

Dr. Rangan Chatterjee 1:37:57 Yeah.

Anil Seth 1:37:58 And then the emotion changes too.

Dr. Rangan Chatterjee 1:37:59 Yeah. I, I love that. Just t-t-two things there. Firstly, relating to what you said a few minutes ago, that we can all start paying a bit more attention, um, to ourselves, what's going on inside. And of course, as we say, meditation is one way we can do that. Um, I've been a fan of barefoot shoes, minimalist shoes for many years for a variety of different reasons. Um, and I think there are all kinds of benefits for our gait and our movements of wearing them. But one of the benefits I also think relates to this, which is often we can go for walks these days and be very disconnected. You know? People will be listening to this right now on a walk with earbuds in, and I have no problem with that. I think that can be a very enjoyable way to have a walk. But you can also go for a walk in a very mindful way, and I think some people can be mindful whilst listening to podcasts and walking for sure. But one of the benefits I found when people, myself included, wear minimalist shoes and these barefoot shoes when walking, is that you naturally become more mindful because you start to really feel what your foot is doing as you're walking, as you're interacting with the ground, and it's a really, it's a really quite beautiful experience. I think that's one of the, uh, untold benefits of, of wearing shoes like this, for example. So that was just one, one sort of reflection I wante- wanted to comment on. The other thing, what you're saying about paying attention to your body, that, that... One of my favorite bits in, in, in, in Being You was I think the section where you were talking about going through the history of how we think about emotions. You know, do we feel sad and then cry, or do we cry and then feel sad? And I think intuitively many of us will go, "No, no. I feel sad. That's why I'm crying." But you sort of unpick why that may not be the case, which I found really interesting. I wonder if you could expand on that in a second. But there was also this study you referenced in the 1970s, which was just brilliant. Uh, my recollection of that study was about these men who were on, you know, going over this narrow bridge where there was gonna be a big fall on either side, and there was something about a, a female questionnaire. Do... Maybe you could explain the study, 'cause it was truly profound.

Anil Seth 1:40:26 It's, it's a wonderful study. Unfortunately, it's the kind of study that would be impossible to get the ethics to do [laughs] these days, for reasons which will become clear. So what happened was... I- it's basically testing the idea, just as you said, that what happens when we have an emotion? Is it that, um, we feel fear and, and that drives changes in our body? Maybe then adrenaline starts flowing so that we can run away or fight or whatever we need to do. Or is it the other way round, where our body starts changing in a particular way and it's the perception of the change in the body that is the emotion? That's the counterintuitive view. That's the view that traces back to William James. Mentioned him before. One of the earliest psychologists already proposed this. And to test this idea, or one of the ways to test it, quite creatively in the early 1970s, these psychologists called, uh, Dutton and Aron took two groups of people. Each group was... I think they were male undergraduate students or young men of some sort, and half of them walked across a very preca- what seemed to be a very precarious bridge. This was above this gorge with a raging torrent and rocks far below. And they'd walk across this bridge, and, um, at the end of the bridge there was an attractive woman, um, who gave them a questionnaire. And the questionnaire was, was quite a vanilla questionnaire. I, I can't remember what it was. It was kind of a deviation, really. What the que- It wasn't that important. What was important was she said at the end of giving them the questionnaire, said, "If you have any questions about the study or the questionnaire, here's my number. Give me a call."

Dr. Rangan Chatterjee 1:42:04 [laughs]

Anil Seth 1:42:06 The other group of male young men went across a fairly boring bridge, much lower down, very sturdy, strong handrails, not a big drop, placid waters beneath. Same thing, woman at the end, questionnaire. Any questions, give me a call. And what the experimenters were interested in was whether more people would call from one group than the other. And of course, what happened was... Well, what do you think would happen? I mean, you know this study.

Dr. Rangan Chatterjee 1:42:31 Well, well, I've read it.

