The Origins Podcast with Lawrence Krauss - Joseph LeDoux

Episode Date: December 5, 2020

Lawrence joins neuroscientist and author Joseph LeDoux in his office at New York University to discuss human consciousness (including its evolutionary development), the difficulties of distinguishing behavior from emotions, his latest book The Deep History of Ourselves: The Four-Billion-Year Story of How We Got Conscious Brains, and more. The Origins Podcast is now a part of The Origins Project Foundation.  For more information, visit originsprojectfoundation.org See the commercial-free, full HD videos of all episodes at www.patreon.com/originspodcast immediately upon their release.  And please consider supporting the podcast by donating to the Origins Project Foundation www.originsprojectfoundation.org Twitter: @TheOriginsPod Instagram: @TheOriginsPod Facebook: @TheOriginsPod Website: https://theoriginspodcast.com Get full access to Critical Mass at lawrencekrauss.substack.com/subscribe

The Origins Podcast is now a part of the Origins Project Foundation. Please consider supporting the podcast and the foundation by going to www.orgensprojectfoundation.org. Hi, and welcome to the Origins Podcast. I'm your host, Lawrence Krause. In this week's episode, I have a conversation with the fascinating American neuroscientist Joseph Ladoe. He has been one of the leaders in trying to understand the nature of consciousness, in particular emotions and among the emotions fear, which he's become well known for. And his evolving view of that relationship between emotion and consciousness and the different parts of human brain, he discusses in an interesting recent book called The Deep History of Ourselves,

the four billion year story of how we got our conscious brains. And that caused me to want to have a discussion with him. It's a perfect topic for our origins podcast. I've been aware of his work for some time and a fan of it and a fan of his books. Also, what I particularly like is he again continues our own efforts to connect science and culture in unusual new ways. In his case, not only did he come into science in a rather unusual way, as you'll hear, but he also has a history in music, and he's actually the lead singer and songwriter for the band, The Amygdaloids. So he's the second rock star scientist we've had

a discussion with on the Origins podcast, the first being Brian May. We focused on how our view the brain has changed over time. And how we're understanding the brain is much more complex than we may have thought. We have to be very wary when we look at brain responses and emotions to try not to assume a kind of chicken and egg relationship, which comes first. The bodily response of fear, for example, and then the conscious awareness of fear or the other way around.

So I hope you'll enjoy this fascinating conversation with a fascinating scientist. And with no further ado, Joseph Ladoo. Well, thank you very much for letting us into your office, Joe, and I'm really looking forward to talking about consciousness, which is a subject that interests everyone. And one of the reasons I wanted to talk to you is the connections you made between consciousness and evolution, which is the subject of your last book, the deep history of ourselves. And there's a lot there, and there's a lot we're going to go through, and I want to get there, hopefully, eventually. But I want to first talk about, since this is an origins podcast, about your own origins. First of all, what got you interested in neuroscience? Why did you choose that area?

Well, it was a perfectly natural route. I had two degrees in marketing. Oh, okay, perfect. And it was the late 60s, and it wasn't very cool to be in marketing. But that's the kind of path I started on. It was too late to get out. And so I started getting interested in, like, consumer psychology and consumer. protection, you know, Nader's Raiders kind of thing back then.

What got you interested in marketing? Was you, I mean, yeah. I grew up in a small town in Louisiana called Eunice, a population of 10 or 11,000 people. And my father was a butcher, and my mother wrapped the meat in the meat market. And the year I was graduating, I was looking forward to going off to college at LSU, I mean, just get the hell out of town. Yeah, because the whole town.

And the year I was graduating from high school, LSU opened up a junior college in town, and they wanted me to stay. Oh, okay. And so we negotiated a deal where I would go to LSU study banking and come back and be a banker, and then I could go to Baton Rouge. I said, okay, and obviously I didn't do that. One thing led to another, and I started taking psychology courses to understand motivation and behavior, and I found I was interested in social psychology, and that I was interested in social psychology,

And then I got interested in experimental. Then I took a class with a guy studying the brain and memory and fell in love with that and said, wow, I didn't know you could do that. And he introduced me to some other folks and I applied to graduate school. And one place got, you know, accepted me. And that was that. That was Stony Brook. And that's where I met Mike Azanaga.

Was that a difficult transition? I mean, you were from thinking about the brain to actually doing experiments? No. No? No. Because, you know, I was studying. I joined Mikea Saniga's lab. and Mike was studying split brain patients.

This was 1974. You know, when you left right, front back, not a lot of gory details in that kind of work. That's all you really needed to know about. So it was a good kind of slow entry point. And after I graduated, I went to Cornell Medical School and worked in the lab of Don Reese, who was a neurobiologist, and he had a kind of neurobiological candy store where every known technique to humans was there, to biologists. So, you know, I spent 12 years, like, first learning more neuroanatomy

and then learning some physiology, then some biochemistry. So it was a good kind of, like, I don't know, mentorship, tutorial ship over 12 years. And that's when I applied to come to NYU and was accepted here to have a faculty job. Well, so, yeah, there was definitely a learning curve there. But the interesting thing when you talked about that, it may sound strange, but I see some connections between neuroscience and cosmology. Okay. Yeah, let's go there.

Good ones, and then some other ones where they're quite different. But one of the things was that when I, my background's in particle physics, but when I started to get interested in cosmology as a way to probe speculative questions, but also to really provide evidence, cosmology was an art. There was a lot of talk. There were a lot of theories. and there were a few observations, and they used to say cosmologists are never right,

but never in doubt. It's true of a lot of science. Yeah, yeah, it's new. Well, I tend to think of neuroscience. In some sense, there's been a lot of talk. But what changed cosmology, I suspect, is the same thing that changed neuroscience. I may be wrong here,

is the sudden import of new tools, new observables that turned cosmology from the 1970s to now, that difference, from an art to a person, well, probably more of a precision science, maybe the neuron science. I don't know. But it turned it into a science. You need new tools, new techniques, and I assume that's what's taken neuroscience

and turned it from sort of an art into a science. Absolutely. But not always in a good way. Okay. Because sometimes the methodology takes precedence over the ideas. Oh, interesting. Because neuroscience is a very, very empirically based, bottom-up-driven thing. But we need big ideas, too.

And that's one of the things that was instilled in me through my mentor, Mike Gazanaga, is like, you know, what's the big question? Why are we doing all this stuff? Okay, well, and so I guess you've been, I mean, you've been known for big ideas, some of which you claim you're responsible for big ideas, at least big ideas that other people seem to think you had, that you've sort of said you feel a little responsible for. I mean, the idea of the fear factor, if you want to call that, that the amygdala and fear are intimately tied,

and somehow, as far as I can tell, part of the purpose of the new book is to is to set things straight. Right, exactly. Well, I did that in my previous book, too, anxious, but it didn't get straight enough. Okay. So I kept on going. So, I mean, I'm not guilt-free in all of this because I was very sloppy with the language. I went back and read The Emotional Brain, which I published in 1996.

And I'm definitely talking about the amygdala and fear in there. So it's like I can't say I'm guilt-free. But do you think of it, interestingly, the big ideas, do you think of yourself as more of a theorist Well, I don't know. See, in physics there's theorists and experiments. I know when most other fields are the same thing. But what drives you? The ideas or the techniques or what gets you most excited?

I mean, because I came into this from, you know, I had no science courses in high school college. Maybe I had chemistry or something in high school, but no math. I was really bad at math. So I'm not a natural scientist at all. And, you know, I have tremendous imposter syndrome, I guess a lot of people. do, but I really deserve mine because I feel like I just kind of flowed through this thing on an easy track through the split brain work, got learned a few techniques, was able to do some stuff. But it was all really about, you know, what I wanted to understand, which was consciousness,

which I studied in split brain patients and got hooked on. But I figured I needed to kind of get the basics down through studying the brain in more detail to come back to that. Okay, well, that's good because I think that's what it'll be, we'll try that arc when we discuss things. I should also say, yeah, I have imposterousatious just a lot. But I do think the other thing that connects neuroscience and cosmology for me, in my own mind, is that they're the two most fundamental questions that I can think of. And for a long time, when I grew up, I didn't know what a neuroscientist was.

And my mother, you know, neither my parents went to finish high school either. And so my mother wanted me to be a doctor. And what I wanted to be was a neurosurgeon because I figured that was understanding the brain. I didn't know the difference between science and medicine. Because the fundamental questions are the origins of the universe and the origins of consciousness. To me, those are the two most interesting sort of fundamental frontier. So I kind of have a little bit of envy because I took the easy route, which was to understand the universe. And I'm always...

