Michael Pollan on Consciousness, Psychedelics, and the Limits of Neuroscience

追加: 2026-05-12

[00:00:00]Psychedelics defamiliarize consciousness. You're suddenly made more aware of it. It's like smudging the windshield through which you normally perceive reality. And suddenly you realize, hey, there's a windshield. How do you get from matter this, you know, 3 lbs of neurons in our head to to mind uh to to subjective experience?

[00:00:20]>> Whatever the right answer is, it's still going to look like a miracle.

[00:00:24]>> I'm here with Michael Pollen. Michael, it's great to see you again.

[00:00:27]>> Yeah, great to be back, Sam. or to see you for the first time. We were just talking about the fact that the last podcast I think was just audio, right?

[00:00:33]We were It was a phone call effectively.

[00:00:35]>> Yeah, it was I actually remember the day really well. It was uh 2018 and I was in a hotel room in Portland, Oregon.

[00:00:44]>> Has that much time passed? Jesus, that's really depressing.

[00:00:46]>> Yeah, it was uh how to change your mind.

[00:00:48]It just come out.

[00:00:49]>> Yeah. Wow. I >> And we were talking about psychedelics.

[00:00:53]This is must be a function of of age.

[00:00:55]But when asked to estimate how much time has elapsed, uh I'm always off by a factor of at least two if not three. I mean I it's always and I'm always wrong in in the direction of underestimating.

[00:01:07]>> Yeah, it's been a while.

[00:01:08]>> Yeah. Well, uh it's great to see you.

[00:01:11]It's great to to uh see that you have a new book and you have you have written a um not not everyone does this. You have written a bestseller on the nature of consciousness and the book is is a world appears a journey into consciousness. Uh which is which is um an all too natural follow on from your your last book on psychedelics how to change your mind. Um before we jump into the deep end of the pool, let's just uh have you connect that uh those dots for me. How did you convince yourself that you wanted to >> go deeper in this direction? You know, I think it's a very common response to psychedelic experience. Uh I had a series of experiences, research trips if you will, from uh when I was working on how to change your mind.

[00:01:55]>> And one of the things psychedelics kind of reliably do for people is defamiliarize consciousness. You're suddenly made more aware of it. I described in the book as like smudging the windshield through which you normally perceive reality. And suddenly you realize, hey, there's a windshield.

[00:02:11]What is that about? because most of the time it's utterly transparent. You can go a long time without thinking about consciousness. So that was um you know so it put it in front of me as as a set of questions and uh of all the thing you know whenever you finish a book there's always a few threads that are left you know untied and you know curious paths it's too late to go down you're on the last chapter and consciousness was definitely one of them. So I thought and I and I had a wonderful editor who was willing to um support me on an expedition with an very uncertain destination >> and cuz I I set off on this really not knowing where I was going, what I was doing um uh and with no sense of uh what to expect. And uh you know, God bless her and she's she's since passed and God offers her name. She's a wonderful editor. She said, "Yeah, you'll do something interesting with that." So, I was off.

[00:03:12]>> Well, you you've certainly done that.

[00:03:14]Um, and we'll spend the next I don't know 90 minutes or so thinking about consciousness, but I I think you arrive at a place that um I've arrived uh I don't know if it's it's stable in the end, but I seem to have occupied this spot for quite some time. that thinking about consciousness and specifically the the hard problem of consciousness which we'll talk about in a moment is something that just utterly kind of subsumed my intellectual interests somewhere in around the the mid '9s and and and uh held them for quite some time. But um I have >> and you wrote a really interesting book on it. I mean it was about the self but it was really about consciousness.

[00:03:53]Waking up had a big influence on me.

[00:03:55]>> Nice. Well, but but you know there I think um you know many of us in this game eventually uh you know beat our heads against the wall long enough that that we we finally admit to ourselves that we're not going to solve the hard problem of consciousness. Now there there are many people in your book who have not admitted that.

[00:04:14]>> Spoiler alert for this podcast episode.

[00:04:17]Okay, we'll talk about this, but I mean ultimately there is something more to do or less to do than think about consciousness, which is to say you can simply be consciousness more and more uh subtly and deeply and and continuously.

[00:04:33]And you know, that's where things like meditation and psychedelics come in. And so your your book almost takes you full circle back to questions of being more than thinking. But the thinking is is fascinating and um you know we need to do it because we need to talk about it.

