Making Sense - Sam Harris - May 12, 2026


#475 — The Hard Problem of Consciousness


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00:00:00.000 you're listening to making sense with sam harris this is the free version of the podcast so you'll
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00:00:22.960 i'm here with michael paul and michael it's great to see you again yeah great to be back sam or to
00:00:29.580 see you for the first time we were just talking about the fact that the last podcast i think was
00:00:33.280 just audio right we were it was a phone call effectively yeah it was i actually remember the
00:00:37.720 day really well it was 2018 and i was in a hotel room in portland oregon has that much time passed
00:00:45.060 jesus that's really depressing yeah it was uh how to change your mind had just come out yeah
00:00:49.520 wow and we were talking about psychedelics if uh this is must be a function of of age but when
00:00:56.420 asked to estimate how much time has elapsed, I'm always off by a factor of at least two,
00:01:02.160 if not three. I mean, I, it's always, and I'm always wrong in the direction of underestimating.
00:01:08.160 So, um, yeah, it's been a while. Yeah. Well, it's great to see you. It's great to see that you have
00:01:14.440 a new book and you have, you have written a, um, not everyone does this. You have written a best
00:01:18.660 seller on the nature of consciousness. And the book is, is a world appears a journey into
00:01:24.000 consciousness, which is an all-too-natural follow-on from your last book on psychedelics,
00:01:29.720 How to Change Your Mind. Before we jump into the deep end of the pool, let's just have you connect
00:01:34.080 that, those dots for me. How did you convince yourself that you wanted to go deeper in this
00:01:40.180 direction? You know, I think it's a very common response to psychedelic experience. I had a
00:01:45.280 series of experiences, research trips, if you will, from when I was working on How to Change Your Mind.
00:01:51.100 And one of the things psychedelics kind of reliably do for people is defamiliarize consciousness.
00:01:57.440 You're suddenly made more aware of it.
00:01:59.700 I describe it in the book as like smudging the windshield through which you normally perceive reality.
00:02:04.740 And suddenly you realize, hey, there's a windshield.
00:02:07.400 What is that about?
00:02:08.560 Because most of the time it's utterly transparent.
00:02:11.120 You can go a long time without thinking about consciousness.
00:02:14.060 So that was, you know, so I'd put it in front of me as a set of questions.
00:02:17.980 and uh of all the things you know whenever you finish a book there's always a few threads that
00:02:23.720 are left you know untied and you know curious paths it's too late to go down you're on the
00:02:28.980 last chapter and consciousness was definitely one of them so i thought and i and i had a wonderful
00:02:34.700 editor who was willing to support me on an expedition with a very uncertain destination
00:02:42.280 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.
00:02:50.840 And, you know, God bless her.
00:02:53.120 She's since passed and got off with her name.
00:02:55.780 She's a wonderful editor.
00:02:57.200 She said, yeah, you'll do something interesting with that.
00:02:59.860 So I was off.
00:03:01.440 Well, you have certainly done that.
00:03:03.160 And we'll spend the next, I don't know, 90 minutes or so thinking about consciousness.
00:03:06.880 but I think you arrive at a place that I've arrived. I don't know if it's stable in the end,
00:03:13.260 but I seem to have occupied this spot for quite some time. Thinking about consciousness and
00:03:17.640 specifically the hard problem of consciousness, which we'll talk about in a moment, is something
00:03:22.180 that just utterly kind of subsumed my intellectual interests somewhere around the mid-90s and held
00:03:30.780 them for quite some time. And you wrote a really interesting book on it. I mean, it was about the
00:03:35.540 self, but it was really about consciousness. Waking up had a big influence on me.
00:03:40.120 Nice. Well, but I think many of us in this game eventually beat our heads against the wall long
00:03:48.580 enough that we finally admit to ourselves that we're not going to solve the hard problem of
00:03:53.680 consciousness. Now, there are many people in your book who have not admitted that.
00:03:56.780 Spoiler alert for this podcast episode.
00:03:59.220 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.