And I really think in a way, and I think I'm not just being facetious there because we physicists have it easier. But at the same time, I'm skeptical. because in physics, there's clear, well-defined experiments, things you can test, things you can falsify, and I'm always suspicious because the brain is so complicated. It's not quite as bad as doing maybe social science where it's even more complicated in the sense of how to separate out variables and determine what an experiment is really telling you. And so I want to put on, to some extent, I'll try while we talk to put on that skeptic hat of how do we know this, because physics is really easy. But your book is very lucid and makes it seem, it seems to me, in retrospect, obvious that some of

the confusions people have are really confusions. But I want to try and understand why, because a lot of it seems plausible. And I've written about plausibility in cosmology too, but plausible and plausible and knowing are two different things. And so I'm still not 100% convinced that we're yet at the point of knowing. And how I'd like to talk about how we can get there, just so you you're aware. Okay. And in terms of that skepticism, actually, it's really, to me, it's perfectly appropriate that there's this big pile of books behind you, many of which are unconsciousness. And I had a friend of mine... This is just things that come in the mail. Yeah, of course. The same thing happens to me in my office is just piled up. They could send the mail, and sometimes I shouldn't

like say that in the mail. Yeah, some of it may be friends. But someone once said to me, it's stayed in my mind, that knowledge in a field is involved. That knowledge in a field is involved. inversely proportional to the number of books about it. And one of the things that you can't help, if you're outsider, it seems to me, is consciousness. There's books every, to all come out all the time, each of which is providing a revolutionary new theory of consciousness. And therefore, they cannot be right. And so one of the things that did frustrate me, because I was looking for this, because I'm not convinced we know, is I didn't find. in the book a definition of consciousness. I found, you know, auto-noetic, noetic, anoetic,

and maybe we'll talk. I like those terms to be defined for people later on because maybe we'll use them. But what is consciousness? Well, you know, that's why there's so many books. Yeah, I think so. And I still don't know. It's like what is life is another group. So rather than trying to, you know, give you a really crisp definition of what it is, I like, I like. to think of it in terms of things about it we can study. Okay. And I think these three categories that you just mentioned, auto-noetic, noetic, and anoetic,

are ways of thinking about it that are not so difficult and mysterious as the big topic is. And so my goal is to try and use those is to leverage some way of relating those concepts to the brain. So auto-no-no-edic consciousness. Let's start with anewetic. A-no-o-o-edic is more of a-no-o-o-e-edic is more of a kind of primitive, one person is called it almost unconscious form of consciousness,

like the most primitive kind of minimal awareness that an organism could have. And so most of the time we talk about these things in terms of mammals. So I don't want to talk about octopus and whatever else. People might plants or whatever they want to throw consciousness into. But let's just stick with mammals because that's hard enough as it is. So anoetic would be some kind of primitive state that a mammal could have and be in the presence of something useful or harmful and maybe have some inkling of awareness about it. But it wouldn't be a very elaborate kind of thing. A more elaborate form would be something called noetic consciousness, which is something where you have a semantic knowledge, piece of information about what something is.

in part based on memory of experiences with that thing. And so the Aenoetic would be almost kind of a more innate sense that you have about something. Noetic is a learned semantic representation. It doesn't have to be verbally semantic. It could be nonverbal semantic. It's just like, you know, if I, even without a word cup, I could know that this thing could be used to drink. So it's knowledge about something, knowledge about. Knowledge about something which is based to some extent on experience.

Yeah, right. So it's not just gained by experience, so you know that this cup you can drink with. And then auto-noetic consciousness is consciousness in which the experiencing individual is part of the experience. So if, for me, for example, I say that emotions are an example of these auto-noetic kinds of states. Because in order to be, to have an emotion about something, it has to be about you. Or something you care about your child. William James said, well, we can have the extended self, which includes our yacht and bank account, but we can drop those and just talk about our family and friends and so forth.

Social. I don't want to drop my yacht and bank. So, yeah, so these three terms come from the psychologist Indel Toving, who was trying to characterize three forms of consciousness in relation to different kinds of memory. And auto-noetic consciousness is related to what he called epapeutic. memory, memory about the episodes of your life, your personal past and your personal future, expected future. So it requires a brain that can do what Tolving said is mental time travel, the ability to put yourself in your past and to predict or have an expectation about what your

future might be and to experience your present. So, but to do that, it can't be just a memory about the past, because a lot of animals can have memories about the past, and they can also make predictions about the future. But to have yourself in those representations where it's you in your past and you in a possible future, that's a special kind of thing that most people, I think maybe there are probably some who would disagree, but many philosophers and scientists would say that that kind of ability is, in terms of scientific evidence, something that humans seem to be able to do. But even apes have trouble with this kind of more personalized mental time travel where their self is moving in space and time. Given that, one of the ideas that I have, and this, you know, every time I write a book, I'm at the end, and then I start to figure something out.

It's too late to, like, get it, in there. I know the feeling. And anxious, it was about the why, my understanding of why, you know, anti-anxiety medications don't work. So I had to write a lot of stuff about that later. And then in this book, it was about how these three kinds of consciousness allow us to maybe make predictions about what different animals might have. Because we know that, for example, other primates have a region called the dorsolateral prefrontal cortex. It's in the prefrontal cortex. It's lateral and in the dorsal part of the lateral area.

But other mammals don't have that. humans being primates have it. But there's also a little spot in the prefrontal cortex of the human called the frontal pole that only humans have. It's kind of a relatively recent discovery. It's not like there's a bump there or anything that you could just look at and see, but in terms of parcelation and analysis of the connectivity and the molecules and the genes, this region doesn't even appear in other primates.

So if we've got a human-specific kind of brain piece, and a primate-specific kind, and then we also have mammalian-specific kinds, maybe if we could figure out what those three things do in the human brain might give us clues about what the other animals that have those and only have those could do. Now, the flaw in that is that the human brain is not just layering, but each of those kinds of things, those systems have continued to evolve as primates and humans come along.

But it would give us clues. Great. We're going to get there. And in fact, the frontal poll, when I was reading your book, I thought, you know, as, wow, there's something just for humans. So, you know, it must be, maybe is that the seat of consciousness? I've learned, of course, reading your book that things are much more distributed. But I think you hit the point of why the confusion and the non-confusion, which intrigued me. Because if I hadn't been aware to some extent of the history of the field, I might have assumed it was natural.

I think most people throughout history from religions on think of the brain, the language, culture, consciousness as a thing that separated us from, quote, animals. Most of them thought it was divinely inspired. That's what God gave us that it didn't give them. So they saw this natural dichotomy. Instead, from what I understand and thinking about this, there's not. In fact, you know, the first one, early on in your book, you say similarities only make sense in terms of differences. And a key goal of the book is to provide an account of the things most different about us. language, culture, our capacities for thinking and reasoning, and our ability to reflect upon who we are. These are new, but have deep roots that extend to the beginning of life. So you want to make those connections, but at the same time show what's different? And in some sense, what's the source of this sudden, you know, for the person on the street, they think, oh, we're not animals.

And then, but at least for neuroscience, suddenly we were. Is it Darwin? Yeah, and I hate to say anything bad about Darwin. I was going to say, is it probably Darwin? But, you know, I mean, obviously he was a great biologist, but it's been said, it was not so hot a psychologist. Yeah. And yet he was very influential in psychology. So Darwin, you know, lived in Victorian England, and this was a time in something called the Society for the Prevention of Cruelty to Animals as an afterthought children was created.

the novel Black Beauty about the horse who had been mistreated by his people, and it was narrated from the point of view of the horse. And so there was a lot of concern with this sort of thing. So Darwin proposed that in his, I think it was 1872 book, The Emotions in Man and Animals, that emotions, human emotions, states of mind that have been inherited from animals. So I don't know how you inherit a state of mind, but that's what he had in mind. He said, well, there's some neural things.

Okay. So someone asked him, you know, a reporter in an interview, he said, Charles, why do you talk about animals as having, and he talked a lot about animals having all these human emotions. Like dogs had a fear, could have a kind of a fear of God. They feared their master and, you know, tried to please them. and so forth. So he was a pretty bad center on the anthropomorphism scale. And so he said, well, so the reporter said, why do you treat animals as having human-like emotions, whereas everything else you're talking about humans as having animal-like things? And he said, well, it's kinder and it will be easier

for the people, for the public to accept than for them to accept that we have animal emotions. So with that, and his book has been revered, and it became the basis of much of the field of the psychology of emotions. And there's a whole field, a gigantic field. Most people think of emotions as these mental states we've inherited from animals. We have a fear. We've acquired fear because every animal has to deal with fear and danger. And obviously, they're afraid. A rat that's freezing in the presence of a cat is afraid of the cat.

why else would it freeze? And that's how I started writing this book because I started asking, well, how far back does this detection of danger go? And I didn't get to the end until I got to the beginning of life. Yeah, in fact, well, you know, your book sets out the premise and starts right at the beginning of life. And I kept asking myself at some sense why we're going so far back. And I understood it later on as I read things. But what is amazing about it is by setting the premise, almost everything else seems not obvious, but so logical after the fact. The fact that, yeah, it's natural for me to assume, I have a dog, I have a cat, and that they're feeling things, and we'll talk about that, of course.

But when you point out very early in the book that behavior, learning, and memory don't even require a nervous system, then a system, I think most people would argue, would accept the fact that a protozoa doesn't have feelings. Right. But the fact that a protozoa or plants can respond to stimuli and move towards it or away from it in response for survival, that once you realize that, it kind of seems obvious that that behavior doesn't depend upon thinking. Not to everybody, because to other people, that means the plants have feelings. Yeah, yeah, of course, yeah, I guess.

Well, but the notion, as you say, I think somewhere at the very beginning, that I will show you that there's any deed good evidence that the same brain systems control survival behaviors in human and other mammals, but these are not the systems that are responsible for conscious feelings we experience. So they occur, so basically there are different brain systems for survival, which looks like it may involve feelings and feelings. And I want to get through a series of steps because it takes the whole book to get there too. Could I just tell you what happened that made me go down this road? Well, I think that's what I was just going to ask. Why don't you give me your own history about split brains with good.

Oh, that, okay. Oh, maybe that's not it. Okay, why do you start? We'll come to split brains. Well, we're on this topic of evolution. So, you know, I'd been studying the amygdala and how it detects in response to danger and how it learns through Pavlovian conditioning that, you know, some neutral stimulus becomes aversive by this conditioning process.

So we worked out the amygdala was involved in all the circuits in the amygdala, all the gory details. And the next step was then to ask, what are the molecules and genes that underlie that. Sure. So how do you, you know... I like reductionism. So we said, how do you figure that out?

Well, you know, people like Eric Kandel had figured this out in eplegia, you know, invertebrates and flies and other organisms like that. And so, and they were studying palbovian conditioning as well. So this was, you know, we could ask, well, maybe those genes and molecules that they discovered are the same as in rats. And sure enough, those were great clues. So we just used what they had figured out because it would be much harder to figure it out from scratch in a mammalian brain. So we did it.