[00:04:50]Let's let's just define our terms at the outset which you do early in the book but we should just distinguish a few concepts. There's sentience, there's consciousness, there's cognition, there's an intelligence I mean we'll talk about AI and intelligence is is something that many people are are thinking about now and in in its various instanti instantiations. How do how do you define or or um disambiguate these terms?

[00:05:16]>> Yeah. So, I I made a distinction um it's not mine alone, but it's not always made between sensience and consciousness. And you see that coming up in the whole discussion about AI. Some people use the word sensient >> to describe these machines that they think may be conscious. Sensience is a is a more basic foundational term. Uh it involves um ability to sense your changes in your environment, assess whether they're good or bad and uh allow you to move toward one and away from the other. It may be a property of life. Um single-sellled creatures, you know, bacteria have chemotaxis which uh so they can distinguish between molecules that are good food and ones that'll kill them and act accordingly. So um so sentience is kind of very basic perhaps um like you know permeates all of life um I can't be sure about that um consciousness is a more elaborate form of sensience uh that involves other things such as a sense of awareness feelings uh in the case of humans not only awareness but awareness we're aware um we layer it and so human consciousness is just how we do sensience And and every creature that is conscious does it in a slightly different way presumably reflecting their sensorium, their body type, the scale at which they operate, all these kind of things. Um, intelligence and consciousness are not um on a spectrum or on a on a together. They're they're orthogonal. I think they're relationship. Um, intelligence is I define pretty much as problem solving ability. So that's quite a part. I mean, we all know people who are conscious and not intelligent. I mean, they they don't necessarily go together. Cognition is is the taking in and processing of information from the world.

[00:07:11]>> Um, I think that's kind of how I define it. Um, so yeah, and and consciousness I define simply as as um experience or subjective experience. Um, pretty simple. I don't you don't have to include things like self-consciousness or metaconsciousness in it. Um those are kind of bells and whistles that humans have added and I I doubt many animals have them.

[00:07:36]>> Yeah. So so consciousness is the fact that the lights are on and and it's synonymous with the fact of experience whatever we're experientially aware of altogether. I guess so sentience is sentience still can be described. I mean I I guess the crucial line for me or and for many people think about this is that things like life, things like sentience uh can can be given a description from the outside in in terms of their functional characteristics. I mean does something reproduce? Does it you know metabolize? Does it grow? E etc. These are characteristics of life. Um and then the you know the boundary conditions can be somewhat uh diffuse and so it can be hard to say whether you know a virus is is alive in the way that you know a bacterium is alive etc. But um and so it is with I think with with sentience you at least under one under the definition you gave it. Uh but consciousness is the fact that it's like something to use Nagel's >> uh now immortal phrase uh to be what we are. And if it's like something to be a bat, well then that would be consciousness in the case of a bat. And that's obviously his his famous example from his essay, what is it like to be a bat? Um, and this discorgg what uh the philosopher David Chalmer's has named the hard problem of consciousness which um I've already invoked without defining it but is just a simple fact that it seems that there's no description there's no third person description of the way the world is that reduces the mystery that um it should be like something from the first person side to be to be associated with any of those any collection of those facts.

[00:09:23]>> Yeah, there's an inside there's an interiority that third person >> uh perspective can't penetrate. It can speculate about. But I think that's a very good point you make about sensience and and and its difference. Um that it it is something we can perceive and make a judgment about from the outside. Yeah.

[00:09:41]>> Um I mean there may be some slight inside to it but basically it's a we can we can assess it from the outside and we can't with consciousness and that's a huge I mean that is the hard problem. Uh >> and I'd put it I'd add also it's I mean it's the problem of how do you get from matter this you know three pounds of neurons in our head to to mind uh to to subjective experience if that is indeed the way it happens.

[00:10:10]>> Yeah. And and ju just to to be clear for people again this it's amazing how hard it is for many people to form an intuition about what makes the hard problem hard and and some of the most celebrated thinkers in neuroscience and philosophy uh you know many of them to to my eye have not had any kind of natural intuition for this and and you know that the symptom of that is they kind of blow past it asserting some reductive explanation of consciousness as though they had solved the hard problem whereas because they really haven't even acknowledged it. Um, and you know, so we might name some of these people, but the hard problem predates Chalmeris. He gave it this this name that was very very sticky. But it goes all the way back to Linets at least.

