Making Sense with Sam Harris - #475 — The Hard Problem of Consciousness

Episode Date: May 12, 2026

Sam Harris speaks with Michael Pollan about consciousness, the mind, and the self. They discuss Pollan's new book, the relationship between consciousness and intelligence, whether consciousness is a product of evolution, the role of psychedelics in consciousness research, AI and the question of machine consciousness, the illusion of the self, and other topics. If the Making Sense podcast logo in your player is BLACK, you can SUBSCRIBE to gain access to all full-length episodes at samharris.org/subscribe.

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please consider subscribing today. I'm here with Michael Pollan. Michael, it's great to see you again. 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? It was a phone call, effectively.

Yeah, it was, I actually remember the day really well. It was 2018, and I was in a hotel room in Portland, Oregon. Has that much time passed? Jesus, that's really depressing. Yeah, it was how to change your mind. It'd just come out. Yeah, wow. And we were talking about psychedelics.

If, this must be a function of age, but when asked to estimate how much time has elapsed, I'm always off by a factor of at least two, if not three. I mean, it's always, and I'm always wrong in the direction of underestimating. Yeah, it's been a while. Yeah. Well, it's great to see you. It's great to see that you have a new book and you have, you have written a, 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, which is an all too natural follow on from your, your last book on psychedelics, how to change your mind. Before we jump into the deep end of the pool, let's just have you connect that, 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. I had a series of experiences, research trips, if you will, from when I was working on how to change your mind. 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 it in the book as like smudging the windshield through which you normally perceive reality. And suddenly you realize, hey, there's a windshield. 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, you know,

so I'd put it in front of me as a set of questions. And of all the things, 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 had a wonderful editor who was willing to support me on an expedition with an very uncertain destination. And because I set off on this really not knowing where I was going, what I was doing, and with no sense of what to expect. And, you know, God bless her. She's since past, and God offers her name. she was a wonderful editor. She said, yeah, you'll do something interesting with that.

So I was off. Well, you've certainly done that, and we'll spend the next, I don't know, 90 minutes or so thinking about consciousness. But I think you arrive at a place that I've arrived. I don't know if it's stable in the end, but I seem to have occupied this spot for quite some time. Thinking about consciousness and specifically the hard problem of consciousness, which we'll talk about in a moment, is something that just utterly kind of subsumed mind. intellectual interests somewhere in around the mid-90s and held them for quite some time. But I've-

And you wrote a really interesting book on it. I mean, it was about the self, but it was really about consciousness. Yeah. Waking up had a big influence on me. Nice. Well, but I think many of us in this game eventually, you know, beat our heads against the wall long enough that we finally admit to ourselves that we're not going to solve the hard problem of consciousness. Now, there are many people in your book. have not admitted that. Spoiler alert for this podcast episode. 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 subtly and deeply and continuously. And that's where things like meditation and psychedelics come in. And so your book almost takes you full circle back to questions of being more than thinking. But the thinking is fascinating and, you know, we need to do it because we need to talk about it. Let's just define our terms at the outset, which you do early in the book. We should just distinguish a few concepts. There's sentience, there's consciousness, there's cognition, there's intelligence. I mean, we'll talk about AI and intelligence is something that many people are thinking about now and in its various

instantiations. How do you define or disambiguate these terms? Yeah, so I made a distinction, it's not mine alone, but it's not always made between sentience and consciousness. And you see that coming up in the whole discussion about AI. Some people use the word sentient to describe these machines that they think may be conscious. Sentience is a more basic foundational term. It involves ability to sense your changes in your environment, assess whether they're good or bad, and allow you to move toward one and away from the other. It may be a property of life. Single-celled creatures, you know, bacteria have chemotaxis,