And a lot of people did this in other parts of the brain, too, following those clues. And I just did it and didn't think too much about it. But at some point, you say, well, where did that, how did that happen? How did the flies and rats get the same genes and molecules? So you've got to go to the common ancestor of those things, which was a flatworm living. about 630 million years ago. And so this guy, Seth Grant, who had been working in Eric Kendall's lab, now had set up his own lab at Cambridge, where I was doing a sabbatical in 2009,

and we became friendly and talking a lot about this, you know, kind of introduced me to the idea that certain things that are important in memory, in particular something called the N-Methyl deosportate or NMDA receptor, which is the main plasticity molecule that, allows all these conditioning things to happen. So Seth was tracing the evolutionary history of these molecules and finding components of it in this bilateral, ancient 630 million-year-old flatworm,

but also in its ancestor, which was a jellyfish-like organism, and its ancestor, which was a sponge-like organism, and in its ancestor, which was a protozoan. So why the protozoa, who, you know, don't have a nervous system, have an MDA receptor components that are used in plasticity in nervous systems. So, well, that means that maybe they're using them because they can learn and they can be conditioned and all of that stuff. But the intriguing thing was that we could follow all this. And once you get to protozoa, you start to say, well, what about bacteria?

And certainly there's a lot of evidence that they behave. They approach and avoid useful and harmful things. There's some evidence, not like strong evidence, but there's fairly compelling evidence, at least in mathematical models, but also some behavioral evidence that they learn. So all of this stuff takes you to, you know, for like 3.8 billion years ago in the beginning of life, when the first organism that survived had to do five things, detect danger, incorporate nutrients, balance fluids and ions, thermoregulate, reproduce. Now, if you're studying psychology and animal behavior, those are the things you study. And so when a rat is freezing in the face of danger, you call that fear. When it's like working to get food, you call that hunger. When it's copulating, you call that sexual pleasure, you know.

And so we project, we do the Darwin thing and project our mental states onto those animals. But those states, those activities that we're talking about go back to the beginning of life. They have nothing to do with psychology. They're about staying alive. And that's why, you know, I wrote the book. Yeah, that's life rather than psychology, although I guess, yeah, sometimes those are the same. But you hit one point, and I want to ask you the details, because again, maybe I missed it in the book, but I want to know the experiments that led.

So, so Candel discovers, you know, a molecular basis for certain things and certain things. And so the set of experiments that then convince people that this is, is relevant. for many other, for everything from all the way up to animals, is to do biochemical tests? Was it chemistry then at that time that you were doing? Well, no. So let's say, you know, at this time in the 90s, this was the age of the knockout mouse genetics thing. And I never got hooked on that because those were, at the time, were body-wide manipulation. So you'd knock a gene out, and you could take that molecule out, but you'd take it out in the whole body.

so it was kind of messy. But the alternative was you could, let's say you had something like an enzyme like protein kinase, or map kinase. These are things that Candell discovered were important in the triggering of protein synthesis, and protein synthesis is important in the stabilization of synapses, and that's how memories get stored.

So there were chemicals you could use and inject into the amygdala that would block PCA, protein kinase, or map kinase, after an animal had learned something. And the question was, would the animal not be able to form a memory of that? And the answer is yes. They can't form a memory. How do you know? Well, you condition them with a tone and a shock.

And if you test the animal immediately after conditioning, they show the memory. after doing that, if you inject a protein synthesis inhibitor or map kinase inhibitor into the amygdala where the learning is taking place, then that short-term memory that you just observe does not get converted into a long-term memory because that requires protein synthesis. So you can either block protein synthesis or you can block some of the enzymes that trigger protein synthesis. But the point is that the memory doesn't get. And you know it doesn't get for them because you do the same chalk and it doesn't show them.

It doesn't. Whereas if you don't put, I just want to make clear the listeners, if you don't put that blocker, then you perform the test later on and they anticipate that. And I also have learned from listening to you in a variety of contexts that the shocks are very mild. Yes. And you only have to do it one time. That's the beauty of this kind of conditioning procedure.

It's really very naturalistic. So give a rat a tone paired with a shock. You do it one time, and then the rat has basically a lifelong memory of that. It's like, you know, it's what happens to us. If we have something kind of dangerous, it happens to us, that gets stored for a long time. Good, because I want to, you know, get at the science, in my opinion, the science is empirical.

I want to try and understand why I should believe logical arguments that you're going to present or anyone else might tell my time. Because they're all eminently plausible and logical, but I want to know. Well, let me just say one more thing about the conditioning procedure. So the tone is simulating, like, the sound of crackling, leaves that a rat might hear before a cat pounces on it. And then the shock is simulating the wound that the cat makes in the rat when he attacks. So it's kind of a naturalistic learning about danger. It's not just like, you know, this weird. Why are you giving a ratatone

shock? There's a reason for it. Oh, that's interesting too. I didn't know that. That's great. So you can do that to rats. How can you, in terms of looking for memories, how primitive an organism can you do these tests on and how do you do them? Pick your organism. Okay, flatworm. Well, so certainly worms. I don't know what's been, well, flat one, yeah, planaria, definitely. How do we do memory in that? So they can be trained to, you know, approach something, you know, like a little maze, for example,

and they can approach the food. And if they get a shock while they're approaching the food, then they don't do it. Or they can be made sick or something. you know. So they're all just the standard kinds of behavioral. So of course, one can imagine if they get a shock, they avoid things. And we'll talk about that even with back, this amazing experience with bacteria that I kind of let you talk about. But do they have long-term memory?

Will they avoid it later on? Right. So this has been done, for example, in sea elegance. And Corey Bargman at Rockefeller has done this work. And, you know, it's been done in flies, worms, jellyfish. So they all have memory. Yeah, yeah. Protizo have memory. Protzoa have memory, too?

Plants? Plants, yeah. I mean, you know, plants will follow the trajectory of minerals as they extend their roots down. And they, you know, will, well, we know that, for example, when the sunflower moves during the day, it can store information about, you know, conditions and movements. Is anyone done an experiment?

This is just currently, me, with plants where, where they're following the minerals. And then you change the soil. Will they go where the minerals were? Will they remember? That's a good experiment. I don't know. I'm not really a...

My bet is if there's some biochemical thing where there's no memory, they just happen to follow biochemically along a certain trail because there's that. But it would be interesting to try it. Well, look, one has now learned that there's many things that we share all the way back to bacteria. And then the key point is that there's some things we don't share.

And therefore, we shouldn't assume that just because we share some things that we share everything. I think that's, but you put it pointedly in a number of ways. Here's one. Consciousness, though useful in humans in ways that we will be discussed later, this is early on in your book, is often a passive observer of behavior rather than an active controller of it, especially with regard to survival mechanisms that originated billions of years ago. That, as I will argue later, research suggests that the approach and withdrawal and other survival behaviors in humans

are mediated by different brain circuits than those result in fear, pleasure, disappointment, and so on. And I think we've gotten the first part because you talk about those circuits. So the circuits that mediate survival and approach and withdrawal behavior are the ones that go all the way back. Yeah.

So like the in mygdil is the manifestation of bacterial survival. Okay, but the circuits that result in emotions, fear, pleasure, disappointment, they're different in our brain, and therefore they don't have. have the same evolutionary background. Okay, but that's a really confused them, but it's because when we're afraid,

we're usually running away. Yeah, sure, exactly. The key thing is not saying the correlation is causation. And that's a sin that a lot of people in my field have made, I think. Well, I think all signs. It's easy sin for everyone to make. And I'm accused, I accuse myself of it. But we'll get to the profane, but first I want to get to the sacred.

When I read all of these recent elements, it seemed to me that those two statements of yours basically are the same statement as the philosopher Hume made when he said, reason is a slave of passion. In fact, your split brain work is when I read that, I thought reason is a slave of passion in the sense that we assign rational or, you know, that basically what's governing us is things that we don't think

our rational mind is telling us about. The two are much more separated than we did before, which is why I now want you to talk about the work you did. with Gazaniga early on, that is so remarkable, to me at least. Well, first of all, split brain is a surgery that is done to help people who have uncontrollable epilepsy that can't be helped in any other way. And so it's not something that's done that often. It was done a lot in the 60s and a few of those patients out there. In the 70s, it was done at Dartmouth. And occasionally there are some that are being done, but it's not that common.

But, and it seems to help, but I'm not qualified really to address that issue. So anyway, so in the Caltech studies, the, you know, they worked out, you know, you put a stimulus into the left visual field that goes to the right hemisphere. Put a stimulus in the right visual field that goes to the left hemisphere. So the brain is split, so information going to the right hemisphere stays there. So left visual field, right hemisphere, the information is here. you say, what did you see? And now you're talking to the left hemisphere, and the left hemisphere says, I didn't see anything.

But if you have the guy or gal reach into a bag and with the right hand connected to the left hemisphere, they can't find it. But left hand, connected to the right hemisphere, they can pull out the banana if there was a picture of a banana. So information in the right hemisphere is, it gets stored there, It gets represented there, but it can't cross over to the left where you can talk about it.

So that was like, what happens when you take the brain import? That's what they did in the 60s. And in the 70s, Mike had gone to Stony Brook, and a new group of patients were being operated on at Dartmouth, and so he started testing those. And that's right around the time I arrived in his lab. And I wanted to do animal studies. He was doing some monkey work, so I do the monkey. your research. He said, no, I want you to work on the human. I just came here to do, you know,

real science. Yeah. And he said, no, give it a try. So, okay. So I gave it a try. And it was like fascinating. And, you know, so, and the way Mike put it is that, you know, we spent X years asking the patient, what did you see? And then in the studies that he and I did, we said, why'd you do that? That was the next question. Yeah, that was, I'm surprised. This took so long, but I don't know why it took us so long. The way it happened was we were up in the, we had a little trailer that we would pull behind a big orange van that Ford van that Mike had. It was a little camper trailer. And we'd set up a lab in there testing, you know, like a table like this size and a screen that you could flash pictures left and right onto.

