Making Sense - Sam Harris - April 22, 2021


#247 — Constructing Minds


Episode Stats

Length

1 hour and 7 minutes

Words per Minute

149.7691

Word Count

10,119

Sentence Count

442

Misogynist Sentences

1


Summary

A new podcast from the Waking Up Foundation, produced by my friend Rob Reed, takes a look at the risk posed by synthetic biology in order to prepare for a pandemic like the one we re currently experiencing. It's called "Engineering the Apocalypse," and it will be released as a single episode on the 23rd of April, with a four-hour episode dropping on the first Friday of the month. To coincide with the release of this podcast, the Wakening Up Foundation will be giving two significant grants to relevant organizations that are working on the front lines of pandemic preparedness. As always, I never want money to be the reason why someone can t get access to the podcast, so if you can t afford a subscription, there s an option at Samharris.org to request a free account, and we grant 100% of those requests, no questions asked. No questions asked! To find a list of our sponsors and show-related promo codes, go to gimlet.fm/OurAdvertisers and use the promo code "MAKINGSENSE" at checkout to receive 10% off your first order of $10 or more. We don t run ads on the podcast and therefore don t need to be sponsored by a major sponsor, we don't need to pay for your ad-free version of the podcast. If you like what you're listening to, please consider becoming a supporter of the show by becoming a patron of The Making Sense Podcast. It helps us make the podcast a better listening experience for you, and it helps us spread the word about what we're doing. . and we'll make it more accessible to more people like you, not less. And we'll give you better listening to you, more opportunities to listen to more of your favorite podcasters, and more of the things you care about making sense of things they're listening about the things they can do more of their day-to-day jobs, and they'll get a better chance to learn more of what they're learning about you, too. Thank you, again and again, for listening to Making Sense. -Sam Harris -- thank you, Sam to quote: "I hope you enjoy what we do it better than you're going to like it better, more of you're getting a better idea of what's going to make sense of it, and you'll think about it, better of it in the future."