[00:10:56]Livveness invoked this um image of a mill. You know, if you just imagine uh you could you could you blow up the brain um to the size of, you know, a mill uh and walk inside it. At no point would you encounter anything that that announced its sufficiency to produce the the inner subjectivity of of uh that organ. And there are many other philosophers who've touched this. Saul Krypkkey and Ned Block and and Frank Jackson and uh >> Joseph Lavine. Um I don't know if he pronounced it lavine or leavine but he he gave us this notion of the explanatory gap which is just you know another way of saying the hard problem.

[00:11:36]Um so there's this the problem is that whatever the right answer for the the emergence of consciousness is if in fact it emerges and so you know there's some description of of you know uh the functional characteristics of a of a system or you know the the um the way the neural coralates of consciousness are arranged and consciousness emerges from that even if we had that description in hand. The fact that that that is the basis of consciousness that that first the lights are not on then all of a sudden you change the wiring diagram ever so slightly and an inner world appears. That is just the you know it doesn't mean it's not true but it would be totally non-explanatory.

[00:12:21]There's just there is this explanatory gap and whatever the right answer is it's still going to look like a miracle.

[00:12:27]>> Yeah. Well, Kristoff Ko, who was involved at the very beginning of modern consciousness scientist science, started out with Francis Crick, the the great scientist who cracked uh inheritance when he discovered co-discovered the double helix.

[00:12:42]>> You know, they went looking for the neural coralates and they thought that would solve the problem. They would find that group of neurons responsible for subjective experience. And it was only a couple years into that quest, and by the way, that quest goes on.

[00:12:58]um that Kristoff realized that oh even if we found the neural coralates it really wouldn't answer the question we're trying to answer um that how did how did that group of neurons if there was such a group produced this feeling of being me this this voice in my head uh and so he was that was the first of several crises he's had along the way >> well like many of us Kristoff has done some drugs in the meantime uh which >> that's given given him another crisis.

[00:13:29]>> Yeah.

[00:13:29]>> Yeah. I mean, the influence of psychedelics on this conversation is is fascinating. I it's not uh it's not surprising given what happened a generation and a half ago, but we had this hiatus in science where these these drugs could not be uh experiment experimented with. And but before we dive into consciousness, I maybe just let's let me just ask your get your opinion on this. I mean, how do you view almost the the the the omnipresence of psychedelics now in the discussion here scientifically, but also in the culture?

[00:14:05]I mean, are are you at all worried that we're on the verge of recapitulating some of the the errors of the 60s where we just we get a little too fast and loose with these drugs and there's a we invite some kind of backlash or how are you feeling about the the psychedelic part of this conversation? Yeah. I mean, well, first to go back a little bit, it was a real surprise. I thought I would mention psychedelics in the introduction of this book as something that inspired it and set me on this path and that would be it and there would be no psychedelics in the book, but they kept popping up and it and I wasn't bringing them up. Um it was the scientists working on the problem who are um partly because they're stuck partly because they're very open-minded to to uh using any tools at hand. Uh many of them you know would talk to me unbidden about their experience with psychedelics and how in many cases it had influenced them. um they're not doing studies, they're not involved in the various university studies, but they're personally using them and and >> in some cases getting insights that they think are really important. Um in other cases, not sure what exactly to do with them, but um it just kind of was this it became this motif in the book of scientists telling me about their psychedelic experiences and how it had affected their work. So I thought that was really interesting. um you know the the whole issue of psychedelics has changed a lot since 2018. I mean it is first of all more acceptable for us to have a conversation about it. Uh I think in waking up you know you were kind of ahead of the curve in your willingness to talk about your own experiences. Many people regarded it as a reputational risk back then. What year was waking up published?

[00:15:50]>> Uh 2014.

[00:15:52]>> Yeah. So that was early. That was before this uh science at Johns Hopkins had gotten a lot of um you know publicity and and and suddenly we were taking psychedelics seriously as a a therapeutic modality. I think we're in a very different moment in the 60s. Uh I think there was a lot of um careless use of psychedelics. Uh things went wrong and uh psychedelics also got really um entangled in the counterculture and that was part of the backlash. I mean, Nixon targeted psychedelics because he thought it was one of the reasons that American boys were refusing to fight in Vietnam.