And, you know, places where the hands could be hidden so they couldn't see them so you could move objects around and so forth. So in the key experiment, we would make the right hemisphere cause the person to do something like stand up. So the guy would stand up and say, oh, I need it to stretch. When you said, why'd you do that? Say, oh, I needed to stretch. But in reality, you told them to stretch. Yeah, it was like we made him do these things, but the left hemisphere didn't know that. So it was like scratch.

So why'd you do that? I had an itch or laugh. And so why'd you laugh? You guys are funny. And these were not like, well, let me think about it. It was like automatic. So the idea that we kind of came up with is that, well, maybe this is what happens all the time in life. We generate behaviors that we aren't consciously aware of, but our conscious mind lives and thrives on free will, the idea of free will.

So if we're not in control of our body, what the hell is going on? So we make up this story. We have this natural mechanism for generating a narrative about why we do what we do. Yeah, it was just fascinating me that people would just immediately, when you told them to do something, and then they had no, the other side of the brain didn't know why, the one that controlled what they were saying, would just come up naturally with a totally false explanation. It really is sobering to think that that's why we explain most of our behavior. And that's what I mean by the women I read that as my thought reason was a slave of passion.

Well, we should, you know, we have to give credit where credit is due. So Mike was good friends with the social psychologist Leon Festinger. and Festinger had the theory of cognitive dissonance where if you do things that don't jive, then it creates dissonance, and so you have to explain it. So we were just applying cognitive dissonance to the split-brain behavior.

But it really suggests that we definitely, yeah, it was very, that's a clear, for me, that's a clear experiment that tells me something, and I love that kind of stuff. I wouldn't call it an experiment, actually. These were like demonstrations. An observation. It's more like in astrophysics, an observation.

You're not tweaking the knobs, but you're observing what happens. And it was one patient and a couple of little tests we did that. Yeah, I guess you don't. Well, you did it presumably on more than one, right? I hope. I mean, yes. But each patient was so different that there was one patient we could really do all this cool stuff on.

The reason is because he could read in his right hemisphere. And that's how we could get him to do all these things. But most of the others couldn't. But because he could read, we also had the opportunity to, for the first time, really ask, is there a conscious mind over in the right hemisphere? So we would put the question over there, who are you in the right hemisphere? Because you can't talk to it, the society.

And so we put out scrabble letters, and the left hand picked up P, A, U, L. Paul, he spelled his name. And then we said, you know, asked him, well, what do you want to do when you grow up? and I forget exactly how we phrased it, but... So the left hemisphere, when it would talk to us, would say, wanted to be a draftsman, architect,

but the right hemisphere spelled out race car driver. Oh, interesting. So, you know, that little demonstration we claimed, showed that he had a sense of self and self-identity, because he knew his name, and he had an aspiration for the future, two things that are important in human behavior. Different aspiration for the future in different atmospheres.

Wow. But how would I go to the mat with that? Yeah, no. Put my life or no. But it's intriguing. Yeah, it was an intriguing thing that makes sense, and we used it to, like, you know, run with and try to explain. Well, what I like about it, and one of the reasons I want to focus on it is that so many times I'm suspicious when, well, you've heard, I don't know whether I heard it from you first,

but the problem of studying brains with brains is very hard because we can study stars with us and we're not. And so I'm suspicious when people tell me they talk to patients because you never know quite what you're really learning. And it's nice to know that there's some clear evidence in this case because of that story, where you can definitively say one thing or another. But one thing, I want to just go totally aside for a second because I think I heard you say this somewhere,

because I was listening to you as well reading you. that people imagine they have free will because they're doing things, but in fact there are other reasons for why they're doing it. But then I was surprised to hear you say you quote unquote believe in free will. Well, I don't just believe in it. Why do you think that there's free will? Because I see no evidence of it whatsoever in any part of science I can see. I don't think there's any evidence.

It's just kind of like I'm hanging on to that as a core belief. That can be your next book, why that's wrong. Yeah, right. But I should say in terms of the patients, my experience ended there, but Mike continued to study other patients and confirmed all this in others. So it wasn't just like as casual as I just said. Yeah, no, no, sure. But it's nice to see them. We're heading towards, you've already said the conclusion in subsets.

And I want to take steps now to get there. We've talked about the one evolutionary aspect of behavior. There's something else that for me as a non-expert was sort of useful. And that's this difference between Pavlovian and instrumental conditioning in terms of understanding different ways the brain works. So would you mind talking about that a little bit? Sure. I think one of the problems that people don't really understand is that there are lots of different kinds of behavior. And every time you ask the brain to do something slightly different, different systems and circuits in the brain are involved.

I think this is a big problem in terms of treatment of mental and behavioral disorders. I don't know if we want to go into that, but let's create a kind of classification of behaviors. So we've got reflexes that's very primitive that every animal has. The next step up would be innate behaviors are what Conrad Lorenz and the ethologist called fixed action patterns. and the next step is a habit. So a habit is like a rigid fixed action pattern, which is repeated the same way every time, more or less, except it's been learned.

A habit has been learned. But it is learned without the consequences mattering. So, for example, let's say you've got a rat that's pressing a bar to get food, and if you repeat that behavior enough, it will continue to press the bar without getting food because the expectation at some point it might come. But you don't know when you're watching that just from the behavior alone, whether the behavior is controlled by a habit circuit, in which case if you eliminate the food, it will just keep going,

or if it's controlled by an instrumental goal-directed kind of circuit, where if you eliminate the food, at some point he'll stop pressing because the food is, not coming. On the outside, this is the work of Anthony Dixon at Cambridge and Bernard Baleen in Australia, showing that you can't tell by observing behavior which of those is at play, a habit or a goal-directed behavior. You have to have tests that dissect all that. And that is a key point about behavior. What it looks like is not necessarily what it is. So above instrumental behavior or what we can call deliberative responses, the response is controlled by cognitive deliberation, which can be either unconscious or conscious. And so that gives you a kind of range of

the types of behaviors. And each of those depends on different circuits. And sometimes they look very similar from the outside, especially, you know, conscious behavior can look like instrumental goal-directed behavior. It can look like unconscious behavior. So we have to, like, you can't just assume it, you have to test it. That's a very important observable that you try and sort of distinguish between them. But the other one, and we started to talk about it, that seems to me in building this picture you have is the key role of memory and schema, which, so if you could talk about that as well, I want to build up the parts. Okay. So a schema is simply kind of what you might call a mental model. It's a kind of body of knowledge about. something. You could have a schema about animals or about danger. And so it's kind of a,

when you're in a situation, let's say, of danger, what happens is, you know, let's say a snake at your feet. So that goes into your brain and that will cause your amygdala to make you freeze very quickly. But at the same time, the threat is also going to cortical areas and to memory-related areas in triggering memories. So it will trigger semantic memory, so you know that snakes are dangerous. And you know that some snakes are dangerous and some are not. You have all kinds of things you've learned about danger throughout your life. You know how you expect people to act in danger, and are you acting that way?

If not, are you disappointed in the way you're acting? And there's all kinds of memories that can be retrieved. But the most important ones are those about you, called episodic memories, experiences you've had in your life about danger. But the point is that all of these things are stored in your brain over the experiences you've had throughout your life. But in the moment, the snake is activating a subset of those memories, which can be the moment, we'll call the momentarily active schema. and that kind of forms a template or a body of knowledge that can be read out in a narrative that now plays out in your conscious mind sphere. Well, let's take it, again, the physiological and maybe biochemical basis of this.

One aspect of all of this is synaptic plasticity in the brain. But, in fact, somewhere you say the synaptic plasticity is a basis for learning. Yeah. But one thing that's sort of a little confusing is you also argue that things as far back as protozoa and, I mean, things that they can learn too. Yeah, right, right. And so if it's a requirement of learning, how can they learn if they don't have it? So, okay, that's a good point. So let's start low and go high.

as we go from low to high, what we see is that bacteria and humans do the same five things that I mentioned, detect danger, incorporate nutrients, balance fluids, stemmer regulate, reproduce. But all the way between bacteria and humans, every organism does that in a different way, because it has a different bowel plan or body type that's evolved in its particular niche. And that body determines how it will respond and how complex its response is consistent. be. So before nervous systems, organisms have cellular membrane responses to detect good and useful things and move towards and away and so forth. But they don't have, you know, arms and legs to move them. So they bacteria and some bacteria have flagella and they use those to kind of propel and they

randomly move through the environment with that propelling. And if they encounter something useful, they keep going, if they found something, kind of encounter something harmful. they flip away and go off into a different direction. So their ability to move around in their world is very limited, and their ability to choose what to do is limited. It's all driven by their membrane. But the next level up would be a protozoa, which has a more sophisticated kind of body because of its larger, for example.

Bacteria have a mass problem that they couldn't get bigger and it has to do with energy dynamics and so forth. Protizoa have mitochondria and this can support slightly... Oxygen suddenly increases by 306 times the amount of energy you can... But protozoa still, it's still one single cell. Now, a multicellular organism, let's take a simple one, which would be like just the beginning of a few cells that are kind of integrated together through a process called alignment of fitness over the course of development.

where the genes, you start with a single cell, but the genetic program allows that cell to divide and reproduce in a way that is tied to a program about what kind of body is going to be built. So you get multiple cells coming out of that single cell, and that allows a true organism, because before that you could have cells that are cleaning together, but they're not starting from a single cell. So their genome is different. But every cell in a multicellular organism has the same genome, and that's why it can live together and be physiologically compatible and have a big body

that's physiological compatible, because they all start with the same genome. Okay, but this is a description of how, indeed, how the importance are going from single cells to multicellular and then to a true multicellular being that, and then oxygen intake. And there's a long history and it's fascinating, but I guess that, I wanted to just say, if, but what I got in terms of your answer to my original question, I'm getting. Okay, learning, okay, good. Okay, so yeah, so the body type you have determines what you can do.