00:04:14.720 and you know that's where things like meditation and psychedelics come in and so your book almost
00:04:20.240 takes you full circle back to questions of being more than thinking but the thinking is fascinating
00:04:27.240 and um you know we need to do it because we need to talk about it let's just define our terms at
00:04:32.060 the outset which you do early in the book we should just distinguish a few concepts there's
00:04:37.340 sentience there's consciousness there's cognition there's an intelligence i mean we'll talk about
00:04:44.120 AI and intelligence is something that many people are thinking about now and in its various
00:04:50.080 instantiations. How do you define or disambiguate these terms? Yeah, so I made a distinction,
00:04:59.100 it's not mine alone, but it's not always made, between sentience and consciousness. And you see
00:05:04.400 that coming up in the whole discussion about AI. Some people use the word sentient to describe
00:05:09.040 these machines that they think may be conscious. Sentience is a more basic foundational term.
00:05:15.440 It involves ability to sense your changes in your environment, assess whether they're good or bad,
00:05:22.760 and allow you to move toward one and away from the other. It may be a property of life. Single
00:05:28.820 celled creatures, you know, bacteria have chemotaxis, which, so they can distinguish
00:05:34.240 between molecules that are good food and ones that'll kill them and act accordingly. So sentience
00:05:40.220 is kind of very basic, perhaps permeates all of life. I can't be sure about that. Consciousness
00:05:48.400 is a more elaborate form of sentience that involves other things such as a sense of awareness,
00:05:56.020 feelings. In the case of humans, not only awareness, but awareness, we're aware,
00:06:01.000 we layer it and so human consciousness is just how we do sentience and and every creature that
00:06:07.560 is conscious does it in a slightly different way presumably reflecting their sensorium their body
00:06:13.720 type the scale at which they operate all these kind of things intelligence and consciousness
00:06:19.660 are not on a spectrum or on a on a together they're they're orthogonal i think their relationship
00:06:26.620 intelligence is i define pretty much as problem solving ability and uh so that's quite a part i
00:06:33.000 mean we all know people who are conscious and not intelligent i mean they don't necessarily go
00:06:37.140 together cognition is is the taking in and processing of information from the world
00:06:42.380 i think that's kind of how i define it so that yeah and and consciousness i define simply as
00:06:48.280 experience or subjective experience it pretty simple i don't you don't have to include things
00:06:54.560 like self-consciousness or metaconsciousness in it those are kind of bells and whistles that
00:06:58.800 humans have added and i doubt many animals have them yeah so consciousness is the fact that the
00:07:07.420 lights are on and yeah it's synonymous with the fact of experience whatever we're experientially
00:07:14.840 aware of altogether i guess so sentience still can be described i mean i guess the crucial line
00:07:21.480 for me or and for many people think about this is that things like life things like sentience can be
00:07:27.260 given a description from the outside in terms of their functional characteristics i mean does
00:07:33.080 something reproduce does it you know metabolize does it grow etc these are characteristics of life
00:07:38.960 and then you know the boundary conditions can be somewhat diffuse and so it can be hard to say
00:07:44.700 whether you know a virus is is alive in the way that you know a bacterium is alive etc but and so
00:07:50.300 it is, I think, with sentience, at least under the definition you gave it. But consciousness is
00:07:56.300 the fact that it's like something, to use Nagel's now immortal phrase, to be what we are. And if
00:08:02.500 it's like something to be a bat, well, then that would be consciousness in the case of a bat.