Anil Seth 1:42:32 Yeah. [laughs]

Dr. Rangan Chatterjee 1:42:33 So, you know, it was, it was... I, I don't know what it teaches us. Does it teach us more about men? Does it teach us more about emotions? [laughs]

Anil Seth 1:42:39 It's a bit hard to interpret, but what happens is of course, more of the people, more of the men who crossed the rickety bridge call the woman, and they call in the hope of getting a date with that woman. And the interpretation of this was that in the group walking across the rickety bridge, they're, you know, they're getting physiologically quite aroused because it's scary. There's a big drop. So the adrenaline starts flowing, the cortisol starts flowing, and they're in a state of physiological excitement. When they get to the end and they have this social interaction with a woman, they can misinterpret their sense of physiological arousal, which was objectively caused by the walking across the bridge, as a sense of romantic or sexual excitement between-

Dr. Rangan Chatterjee 1:43:30 So, so-

Anil Seth 1:43:30 ... the man and the woman.

Dr. Rangan Chatterjee 1:43:31 So the, um, the body is being stimulated. There, there's a degree of arousal in the body from being on top of this bridge. But the meaning, going back to what we've been talking about all throughout this conversation, the perception, the meaning that we give- ... to that arousal depends on the scenario. So if there was no woman there, let's say, there was n- they just finished and went on, they presumably would be interpreting that as fear. "That's why I'm feeling like this. That's why I'm feeling exhausted or a bit fraught," or whatever. But because there was a woman there who gave them their phone number, and, and I, I, I gotta say that as we're talking about this, I appreciate how politically uncorrect, uh, this kind of conversation is in 2023.

Anil Seth 1:44:23 Exactly.

Dr. Rangan Chatterjee 1:44:23 This was a study done in the 1970s.

Anil Seth 1:44:25 This was in the early 1970s.

Dr. Rangan Chatterjee 1:44:26 Right. Okay. So we're putting it out there on the table-

Anil Seth 1:44:29 Yeah

Dr. Rangan Chatterjee 1:44:29 ... so there's no misinterpretation. But that same physiological arousal in the body was interpreted differently, which is really quite remarkable, isn't it? So that then speaks to this idea that what our body picks up the signals first, and then our brain gets involved to put a meaning to it.

Anil Seth 1:44:50 I think rather than it being a, like, one thing happens, then, then the other-

Dr. Rangan Chatterjee 1:44:54 Mm-hmm

Anil Seth 1:44:54 ... I think m- for most of us, most of the time, these things are happening at once. Like-

Dr. Rangan Chatterjee 1:44:58 Yeah

Anil Seth 1:44:58 ... the emotion that you feel will indeed control your body, too. You know, it's, it's this kind of circular causality here. But w- I think the important lesson I certainly draw from this is it underlines the same principle is applying when we experience the world and our brain comes up with an interpretation of what we see, what we hear. You know, did that person say this thing? Or, you know, what color is that car? It's the same process that's happening when we feel an emotion, that, yes, there's some sensory information. In this case, it's saying, like, the heart is beating fast and cortisol levels are high. But the emotion that we feel that corresponds to that is not given purely by that change in, in the body. It's the brain's interpretation of the meaning of that change.

Dr. Rangan Chatterjee 1:45:46 Yeah.

Anil Seth 1:45:47 That's what the emotion is.

Dr. Rangan Chatterjee 1:45:50 So interesting, Anil. It really is. Um, just to close off this part of the conversation on the self, let's say. One thing I really wanted to ask you is if the self is changeable, if it really is a series of perceptions, in your view, and I'm not sure how familiar you are with the research on psychedelics and, uh, potential therapeutic applications of things like depression. But if we're saying that sometimes in depression people get stuck in a way of thinking, in a way of being, they have maybe a rather fixed perception of self. One thing we know that many people report on the other side of psychedelic experiences is that you almost bust through the idea of a fixed self. That, that sense of self often gets stripped away, where people will talk about there being, oh, there are multiple experiences here. There, there's a sense of connection with other people, the natural world, all kinds of things, right? So, and again, as a medical doctor, I have to highlight, you know, psychedelics in many countries, in the UK, are currently illegal. Yes, research is being done on them in very prestigious institutions like Imperial College London, I think King's College London, Johns Hopkins in America. But in your view, is that one of the reasons why they may well have such profound implications for some people suffering with mental health problems?