So animals have nervous systems. So why do they have nervous systems? Well, the action potential, which is important in a nervous system, was used in a single cell as a way to repair the cell membrane. And so then that became useful as a means of communication within the cell so that when cells, when you have a multicellular organism that is capable of having specialized cells, you have a cell that's trying to communicate with another cell. And the body is getting bigger because you have many more cells.

And like in a tree, it takes forever for the chemical transmission from the roots to go to the leaves and all that. But if you had some way of speeding up that chemical transnational. transmission from cell to cell, those cells could be separated in distance, and so you could have a bigger body with lots of parts, and so you could behave in different ways. So the point is that snapping plasticity in animals with nervous systems is the basis of learning, but that's based on principles that were figured out for learning in bacteria and protozoa as well. And the key point is that the nervous system, it sort of grew out of physical requirements in some sense. Two, that as far as I can tell,

One, that electricity travels, electronics travels better in chemistry in some sense, although chemistry basis of us. But chemical interactions are less fast than sending electronic impulse, so it's useful if you're larger for systems to communicate that way. And the other is bilateral symmetry. So in terms of the electrical thing, though, and it's important to point out that the standard way that cells communicate is by releasing a chemical and the, that chemical diffuses to the next cell.

And so, in order to have communication across long distances, they had to have some other means. And as you said, electricity that's generated in the cell body can travel down some appendage that's connected to the cell body and then be allowing the release of the chemical a long distance away. So that's how communication takes place in a large body. Now, bilateral symmetry is something that happened, So the first animals were sponges, and then they gave way to jellyfish.

Now, the interesting question is, how did a sponge become a jellyfish? Well, you can't understand that by thinking of the adult organism. You've got to understand it from the point of view of the larva. So the sponge larva and the jellyfish larvae look very similar. So it was a small change to go from a jellyfish larva to a sponge larva, and it's all about the development program in those two organisms that then unfold as. So jellyfish are radial in shape.

Sponges have no particular shape. Jellyfish are radial. They have a top and a bottom, but not a front and the back or a left and the right. But flat worms have a left, right, front, back, and top bottom. So that was the first kind of bilaterally symmetric organism. And they also had a tiny little brain, it's believed, a few collection of neurons in the head.

And that was important because the head is where the eyes are, the head is where the mouth is. And so you can have the forward direction of locomotion can be guided by the senses, and the food can be taken in there. Yeah, that's what amazed me. It's just a simple physical fact. It never occurred to me before

that when you have bilateral symmetry that way, there's a forward motion. And it's reasonable to have a system that controls forward motion in the front. And that seems to be so remarkable. And the other good part is that the tail is the most dispensable part. So the back, if a predator comes up from behind and bites off the back, you can still keep going because the head and stuff is in the front.

Yeah. Right. So it's, well, as always say, everything's physics. You know, I didn't know any of this stuff when I started right. I had to learn. I wrote most of the book as a journalist rather than a scientist. Well, that's a good way to do it because then you can explain it to others, I think. But it's interesting that the physical requirements, well, it's very satisfying for me.

The physical requirements drive many things and things you might not have thought of, just the simple fact that having a brain in the head is... You'll like this one then. So, you know, we think of approach and avoidance as psychological behavior, but they are just the two things that can happen between two physical objects. They need to be closer or further away. You say that somewhere, that approach of avoidance is basically just physical. It's physics.

Okay, well, so I wanted to walk through that. a little bit, but then I want, before we go to cognition and then we all, then I have some general questions for the listeners who are feeling overwhelmed already, but I want you to work through the, so we have those systems, but now we have a brain. So all brains, all vertebrate brains, consist of three parts, a hind brain, midbrain, and a four brain. The four brain is the part we care about most because that's where all the cognition and a lot of our learning and so forth take place. The midbrain is more kind of reflexive and instinctual, and the hind brain is more necessary for life. So the mammalian brain, the brain that all mammals have, has expanded quite a bit.

The first mammals were primitive ground-dwelling organisms. They depended on smell a lot. With primates, the involvement of vision became more important, and new learning capacities came in. And in humans, we got in the further changes. But all of these things are happening in the forebrain itself, not in the other two parts. I mean, you know, there are advances in each part, but the big changes in mammals was in the forebrain, and the big change in primates was also in parts of the forebrain. So, when we talk about cognition, we're usually talking about the cerebral cortex. That's the wrinkle part you see when you look at a picture of the brain.

And underneath that, because it's below the cortex, it's called the subcortical area. And when you hear things like the limbic system, something I'm not a big fan of, but the limbic system is part of the forebrain. and it has both subcortical and cortical parts. So the cortical parts of this limbic brain would be on the middle side. Imagine a hot dog bun, we pull it apart, and the white, untoasted part in the middle is where these old cortical areas are. On the outside, the brown toasty part is where the newer cortical areas are.

And in the front is where the prefrontal cortex is, which we talked about earlier. And we have the lateral prefrontal cortex, which is where we talked about having primate specializations, and the frontal pole is also in the lateral prefrontal cortex. In the middle part, in the medial prefrontal cortex, we have these older cortical areas that are present in all mammals, but are particularly important in non-primate mammals because that's all they have. Okay, good. Now, that sets the basis for the realization that behavior does not necessarily represent cognition and emotion. Those are really governed by different circuits in principle.

And maybe because we've become technical, I won't go into too much about that, but I'd like you to at least talk about how one focused on the amygdala, and what that governs and how one knows, or at least now knows, and by no, I mean experimentally know, that that doesn't necessarily relate to emotions. All right. So first of all, I didn't invent the amygdala. I've worked on a long time, but people associate me with it a lot. But researchers were studying the amygdala long before I got involved in all this.

What I did was help treat it as not a lump in the brain, but as a part of a circuit. at where danger comes in is detected and a set of responses that allow you to cope with that danger or orchestrated. And the way I was able to do that is by following the logic I'd learned through the split brain research, where you put a stimulus into this part of the visual feel, he goes to this part of the brain and it crosses over, but if the section, if the parts are cut up in the split brain, then they can't travel. So I came to think of the brain as like a big wiring diagram. So when I decided I was going to go from studying humans to studying rats because I wanted to figure out how emotion systems might be generating

some of these non-conscious behaviors that we then generate an explanation of. So I said, well, there's no technique for studying this in the human brain. I need to turn to animal studies. So I turned to rats and I followed this logic of take a stimulus and put it in and goes into the ear and then comes out the muscle. So it's a matter of connecting the dots in the brain. How does the ear get connected to the muscle? And the amygdala was a major part of that connectivity.

The process was one of starting with a tone that's been paired with shock. It goes in the ear. And the question was, did it have to go all the way to the auditory cortex, which is the highest level of the auditory system? was some other, did the stimulus exit the auditory pathway somewhere lower. So rather than starting at the ear and making the animals deaf, which they wouldn't hear anything, so we started at the top, auditory cortex. Lesion the auditory cortex on both sides of the brain, the animals could still learn to freeze

to a tone that had been paired with shock. But if we lesion the next station down, the auditory thalamus, the animals no longer could learn. So then we trace the connections of the thalamus, and of course it went to the auditory cortex. How do you trace that? You inject a chemical, and this is what I had learned in that anatomist lab at Stonebrook, you inject a chemical, and it gets picked up by the cell bodies and gets transported down the axons, and you can then slice the brain later and see where the label is, do enzymatic reactions and stuff. So the tracer went to the auditory cortex, but it also went to the amygdala.

So, uh-huh, okay, so auditory cortex wasn't necessary. Maybe the amygdala was. So indeed, we went in, lesion the amygdala, and the animals still couldn't, you know, they couldn't learn. And so that allowed it. The tracer didn't go to the entire amygdala, it only went to a small port. So maybe if we just lesion that tiny port, then we'd get the same effect as a big lesion, and that was the case. So we then asked how does that little part connect with other ports? And that took us from the input part of the amygdala to the output port.

And the output part inject that and it goes to lots of other ports. And so we lesion each of those. So it was a matter of just like, you know, lesion injection, lesion injection, and through that systematic approach, we're able to get from the ear to the muscle. That tells you how the behavior works, not the cognition. And so it tells you you put this shock in and you freeze. So that's good, that's a mechanistic thing, but it doesn't tell you anything about cognition,

or at least to me, it's not obvious. So that's important, but now one's focused that that's somehow a pathway that produces a behavior that you might associate with fear. And that's what everybody called it, including me. We tell you, well, they made the list controlling fear responses. But I'd also said that the conscious experience of fear

is likely to be a cortical process, because of my understanding of consciousness from the split brainware. So even though I was talking about conscious fear, I wasn't studying it. I was all just kind of hung up and studying all this kind of basic biology. And it wasn't just like freezing behavior. We're also studying blood pressure and heart rate and stress hormones that are being released and so forth. And so this allowed us to then also do studies in humans. So I teamed up with Elizabeth Phelps, who was a colleague.

colleague here, now she's at Harvard, but for 20 or 30 years, we did studies together. She would do palboving conditioning studies in humans and was able to show that the human amygdala is also involved in palboving conditioning. Well, again, I mean, I just want to interrupt each stage to say, how do we know that? Because she didn't take the human brains out later in section. But there are people who have amygdala damage because of epilepsy and so forth, and they can't be condition. And she put people into imaging machines and showed that when she used visual stimuli, when the visual stimulus that had been paired with a shock was presented, the amygdala would be activated. Now, the important part was that she and others showed that those stimuli could also be

presented subliminally. That means you don't know the stimulus is there. It's presented in a very brief flash, like 20 milliseconds. You can then follow that with a a visual white noise, a big massive pattern of stuff that blocks the, helps prevent it from entering consciousness. So the person will, let's say you present a picture of a snake, or it's been an orange square that had been paired with a shock. Same thing, snake or orange square, paired with a shock. The amygdala is activated. And you say, what did you see? The person says, I didn't see anything. and you say, well, do you feel anything? No, I don't feel anything.