00:08:06.700 And that's obviously his famous example from his essay, What Is It Like to Be a Bat? And this
00:08:11.640 disgorges what the philosopher David Chalmers has named the hard problem of consciousness,
00:08:18.240 which I've already invoked without defining it. But it's just a simple fact that it seems that
00:08:24.240 there's no third-person description of the way the world is that reduces the mystery that it
00:08:32.900 should be like something from the first-person side to be associated with any collection of
00:08:38.400 those facts. Yeah, there's an inside. There's an interiority that third-person perspective
00:08:43.720 can't penetrate. It can speculate about. But I think that's a very good point you make about
00:08:47.800 sentience and its difference that it it is something we can perceive and make a judgment
00:08:53.280 about from the outside i mean there may be some slight inside to it but basically it's uh we can
00:08:59.980 we can assess it from the outside and we can't with consciousness and that's a huge i mean that
00:09:05.500 is the hard problem i'd put it i'd add also it's i mean it's the problem how do you get from matter
00:09:10.400 three pounds of neurons in our head to mind, to subjective experience, if that is indeed the way
00:09:19.320 it happens. Yeah. And just to be clear for people, again, it's amazing how hard it is for many people
00:09:25.300 to form an intuition about what makes the hard problem hard. And some of the most celebrated
00:09:30.940 thinkers in neuroscience and philosophy, many of them to my eye, have not had any kind of natural
00:09:37.840 intuition for this. And, you know, the symptom of that is they kind of blow past it,
00:09:42.880 asserting some reductive explanation of consciousness as though they had solved the
00:09:46.720 hard problem, whereas they really haven't even acknowledged it. And, you know, so we might name
00:09:53.220 some of these people. But the hard problem predates Chalmers, and he gave it this name
00:09:58.040 that was very, very sticky, but it goes all the way back to Leibniz, at least. Leibniz invoked
00:10:04.220 this image of a mill, you know, if you just imagine you blow up the brain to the size of,
00:10:11.540 you know, a mill and walk inside it, at no point would you encounter anything that announced its
00:10:18.600 sufficiency to produce the inner subjectivity of that organ. And there are many other philosophers
00:10:25.020 who've touched this, Saul Kripke and Ned Block and Frank Jackson and Joseph Levine. I don't know
00:10:32.040 we pronounce it Levine or Levine, but he gave us this notion of the explanatory gap, which is just
00:10:36.720 another way of saying the hard problem. So there's this, the problem is that whatever the right answer
00:10:42.340 for the emergence of consciousness is, if in fact it emerges, and so there's some description of
00:10:48.560 the functional characteristics of a system or the way the neural correlates of consciousness are
00:10:55.240 arranged, and consciousness emerges from that. Even if we had that description in hand,
00:11:00.400 the fact that that is the basis of consciousness, that first the lights are not on, then all of a
00:11:06.620 sudden you change the wiring diagram ever so slightly and an inner world appears, that is
00:11:14.160 just the, you know, it doesn't mean it's not true, but it would be totally non-explanatory. There's
00:11:19.460 just, there is this explanatory gap and whatever the right answer is, it's still going to look like
00:11:24.540 a miracle. Yeah. Well, Christophe Koch, who was involved at the very beginning of modern
00:11:29.380 consciousness science, started out with Francis Crick, the great scientist who cracked inheritance
00:11:36.020 when he discovered, co-discovered the double helix. You know, they went looking for the neural
00:11:40.680 correlates and they thought that would solve the problem. They would find that group of neurons
00:11:46.240 responsible for subjective experience. And it was only a couple of years into that quest.
00:11:51.460 and by the way, that quest goes on, that Christophe realized that, oh, even if we found the
00:11:58.340 neural correlates, it really wouldn't answer the question we're trying to answer. How did that
00:12:04.500 group of neurons, if there was such a group, produced this feeling of being me, this voice
00:12:09.960 in my head? And so he was, that was the first of several crises he's had along the way.
00:12:15.420 Well, like many of us, Christophe has done some drugs in the meantime.
00:12:18.580 uh which that's given him another crisis yeah yeah yeah i mean the influence of psychedelics
00:12:24.480 on this conversation is is fascinating i mean it's not it's not surprising given what happened
00:12:29.860 a generation and a half ago but we had this hiatus in science where these these drugs could
00:12:35.440 not be experimented with and but before we dive into consciousness i maybe just let's let me just
00:12:41.660 ask your get your opinion on this i mean how do you view the um almost the the the omnipresence
00:12:49.040 of psychedelics now in the discussion here scientifically but also in the culture i mean
00:12:56.040 are you at all worried that we're on the verge of recapitulating some of the errors of the 60s
00:13:02.120 where we just we get a little too fast and loose with these drugs and there's a we invite some kind
00:13:07.620 of backlash? Or how are you feeling about the psychedelic part of this conversation?