Anil Seth 1:47:33 I think it might be. There's this phrase in the psychedelic literature of shaking the snow globe. You know-

Dr. Rangan Chatterjee 1:47:38 Mm-hmm

Anil Seth 1:47:39 ... our normal modes of encountering the world and the self are thrown up in the air. They're thrown up for grabs a little bit in the psychedelic state, which gives the opportunity for them to resettle in different ways.

Dr. Rangan Chatterjee 1:47:51 Mm-hmm.

Anil Seth 1:47:53 And it happens directly in experience. I think one of the, one of the reasons psychedelics for some people might work is precisely they reveal in the first person, directly in experience, how indirect and constructed our perceptions can be. Things that we would take for granted become harder to take for granted. One common experience in psychedelics is that of ego dissolution-

Dr. Rangan Chatterjee 1:48:17 Mm-hmm

Anil Seth 1:48:18 ... which is a way of saying that our experience of the self as being this inner essence, totally distinct from, from the world around us, that, that fades away, and we feel a greater sense of continuity-

Dr. Rangan Chatterjee 1:48:31 Mm-hmm

Anil Seth 1:48:31 ... with the world, with nature, with each other, with the universe. And that's a, you know, positive emotion to feel in some ways anyway, but, but I think the deeper meaning of that is it, it can suggest to the person that their normal way of experiencing the self is... doesn't always have to be like that.

Dr. Rangan Chatterjee 1:48:47 Yeah.

Anil Seth 1:48:47 It is, it is a construction. I think the other really important thing to say, though, is that, you know, psychedelics by themselves are not a, you know, magic bullet. They're not a panacea. They open up this gap. But then the context is so important. In psychedelics, people talk about set and setting.

Dr. Rangan Chatterjee 1:49:03 Yeah.

Anil Seth 1:49:04 And, and it's psychedelic-assisted psychotherapy that I think shows the, the real promise where the psychedelics open up a space to work with that you can then, you can then utilize to explore what ways were you perceiving yourself, your body, your world that might resettle in, in different, more helpful ways.

Dr. Rangan Chatterjee 1:49:28 Yeah. It's, you know... We started off talking about death. And we were talking about the different beliefs around death, but also the importance of ritual to allow those beliefs to maybe, um, come to fruition and actually have their impacts. And I, and I, I hear a similar thing here whereby it's the psychedelic in a controlled setting- ... with ritual attached to it to allow it to do its work. Do you, is that, is that a fair comparison? So may- I know it's not quite the same thing, but I, I, I certainly heard something quite similar how ritual is really important.

Anil Seth 1:50:06 Right. Actually, that's a really good point. So ritual, back to the beginning of our conversation, that provides some of the context-

Dr. Rangan Chatterjee 1:50:12 Yeah, exactly

Anil Seth 1:50:13 ... in, in which we experience something like death happening-

Dr. Rangan Chatterjee 1:50:16 Yeah

Anil Seth 1:50:16 ... to somebody else. The ritual, yeah, it provides this, this larger set of... It gives the brain, if you like, some existing predictions, interpretations to draw on-

Dr. Rangan Chatterjee 1:50:30 Mm

Anil Seth 1:50:30 ... when making sense of what's happening in the body or in the world, and I do think it's important. And one of the other projects that I've been doing since the, since I finished writing Being You is this project called Dream Machine. It was actually this artist, Brian Gysin, who started this in the 1950s, and it's the use of s- fast flickering light on closed eyes, which can also give people quite interesting and quite unexpected visual hallucinations and experiences. And a lot of people feel better after this kind of experience. But we, we put it in a setting where there was a lot of context, where there was a lot of structure around it-