[00:16:29]>> And he may well have been right. Um, >> well, we should say that people, some people like Timothy Liry, perhaps most notably made that connection, that political connection explicit, right?

[00:16:40]It's like, you know, >> Yeah. But so did Nixon. Nixon said, you know, it was well, he said Liry was public enemy number one.

[00:16:46]>> Yeah. The most dangerous man in America, I think. Yeah, >> that's right. Most dangerous man in America, which is quite a statement. Now psychedelics are being are not no longer coded liberal or left or counterculture.

[00:16:58]I mean there I mean look at you know last week the president issued an executive order >> um supposedly easing the approval process and access to psychedelics. He's he's been driven in that direction by concern for soldiers uh veterans dealing with PTSD and the high rates of suicide among soldiers. And that that was a very deliberate uh I think move on the part of Rick Doblin at MAPS uh who was really one of the pioneers of getting research started again. Um he he made overtures to to vets groups to the VA and to people like Rick Perry um former governor of of Texas who's a big supporter now of psychedelics. So I would say if anything there's more support on the right than the left. So I don't I don't know that it's going to fall into the same backlash politics. It may if things go terribly wrong.

[00:17:54]>> Um there's also so much um university research going on. So many trials that uh and and it's it's you know rapidly being accepted as a legitimate uh area of study. There have been NIH grants um for to support psychedelic research.

[00:18:13]>> So I don't I don't see us on the verge of that. I mean, people are still doing stupid things with psychedelics and there's still accidents happening and um uh but I think we learned or I think a lot of people learned a lesson from the 60s which they're powerful substances.

[00:18:30]They have to be used with with intention. People are tending to use them more in guided uh guided situations uh which really mitigates a lot of the risk.

[00:18:40]>> So yeah, I I'm not I'm not overly concerned about that. Um, I think there's going to be, you know, all sorts of, uh, nasty things happening. There's going to be profitering and and, uh, attempts to limit access. Um, attempts to patent things that shouldn't be patented. I mean, all sorts of things are going on that, you know, uh, and there's there's a a tremendous hype cycle with lots of capital rushing in and then the capital rushes out and now it's back in. Um, so it's going to be messy. You know, whenever capitalism gets a hold of something like this, it gets really messy.

[00:19:15]>> Yeah. Well, we're that's uh especially obvious in AI at the moment. We'll talk about >> Yes.

[00:19:22]>> the implications there. Um I mean one concern I have about the way the influence of psychedelics on this conversation is that there's some um there's some way in which I think that the psychedelic experience to speak generically um can be indispensable but also misleading. I mean it certainly can be with respect to the goal of meditation and what there is to to recognize about the the nature of consciousness there that is that is liberative or or you know worth paying attention to. Uh there's something I think I think the the experiences the peak experiences people have on psychedelics while they advertise to them the possibility of of of living a very different kind of life in the world. Um they off they also can give the false impression that freedom is a matter of radically changing the contents of consciousness radically expanding it and >> and achieving something >> some kind of permanent state that is analogous to what you enjoyed on the peak of whatever it was you know acids psilocybin MDMA DMT whatever your whatever your moment was so anyway we'll talk about that because I think the >> yeah no and I think that's a fundamental misunderstanding of of the mystical experience which which is what you know how people kind of assess these experiences um >> that a mystical experience that was permanent would probably be schizophrenia um it's you know it's it's something in the context of everyday life it's a it's a period of transcendence but it's not something you sustain >> and you know as I mean you know this history well but many of the Americans who brought Buddhism to America started with psychedelics and then had the the similar realization to what you're talking about which is that it's not a practice.

[00:21:12]>> It's not something you can you can sustain day after day and they moved into meditation which was a place you could have a practice obviously.

[00:21:21]>> Yeah.

[00:21:22]>> Um but the links are very interesting and and I think psychedelics may be a very good way to start a meditation practice. Um >> I'm always taken with the fact that most of the experience is not the you know profound climax but this long tale um which can go on for hours and is a meditation a and a very um often a very um good meditation in that you're totally undistracted and you can go really deep but you still have some control over your mind. So I think the links are very interesting and I and I do think psychedelics are a legitimate tool for the study of consciousness, the scientific study of consciousness.

[00:22:04]>> You know, the first big study that was done at John's Hopkins by Roland Griffith was was of mystical experience.

[00:22:11]That's a very interesting aspect of human consciousness. And the fact that we have a tool that can pretty reliably induce it uh opens up all sorts of experimental possibilities.