Transcript

00:00:00.000 Welcome to the Making Sense Podcast.
00:00:08.860 This is Sam Harris.
00:00:10.900 Just a note to say that if you're hearing this,
00:00:13.120 you're not currently on our subscriber feed,
00:00:15.520 and will only be hearing the first part of this conversation.
00:00:18.460 In order to access full episodes of the Making Sense Podcast,
00:00:21.580 you'll need to subscribe at samharris.org.
00:00:24.180 There you'll find our private RSS feed to add to your favorite podcatcher,
00:00:27.580 along with other subscriber-only content.
00:00:30.300 We don't run ads on the podcast,
00:00:32.400 and therefore it's made possible entirely through the support of our subscribers.
00:00:35.920 So if you enjoy what we're doing here, please consider becoming one.
00:00:39.420 As always, I never want money to be the reason why someone can't get access to the podcast.
00:00:43.880 So if you can't afford a subscription,
00:00:45.800 there's an option at samharris.org to request a free account.
00:00:49.060 And we grant 100% of those requests.
00:00:51.480 No questions asked.
00:00:52.280 Okay, some housekeeping today.
00:01:03.740 I have a new podcast to announce.
00:01:07.200 A single episode, which we will be dropping, I believe, Friday of this week,
00:01:13.640 if all goes according to plan.
00:01:16.420 So look for it in your feed on the 23rd of April.
00:01:22.920 The title of this episode is Engineering the Apocalypse.
00:01:26.700 And it was produced by my friend Rob Reed, who is a podcaster and author, also a tech entrepreneur.
00:01:35.120 I met Rob at the TED conference some years ago.
00:01:39.700 And then he started his own podcast, the After On podcast.
00:01:43.700 And he interviewed me, I think, for the first episode there.
00:01:47.640 And I thought it was probably the best interview anyone had ever done of me.
00:01:51.540 So we aired that here on Making Sense.
00:01:54.940 I believe we titled it the After On interview.
00:01:57.300 Anyway, in the intervening years, Rob has gotten very interested in existential risk.
00:02:04.720 And in particular, the risk posed by advances in synthetic biology,
00:02:08.640 which could very well lead to an engineered pandemic.
00:02:12.180 But everything he says in this podcast is relevant to a naturally occurring pandemic,
00:02:17.060 like the one we are currently suffering.
00:02:19.720 Anyway, this is a deeply researched and, by turns,
00:02:23.920 harrowing and hopeful look at advances in synthetic biology.
00:02:30.320 And it's broken into four chapters,
00:02:32.420 which are separated by interstitial conversations that I have with Rob.
00:02:37.200 Anyway, I thought the job he did was fantastic.
00:02:40.920 Pandemic preparedness has to be a huge priority for us going forward.
00:02:45.460 And this is our best effort to argue that it really must be.
00:02:51.400 COVID has been a dress rehearsal.
00:02:53.920 For something far worse.
00:02:57.780 And as such, it has been pretty much an unmitigated disaster.
00:03:02.660 We may have lost sight of this,
00:03:04.280 given how successful our vaccine production has been,
00:03:07.620 and how the rollout has ramped up.
00:03:10.220 But our response to COVID,
00:03:13.160 in particular our failure to organize a globally coherent response,
00:03:17.260 was just a terrifying failure.
00:03:20.220 Terrifying, given how much worse a pandemic can be.
00:03:25.980 And how much worse it's likely to be if it's ever consciously engineered.
00:03:31.040 So anyway, this upcoming podcast will be dropped as a single episode that's nearly four hours in length.
00:03:39.020 And again, the title is Engineering the Apocalypse.
00:03:41.440 And needless to say, we'll be releasing that as yet another PSA,
00:03:46.680 which is to say the whole thing will be freely available.
00:03:50.080 But of course, if you find this work valuable,
00:03:53.820 the way to support it is to subscribe at samharris.org.
00:03:58.140 And to coincide with the release of this podcast,
00:04:02.900 the Waking Up Foundation will be giving two significant grants to relevant organizations
00:04:09.120 that are working on the front lines of pandemic preparedness.
00:04:13.280 As many of you know from my conversations with the philosopher Will McCaskill,
00:04:18.000 I've been thinking more about how to effectively do some good in the world,
00:04:21.880 in addition to just talking about what is good to do.
00:04:25.220 So we formed the Waking Up Foundation for that purpose.
00:04:30.220 And at least 10% of the corporate profits of Waking Up go there,
00:04:34.100 as does a minimum of 10% of my own income.
00:04:37.740 And the foundation works as a pass-through to other organizations.
00:04:42.580 So 100% of the funds leave it and go elsewhere.
00:04:46.720 And so these next donations are focused on this problem of pandemic preparedness.
00:04:51.820 And in this vein, we're supporting the Center for Communicable Disease Dynamics,
00:04:55.220 at Harvard University, which focuses on improving our methods of understanding
00:05:00.020 the data around infectious disease.
00:05:03.300 And it engages policymakers to improve their decision-making,
00:05:07.060 which often leaves a lot to be desired.
00:05:09.780 And the second organization is the Coalition for Epidemic Preparedness Innovations,
00:05:15.340 the CEPI,
00:05:17.000 whose mission is to accelerate the development of vaccine technology.
00:05:20.620 They're funding new platforms so that we can develop vaccines even more quickly than we did
00:05:26.680 for COVID, and really do it just in time in response to a novel pathogen,
00:05:33.080 which is precisely what we're likely to face in the case of a synthetically engineered pandemic.
00:05:38.880 Now, neither of these organizations are set up to take small, individual donations.
00:05:45.560 But if you're a philanthropist,
00:05:47.520 and you want to come along with us in helping to improve our pandemic preparedness,
00:05:51.400 I would certainly encourage you to support these organizations.
00:05:55.440 Once again, that's the Center for Communicable Disease Dynamics
00:05:58.440 at Harvard University and the Coalition for Epidemic Preparedness Innovations.
00:06:04.280 And I should say that the Waking Up Foundation is getting great advice
00:06:07.360 on this front from Natalie Cargill of Longview Philanthropy.
00:06:12.880 This is an organization that advises individuals and foundations
00:06:16.220 who want to deploy significant funds to solve long-term problems.
00:06:21.760 And I was introduced to Natalie through Will McCaskill.
00:06:25.560 And I've been extremely impressed with the research that they've done at Longview
00:06:30.760 and the clarity of their advice, all of which is given free of charge.
00:06:36.080 Longview is independently funded.
00:06:38.580 So if you're running a foundation, or you're a wealthy person who wants free advice
00:06:43.380 about how to give most effectively, I highly recommend that you get in touch
00:06:47.480 with the people at longview.org.
00:06:49.960 Again, this is not a recommendation for small donors.
00:06:53.980 I believe you need to be giving away at least a million dollars a year
00:06:57.120 before Longview can help guide you.
00:07:00.360 But for those of you who are in the philanthropy space,
00:07:03.180 I recommend you get in touch.
00:07:05.800 But if you are an individual donor and you want to ride along with me,
00:07:09.620 we will be detailing all the orgs we support at the Waking Up Foundation
00:07:13.900 once that website is launched.
00:07:16.420 And on that point, I want to say that the Making Sense audience
00:07:18.900 has been fantastically generous in the past.
00:07:24.120 On the occasions where I've discussed specific non-profits on this podcast,
00:07:29.180 the people who run them always come back astonished at the result.
00:07:36.580 To give you just a couple of snapshots here,
00:07:39.980 GiveWell.org reached out recently to say that
00:07:43.280 just by my mentioning their organization a few times on this podcast.
00:07:49.500 This is the group that does exhaustive research on the effectiveness of charities
00:07:53.440 and recommends what they consider to be the most effective ones in several categories.
00:07:58.600 My discussing their work a few times, once with Will McCaskill,
00:08:04.420 resulted in you guys donating $1.8 million through them directly
00:08:10.380 and pledging another $1.8 million in recurring donations.
00:08:15.200 So that's $3.6 million through the end of this year.
00:08:20.060 And Will McCaskill's organization, Giving What We Can,
00:08:23.760 which was started by Toby Ord, who's also been on the podcast,
00:08:27.280 has told me that in response to my discussing their pledge,
00:08:32.580 this is the pledge to give a minimum of 10% of one's lifetime earnings
00:08:36.140 to the most effective charities,
00:08:38.240 which you can do at any level,
00:08:40.460 whether you're making $30,000 a year or $30 billion.
00:08:45.140 I'm told that my discussing this pledge with Will
00:08:48.600 caused hundreds of you to take this pledge yourselves.
00:08:52.320 And after waking up, became the first company to take the pledge,
00:08:57.200 10 more companies soon followed.
00:09:00.000 Now, I don't know how much money to the most effective charities this represents,
00:09:04.360 but it's surely many, many millions of dollars.
00:09:08.880 I believe, Giving What We Can just passed the $2 billion mark
00:09:12.380 in lifetime earnings that have been pledged.
00:09:16.580 Anyway, my point in mentioning this isn't to brag about the influence of this podcast,
00:09:20.320 but rather to convey my gratitude and astonishment, frankly.