Dr. Rangan Chatterjee 1:51:13 Mm

Anil Seth 1:51:13 ... so that the experience wouldn't be dis- destabilizing for people. You know, people were held-

Dr. Rangan Chatterjee 1:51:17 Yeah

Anil Seth 1:51:17 ... throughout the journey in a way that encouraged them to reflect on what having this unusual experience meant for the way they would perceptually encounter the world and the self in the rest of their daily lives. But it's potentially an interesting intervention because it's, it gives you a, a powerful experience-

Dr. Rangan Chatterjee 1:51:37 Yeah

Anil Seth 1:51:37 ... but it doesn't rely on psychedelics. It's something that's much more-

Dr. Rangan Chatterjee 1:51:40 No

Anil Seth 1:51:40 ... in principle accessible to people.

Dr. Rangan Chatterjee 1:51:42 Super fascinating. Circling back to consciousness, if an eight-year-old child was sitting here right now and said, "Anil, what is consciousness, and why does it matter to me?" What would you say to them?

Anil Seth 1:52:01 To the eight-year-old child, I would say consciousness is what goes away when you go to sleep and you're not dreaming, and it's what comes back when you wake up. Consciousness is what gives... [laughs] I'm gonna start this again. It's incredibly hard to define what consciousness is even after, even after studying it for so long, especially when you try and explain what it is-

Dr. Rangan Chatterjee 1:52:29 Yeah

Anil Seth 1:52:29 ... to an eight. Because we take it for granted. This is the thing. It's so hard to define something that is kind of always there for us. Perhaps the easiest way to define consciousness, it's the redness of red. It's the painfulness of pain. It's the sweetness of honey. It's the fact that for everything we do and everything we are, there is something it is like. It feels like something to taste honey. It feels like something to be happy or to be sad. It feels like something simply to touch a piece of wood. It's what makes us more than biological objects roaming around in the subjective dark.

Dr. Rangan Chatterjee 1:53:17 It's magical to hear you explain it like that. Part of what you said reminded me of a conversation I had with Dacher Keltner a few months ago. He, he's a scientist in Berkeley. He wrote a book on awe. What's interesting is in, in that book, they... he kind of... There's a bit of a struggle with a definition, maybe a bit like consciousness, and I actually find that very comforting that there are some things in life, like consciousness, like awe, that we can't necessarily accurately define, that we can't put an envelope around, that we can't use our kind of human language that, by definition, in many ways is limiting. I, I actually really like that. I, I think it, it leaves room for the mysterious, and the mystical, and the fact that, as humans, we don't know everything yet. Do you know what I mean? I quite like that personally. It may, may be difficult for you as a scientist who's trying to study it, so you define it so you can actually measure things, but to me, I actually really like that.

Anil Seth 1:54:25 No, I, I think it's, I think it's important that there is this space, and it's a bit of a misconception about how science progresses that we need these kind of watertight definitions that exhaustively capture-

Dr. Rangan Chatterjee 1:54:37 Mm

Anil Seth 1:54:38 ... every aspect of a phenomenon. And I think about how we've come to define and, and think about life. I mean, life 150 years ago was as perplexing to people as consciousness might be now, and people didn't understand how life could appear from, from matter. You know, did we need a spark of life, an élan vital? A divine spark perhaps. And now even though we, you know, as scientists, as, as doctors, we don't understand everything about life, there's no longer this big sense of mystery. You know, life is part of nature, and we understand that. We can control aspects of life. We can even synthesize life in the lab now. But there's still something that's very difficult if you ask people to define what life is.

Dr. Rangan Chatterjee 1:55:27 Yeah.