so they can distinguish between molecules that are good food and ones that will kill them and act accordingly. So sentience is kind of very basic, perhaps, you know, permeates. all of life. I can't be sure about that. Consciousness is a more elaborate form of sentience that involves other things such as a sense of awareness, feelings. In the case of humans, not only awareness, but awareness we're aware. We layer it. And so human consciousness is just how we do sentience. 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. Intelligence and consciousness are not on a spectrum, or on a together. They're orthogonal, I think,

their relationship. Intelligence is, I define pretty much as problem-solving ability. And so that's quite a part. I mean, we all know people who are conscious and not intelligent. I mean, they don't necessarily go together. Cognition is the taking in and processing of information from the world. I think that's kind of how I define it. So, yeah, and consciousness, I define simply as experience or subjective experience. Pretty simple. You don't have to include things like self-consciousness or meta-consciousness in it. Those are kind of bells and whistles that humans have added.

I doubt many animals have them. Yeah, so consciousness is the fact that the life. lights are on. And it's synonymous with the fact of experience, whatever we're experientially aware of altogether. I guess so sentience still can be described. I mean, I guess the crucial line for me and for many people think about this is that things like life, things like sentience, can be given a description from the outside in terms of their functional characteristics. I mean, does something reproduce, does it metabolize, does it grow, et cetera? These are, characteristics of life. And then the boundary conditions can be somewhat diffuse, and so it can be

hard to say whether, you know, a virus is alive in the way that, you know, a bacterium is alive, et cetera. But, and so it is with, I think, with sentience, you know, at least under one, under the definition you gave it. But consciousness is the fact that it's like something, to use Nagels, now immortal phrase, 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 famous example from his essay, what does it like to be a bat? And this disgorges what the philosopher David Chalmers

has named the hard problem of consciousness, which I've already invoked without defining it. But it's just a simple fact that it seems that there's no third-person description of the way the world is that reduces the mystery that it should be like something from the first-person side

to be associated with any of those, any collection of those facts. Yeah, there's an inside. There's an interiority that third person perspective can't penetrate. It can speculate about. But I think that's a very good point you make about sentience and its difference that it is something we can perceive and make a judgment about from the outside. I mean, there may be some slight inside to it, but basically it's a, 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. 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 mind, to subjective experience, if that is indeed the way it happens. Yeah, and just to be clear for people, again, it's amazing how hard it is for many people to form an intuition about what makes the hard problem hard. And some of the most celebrated thinkers in

neuroscience and philosophy, you know, many of them, to my eye, have not, had any kind of natural intuition for this. And, you know, 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 they really haven't even acknowledged it. And, you know, so we might name some of these people. But the hard problem predates Chalmers. And he gave it this name that was very, very sticky, but it goes all the way back to Leibniz, at least. Leibniz invoked this image of a a mill, you know, if you just imagine you blow up the brain to the size of, you know, a mill and walk inside it, at no point would you encounter anything that announced its

sufficiency to produce the inner subjectivity of that organ. And there are many other philosophers who've touched this as Saul Kripke and Ned Block and Frank Jackson and Joseph Levine. I don't if he pronounced it, Levine or Levine, but he gave us this notion of the explanatory gap, which is just another way of saying the hard problem. So there's this, the problem is that whatever the right answer for the emergence of consciousness is, if in fact it emerges, and so, you know, there's some description of, of, you know, the functional characteristics of a system or, you know, the way the neural correlates of consciousness are arranged, and consciousness emerges from that, even if we had that description in hand, the fact that that is the basis of

consciousness, 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. There's just, there is this explanatory gap and whatever the right answer is, it's still going to look like a miracle. Yeah. Well, Christoph Koch, who was involved at the very beginning of modern consciousness science, started out with Francis Crick, the great scientist who cracked inheritance when he discovered, co-discovered the double helix. You know, they went looking for the neural correlates 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, that Christoph realized that, oh, even if we found the neural correlates, it really wouldn't answer the question we're trying to answer. How did that group of neurons, if there was such a group, produced this feeling of being me, this voice in my head? And so he was, it was the first of several crises he's had along the way. Well, like many of us, Christoph has done some drugs in the meantime.