00:09:28.140 I mean, it's just amazing to see the knock-on effects of discussing these things.
00:09:33.220 Anyway, I will keep you all informed about this,
00:09:36.080 but this is just to let you know that over at Waking Up and here at Making Sense,
00:09:41.320 we have transitioned into doing more than just talk about specific problems.
00:09:49.140 We're marshalling our own resources to try to do some good directly ourselves.
00:09:55.740 Okay.
00:09:57.340 Today I'm speaking with Lisa Feldman Barrett,
00:10:00.680 who is one of the most cited scientists in the world
00:10:03.380 for her research in psychology and neuroscience.
00:10:06.220 She's a professor at Northeastern University
00:10:09.360 with appointments at Mass General Hospital and Harvard Medical School.
00:10:14.620 Lisa was awarded a Guggenheim Fellowship in Neuroscience in 2019,
00:10:19.200 and she's a member of the American Academy of Arts and Sciences
00:10:22.420 and the Royal Society of Canada.
00:10:25.600 And she's the author, most recently, of a very enjoyable book,
00:10:30.660 Seven and a Half Lessons About the Brain.
00:10:32.640 And we cover a few of those lessons in today's podcast.
00:10:36.620 We talk about how the human brain evolved,
00:10:40.580 the myth of the triune brain, which has been all too influential.
00:10:45.780 We discuss how the brain is organized into networks,
00:10:49.560 the predictive nature of perception and action,
00:10:52.980 the construction of emotion,
00:10:56.340 concepts as prescriptions for action,
00:10:59.280 culture as an operating system,
00:11:01.020 and many other topics.
00:11:04.060 And now, without further delay,
00:11:06.200 I bring you Lisa Feldman Barrett.
00:11:14.880 I am here with Lisa Feldman Barrett.
00:11:17.640 Lisa, thanks for joining me.
00:11:19.900 It's my pleasure.
00:11:20.980 So you've written this wonderful little primer on the brain,
00:11:24.800 Seven and a Half Lessons About the Brain,
00:11:26.640 which I think will be the focus of our discussion,
00:11:30.680 although we'll probably wander to other topics.
00:11:34.000 But I just want our listeners to know that this is a marvelously accessible book,
00:11:42.020 and a short one.
00:11:43.800 It's only 130 pages or so.
00:11:47.160 And, you know, we need more of this kind of thing.
00:11:50.120 There's this kind of awful property of the brain and neuroscience generally,
00:11:57.840 which is, when you get into the details,
00:12:00.840 it becomes just a catalog of anatomical names that are certainly not written by writers,
00:12:09.460 especially ones who wanted to write books for a general audience.
00:12:12.520 And it becomes this blizzard of mnemonic challenges for a reader.
00:12:18.060 And you've managed to avoid all of that
00:12:20.300 and still deliver a very interesting discussion about the brain and the mind.
00:12:25.800 So congratulations.
00:12:26.560 Thank you so much.
00:12:29.780 So before we jump in, perhaps you can summarize your background intellectually.
00:12:36.280 What kinds of questions have you focused on as a scientist?
00:12:39.680 Well, I, you know, I started my training as a clinical psychologist
00:12:44.060 and then very quickly went through a series of retrainings in physiology
00:12:49.700 and then in neuroscience and more recently in engineering,
00:12:54.580 learning something about systems theory and in evolutionary and developmental aspects of neuroscience.
00:13:01.820 So the questions I really think about now relate to, you know, how, how is the brain,
00:13:10.860 how is your brain in constant conversation with your body
00:13:15.100 and the other brains and bodies, you know, that surround you?
00:13:19.480 How is it conjuring the features of your mind?
00:13:23.120 How does it control your, the internal systems of your body at the same time as it's,
00:13:30.160 you know, controlling your behavior and giving you memories and thoughts and feelings and so on?
00:13:35.200 And that may sound like, you know, too big of a question to answer,
00:13:39.920 but I would say I'm really interested in understanding a systems level kind of approach to,
00:13:46.840 to brain function.
00:13:48.680 And that encompasses a lot of things.
00:13:50.460 So I have a large, a large-ish lab and we have a lot of different research projects going on.
00:13:57.700 So it's really hard when someone asks me, so what are you, what is your newest research project?
00:14:01.660 And I'm like, well, we have like probably 40 of them going on.
00:14:04.420 So it's hard to, it's hard to summarize in one sentence.
00:14:07.580 And you're currently a professor as well, right?
00:14:09.660 So do you spend some time teaching or is it all research at the moment?
00:14:13.120 I mean, I know we're talking in COVID land or at the tail end, one hopes of COVID,
00:14:18.200 the COVID pandemic.
00:14:19.140 So nothing seems normal, but what is your general life like as a professor?
00:14:24.820 Yeah.
00:14:25.160 So I run a lab which has 25 full-time people in it.
00:14:31.280 And then usually we have, not during COVID, but usually at other times we have about a hundred,
00:14:39.100 150 undergraduate researchers, researchers in the laboratory in any given year.
00:14:46.040 And the lab is spread out across two different places.
00:14:49.120 So I have personnel at two different places, graduate students, postdocs, and so on,
00:14:53.740 postdoctoral fellows.
00:14:54.660 I teach one course a year for undergraduates.
00:14:57.560 It's a lab course.
00:14:58.640 And then occasionally I will also teach, formally teach graduate seminars, but I also run a weekly
00:15:07.580 or now bi-weekly seminar that I've been running for, I guess about eight or nine years that
00:15:14.180 I don't get any credit for.
00:15:15.520 We just do it out of the love of doing it with engineers and computer scientists and other
00:15:20.360 neuroscientists and psychologists.
00:15:21.840 And so I and another, and my colleague in engineering, we run this seminar for all of our peeps.
00:15:29.600 So it's about 25 people who attend this seminar and it's been going on, like I said, for quite a number
00:15:35.060 of years.
00:15:35.540 And then I also run other reading groups that people attend on particular topics, depending on what we're
00:15:44.120 interested in, for example, on predictive processing or on energetics, which is a word that we use to
00:15:52.860 refer to brain metabolism and the way that the brain is regulating the metabolic functions of the body.
00:15:59.940 So one of the things you do throughout this book, especially at the outset, is debunk a few myths and bad
00:16:10.520 metaphors we've relied on to understand the brain or seem to understand the brain.
00:16:17.720 And this seems like a very useful thing to do.
00:16:20.600 So perhaps we should just start where you start with the larger context of evolution and what we think we
00:16:28.700 understand about the evolution of the human brain.
00:16:31.980 And perhaps this is a good place to part company with Paul McLean.
00:16:37.300 So how do you think about the brain in evolutionary terms?
00:16:42.860 I love this question.
00:16:44.680 This is one of my, I think this is one of the most fun questions, really.
00:16:47.940 It occurred to me at some, at one point, like, why don't we even have a brain?
00:16:52.420 It's, it's a really expensive organ, right?
00:16:55.160 That three pound blob of meat between your ears costs you about 20% of your entire metabolic budget.
00:17:01.740 So it's pretty expensive.
00:17:03.420 And I'll just point out, depending on what you do with it, it can cost you much more than that.
00:17:07.300 It certainly can.
00:17:08.720 Especially on social media.
00:17:11.560 Certainly can.
00:17:13.000 That's absolutely right.
00:17:14.220 And so I'm very fortunate in that I've been, we meeting really weekly with Barbara Finley,
00:17:23.620 who is an evolutionary and developmental neuroscientist.
00:17:25.900 And she's basically, you know, to use her words, she's like downloading all of her knowledge into
00:17:31.560 my brain, which really means that she repeats herself frequently and has to explain things
00:17:36.700 often more than one time.
00:17:38.840 And this is pretty, pretty, you know, not to make a bad pun, but like pretty heavy stuff.
00:17:44.260 It's pretty complicated.
00:17:46.440 You know, I had to learn embryology and I, you know, barely understand what I'm reading,
00:17:51.560 but I understand a little bit now at least.
00:17:53.640 But that, the really cool thing I think is that if you go back, you know, 550 million years
00:18:00.260 ago to a time in the earth's history called the Edicarion, animals didn't have brains.
00:18:06.880 And so I was just really interested to try to understand, well, why, you know, why did
00:18:12.520 brains evolve?
00:18:13.660 And Sam, you know, you know, you can never really answer the why question very easily
00:18:19.620 in evolution, but you certainly can answer what question.
00:18:23.500 So like, what is the brain's most important job?
00:18:26.820 What is a brain really good for?
00:18:28.400 And you can look at the evolutionary, the evolutionary story that, that molecular geneticists and
00:18:37.280 anatomists and so on, ecologists have, have crafted.
00:18:42.320 And it's a really cool and interesting drama.
00:18:45.860 And it, what it suggests is that your brain's most important job isn't thinking or seeing or
00:18:55.260 even feeling.
00:18:56.380 So these are characteristics.
00:18:58.800 These are features that the brain performs or computes, but they're not actually the brain's
00:19:05.940 most important job.