But the amygdala is activated. The heart is beating faster. The palms are sweating. So if we don't need fear to explain why a human is responding that way, why would we be talking about fear and a rat? Okay. Of course, what I understand is some people question that and say, ah, but was it really subconscious?

Yeah, you saw it for a little bit. Maybe it was conscious because maybe they just don't know that, you know, but it was really conscious because it was so far. fast. And that leads me to this next thing, which is really the basis of a lot of we talk about, which you call hot or higher order theory. I don't know whether as a theorist, as a physicist, I would call it theory. But the whole idea, well, no, the whole idea, which again seems eminably plausible, is that the brain as a processor is taking these inputs, you know, doing something processing, which you might call cognition, I would as a naive person, and then

feeding it back and doing something else. So somehow there's all this stuff happening in some part of the brain that is producing all sorts of stuff, like maybe fear, emotion, love, thinking, physics, who knows, and it's feeding back down. But you say that that's controversial and maybe for the same reasons. So maybe you can take us through higher order theory. Obviously I gave the baby version. Research on consciousness has been going on a long time, but it really kind of took off. in the 1990s, and this was due to Francis Crick getting involved and proclaiming that we should study visual consciousness because we know so much about the visual system. The fact is that, you know, all of the split brain work was done on visual processing, and there's been a lot of work on

consciousness. So Crick didn't invent consciousness for us, but he did, like, mobilize a lot of people to get involved, Rick and Christoph Koch. So a lot of the work that's been done has involved visual perception. And so many of the theories and arguments that are around today are based on visual perception. So, for example, if you show a person a picture of an apple that they can give a report on and say, well, that's an apple, you activate visual cortex but also prefrontal cortex. If the stimulus is presented in a way that the person can't give a report, but through imaging, you can show that the brain is still active. What you see is that only the visual cortex is active. So in the absence of the ability to say what is on your mind, what you saw, the prefrontal cortex is not active.

So that has led to the idea that maybe prefrontal cortex is important in taking a visual perception and turning that into a reportable conscious experience. Now, some people say, well, that's just, it's called access consciousness. It's really all about visual cortex and blah, blah, blah. But, you know, and those arguments are fine, and they've been going on between philosophers and scientists for a long time. But, you know, that's not going to explain what we really want to know about. How do we experience emotions and memories and all the things that drive us and, you know, that we love and hate about life? Visual cortex activity alone is not going to explain that. So I'm a fan of what's called the higher-order theory.

This has been most popularly presented by the philosopher David Rosenthal at City University here in New York. And his idea is that visual cortex information has to be re-represented in prefrontal cortex. and as a result of that, you can have a conscious experience of. Now, his theory is that it allows you to be conscious of what's in visual cortex. An alternative view that I prefer is that the prefrontal cortex is part of a system where the awareness is actually taking place rather than in the visual cortex. And so for an emotion, I'm saying, well, the brain systems involved, let's assume that the brain system's involved in making consciousness only evolved one time,

And the same system is involved, whether you're looking at an apple, or you're experiencing fear or love or anything else. What's different is the information that that system is working with. And so if it's just an apple, you're working with visual cortex. If it's fear, you're working with the visual cortex, but also the amygdala and the body signals that are coming back and all kinds of other things. So the basic idea then is that we have all of these stimuli that are present, in a dangerous situation, come into the brain. The visual cortex is certainly activated. But even if it's the picture of an apple, you really need more than visual cortex and prefrontal cortex. You need memory to know what it is. We don't have apples innately in our brain, so you need

some memory in there as well. So the whole, like, it's just visual cortex and prefrontal doesn't play out anyway. You've got to have memory as a sidebar that's informing what telling prefrontal cortex, what that is. So in the case of emotion, in addition to having memory, you've got all this amygdala stuff, but maybe that's not even necessary because one of the things we didn't talk about, people with amygdala damage can still report feeling fear. So, for example, Liz Phelps had a patient, and the patient was asked, you know, you've gone through this conditioning experiment and you didn't respond very much, what do you make of that? And she said, said, well, I know I don't sweat.

So she learned that in time, people talk about sweating when they're afraid or they've been scared about something, she doesn't sweat. So I said, I know that. But I never noticed anything unusual about my fear. So what is fear? It's your awareness of something bad happening to you. And it can all be totally cognitive. If you don't have an amygdala to make it juicy, you can still be afraid.

That seemed a very compelling evidence, which again, it seemed to be obvious in retrospect that fear is not in the amygdala. No, it's your awareness that you're in danger. And so you, this goes back to auto-knowity consciousness, you have to be part of that. Because if it's not going to bite you and harm you, then it's not something you're afraid of. Okay. I want to sort of move now as we near the end to the more general questions, less technical in some sense. but grander ones, the kind of thing that interests people and everyone, that drives everyone and presumably drives your research. But every time it seemed to me some claim is made about a part of

the brain being uniquely responsible for something, there's always evidence that says no, in fact, it's distributed. And because of that, how will we ever know what happens? Well, you know, I think a lot of what we know, we know because we've simplified things in a way we can find out. So I think there's no doubt that a tone paired with shock or visual simus paired with shock or a picture of a snake is going to go through the visual system of the auditory system, some sensory system. It's going to get to the amygdala and it's going to trigger a response. Whether there's other branches and other things going on, probably most likely. but that pathway is necessary and seems sufficient,

but maybe there are other things that... Yeah, but that's not the kind... But what I'm saying is that that's right. That we can know, that's science. But what people care about is, why do I love or how do I... And then when people say, well, you know, it's that pole there.

But then it doesn't look like it's just that because it's distributed over the whole cortex and at least and maybe other parts. And so does it just remain a black box? Well, you know, we're kind of at the early phase of this stuff. and there hasn't been much interest in consciousness beyond vision. And that's what I hope has been part of my contribution to that field,

because I'm really an outsider in the consciousness world, there are whole societies that are created around this whole research topic. But it's all about vision. And so I've tried to give lectures there saying, well, let's think about emotions and memories and the other things that people care about. And I think it's having some impact and people are getting more interested in this topic. But so let's just talk about the frontal pole because that's something a lot of people haven't heard about.

And it's kind of interesting. It is interesting. The many of you hear there's something that's only in the human brain anywhere else. Boy, it's caught my attention. There's a lateral frontal pole and a medial. So the brown part of the hot dog one, the white part of the hot dog one. Apes have the white part of the hot dog one frontal pole inside the middle, but only humans have the lateral part. So it's a kind of expansion of the human prefrontal cortex.

Now, what do we know about it? Well, it's a part of the brain that only gets high-level, highly processed conceptual kinds of input. So things that have been integrated across sensory modalities, it only gets a lot of this multimodal kind of input. but also it gets inputs from other prefrontal cortex areas that have also been getting these integrated things. So the frontal pole is kind of like at the top of the integration hierarchy. It's like the most conceptual kind of thing in the brain that we have. And there isn't a lot of research on it, but there's some studies at this point showing, this is work that Steve Fleming at University College in London has done,

that suggests that it's involved in what we might call subjective metacognition. So metacognition is cognition about cognition or a thought about a thought. But subjective metacognition is a thought about you as part of that thought. It's about how you can change your mind as you're thinking about something. So is that the home run for saying the frontal pole is involved in a mode? No, but it's like it's an anchor. It's a starting point. This work just came out like a year or so.

So we're just at the beginning of this. I think it's really the beginning. And the frontal pole may turn out to be a red herring, but it's a good thing to look at it as a starting point because it seems so obvious that it could be. Well, yeah. And so there's an example of maybe, but because I keep hearing whenever there's a damage,

it seems to me, every time I see that, someone makes a supposition, and then says, oh, no, but that area is damaged, and you still are able to do it. Exactly. Exactly. And so that's one, I mean, that's just an open question. And it's a question, how will ever know? I'd like to address that because we tend to sort of lump things together. And so let's say this idea of subjective metacognition. So, okay, the frontal pole was damaged in patient X, and the person can still have some kind of subjective metacognition.

But that's a term, subjective metacognition. It's just, it came out of a specific kind of experiment, but it may not be the kind of subjective metacognition that's required for an emotion. So we can't just, we are too quick to draw conclusions on the basis of buzzwords that we label things with, and that is a big problem in science in general. No, it doesn't matter if a physicist calls something a quark

or whatever you guys call the cute things you name things. But we have to be careful when we're talking about psychology when we name things because when we name things that come from our subjective experiences and attach those names to parts of the brain, it's very hard to like unshackle those things. That's why fear is so stuck in the amygdala, it's almost impossible to get it out.