That's given them another crisis, right? Yeah. Yeah, I mean, the influence of psychedelics on this conversation is, fascinating. I mean, it's not, 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 experimented with. And before we dive into consciousness, maybe just, let me just ask your, get your opinion on this. I mean, how do you view the, almost the, the omnipresence of psychedelics now in the discussion here scientifically, but also in the culture. I mean, are you at all worried that we're on the verge of recapitulating some of 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 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 is 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 I wasn't bringing them up. It was the scientists working on the problem who are partly because they're stuck, partly because they're very open-minded to using any tools at hand. Many of them, you know, would talk to me unbidden about their experience with psychedelics and how, in many cases, it had influenced them. They're not doing studies. They're not involved in the various university studies, but they're personally using them.

And in some cases, getting insights that they think are really important, in other cases, not sure what exactly to do with them. But 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. You know, 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.

conversation about it. I think in waking up, you know, you were kind of ahead of the curve and your willingness to talk about your own experiences. Many people regarded it as a reputational risk back then. What year was waking up published? 2014. Yeah. So that was early. That was before this science at Johns Hopkins had gotten a lot of, you know, publicity and suddenly we were taking psychedelics seriously as a therapeutic modality. I think we're in a very different moment than the 60s, I think there was a lot of careless use of psychedelics. Things went wrong, and psychedelics also got really 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, and he may well have been right. Well, we should say that people, some people like Timothy Leary, perhaps most notably, made that connection, that political connection explicit, right? It's like, you know. Yeah, but so did Nixon. Nixon said, you know, well, he said Leary was public enemy number one. Yeah, the most dangerous man in America, I think. That's right.

Most dangerous man in America, which is quite a statement. He also said that about Daniel Ellsberg, though, so most, he had a pretty broad definition of most. Now, psychedelics are no longer coded liberal or left or counterculture. I mean, look at, you know, last week the president issued an executive order. Yeah. Supposedly easing the approval process and access to psychedelics. He's been driven in that direction by concern for soldiers, veterans,

dealing with PTSD and the high rates of suicide among soldiers. And that was a very deliberate, I think, move on the part of Rick Doblin at Mapps, who was really one of the pioneers of getting research started again. He made overtures to vets groups, to the VA, and to people like Rick Perry, a former governor 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 know that it's going to fall into the same backlash politics. It may, if things go terribly wrong.

There's also so much university research going on, so many trials. and it's rapidly being accepted as a legitimate area of study. There have been NIH grants to support psychedelic research. So 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. But I think a lot of people learned a lesson from the 60s, which they're powerful substances.

They have to be used with intention. People are tending to use them more. guided situations, which really mitigates a lot of the risk. So, yeah, I'm not overly concerned about that. I think there's going to be, you know, all sorts of nasty things happening. There's going to be profiteering and attempts to limit access, attempts to patent things that shouldn't be patented. I mean, all sorts of things are going on. And there's a tremendous hype cycle, but lots of capital rushing in and then the capital rushes out and now, it's back in. So it's going to be messy. You know, whenever capitalism gets a hold of something

like this, it gets really messy. Yeah. Well, it's especially obvious in AI at the moment. We'll talk about the implications there. I mean, one concern I have about the influence of psychedelics on this conversation is that there's some way in which I think that the psychedelic experience to speak generically can be indispensable but also misleading. I mean, it certainly can be with respect to the goal of meditation and what there is to recognize about the nature of consciousness there that is that is liberative or, you know, worth paying attention to. There's something that I think the experiences, the peak experiences people have on psychedelics, while they advertise to them the possibility of living a very different kind of life in the world,