00:19:06.820 It's most important job is regulating the systems of your body, your heart, your lungs, your immune
00:19:14.240 system, your, you know, endocrine system and so on.
00:19:17.880 And of course, you know, we don't experience every delight and, or, you know, every drama
00:19:26.820 in our lives this way.
00:19:28.740 We don't experience every hug that we get or used to get before COVID or every insult that
00:19:34.580 we bear.
00:19:35.600 We don't, we don't experience things this way, this way, but this is actually what is going
00:19:40.680 on under the hood.
00:19:41.660 And when your brain thinks and decides and sees and hears and feels, it's doing this
00:19:49.940 in the service of the regulation of your body.
00:19:53.820 And that turns out to be a really important insight.
00:19:58.220 I would add one piece here.
00:20:00.480 I know you, I don't recall if you put it this way in your book, but it does strike me that
00:20:05.140 just by the logic of evolution, the motor behavior is in some ways primary here, because if you
00:20:13.500 can't move, if you can't do anything with a brain, if there's no way that it can influence
00:20:20.060 the differential success of an organism in the contest for mates or survival, then there
00:20:27.460 would have been no evolutionary pressure in this direction.
00:20:30.340 So it seems to presuppose an ability to do something with respect to the environment.
00:20:36.380 I don't think there's a bright line between that story and the story of regulating the
00:20:41.900 internal states of the body.
00:20:43.620 I think we'll get to that.
00:20:44.920 But don't you see an ability to actually act in some way as being the necessary context
00:20:51.440 for this evolutionary pressure?
00:20:54.480 Absolutely.
00:20:54.740 In fact, really, you know, I guess I'm very persuaded by work in motor neuroscience and
00:21:02.660 certainly in philosophy, the idea that motor action is primary and all sensory processing
00:21:12.300 is in the service of motor action.
00:21:14.040 I think that's absolutely right.
00:21:15.420 The one thing I would say, though, is that, you know, in vertebrates or in all vertebrates,
00:21:23.080 certainly, and in, in, I would maybe hazard to say all animals who have limbs that move
00:21:31.560 or parts that move, there's usually an internal set of systems that support that movement.
00:21:39.620 Now, in vertebrates, you know, like us, that's, you know, a cardiovascular system and a respiratory
00:21:45.580 system and so on.
00:21:48.000 You know, not all animals have the kind of viscera that we have, that vertebrates have.
00:21:52.180 So invertebrates, you know, have their own systems, but there is no external movement
00:21:58.540 of bodies without internal systems to support that.
00:22:02.260 And in motor neuroscience, as much as I respect that work, and I really do, I think they're
00:22:06.780 really ahead of the curve in certain ways.
00:22:09.060 They, they tend to ignore the internal systems of animals' bodies.
00:22:13.460 And I really think that that's an important part of the story that is missing.
00:22:18.180 So when I say, you know, that the brain is regulating the body, I really mean everything
00:22:26.240 motor about the body.
00:22:27.540 That would include what we call visceral motor, which means the beating of your heart and the,
00:22:32.060 you know, contraction of your lungs and so on.
00:22:34.700 But it also means the movement of your skeletal motor system, your muscles, the voluntary movements
00:22:42.160 of your muscles.
00:22:42.800 And in fact, if you look at, for example, primary motor cortex in a monkey brain, a macaque
00:22:49.820 brain, it has visceral motor maps in it.
00:22:53.080 And some of the regions that are considered to be, you know, sort of association regions
00:22:58.900 for the motor system are actually the primary cortical controllers of visceral motor regulation,
00:23:05.220 meaning regulation of the viscera of your lungs and your heart and so on.
00:23:08.280 So in your brain, the internal systems of your body, the, the, the source, the, the neurons
00:23:17.780 that are controlling the internal systems of your body and the neurons that are controlling
00:23:21.480 your skeletal motor system, the, you know, your voluntary muscle movements are really intertwined.
00:23:27.820 And that's not well documented in motor neuroscience work, but it's present in the anatomy.
00:23:39.180 You can just see it.
00:23:40.060 It's there.
00:23:41.960 Yeah, but we'll talk about emotion, but I tend to think about emotion now as a kind of covert
00:23:47.540 behavior, right?
00:23:49.120 So the, the line between emotion and action that is, um, commonsensical, I think can break
00:23:55.860 down if you follow that framing, but, uh, let's, let's not leap to emotion just yet.
00:24:00.880 The evolutionary story we have told ourselves for a long time has been, uh, summarized by this
00:24:08.200 concept given to us by, uh, Paul McLean of the triune brain.
00:24:13.280 And, uh, you know, so people refer to their, their lizard brain, or they think of a stepwise
00:24:20.580 evolution from reptiles to mammals generally, and then to primates as having kind of climbed
00:24:27.560 up from the brainstem to the cortex.
00:24:30.660 What's wrong with this picture?
00:24:33.940 Well, what's wrong with that picture is that it doesn't really match the best available
00:24:40.340 scientific evidence for how brains evolved.
00:24:43.280 I mean, if you look at a lizard brain and say, uh, a mammal brain, like a, like say, um,
00:24:53.040 a rat or like a rodent brain, say, and you look at a monkey brain and a human brain, you
00:24:59.020 know, they look different to the naked eye.
00:25:00.680 It looks like the rat, or I should say, it looks like, it looks like the lizard doesn't
00:25:05.620 really have much of a cerebral cortex.
00:25:07.260 It looks like the rat has, you know, maybe a little bit of, of kind of old cortex and,
00:25:14.980 um, that, that the monkey and the human have quite a bit and the human having, you know,
00:25:19.300 substantially more than a, the monkey.
00:25:21.580 That's how it looks to the naked eye.
00:25:23.180 But, and this, you know, led Paul McLean and others, you know, guided by, I think, certain
00:25:30.800 cultural beliefs to describe brain evolution in, in much the way that you just described
00:25:38.840 it.
00:25:39.080 Although your description, Sam is slightly more lyrical than maybe what McLean wrote, but,
00:25:43.500 you know, the idea that a lizard brain is mostly has parts for instincts, you know, like freezing
00:25:52.300 and fighting and fleeing and copulating, which, you know, neuroscientists make a funny joke,
00:25:59.640 you know, like they refer to it as the four Fs.
00:26:02.040 So that's neuroscience humor for you.
00:26:03.880 And then layered on top of that evolved what's called a limbic system, limbic meaning border,
00:26:11.340 bordering this, you know, these lizard parts for emotion.
00:26:16.100 And then what lay, and then what evolved on top of that is the cerebral cortex or the neocortex,
00:26:23.380 the new part of the cortex, which you only see in what are referred to as higher, uh, mammals,
00:26:32.180 you know, like us.
00:26:33.880 And the idea is that, you know, your lizard brain contains your instincts, your limbic system
00:26:40.100 contains your emotions.
00:26:41.100 And then these are, these make up your inner beast and they are constantly in battle with
00:26:46.540 the more rational side of yourself, which resides in your cerebral cortex.
00:26:52.160 So your brain is a battleground between your inner beast and your rational self for control
00:26:59.480 of your behavior.
00:27:00.160 And the idea is that, you know, when your cortex wins and you behave rationally, you're a moral
00:27:10.780 person and you're healthy.
00:27:12.820 And if your inner beast wins to control your behavior, then you're either immoral because
00:27:18.740 you didn't try hard enough or you're sick because it didn't work.
00:27:24.200 You know, that there's something wrong with your, with your rational cortex.
00:27:28.360 And the problem with this, even though it makes a lot of sense in terms of our, you know, the
00:27:34.700 stories that we tell ourselves about what, what it means to be moral and responsible for
00:27:39.220 behavior.
00:27:39.580 And it's, you know, it's very consistent with Western views of the self.
00:27:43.740 The problem is that it doesn't actually match the evidence that when you peer into neurons
00:27:49.420 and you look at their molecular structure, in particular, you know, the, the genes that
00:27:56.240 guide the formation and function of, of those neurons, you see a really, really different
00:28:03.760 story.
00:28:04.900 And the story is that really all mammals who've, whose brains have ever been studied, actually
00:28:12.720 their brains follow the same developmental plan.
00:28:15.880 Their neurons actually, there are no new neurons, really no new neurotypes.
00:28:21.300 And remarkably, the stages of development, and I'm talking about, you know, embryological development
00:28:26.600 forward, the stages of development in, in all of these mammal brains that have been studied,
00:28:31.680 different species, proceeds in exactly the same order, pretty much it, what's, what changes
00:28:37.780 is the duration of each stage.
00:28:43.440 And there's this really interesting observation that George Streeter, the, the neurobiologist
00:28:51.740 made about brains in his book on brain evolution, by the way, excellent book, if anyone wants a
00:28:56.480 primer on, you know, brain evolution, it's, it's a really fantastic book.