00:13:12.480 Yeah. I mean, well, first to go back a little bit, it was a real surprise. I thought I would
00:13:17.440 mention psychedelics in the introduction of this book as something that inspired it
00:13:21.060 and set me on this path. And that would be it. And there would be no psychedelics in the book,
00:13:25.920 but they kept popping up and I wasn't bringing them up. It was the scientists working on the
00:13:31.020 problem who are partly because they're stuck, partly because they're very open-minded to
00:13:37.300 using any tools at hand uh many of them you know would talk to me unbidden about their experience
00:13:43.760 with psychedelics and how in many cases it had influenced them they're not doing studies they're
00:13:49.120 not involved in the various university studies but they're personally using them and and in some
00:13:54.480 cases getting insights that they think are really important in other cases not sure what exactly to
00:14:00.900 do with them but it just kind of was this it became this motif in the book of scientists telling me
00:14:06.800 about their psychedelic experiences and how it had affected their work. So I thought that was
00:14:11.140 really interesting. You know, the whole issue of psychedelics has changed a lot since 2018. I mean,
00:14:18.180 it is, first of all, more acceptable for us to have a conversation about it. I think in waking
00:14:23.280 up, you know, you were kind of ahead of the curve in your willingness to talk about your own
00:14:27.500 experiences. Many people regarded it as a reputational risk back then. What year was
00:14:32.840 waking up published 2014 yeah so that was early that was before this uh science at johns hopkins
00:14:40.220 had gotten a lot of you know publicity and and and suddenly we were taking psychedelics seriously as
00:14:46.140 a therapeutic modality i think we're in a very different moment than the 60s i think there was
00:14:52.040 a lot of careless use of psychedelics things went wrong and psychedelics also got really
00:14:59.520 entangled in the counterculture and that was part of the backlash i mean nixon targeted psychedelics
00:15:05.760 because he thought it was one of the reasons that american boys were refusing to fight in vietnam
00:15:10.220 and he may well have been right um well and we should say that people some people like
00:15:14.960 timothy leary perhaps most notably made that connection that political connection explicit
00:15:20.640 right it's like you know yeah but so did nixon nixon said you know well he said leary was public
00:15:26.520 enemy number one. The most dangerous man in America, I think. That's right. Most dangerous
00:15:30.520 man in America, which is quite a statement. He also said that about Daniel Ellsberg though. So,
00:15:34.780 so most, he had a pretty broad definition of most. Now, psychedelics are not, no longer coded liberal
00:15:42.880 or left or counterculture. I mean, they're, I mean, look at, you know, last week the president
00:15:47.940 issued an executive order. Yeah. Supposedly easing the approval process and access to
00:15:54.320 psychedelics. He's been driven in that direction by concern for soldiers, veterans dealing with
00:16:00.520 PTSD and the high rates of suicide among soldiers. And that was a very deliberate, I think, move on
00:16:08.900 the part of Rick Doblin at MAPS, who was really one of the pioneers of getting research started
00:16:14.200 again. He made overtures to vets groups, to the VA, and to people like Rick Perry,
00:16:21.080 um uh former governor of of texas who's a big supporter now of psychedelics so i would say
00:16:28.660 if anything there's more support on the right than the left so i don't i don't know that it's
00:16:32.800 going to fall into the same backlash politics it may if things go terribly wrong there's also
00:16:38.940 so much university research going on so many trials and and it's it's you know rapidly being
00:16:46.580 accepted as a legitimate area of study. And there've been NIH grants to support psychedelic
00:16:52.720 research. So I don't, I don't see us on the verge of that. I mean, people are still doing stupid
00:16:58.300 things with psychedelics and there's still accidents happening. And, um, but I think we 0.98
00:17:03.120 learned, or I think a lot of people learned a lesson from the sixties, which they're powerful
00:17:08.180 substances. They have to be used with, with intention. People are tending to use them more
00:17:12.920 in guided situations, which really mitigates a lot of the risk. So yeah, I'm not overly concerned
00:17:21.840 about that. I think there's going to be all sorts of nasty things happening. There's going to be
00:17:27.100 profiteering and attempts to limit access, attempts to patent things that shouldn't be patented. I
00:17:34.580 mean, all sorts of things are going on there. And there's a tremendous hype cycle with lots of
00:17:40.060 capital rushing in and then the capital rushes out and now it's back in. So it's going to be
00:17:45.320 messy. You know, whenever capitalism gets a hold of something like this, it gets really messy.