They also can give the false impression that freedom is a matter of radically changing the contents of consciousness, radically expanding it and achieving something, some kind of permanent state that is analogous to what you enjoyed on the peak of whatever it was. You know, acid, psilocybin, MDMA, DMT, whatever your moment was. And so anyway, we'll talk about that because I think the... Yeah, no, and I think that's a fundamental misunderstanding of the mystical experience. which is what, you know, how people kind of assess these experiences, that a mystical experience that was permanent would probably be schizophrenia. You know, it's something in the context of everyday life. It's a period of transcendence, but it's not something you sustain. And, you know,

I mean, you know this history well, but many of the Americans who brought Buddhism to America started with psychedelics and then had the similar realization to what you're talking about, which is that it's not a practice. It's not something you can sustain day after day. And they moved into meditation, which was a place you could have a practice, obviously. Yeah. But the links are very interesting.

And I think psychedelics may be a very good way to start a meditation practice. Yeah. I'm always taken with the fact that most of the experience is not the profound climax, but this long tail, which can go on for hours and is a meditation. and a very, often a very 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 do think psychedelics are a legitimate tool for the study of consciousness, the scientific study of consciousness. You know, the first big study that was done at Johns Hopkins by Roland Griffith was of mystical experience. That's a very interesting aspect of human consciousness. And, the fact that we have a tool that can pretty reliably induce it opens up all sorts of experimental possibilities. Yeah. I mean, the reliability, apart from the tiny percentage of people who seem impervious to psychedelics for reasons that, I don't know, whether they've been explained at the level of their 5HT, 2A receptors or not, but, I mean, 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. The gurus, the guru stories, yes. No, I'm not talking about that. I'm talking about it just people who are ordinary people who are seeking to have an experience on psychedelics 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 know, for whatever reason, don't have the right neurons for better. I was thinking more of the, you know, the stories, Ram Dass tells the story of his guru. And just upping the dose, upping the dose,

getting up to six or 700 micrograms and nothing happens. Yeah, yeah. And then being in doubt as to whether or not he, you know, had just palmed the medication and didn't take it. And then so then when he went back, he did it again. And it worked the same way or didn't work. So consciousness is the fact that it's like something to be us, the fact that the lights are on.

And there is a deep intuition or dogma or expectation in biology, at least, that the explanation for this must be evolutionary in some sense, right? But consciousness must have either evolved for some reason because certain things that are adaptive and indispensable for us can only occur in the light of consciousness. or I guess it could be an epiphenomenon, which I'm a view which sounds really counterintuitive to people, but which I've always thought had a lot going for it. Famously, T.H. Huxley, who was a great defender of Darwin's theory back in the day, said that consciousness was like the steam whistle on a train, right?

It's this super salient feature of the train's operation, but not at all integral to anything that's happening. I don't think he used the word epiphenomen. but the concept of this is a phenomenon that rides alongside 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. 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. It's processing information, taking in sensory data all the time and making changes, running homeostasis, you know, keeping your body in the right temperature and blood gases and all this kind of stuff. So why should any of it be conscious? Why don't we automate everything? Why aren't we zombies? I think that's a kind of subset of a hard problem. And you can construct a good evolutionary story that would explain why it would be useful. And the best one I heard was from Carl Fristin, who's a English neuroscientist. And I put this question to him, why? What good What good is consciousness?

And he said that 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, much longer than any other mammal, consciousness allows us to navigate social life, which is too complex and changeable to program. you couldn't hardwire everything you have to know to succeed in a 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. And you can easily imagine, you know,

a couple of proto-humans, some of whom have that imaginary ability, call it theory of mind or something that, you know, proto-theory of mind, and are very good students of the other person and can read facial expressions 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 good bond and reproduce? So, you know, who knows if that's true, but that would create a pressure for something like consciousness to emerge from unconscious or from sentience, say. I don't know, you buy it? No, I don't buy any of that.

Members can hear the full conversation by subscribing at samharis.org. Subscribers get a private RSS feed you can use with your favorite podcast player. We already believe they're conscious, and they will convince us their conscious. It's in their interest to convince us their 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 we have just created hell and populated it.