00:29:00.080 But, you know, he says, you know, brains reorganize as they grow larger.
00:29:06.280 And so it can look like there are new structures there, just because there are more of certain
00:29:11.440 neuron types, but actually the, you know, there's nothing new in terms of the neurons.
00:29:17.720 It's just there, they look like they're reorganized and they look like there are miraculously new
00:29:23.880 parts there, but there are really no new parts.
00:29:25.560 It's just that certain types of neurons have certain stages in development have gone on
00:29:30.520 for longer.
00:29:31.020 And so there are certain types of neurons, there's just more of them.
00:29:34.900 And if you go back even further and you look at other animals, you know, other vertebrates,
00:29:40.960 you see that many of them have also really striking similarities to the, to mammalian brains.
00:29:48.180 So for example, birds don't have a cerebral cortex, but they certainly have neurons that
00:29:53.560 are the same as the neurons that make up our cerebral cortex and that seem to perform some
00:29:58.360 very similar functions to what our cerebral cortex, the various functions our cortex performs.
00:30:03.760 So basically there is no, you know, lizard brain.
00:30:09.500 I mean, you don't have a, an ancient beast lurking inside your brain and the only animal who
00:30:15.680 has a lizard brain is a lizard.
00:30:17.860 Are there any exceptions to this?
00:30:19.060 I had thought that, um, Von Economo neurons were an exception that they were just, they were
00:30:26.100 present in great apes and, uh, I think cetaceans and elephants and a few other, you know, charismatic
00:30:33.660 vertebrates, but were not found in, in reptiles or birds or.
00:30:39.740 So Von Economo neurons are very contentious.
00:30:43.520 I mean, there, there are some anatomists who will tell you that Von Economo neurons are not
00:30:49.840 a special class of neurons.
00:30:51.160 They're just really big honking pyramidal cells.
00:30:55.980 So, you know, you find them in large brain animals because, you know, as brains get bigger,
00:31:03.040 sometimes the neurons also get bigger.
00:31:06.580 And, you know, one thing that's happened, for example, in large brain animals, what often
00:31:10.420 happens is that there are certain parts of the cortex in particular that as they grow,
00:31:18.800 what happened, you know, evolutionarily, but also in development, what happens is not that
00:31:24.060 they develop more neurons, but they develop fewer neurons that get much bigger and they
00:31:28.780 have much more connectivity.
00:31:30.540 And the reason for that is, um, I don't know the reason for it, but the, the functional
00:31:36.340 consequence of that is that, which something I explained in essay seven, which is that it
00:31:44.820 means that the animal's brain can summarize information much more efficiently and maybe even
00:31:52.240 do some abstraction, meaning can find similarities in things that look and feel and smell and taste
00:31:59.440 different, find functional similarities.
00:32:01.980 So this is abstraction.
00:32:03.200 This is what we call abstraction, right?
00:32:05.320 And that's really, you know, maybe what these very large pyramidal neurons are for, but there
00:32:11.880 are some anatomists and some neuroscientists who look at von Economo neurons and say, well,
00:32:17.760 these are just ordinary big, you know, neurons.
00:32:21.400 They're not, there's nothing really special about them.
00:32:23.420 Um, and you find them in animals who have large brains relative to their body size.
00:32:28.000 Right.
00:32:29.180 Right.
00:32:30.020 So what is the appropriate picture of the structure of, uh, what we have in there?
00:32:38.640 If it's not this cartoon of descent from reptiles, what picture of complexity and, and, you know,
00:32:48.060 now leading the witness network complexity, uh, should we, uh, should we have in our heads?
00:32:54.680 Yeah, I think I'm going to ask your question, but I just want to take one step back for a
00:32:58.580 minute and say that, you know, we live in a world where we see objects and we, we see boundaries
00:33:06.300 between objects and, you know, like here's a book, here's a purse, here's a computer, here's a glass,
00:33:11.200 whatever.
00:33:12.140 And so we have a tendency to think about things in terms of objects instead of in terms of
00:33:20.020 relationships between features.
00:33:24.140 And so for a really long time, people have thought about the brain as having these distinct parts,
00:33:30.500 you know, like there's this group of neurons called the amygdala, which performs emotion.
00:33:35.080 And there's this other group, you know, called the basal ganglia, which performs, you know,
00:33:40.460 movement.
00:33:40.940 And then there's this other part called the cerebral cortex.
00:33:43.380 And the prefrontal part of that really performs decision-making or rationality or what have you.
00:33:48.060 And that's just, I mean, there are people who still hold to that view and, and it's certainly
00:33:53.460 people have built their whole careers on such notions and, and been very successful.
00:33:59.060 But I think there's also a growing understanding that that's really not how the brain works.
00:34:05.760 It's not how the brain is structured.
00:34:07.340 There are no objects, you know, there are no kind of mental organs in your brain.
00:34:11.720 That's just not really the way, that's just not really the best way to understand the anatomy
00:34:17.680 or the function.
00:34:18.540 And that instead we should be understanding neurons in terms of their relationships to one
00:34:24.040 another and the features that they compute.
00:34:26.400 And so they're really, this can take many forms in published papers on neuroscience, but
00:34:33.400 one that's very popular at the moment is to think about the brain, think about, you know,
00:34:38.040 neurons as in a large dynamically fluctuating network.
00:34:43.520 And so if you think about, you know, instead of thinking about neural signals as being passed
00:34:49.920 from one, you know, region to the other, like a baton in a race, you can think about neural
00:34:57.720 activity and the patterns that are created more like weather patterns or something where,
00:35:03.200 you know, many, many, many neurons are participating in computing an event that has a set of features
00:35:13.260 and some of those features are, you know, very close to the data that you get from your
00:35:19.940 sensory surfaces, like your retina and your cochlea and all the sensory, all the sensors
00:35:25.940 in inside your body.
00:35:27.420 So, you know, like a line, for example, or color, like the color red, your experience of
00:35:32.780 the color red is a feature that your brain computes.
00:35:35.480 It doesn't detect, as you know, and it's computing it using information from not one color
00:35:42.800 detector detector, you know, like as so-called cones.
00:35:47.140 And, you know, you have three, you have cones in these cells in your retina that register
00:35:52.160 three different ranges of wavelengths of light.
00:35:55.400 And you need all three to see red or green or any color.
00:36:00.960 And so your brain computes these features.
00:36:03.340 And it also computes features like, like seeing a face.
00:36:06.960 It computes features like a threat.
00:36:09.740 It computes features like novelty.
00:36:11.860 It computes features, all kinds of features.
00:36:14.240 And in a given event, your brain is sort of computing sequences of events.
00:36:20.080 And in computing an event, what it's doing is computing features in the service of regulating
00:36:24.980 the body, regulating action and the, all the visceral, you know, changes that will support
00:36:30.920 that action.
00:36:31.500 And so the way to think about it is your brain is a single structure with, you know, 128 billion
00:36:39.420 neurons, give or take, and it can take on trillions of patterns.
00:36:43.460 And these patterns are, you know, helped along by the chemical bath that surrounds these neurons.
00:36:52.300 So your neurons are bathed in a chemical system.
00:36:55.860 And, and it's just, your brain is basically dynamically along a trajectory from one pattern
00:37:03.340 to another pattern, to another pattern, to another pattern, and trying to understand what
00:37:07.320 launches those patterns, what maintains those patterns, what features your brain is, is computing.
00:37:12.780 That's really the goal of understanding brain function.
00:37:16.020 Yeah, I would also just point out that the methods we use to understand brain function,
00:37:22.200 like increasingly functional neuroimaging, can also give a, a false picture of the modularity
00:37:29.920 of the brain and therefore the mind.
00:37:32.000 Because, you know, we just, by the nature of the tool that we look at the data in terms
00:37:37.260 of these pretty pictures of certain regions of the brain, so-called lighting up in response
00:37:42.100 to stimuli or tasks, and it can give a sense, you know, not to actual neuroscientists generally,
00:37:49.360 but perhaps in a more subtle way, can even corrupt their thinking.
00:37:53.320 But it certainly can give a sense to the general public that this is a question of other areas
00:37:59.220 of the brain actually not doing anything when they're not part of the illuminated map of,
00:38:06.100 you know, what is most active during a certain function.
00:38:09.240 So it can just give this, this false picture of separate organs in the brain that are, albeit