That's why physics, I repeat, is easier than brain time. Because brain studying brains, the term means something, your absolute physics, We can study how protons are built up, and it doesn't matter what you call them, and no one's gonna be confused, because mostly it's mathematics anyway, but yeah, when you're studying the brain,

these terms can be very, well, are creamly influential. And then there's this other thing that intrigues me, because I've sometimes been claimed to be disparaging about philosophy in various things I've written, and I pointed out that in physics, and I'll get letters for this,

but in physics philosophy is largely, irrelevant. It isn't irrelevant in brain science because here's an area where the questions, where science is well formulated with empirical evidence and conclusions, it's sort of gone, if you wish, beyond philosophy. But when you don't know what the questions are and things are still very fluid, there's this interconnection between philosophers and scientists that's clearly that you clearly mentioned because you say philosopher X and scientists, we're thinking about these things. but I was intrigued when I thought about higher order theory, quote unquote, and then I look back at early parts of the book or earlier things I know about

at William James or Helmholtz who were really talking out of their various body parts. I mean, they were just speculating. And there was intelligent logical speculation that those speculations in some sense are so similar to higher order theory. And I just wonder, is calling higher order theory giving it a kind of, of scientific premature that it maybe isn't that different than with, I'm just being a devil's advocate here, but I want to hear what you're doing. Higher order, I'm not, I don't like the term, but it came out of philosophy.

And it's based on this assumption that you have a higher order in a first order state. And that's all that's important. So I think it's not a great terminology. But I think the message is important because the higher order representation is not itself conscious. In order to be conscious of what's in that representation, you need another representation of it. Yeah, sure, but I guess what I'm trying to say, I didn't say it very well, is what they argued was plausible. Yeah. What I'm reading from you is plausible.

Right. Is it anything yet more than plausible? It's more than what William James had because there was no data to go with it. But there's a lot of data that's coming up with imaging and, you know, being, it's correlational, of course. but there are new techniques, for example, TMS that you can use to functionally inactivate small errors of the brain and perhaps get some causal significance. But I'll go back to the difference between physics and psychology again. I think there's no way folks that physics has relevance for physics, except as a starting

point for doing your work. But in psychology, I think we've been too easy to, too quick to dismiss folk psychology, because we live our lives in folk psychological space. And so I agree that folk psychology has nothing to do with what the amygdala is doing and other parts of, you know, more automatic parts of the brain. But in terms of consciousness, folk psychology is what it's all about. And so I think we need to come to the understanding that when we talk about fear, that word has meaning. And so when some of my colleagues want fear to stay in the amygdala because, you know, that is a useful way of thinking about disease. I don't think it is, but that they do, that we have this kind of fear generator and so forth. I think that's wrong because it gives you the feeling, the impression that the amygdala is the fear center because that's what that word means.

Yeah. So our words are so powerful. Yeah, the words are so, well, because the brain is the brain. And that's why it's so complicated. And, you know, we've hopefully addressed some of these issues. Okay, let's even go more meta. Okay. About things that I think we can all talk about without knowing anything.

At least some of us can. Well, one, we could talk about, and it's relevant here, and we haven't mentioned the word language, although it's vitally important. Right. I spent a lot of time with Noam Chomsky. and talk to him and this program and other times. And one of the things that he surprised me with in one of our early dialogues, and I never thought of it in those terms,

and I started to read up on it, is when he said language has nothing to do with communication, not nothing, but it evolved not to communicate, but to talk to yourself. And it was in a sense, it evolutionarily was useful because when you can talk to yourself, then you can, that's the first step to kind of, and planning.

And so it's really much more important. And I got some of that from reading your book as well. And I wanted if you could comment on that notion, that language is better. If we go back to the split brain patient and the tails they're weaving about why they do the behaviors they're doing, where's that coming from? So they have, their brain is forming some schema, some understanding of, what is going on, and out of that is coming a narration, I guess similar to what Thompson was talking about, verbal narration of what is in that schema, that then is what you, you know, you're talking to yourself about it. So that is where, what you're experiencing is the content

of that narration. That's what I do. I talk to myself all the time. I mean, I'm not being physitious. I mean, I can't imagine doing anything without talking to myself. And, well, I mean, so you'd agree with that notion that that that but and I think but a lot of people might then push further and I don't know about the evolution of it but yeah but well a lot of people might go further and I guess I would have saying that without well the question is without language can you be conscious in conscious in the sense that really matters right so that's that's vague right there but yeah of course well I was going to get there to me when you talked about consciousness and you talk about auto-noetic what really matters is self-awareness. To me, self-awareness is at the heart of it. Yes. And we'll get,

I want to get to AI, but then the question is, can we, well, not much, but when we talk about, to me, if you ever had a machine that was self-aware, then you've got the whole thing. However, whatever else comes along with it. So yeah, but let's, okay, so we got auto-noetic, and so we agree that's the, you know, what we really want to know about. Yeah. But other animals certainly can have no-edic. Sure, sure. And, or ain't no-edic. And that's why I like that distinction between those three kinds, because it doesn't mean you have to dismiss animal consciousness to say that there's something unique about humans. People get all upset about saying, oh, humans, we say humans are different from animals. Every species is different from

every other species by definition. Well, we'll get some hate mail for you in a second because I want to talk about animals and emotions, but do you think language is necessary for self-awareness? For what we call self-awareness, I mean, yes. I think there's developmental data that a very well-respected developmental psychologist named Michael Lewis from Rutgers has a book on the emergence of consciousness or something like that. And what he claims, and other developmental people do this too, that personal pronouns are key to the development of, of self-awareness. You know, it gives you something to hang it on, I, me, mine. And once you have those concepts, then it just opens up that world of, you know, I'm different

from X as opposed, so this is what's called subjective self-awareness, as opposed to awareness of self as an object. You know, awareness of self as a subject versus an object. Any organism, or any animal can have a body awareness for certain, but that's different from knowing that it is you that is having the... In that context, I also obviously oversimplied Chomsky. When we talk about language, it isn't just labeling or expressing ones. For Shomsky, the thing that led to blatant development is that the language is infinitely malleable,

that you can create an infinite number of different sentences, and therefore it opens up a world of possibilities, and it's the possibilities that in some sense, you know, so I think that's vitally important. So, yeah, I mean, people say, well, people who are born deaf and dumb, they're not unconscious. Of course not, because they have all of the cognitive arts. architecture that language has changed and make the human brain the way it is. Your point is that human brains are different than animal brains. Not necessarily better, just different. Yeah, different. And that's vitally important to realize. And there are certain things that

we can't assume, therefore, that just because we share certain behaviors, that we share cognition. And you point out that therefore, there's no evidence that animals have feelings, more or less. And I guess what I want to ask you is you make it sound like it's Occam's Razor. Since we don't need to assume that animals have feelings to see their behaviors, even if it looks like

my dog looks sad or embarrassed if I, all the things that make me impute emotion. And I'm going to always do that because that's what is. I pet my cat, purrs. Yeah, absolutely. Now, is that really Occam's raising?

Or is it also another way of thinking of Occam's razor to say, well, I don't need to assume it doesn't. I don't see why one is more, I mean, what is true is we have no idea. And I guess I want to ask you if you think we'll ever know. I can't imagine an experiment. I'd like to ask you if there are any experiments you could ever imagine in principle that would allow us to know. But, I mean, is there anything other than saying it's a matter of opinion right now? Well, so, you know, I think here's the thing. When I'm in the laboratory, I have to adopt certain principles.

Sure. When I go home, I don't have to have that hat on. I'm a pet-loving person. I'm not a scientist. And I think that's true in life, that there are situations where we need science and other times we don't. In fact, it's not very useful. It's been said that anthropomorphism is an innate feature of the human brain because it was useful for our ancestors to treat animals like little people.

use them and, you know, so they lived with cows, and the cows were part of their life, and they were partners in farming and all of this. Yeah, absolutely. I can see it being evolutionally useful, but I guess the question I'm having is, just because it's evolutionally useful doesn't mean it's wrong. Doesn't mean it's right, exactly. It doesn't mean it's right. I think the point that's fully important in your book is it doesn't mean it's right.

We shouldn't assume it just because behavior is separated from emotion. And I, you know, you've really converted me there. or at least illuminated for me there. I don't know if I had an opinion one way or another, but that behavior and emotion are two separate things, just because they are, it doesn't mean it's right, it doesn't mean it's wrong, and I'm totally agnostic,

even after reading your book, to say that animals don't have feelings. I don't say that. I don't know either. There's no way to test it. Do you imagine, can you, that's absolutely right. And I go home and I pet my cat in here? Okay, so the question is, can you imagine if you had,

forget infinite resources, but infinite technology. No, it's just like a methodological hurdle that no one has an answer to. And the stomach block is language. With humans, you can ask them what they're feeling and thinking with animals you can't. Is that basically the fundamental difference? It's a little more complicated. A human can respond verbally or non-verbally to something that they're conscious of,

but can only respond non-verbally if they're not conscious. Animals only have the nonverbal mode of response. So there's nothing to fractionate the other states with. So, you know, I personally believe that animals have feelings and are aware. Oh, you do? Yes. Oh, okay. Interesting.

But not as a scientist. Not as a scientist. As a person, I believe that. Yeah. Now, Marion Dawkins, who's at Oxford and a professor in the Animal Behavior Department there was a student of Tinberg, and she's a very well-respected person. But her thing is animal welfare. and she makes the point that tying the problem of animal welfare to the problem of animal consciousness is really bad

because we can't prove animal consciousness. So it just brings controversy into the thing and it's actually harmful to animals to tie those two things together. Of course we have to treat animals in a proper way. We can't just be cruel and horrible. I mean, there are standards in every nation that I know of for research. And, you know, you can say, well, the research shouldn't be done. So that's a social question that we all have to address. And I think, you know, valuable findings come out of animal research.

But that's not the question of animal consciousness. That should be separated. Well, I guess I always thought that the criteria was feeling pain, whatever that means. Well, that's so complicated. Yeah, okay, maybe it's too cool. You see a dog that's been hit by a car, and you see it writhing and making noise. Those are reflexes. I mean, you're not seeing its pain. I think that dog is feeling pain, but that's not what you're seeing. And that's why it's so complicated. It is very complicated.