00:17:51.080 Yeah. Well, it's especially obvious in AI at the moment. We'll talk about
00:17:56.840 the implications there. I mean, one concern I have about the influence of psychedelics on
00:18:03.580 this conversation is that there's some way in which I think that the psychedelic experience
00:18:10.040 to speak generically can be indispensable but also misleading i mean it certainly can be with
00:18:15.440 respect to the goal of meditation and what there is to to recognize about the nature of consciousness
00:18:20.700 there that is that is liberative or or you know worth paying attention to there's something that
00:18:26.720 i think i think the the experiences the peak experiences people have on psychedelics while
00:18:31.820 they advertise to them the possibility of living a very different kind of life in the world they
00:18:38.340 also can give the false impression that freedom is a matter of radically changing the contents
00:18:44.180 of consciousness, radically expanding it and, and achieving something, some kind of permanent
00:18:50.220 state that is analogous to what you enjoyed on the peak of whatever it was, you know, acid,
00:18:56.080 psilocybin, MDMA, DMT, whatever your, whatever your moment was. And so anyway, we'll talk about
00:19:02.740 that because I think the. Yeah, no, and I think that's a fundamental misunderstanding of, of
00:19:06.580 the mystical experiences which is what you know how people kind of assess these experiences
00:19:13.000 that a mystical experience that was permanent would probably be schizophrenia um it's you know
00:19:19.760 it's it's something in the context of everyday life it's a period of transcendence but it's not
00:19:25.040 something you sustain and you know as i mean you know this history well but many of the americans
00:19:31.320 who brought buddhism to america started with psychedelics and then had the similar realization
00:19:36.040 to what you're talking about, which is that it's not a practice. It's not something you can sustain
00:19:41.460 day after day. And they moved into meditation, which was a place you could have a practice,
00:19:47.320 obviously. But the links are very interesting. And I think psychedelics may be a very good way
00:19:53.100 to start a meditation practice. I'm always taken with the fact that most of the experience is not
00:19:59.880 the profound climax, but this long tail, which can go on for hours and is a meditation and often
00:20:08.720 a very good meditation in that you're totally undistracted and you can go really deep, but you
00:20:14.780 still have some control over your mind. So I think the links are very interesting. And I do think
00:20:19.780 psychedelics are a legitimate tool for the study of consciousness, the scientific study of
00:20:25.760 consciousness you know the first big study that was done at johns hopkins by roland griffith was
00:20:30.860 was of mystical experience that's a very interesting aspect of human consciousness
00:20:36.380 and the fact that we have a tool that can pretty reliably induce it opens up all sorts of
00:20:43.280 experimental possibilities yeah i mean the the reliability apart from the tiny percentage of
00:20:50.920 people who seem impervious to psychedelics for reasons that, uh, I don't know whether they've
00:20:56.000 been explained at the level of, uh, their 5-HT2A receptors or not. But I mean, some people
00:21:01.120 apparently, I never believe this. I mean, I accept it as a fact, but I just can't, I can't
00:21:05.060 believe that there are people who, if given, you know, 500 micrograms of LSD have no experience.