00:38:17.300 connected, are really independently responsible for an emotion like disgust, say, or a certain
00:38:26.100 kind of perceptual task.
00:38:27.680 And you just can't visualize the network behavior and the fluctuating network behavior and the,
00:38:34.880 and the weighting between nodes in the network as easily as you can, just aggregate the data
00:38:40.620 by subtracting, you know, two states of the brain and showing one to one where these regions were
00:38:47.400 more active than in the other.
00:38:50.600 Yes and no.
00:38:51.180 I think I mostly agree with you, but I would, I would probably just push back maybe a little
00:38:56.020 bit on a couple of points.
00:38:57.160 One, I would say it's not the fault of, of brain imaging techniques.
00:39:00.380 It's really the fault of the analysis techniques that we use and the sample sizes we have.
00:39:06.060 So I would say that with fMRI, you know, fMRI has its problems for sure.
00:39:12.660 It's, it has limitations in terms of its temporal, you know, resolution and also even some spatial
00:39:20.060 resolution issues.
00:39:21.860 But really it, it has, it has much more to do with the kinds of designs that scientists
00:39:27.320 use and the kinds of analytic techniques that they use.
00:39:30.820 And I'll give you a really good example.
00:39:33.600 There's a, what I think of as a really brilliant paper that was published in the proceedings
00:39:41.240 of the National Academy in 2012.
00:39:44.440 The first author is Gonzalez Castillo.
00:39:46.640 And it's this really nice paper where they, you know, compare the sort of standard, you
00:39:56.880 know, experimental design really for a very, very simple task, which is, I believe it was
00:40:04.040 a visual, visual perception task, maybe visual orientation.
00:40:07.420 I think it was, but very, very straightforward task.
00:40:10.740 So visual attention task.
00:40:11.860 And when you run, you know, some subjects and you, you have maybe, you know, 40, 50 to
00:40:20.280 a hundred trials where a trial is, you know, you show something unexpected to the subject
00:40:25.760 and then they, you know, they have to make a judgment of whether, you know, lines are pointing
00:40:30.800 in the left direction or the right direction or what have you.
00:40:33.240 So what you see in the, the way the analysis is done, the way that choices, analytic choices
00:40:39.880 are made to separate signal from noise and so on.
00:40:43.060 You see a couple of islands of, of, of increase in activity that are depicted on a brain, you
00:40:51.760 know, image as like spots that light up, like the light bright, you know, sort of brain.
00:40:57.000 And it's important to really understand here that these images that we see in magazines
00:41:03.380 and in journal articles and so on are curated by scientists.
00:41:06.480 They don't just pop out of the data on their own.
00:41:09.280 They're made contingent that these images are contingent on a bunch of analytic decisions
00:41:15.100 that are made.
00:41:16.640 Now, if you expect that there are islands of activity because, you know, different parts
00:41:23.960 of your brain are responsible for different specific psychological functions and that's
00:41:28.520 what you expect and you've designed your study that way and you've only, you know, tested
00:41:33.420 your subjects on 50 to 100 trials and you threshold, that is, you make decisions about signal versus
00:41:39.980 noise in particular ways, what you get are a couple of islands of activity.
00:41:44.600 However, what this paper showed is that if you run 400 trials for each subject, so you bring
00:41:52.100 them back for multiple scanning sessions and you analyze the data in a slightly different
00:41:59.100 way by instead of assuming that every part of the brain has that the, that the, the shape
00:42:08.200 of the, the response is the same.
00:42:11.940 And instead of assuming that you model, you know, this, the variability and how the different
00:42:16.520 parts are responding, what you see is that 85% of the brain shows an increase in activity.
00:42:25.800 That means 85% of the brain is showing a change to make a very, very simple decision that is
00:42:33.420 considered.
00:42:34.220 Yeah.
00:42:34.460 So the point is that if your, if your studies are designed in a way that is underpowered,
00:42:40.400 you're not going to realize that you're making what we would call a type two error, which
00:42:46.420 is that you're missing a lot of important activity that's there because, you know, you're
00:42:51.580 expecting to see blobs and what you get are blobs.
00:42:54.500 And so, you know, if what you expect is islands of activity, you'll perform your studies, you
00:43:00.420 know, with something I used to call blobology, which is that, you know, you'll identify these
00:43:04.340 blobs of activity.
00:43:05.120 I think people have to realize that these, these images are really curated by humans who
00:43:10.300 have a set of assumptions.
00:43:11.200 I'll just give you one other really quick example.
00:43:13.280 And that is, you know, when people started looking at networks in the brain, so this is
00:43:22.000 regions that are, have correlated that where the brain response is correlated.
00:43:27.700 So, you know, you take a brain and you divide it up into lots of little cubes called voxels.
00:43:33.200 And so you look for sets of voxels that have a similar change in blood flow during an experiment.
00:43:41.540 And you call that a network.
00:43:43.500 And it turns out, you know, this actually does reveal something about the underlying structure
00:43:48.400 of the brain.
00:43:49.780 But when you look at the way that scientists mostly study these networks, they're, they
00:43:56.340 look like Lego blocks, like they're completely unrelated to each other and like, like, you know,
00:44:01.000 pieces of a puzzle and you put them all together and you get a brain, but, you know, that's
00:44:05.300 a decision.
00:44:05.960 Those are computational decisions that are made on, based on analytic, you know, choices that
00:44:10.120 are guided by certain assumptions.
00:44:11.340 If you do the analysis slightly differently, which is what we did.
00:44:14.520 So we took, you know, almost a thousand subjects and we, instead of asking, you know, using kind
00:44:23.260 of standard way of looking for signal and noise, we said, okay, anything which replicates from
00:44:28.860 one subject to another is signal by definition and anything which doesn't is noise.
00:44:34.720 And so let's just try to parse the, you know, networks in the brain by doing this.
00:44:40.500 And what we found was, you know, we found that the sort of networks that people often talk
00:44:45.120 about, but they're really, they overlap.
00:44:48.160 They're not, they're not disconnected.
00:44:50.040 They're actually overlap and they overlap in, in particular regions of the brain, which
00:44:54.120 are known to be, they're called hubs or rich club hubs, meaning densely connected regions
00:44:59.540 that are responsible for really coordinating activity across the whole brain.
00:45:06.020 They're called, you know, these rich club hubs are called the backbone of neural communication
00:45:10.860 in the brain.
00:45:11.480 There's a really nice paper by Olaf Spornes and, and Vanden Heuvel Spornes.
00:45:17.720 I think it's Vanden Heuvel and Spornes in 2013 in the Journal of Neuroscience.
00:45:24.360 And so my point is that these images that you see, they're beautiful and awe-inspiring, but
00:45:31.640 they're curated by humans who have a set of assumptions.
00:45:33.860 Yeah, and it's also easy to see the temptation to think in those terms, because I mean, we
00:45:39.680 have, you know, something like 170 years of neurology attesting to the fact that highly
00:45:47.800 focal lesions, you know, brain damage can lead to very specific deficits.
00:45:55.900 Again, this can be understood in network terms, but it is in fact descriptively true that you
00:46:02.820 can have a small region of the brain damaged and that can dissect out a very specific mental
00:46:11.620 capacity, you know, language use or an ability to recognize faces or, or even to recognize
00:46:18.280 specific classes of objects like, you know, tools versus animals.
00:46:23.820 And that's, that does give you this sort of jigsaw puzzle, like Lego, like intuition about
00:46:31.380 the modularity of the mind.
00:46:34.220 Yeah, you're right.
00:46:35.080 But even there, it's more complicated than it first appears, right?
00:46:38.080 Because when you damage a part, when you damage tissue, you don't really know whether what
00:46:46.900 you've damaged, the critical part, you know, to the function that you've lost are the neurons
00:46:53.360 that are damaged or what are called fibers of passage, which means, you know, axons that
00:46:59.080 run through that area, which are really important.
00:47:01.780 And I just learned about this really, this phenomenon that I, I just, this is the kind
00:47:07.260 of stuff I just love, honestly, where, you know, you can lose, if you damage one part of
00:47:15.160 your primary visual cortex, so this is in animals, they'll ablate a part of the primary visual
00:47:21.420 cortex and the animal will lose the ability to see.
00:47:25.680 And so obviously, you think, oh, well, okay, this, this region must be super important to
00:47:32.080 seeing.
00:47:33.000 And it is important, except that you can recover some of that function by a second lesion in
00:47:39.400 the superior colliculus in the midbrain.
00:47:42.060 So there's information that could make it from your retina to your primary visual cortex,