And that actually has implications in our society for legal things having to do with things like abortion. But there's no answer. We shouldn't, we should, exactly. I think that's, but that's a very important point. We will hear people say certain things should not be allowed because I believe X. And it's just a belief that we shouldn't assume is there because, and sometimes it's motivated by a religious belief, and therefore it's irrelevant, in my opinion, but that's me. But it's really important, I think your point is, if we're going to think about how to behave, we should try, at least we think what's useful to us, but we should also think about what the science tells us at some level, which now leads me to the next question. I just want to say one last thing, that, you know,

we shouldn't be using science to make these ethical decisions. But, well, yes and no. I disagree in the sense. We shouldn't be, I've had this discussion numerous times with people, but whether you can get an offer from it is is an interesting question. But science may not alone determine things, but I believe that you need to be informed by the science. If you're not informed by this and then use rationality.

And in my opinion, that basically comes as close as you're going to be able to get. a combination of the empirical evidence of science with rational thought should lead you to ought. But that's, you know, whether it's 99% of the way or not. Right. But if you have a question that can't be scientifically answered. Then absolutely. But certain questions can. And you should at least, you should know what we know and what we don't know. I guess that's the important thing. I agree completely.

And I think the whole point of this is that the things we don't know, but we do know that emotions are separate than behavior. I think that's, or at least that they're independent. That's kind of where we are right now. Yeah, but that's a profound, I mean, it's certainly worth a book. But that's a really important realization. But given that and the fact that I think it should govern not just how we behave towards animals and abortion issues, I want to talk about what the implications are for that very fact for treatment, for medical treatments. Because I think that's something I know you talk about and something important that the public should be thinking about.

So the idea has been that the amygdala is this fear center, and so that if you find medications that can change that fear center, you'll make people less fearful and anxious. So an animal is put through a behavioral test of some challenging situation where there's some kind of thing that's dangerous to it. And so you give the animal in medication. If it behaves less, in a less threatened way, in other words, is less timid, then you assume that the animal is less fearful. And so when you give the drug to a person, they should be less fearful.

But that's not what happened, and that's why the drug companies are all getting out of the anti-anxiety, anti-fear business, because nothing is working. So what's the problem? Well, the problem is that you're studying behavior, in an animal, you're not studying consciousness. You're not studying its fear. And so the person who is on the medication might actually find it easier to go to a party. Let's say you have a social

anxiety patient. The patient might find it easier to go to the party, but still feel anxious while there. And so the drug is a failure because the patient was told this is an anti-anxiety medication, not an anti-avoidance medication. But it's doing exactly what it was designed to do in the animal, which is to reduce avoidance and timidity. So I think because of the way we label things and talk about them and the assumptions we make about what we can and can't understand through animal research have gotten us into a big morass. And billions of dollars have gone into this. And I think the medications are useful in helping a person cope with the symptoms of fear and anxiety, but not necessarily with the experience of fear and anxiety. And that has to be treated separately.

So, yeah, so it's, again, a problem of label, incorrect labeling. They do what they're supposed to do, but they don't do what their claim to do. Exactly. Yeah, yeah, okay. But that's important. The companies could be selling these things in a thoughtful way that people would understand. No one, I've been saying this for years, but no one has come to me from a drug company either said, shut up or that's useful. Well, you know, you started your life in marketing, right?

And I think they've learned it's a lot easier tell people your fear will go away than you're sweating. Yeah, but now they're getting out of the business. Yeah, yeah. Okay, let me now, the last few questions, and they're easier to answer because they're incredibly grand questions. And one of them relates near the end of the book. Do you think ultimately consciousness

is an evolutionary advantage in the long term or a disadvantage? Well, that remains to be seen. Of course, but I want to ask you to... Well, it depends on whether we destroy the environment to the point where our kind will no longer exist. Yeah, so I said it does seem in the short-term consciousness was, in short term, I mean,

the last few million years in terms of the human evolution and becoming the dominant species in the planet. But in the long term, it may be much more efficient to be a flatworm or something else. Well, we know, for example, that, you know, when you have drastic climactic conditions, large energy-demanding organisms don't survive. The dinosaurs didn't do well. But tiny little mammals that had low energy needs did survive. So as we continue to change the environment in which we live, each time we lose a species and we're losing a lot of them now, it makes a subtle difference in the ecosystem. And so at some point, we're going to have an environment in which the genes that we have

are not the ones that are good for surviving. And so whether our kind will continue to survive. I mean, it's been an astrophysicist, I forget his name. So Earth is going to be fine. We're not going to destroy the Earth, but it's not going to be Earth we can live on. Well, that's going to happen in the long term, no matter of it. That's the point. The question is, are we like hurtling ourselves towards you.

But the interesting thing is that because of consciousness, we can change the environment that we live in. Right. So if we're not a, if it's true, we're not a well. Well, every organism changes its environment. Well, we do it in a grand. Yeah, we can adapt. We can completely change the environment. And mess it up.

And that's what we're doing in a bad sense, but we can do it. We can move to a different location, et cetera. So, I mean, consciousness is responsible for our greatest achievements. It's as we see art literature, mathematics, physics, medicine. What it means to be human. But also for North. narcissism, selfishness, greed, hatred, you know, murder. But in an evolutionary sense, it's not just responsible for what we value to be human,

because consciousness and being human are the same thing. It's probably what makes us, has made us so evolutionarily successful to be able to be the only species far enough that can, except for maybe bacteria, that can inhabit the entire planet effectively because of its consciousness. Well, the other thing that we're the only, I think, species that can do is decide to terminate ourselves. Yeah.

as an intentional act. Exactly, that we can, either on an individual level or a human level with nuclear weapons or something, we can choose to do something that an evolutionary sense is prohibited, which is to stop reproduction. And this goes back, you know, again, to the first cells and the first multicellular organisms and how they acquired genetic physiological compatibility. But with the arrival of consciousness in the human brain, self-autinuity consciousness, that was a rogue system that could make decisions that go against the better good of the entire

rest of the body. Yeah, the rogue decisions, which may be, as you say, responsible for good and bad. And, okay, what's the future of neuroscience? Where do you think the next, and it's always weird, when people ask me that, I say, if I knew what the next big thing was, I'd be doing it. But I don't mean it that way. What techniques? Where do you think that likely the greatest advances are going to happen and what questions are the most accessible?

Well, we've never been more technically sophisticated than we are now. The problem is that students come in applying to graduate school and you say, what do you want to do? They say, I want to study optogenetics. In other words, they want to study a technique. But what do you want to understand? Well, I'll figure that along the way. So I think what we need is better training in asking questions. and conceptualization.

I think it would be good for neuroscience programs to have classes on philosophy. Physics, I would argue, was a good training. Yeah, I mean, we don't, I'll probably get in trouble for saying this, but we don't teach our students how to think, we teach them how to do. And philosophy teaches their students how to think, maybe physics. I don't know, I don't know, although when I was a graduate student,

my first advisor always said, me, don't think, do. So, you know, I don't know. Oh, anyway. So I used to think too much. The big question, we need to know what to do with all these techniques. We can have the greatest techniques, but if we don't know what we're asking of the brain, then we're not going to get anywhere. We have to have conceptualizations.

Okay. The last thing I do want to briefly touch on before we end is AI in the sense that it seems to me, again, I'll give you my opinion, you can tell me why I'm wrong. Not next. No, no, no. I don't want to, there's so much one can talk about AI. But because my key questions here always are how do we know how the brain works? And there are fundamental stumbling blocks that we've talked about.

And that's what's so challenging. As I say, that's why I handled simple physics, simple systems with the universe. But it seems to me that potentially the greatest tool to understand consciousness may be machine. And I'm not someone who thinks it's around the corner or that it may even ever practice. I think that's overly hyped in so many ways when we call AI versus machine learning. But it will allow us systems where we can tweak knobs and see what works and what doesn't work. I wanted to get a sense of whether you are, have any optimism in that regard. I have a lot of optimism for understanding cognition through that.

Yeah. But not necessarily phenomenal consciousness. Well, what I would say self-awareness. So you don't think that machines will ever be self-aware? Well, my little brain can't figure that out. See, for me, I see no one, I mean, I just see it all as physical systems, and one physical system looks the same to me as the other. I mean, mechanisms may be different, and it may be, but, you know, I can imagine using what we know about evolution. So, in the long term, I see it as possible. Do we see it as practical? Not so clear.

I mean, possibly that, you know, there were so many random biological twists and turns that, you know, came between the beginning of life and us, that maybe it's just some, you know, set of, strange conditions that... Yeah, well, the question is, can we reproduce those conditions, not... Yeah, but you might not be able to do it, but you'd have to reverse engineer all the way back. Well, yeah, I mean, certainly from a physicist, and this is a... I've said this before, maybe even in the context of the podcast, but it's just, what made me realize the stumbling block was when I first realized that if you wanted to build a regular computer along the lines we do with storage and memory that had the storage

memory and processing power of something like the human brain, probably say 20 terawatts of power right now, which is the total energy consumption of humanity. The brain uses 20 watts. That's a factor of a million, million difference. And there's something fundamentally different about the way we think. And so there's a long way to go, and I'm so happy that there are people like you who are willing to take us step by step and have the patience to do that. Whereas as I say, I just go for the Low-hanging fruit, the universe. So it's been a pleasure to learn from you and to talk to you. Thank you very much.

My pleasure. The Origins Podcast is produced by Lawrence Krauss, Nancy Dahl, John and Don Edwards, Gus and Luke Holwurda, and Rob Zeps. Audio by Thomas Amoson, web design by Redmond Media Lab, animation by Tomahawk Visual Effects, and music by Rickalus. To see the full video of this podcast, as well as other bonus content, visit us at patreon.com slash Origins Podcast. Thank you.