00:21:09.560 The gurus, the guru stories. Yes. No, I'm not, I'm not talking about that. I'm talking about
00:21:13.460 just people who are ordinary people who are seeking to have an experience on psychedelics
00:21:18.660 and they, in the presence of a guide, you know, administering whatever, five grams of mushrooms.
00:21:23.220 I mean, I know people like this. I know at least two people who have taken
00:21:25.780 whopping doses of psychedelics and literally nothing has happened. And so there are people
00:21:31.540 who just, you know, just for whatever reason, don't have the right neurons for better or worse.
00:21:35.700 I was thinking more of the, you know, the stories, Ram Dass tells the story of his guru.
00:21:40.960 And just upping the dose, upping the dose, getting up to six or 700 micrograms and nothing
00:21:45.420 happens. Yeah. Yeah. And then being in doubt as to whether or not he, you know, had just palmed
00:21:51.500 the medication and didn't take it. And then, so then when he went back, he did it again and
00:21:57.220 it worked the same way or didn't work. So consciousness is the fact that it's like
00:22:02.580 something to be us, the fact that the lights are on. And there is a deep intuition or dogma or
00:22:09.340 expectation in biology, at least, that the explanation for this must be evolutionary in
00:22:16.080 some sense, right? Consciousness must have either evolved for some reason, because certain things
00:22:23.080 that are adaptive and indispensable for us can only occur in the light of consciousness. Or I
00:22:32.040 guess it could be an epiphenomenon, a view which sounds really counterintuitive to people, but which
00:22:38.600 I've always thought had a lot going for it. Famously, T.H. Huxley, who was a great defender
00:22:45.920 of Darwin's theory back in the day, said that consciousness was like the steam whistle on a
00:22:52.320 train, right? It's this super salient feature of the train's operation, but not at all integral to
00:22:58.140 anything that's happening. I don't think he used the word epiphenomenon, but the concept of this
00:23:02.980 is a phenomenon that rides alongside the thing you're interested in. It seems to be part of it,
00:23:08.300 but it's really doing absolutely nothing.
00:23:10.560 Tell me what you encountered
00:23:12.160 when you asked people about the evolutionary role.
00:23:15.960 Well, that was a real question I had.
00:23:17.580 I mean, as you know, the brain,
00:23:20.060 most of what the brain does, we're not aware of.
00:23:22.560 It's processing information,
00:23:24.100 taking in sensory data all the time
00:23:26.260 and making changes, running homeostasis,
00:23:30.680 keeping your body in the right temperature
00:23:33.000 and blood gases and all this kind of stuff.
00:23:35.340 So why should any of it be conscious?
00:23:36.980 Why don't we automate everything? Why aren't we zombies? I think that's a kind of subset of the
00:23:41.440 hard problem. And you can construct a good evolutionary story that would explain why
00:23:47.660 it would be useful. And the best one I heard was from Carl Friston, who's a English neuroscientist.
00:23:55.500 And I put this question to him, what good is it? What good is consciousness? And he said that
00:24:01.500 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.
00:24:24.300 You couldn't hardwire everything you have to know to succeed in a human social context.
00:24:29.420 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.
00:24:39.780 And you can easily imagine a couple of proto-humans, some of whom have that imaginary ability, call it theory of mind or something, 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.
00:25:00.760 compare that to someone who's kind of dense and doesn't pick up on social signals who's more
00:25:05.660 likely to make a good bond and reproduce so you know who knows if that's true but that would
00:25:11.860 create a pressure for something like consciousness to emerge from unconscious or from sentience say
00:25:17.200 yeah i don't know you buy it no i don't buy any of that members can hear the full conversation by
00:25:22.240 subscribing at samharris.org subscribers get a private rss feed you can use with your favorite
00:25:27.600 podcast player. We already believe they're conscious, and they will convince us they're
00:25:32.920 conscious. It's in their interest to convince us they're conscious. We could inadvertently build
00:25:37.120 conscious machines that can suffer and be immiserated, and we will have just built them
00:25:42.220 like black boxes. Then we'll have no sense that, you know, we have just created hell and populated it.