Anil Seth 1:55:28 You know? It's not one thing. It's many things, and I think the same is true for consciousness. It's not one thing. It's many things, but it's a collection of things that share this property that feels like something-

Dr. Rangan Chatterjee 1:55:39 Yeah

Anil Seth 1:55:40 ... to be conscious.

Dr. Rangan Chatterjee 1:55:41 No, I love that.

Anil Seth 1:55:41 And we can hold that definition. And so long as we know intuitively what we're talking about, that's fine. That's enough.

Dr. Rangan Chatterjee 1:55:53 One of the things that is- I think remarkable for me when I think about your work, when I think about your book, when I think about this, this topic of consciousness, is how it speaks to so many different disciplines. It speaks to psychology, philosophy, maths, science, spirituality. It kind of... Everything converges in this topic. It must make it very fun, um, and challenging as well to study and write about. But I think that's... Yeah, it's really exciting for me to think of, of it through that lens. And as I said, when, when I was researching for this conversation, because consciousness is not something we've covered on this podcast before, right? And I've been really trying to think deeply about it, both from your work and from observing how other people are talking about it. Um, Eckhart Tolle, the spiritual teacher, says, "You don't have consciousness, you are consciousness." Okay? So from his perspective, I found that really, really interesting. Uh, I was watching a, a Swami talk about consciousness through the lens of, I think, the Vedanta school of thought. Uh, and again, I don't claim to be an expert here, but I, I really resonated with this, where they said consciousness is actually within you. This Swami was saying, it's not a part of your body and mind. It illuminates, um, and pervades your body and mind. It exists outside your body and mind. You may have a different perspective here. It is known through our minds and bodies, and without our minds and bodies, it is there, but it can't be known or experienced. And, and the, the way he was describing it was, again, I'll try and make this relevant to the audio listeners as well as the people watching on video, but there's light here now in this space between us, right? But if I put my hand there, I can now really see the light. The light is reflecting. I'm aware of that studio light that's there and how it's coming off that. And I think he was explaining consciousness like that, as in, without the hand there, the light's there, but I can't feel it and experience it until my hand is there. So to me at least, and I think this is a good place to try and close off this conversation, is, is consciousness, in your view, generated within us, or does it exist there out in the ether and we simply experience it?

Anil Seth 1:58:59 I think consciousness is the medium through which we experience everything, whether that's the self or the world. This means, in a sense, it's out there because we... The... If I, if I look at you now, I, I, I experience a person sitting across a desk from me. So that seems to be out there in the world. There's something out there. You know, there's a body. There's all kinds of things going on out there. But my experience is of something external to me. But the mechanisms of consciousness, the s- the actual stuff that gives rise, that makes experience of any kind possible, that I do think is inside the brain. But the contents of consciousness, and that's what's important in our lives to each of us, it's not the fact that consciousness happens to exist, so, per se. It's, it's the varied things that are experienced, the world, the self, other people, emotions, light, color, beauty, awe. These are not purely within the brain. They depend on the body. They depend on the world. I mean, maybe in a trivial way, if you could, if you could get... So here's what I, I would believe, and again, I might be wrong, that in any given instant, what you're experiencing depends on the state of your brain at that point. Put the brain in a particular state, you get a particular experience of the world, of the body, of other people. But in our lives, to get the brain to be in particular states, we need the body, we need the world, we need other people. And in that sense, the contents of our consciousness depend fundamentally on the interactions between the brain, the body, the world, society, culture, the universe.

Dr. Rangan Chatterjee 2:00:50 Anil, you're doing incredible work. You are leaving us with a lot of things to think about and reflect on. That's coming up to the studio.

Anil Seth 2:01:00 Thanks, Rangan. It's been a delight.

Dr. Rangan Chatterjee 2:01:02 If that conversation resonated with you, here is another incredibly powerful one that I really think you're going to enjoy. Give it a click.

Speaker 2:01:09 If you actually went to the happiness gym several times a week, you will actually have a happier life, right? And the happiness gym is very straightforward. It's a set of skills, hmm, that you need to practice