[00:22:24]Yeah, I mean the the the reliability uh apart from the the tiny percentage of people who seem impervious to psychedelics for for reasons that uh uh I don't know if whether they've been explained at the level of uh their 5HT2A receptors or not but um I mean some people some some people apparently I never believe this. I mean, I accept it as a fact, but I just can't I can't believe that there are people who if given, you know, 500 micrograms of LSD have no experience.

[00:22:53]>> The gurus the guru stories. Yes.

[00:22:55]>> No, I'm not I'm not talking about that.

[00:22:57]I'm talking about just just people who are ordinary people who are seeking >> to have an experience on psychedelics and they and they in the presence of a guide, you know, administering whatever five grams of mushrooms. I mean, I know people like this. I know at least two people who have taken whopping doses of psychedelics and literally nothing has happened. And so there are people who just you for whatever reason >> don't have the right neurons >> um >> for better or worse.

[00:23:23]>> I was thinking more of the you know the stories Ramdas tells the story of his guru >> and just upping the dose upping the dose getting up to 6 or 700 micrograms and nothing happens.

[00:23:33]>> Yeah. And then being doubted as to whether or not he uh he you know had just palmed the the medication and didn't take it. And then so then when he went back he he he did it again. And uh it worked the same way um or didn't work. Conc. So consciousness is the fact that it's like something to be us. The fact that the lights are on and there is a um a deep uh intuition or or a dogma or expectation in biology at least that the the explanation for this must be evolutionary in some sense, right? like consc consciousness must have either evolved for some reason uh because certain uh things that are uh adaptive and and indispensable for us can only occur in the light of consciousness. Um or I guess it could be an epiphenomenon um which I'm a view which um sounds really counterintuitive to people but which uh I've always thought had a lot going for it. Um, I mean to to famously th Huxley who's was uh a great defender of of Darwin's theory back in the day um said that consciousness was like the the steam whistle on a train, right? It's it's this super salient feature of the train's operation but not at all integral to anything that's happening.

[00:24:57]It's it's it's he didn't I don't think he used the word epiphenomenon, but the concept of of this is a phenomenon that rides alongside the the thing you're interested in. It seems to be part of it, but it's really doing absolutely nothing. Tell me what you're what you encountered when you when you ask people about the the evolutionary role.

[00:25:15]>> Well, that was a real question I had. I mean, as as you know, the brain most of what the brain does, we're not aware of.

[00:25:22]It's processing information, taking in sensory data all the time and uh making changes, running, you know, homeostasis, you know, keeping your body in the right uh temperature and blood gases and all this kind of stuff.

[00:25:35]>> So, why should any of it be conscious?

[00:25:37]Why don't we automate everything? Why aren't we zombies? I think that's a kind of subset of the hard problem.

[00:25:43]>> And you can construct a good evolutionary story uh that would explain why it would be useful. And the best one I heard was from Carl Fristen who's a uh English um neuroscientist.

[00:25:56]And I put this question to him. Why why what good is it? What good is consciousness? And he said that in uh for us creatures who are fundamentally social beings who depend on other people to survive, who have a long childhood where we're utterly dependent uh much longer than any other mammal. Um, consciousness allows us to navigate social life, which is too complex and changeable to program.

[00:26:29]>> You c you couldn't hardwire everything you have to know to succeed in a social human social context. So, having the ability to predict what the other person is going to say or do, to imagine your way into their point of view, these are all highly adaptive skills. Um and you can easily imagine you know a couple of protoans some of whom uh have that imaginary ability call it theory of mind or something that you know proto theory of mind >> uh and are very good students of the other person and can read facial expressions and and um and figure out what's going to happen next. Compare that to someone who's kind of dense and doesn't pick up on social signals. Who's more likely to make a a good bond and reproduce? So, you know, who knows if that's true, but that that would create a pressure for something like consciousness to emerge from unconscious or from sensient. Say, >> yeah, >> I don't know. You buy it?

[00:27:27]>> No, I don't buy any of that.

[00:27:29]>> We already believe they're conscious and they will convince us they're conscious.

[00:27:33]It's in their interest to convince us they're conscious. We could inadvertently build conscious machines that can suffer and be be emiserated and we will have just built them like black boxes. Then we'll have no sense that you know we have just created hell and populated it.