00:47:48.900 but it's being suppressed by the colliculus, right in a regular fat in a regular neurotypical
00:47:54.240 brain, but you can recover function by a second lesion.
00:47:57.960 And so it's just things like that, right, that make you, or here's another example, another,
00:48:02.980 you know, example, which I find just absolutely fascinating.
00:48:07.280 I find it slightly horrifying as a person, but because of what happens to the animals, but
00:48:12.400 as a scientist, it's really fascinating.
00:48:15.080 So they took these rats and train them to run on a wheel and, you know, recorded directly
00:48:22.760 from neurons in the visual cortex, primary visual cortex, and then they ablate the damage,
00:48:31.500 the retinas, destroy the retinas of these animals so they can't see.
00:48:36.620 And V1 neurons, primary visual cortex neurons, quieten down.
00:48:42.480 And then over 24 hours, they ramp up again and start firing at normal rates.
00:48:50.560 So what's causing these neurons to fire?
00:48:55.120 You know, you put the rat back on the wheel and its neurons, the pattern of firing looks
00:49:00.360 really similar to what it looked like when the animal was sighted.
00:49:02.860 So what is it exactly that's driving the activity in these neurons?
00:49:08.700 And the answer probably is regions of the anterior cingulate cortex, which have direct connections
00:49:17.500 to V1.
00:49:19.200 And the reason why this is interesting is that this region of the brain is a primary regulator
00:49:26.280 of the systems of your body.
00:49:27.900 Both it is a primary motor area for the viscera of your body, and it's an association region
00:49:34.780 for your skeletal motor system.
00:49:37.660 And what this activity is, essentially, what you can think about it is, are a set of visual
00:49:45.080 predictions that are coming from past experience from that, you know, that these motor regions
00:49:56.080 are able to reinstate.
00:49:59.440 And so it's just trickier, Sam, than, you know, I mean, if you start to just poke at it a little
00:50:06.740 bit, modularity starts to fall apart.
00:50:09.100 Yeah, yeah.
00:50:10.380 Well, I think we found the seminar you can teach at Esalen one day, ablating brainstem nuclei
00:50:16.480 so as to recover a proper vision of the world.
00:50:20.300 Yeah, I really wouldn't recommend that people try that at home.
00:50:22.660 It's not advised.
00:50:24.120 So let's talk about prediction and just this uncanny circumstance we're all in, which very
00:50:33.140 few people realize, and those of us who realize it, I think, rarely think about, which is, we
00:50:40.480 have this venerable philosophical thought experiment of the brain in the vat, and, you know, this
00:50:47.880 is a kind of device to think about many things in the philosophy of mind, but rarely is it
00:50:55.700 pointed out that we really are brains in vats already.
00:50:59.860 The vat is our skull, and we do not have direct contact with the physical environment, much
00:51:07.940 less reality itself, in any straightforward way.
00:51:11.820 It's not like our senses are windows through which we're peering or hearing or sensing directly.
00:51:19.440 There's a very active and even anticipatory, to use your term, predictive activity that
00:51:27.280 is producing a visionary experience, a dreamlike experience of the world.
00:51:33.340 I mean, it's exactly like a dream, except for the ways in which, in the waking state, our
00:51:40.760 envisioning of the world is constrained by sensory input, and, you know, to a different
00:51:47.320 degree.
00:51:47.720 So, how do you think about the situation we're in, you know, just epistemologically, existentially,
00:51:55.340 we are, and this is a phrase you use at some point in the book, we are experiencing a kind
00:52:00.680 of controlled hallucination.
00:52:03.080 It's not to say that nothing is veridical or nothing is, that no statement about the world
00:52:08.160 as it is, is better than any other, you know, or more convergent with facts that we could
00:52:14.380 intersubjectively find credible, but, you know, it's much more like the matrix than we
00:52:21.120 give it credit for most of the time.
00:52:24.100 And so that's, you know, perhaps that can get you going in the direction of how you think
00:52:30.020 about the mind as a, and the brain as a predictive computational system, and not one that's merely
00:52:38.420 passively encountering the world as it is.
00:52:42.020 Well, I think you just did a beautiful job describing it in very poetic terms, actually,
00:52:48.200 calling it a dreamlike, calling the brains, you know, or describing the brain's function
00:52:53.320 as conjuring a dreamlike state is actually something that I just came across in this really
00:53:00.260 wonderful book by Carlo Rovelli.
00:53:04.060 It's his new book called Helgoland.
00:53:06.660 I don't think it's available yet in the US, I had to order it from the UK.
00:53:11.760 And I, and, you know, he's really he what he's doing, he's explaining his understanding
00:53:18.100 of quantum mechanics for a civilian like me, you know, I'm not, I don't, I'm not a physicist.
00:53:24.680 And, but, you know, and with, with very, very little math, and, and then, you know, as often
00:53:31.380 seems to happen, you know, everyone wants to take a shot at explaining what the brain
00:53:35.840 does.
00:53:36.240 And, you know, what consciousness is, doesn't matter if you trained as a, you know, a physicist
00:53:41.900 or what have you, everyone takes their shot.
00:53:44.060 And, but his shot, you know, he's describing, trying to describe prediction based on, you
00:53:50.080 know, I, I'm imagining what he, what he read from the literature in visual neuroscience,
00:53:55.360 where a lot of this work has taken place.
00:53:57.780 I think though, there's much, there's a lot more work, which is very consistent with, you
00:54:03.740 know, your description.
00:54:05.700 And there's a really, really nice paper that was written, actually, which was my review.
00:54:12.560 I was, I reviewed this paper, actually, for behavioral and brain sciences, which is a really
00:54:16.920 great journal.
00:54:18.040 And this is what alerted me to this growing literature.
00:54:23.080 This was back like in 2010, I think, maybe, or 2011, this growing literature on what's called
00:54:29.240 predictive coding or predictive processing.
00:54:31.520 It's a paper by Andy Clark.
00:54:34.180 Philosopher, right?
00:54:34.740 Philosopher, but also, you know, just writes beautifully about, very intuitively and beautifully
00:54:43.060 about the brain as a predictive organ.
00:54:46.600 And, but you know what, for me, I'm, I, you know, I don't know about you, but I am like
00:54:52.140 inherently skeptical person.
00:54:54.900 I, I really, I don't even believe my own data necessarily.
00:55:00.140 It takes me a really long time before I, I don't jump on bandwagons typically.
00:55:04.460 And I also really don't, I mean, scientists, I think in general, wouldn't you agree?
00:55:09.460 We don't really like to use the F word, you know, fact, that's a really scary word.
00:55:13.660 So we try to avoid it.
00:55:15.340 And, but, you know, if you look in the literature, if you look at anatomy and you look at any number
00:55:22.580 of literatures in neuroscience and you look at signal processing literatures and engineering
00:55:28.300 and so on, what you see is that exactly the same discovery is being made over and over
00:55:36.520 and over again by literatures that don't talk to each other.
00:55:40.100 And I found this really compelling.
00:55:42.920 And that is this idea that your brain is trapped in a dark, silent box called your skull.
00:55:52.020 skull and it is constantly receiving sense data from the world, you know, through its sensory
00:56:02.640 surfaces, your retina, your cochlea, whatever, and also in, inside your body.
00:56:06.960 So it's, it's, it's the world to your brain is everything outside of the skull and it's receiving
00:56:15.500 these, this sense data that it has to make sense of, and this is an inverse problem because
00:56:21.180 it, these sense data are the effects that they're the outcomes of some set of changes,
00:56:27.720 but your brain doesn't have access to those changes.
00:56:32.140 It only has access to the outcomes, the consequences of those changes.
00:56:37.220 So how does it, you know, if your brain, if your brain is exposed to a loud bang, how does
00:56:42.520 your brain know what that loud bang is, how does your brain know what to do about it?
00:56:48.280 Um, you know, it, it, it, your, you would do something different if it was, uh, a slamming
00:56:55.200 door or a dropped box or a gunshot.
00:56:57.940 And similarly, you know, when you feel a tug in your chest, how does your brain know, how
00:57:03.300 does your brain know when it detects a tug, right?
00:57:06.080 Whether with, when it's sensing a tug, whether that's, you know, anxiety or,
00:57:11.980 you know, that there's some uncertainty or that you just ate a big meal and, uh, you're
00:57:17.440 having a little trouble digesting it or the beginnings of a heart attack, it has to guess.
00:57:22.340 And what does it use to guess?
00:57:24.340 It uses the only other source of information that it has, which is past experience that
00:57:28.480 it can re-implement, re-instate in its own wiring.
00:57:33.520 So colloquially we would call that memory.
00:57:36.060 So when a brain remembers, when your brain remembers, when my brain remembers, my brains
00:57:41.940 don't store memories and then call them up like files in a file drawer.
00:57:47.240 Basically remembering is reassembling, reassembling the past in the present for the purposes of,
00:57:53.600 of making sense of sense data.
00:57:55.580 And for a number of reasons, some of which are metabolic, your brain is sort of doing this
00:58:01.900 predictively, so it's not waiting to receive the input and then trying to make sense of
00:58:07.640 it.
00:58:08.300 And there are lots of ways to demonstrate this to people.
00:58:11.640 Sometimes when I'm giving talks, you know, I'll use a baseball example and I'll kind of
00:58:15.340 walk people through the timing of the baseball example.
00:58:19.060 You know, baseball couldn't exist as a sport.
00:58:22.540 No actual ball related sport could exist if we had reactive brains.
00:58:27.660 There just isn't physically enough time for, you know, to, for a batter to wait, to see
00:58:33.240 a ball before he swings and actually hit the ball.
00:58:36.260 And there are lots of really, lots of really cool, interesting examples from everyday life.
00:58:40.040 But the point is that metabolically speaking, it's much cheaper for the brain to use past
00:58:45.000 experience, to guess what's going to happen next, where the guess is not some abstraction.
00:58:49.880 It's actually your brain changing the firing of its own neurons to prepare you to see and
00:58:56.740 hear and smell and feel and do something in the next moment.
00:59:00.960 And then it checks those predictions against the incoming sense data from the body and from
00:59:09.300 the world.
00:59:11.420 Scientists call this, you know, running a model of the world.
00:59:18.020 But really what your brain is doing is it's running a model of your body.
00:59:25.100 And it, it's the model of your body in the world, but it only knows the world by virtue
00:59:32.820 of the sense data that it gets from the sensory surfaces of your body.
00:59:38.440 So essentially, every feature that your brain computes, it's computing in relation to your
00:59:44.080 body in a particular moment in time, in a particular context or location relative to or related to
00:59:52.420 the particular shape of your ear and the particular distance of your two eyes from one another and
01:00:00.240 the particular state of your mitochondria and so on and so forth.
01:00:06.120 It's all relative.
01:00:08.120 That doesn't mean some kind of postmodernist morass, but what it does mean is that we really have
01:00:16.820 to realize that everything that we experience, we experience from a particular perspective.
01:00:24.220 And there is nothing really called objectivity.
01:00:30.020 The best we can hope for, according to the historian of science, Naomi Oreskes, is that a bunch of
01:00:39.860 people with their own subjectivity, you know, with different histories and different backgrounds
01:00:45.500 and different experiences in the world, that they can come to consensus over a scientific set of observations.
01:00:53.220 And that's about as close to objective fact as we can get.
01:00:56.420 And it's a pretty, it's pretty darn good.
01:00:58.060 It's worked out pretty, pretty well for us, you know, but the idea that there are universal facts that can
01:01:03.920 be objectively adjudicated by being rational or something is just, it's a fiction that interestingly,
01:01:11.160 that brains tell themselves, even though, you know, brains are completely incapable of doing such things.
01:01:18.060 Well, to say that there's no true objectivity is not the same thing as saying that it's not possible to be wrong, right?
01:01:26.720 And we know certain things are wrong.
01:01:29.600 Oh, for sure.
01:01:30.280 And it's also not saying that anything is possible, right?
01:01:32.920 So, I mean, sometimes when I say, well, there's more than one, you know, there's more than one,
01:01:38.620 you know, when I talk about, you know, variability is the norm, right?
01:01:41.920 That in many places in biology and in psychology, there's much more variation than we often acknowledge
01:01:49.160 or would like.
01:01:50.460 But that doesn't mean that anything is possible.
01:01:54.340 You know, it means that there's just more than one possibility.
01:01:57.640 And similarly, I would say, look, you know, we can all agree, right, that we're going to have
01:02:03.700 ground glass for dinner, but that doesn't necessarily translate into the objective reality
01:02:09.480 that we can actually eat glass, right?
01:02:11.540 It doesn't really matter what we believe.
01:02:12.900 We could all agree that COVID is not infectious and that we don't have to wear masks.
01:02:18.040 But, you know, the virus doesn't care about that.
01:02:22.840 I mean, viruses don't care about anything.
01:02:24.060 But really, all the virus needs is a nice, wet set of lungs.
01:02:28.080 It doesn't matter what that person's brain believes.
01:02:32.420 But there are many, many, but I think, you know, there are many, many cases where what
01:02:38.220 we believe really matters to what we experience.
01:02:42.400 But even if you want to take belief out of the equation, you know, what you experience,
01:02:46.820 what your reality is, how you experience the world is very much relational.
01:02:52.840 It's in relation to the body that you have.
01:02:56.400 And you don't experience yourself that way.
01:03:00.060 I certainly, I mean, I can't tell you what you experience.
01:03:02.160 I don't experience myself that way.
01:03:04.000 And if I wasn't a scientist, and somebody just told me that, I'm not sure that I would
01:03:08.520 believe it, actually.
01:03:09.520 But it is, that is the best available evidence that your brain is constantly cultivating your
01:03:21.440 past for the purposes of predicting your future, which will become your present.
01:03:26.640 Yeah, let's see if we can make this concrete for people, because this is really ground upon
01:03:33.860 which the scientific framing of what's going on can unlock a kind of psychological freedom
01:03:42.980 to just change one's sense of what one is as a subject in the world.
01:03:49.860 And it, and I think it can relieve certain kinds of suffering.
01:03:55.620 In the simplest case, just to take this predictive piece, which can sound spooky, you take something
01:04:01.900 like a voluntary motor action, like so I can decide to reach and pick up a cup on my desk.
01:04:07.940 And this is, this does relate to this controversy that, that I keep resurrecting for myself over
01:04:13.760 the reality or lack thereof of free will.
01:04:17.800 I don't know if you know how far down that rabbit hole I've gone, but...
01:04:21.420 Oh yes, I've enjoyed, I've enjoyed, I guess, following you down that rabbit hole.
01:04:27.620 Yeah.
01:04:28.680 So we can talk about that if it interests you, but people have a sense that they are subjects
01:04:34.760 that have this capacity to freely initiate behavior, and that's different.
01:04:42.360 You know, I would certainly agree that voluntary behavior is different from involuntary behavior,
01:04:46.400 but I just don't think we need the concept of free will to differentiate the two.
01:04:51.740 So one way they're different is when I'm doing something, you know, of my own volition,
01:04:57.960 you know, reaching and picking up a cup, that feels a certain way, and it feels a certain
01:05:01.960 way because there are certain implicit processes that we know must be going on neurophysiologically
01:05:09.440 there that do follow this kind of predictive mapping of things.
01:05:15.440 So when I'm reaching, and I'm not consciously aware of it, but I can be made consciously aware
01:05:20.920 of it, certainly when anything goes wrong.
01:05:24.860 So I'm not aware that I'm a prediction machine when I'm reaching to grasp this cup, but if
01:05:32.820 I reached and my fingers passed through it, right, if it was a hologram of a cup and not
01:05:38.340 a real one, or if it felt, you know, squishy, if it was made of, you know, rubber and I wasn't
01:05:44.740 expecting that, all of those occasions of surprise are built on some set of expectations that I
01:05:53.840 wasn't aware of having until I became disillusioned.
01:05:57.320 So I was not aware of expecting solidity, though of course I was.
01:06:02.540 I mean, everything about the grasping behavior of my hand was anticipatory in a certain way.
01:06:09.160 And you can make those, that predictive program consciously felt, certainly in the moments in
01:06:16.540 which it's violated, but it's just simply neurologically the case, that we are comparing,
01:06:22.720 in order, the only way to detect anomalies in the environment is to have this background
01:06:28.500 modeling going on of what's likely to happen in each moment based on what I'm doing now
01:06:35.680 and what I'm doing next.
01:06:36.960 And this question of what to do next really does cover so much of what we're about as minds.
01:06:44.460 We're constantly deciding what to do next on some level.
01:06:49.140 Oh, absolutely.
01:06:50.000 And there's so much to say about, there's so much to unpack that's interesting about what
01:06:55.780 you just said.
01:06:57.200 I mean, first of all, I would say, it seems to me that, you know, because for whatever
01:07:03.080 reason we've talked about why.
01:07:04.500 If you'd like to continue listening to this conversation, you'll need to subscribe at
01:07:13.040 samharris.org.
01:07:14.460 Once you do, you'll get access to all full-length episodes of the Making Sense podcast, along
01:07:18.940 with other subscriber-only content, including bonus episodes, NAMA's, and the conversations
01:07:24.460 I've been having on the Waking Up app.
01:07:26.580 The Making Sense podcast is ad-free and relies entirely on listener support.
01:07:30.660 And you can subscribe now at samharris.org.