Episode 30 - Brain in a Vat
Transcript
David: 0:07
Hi, I'm David Peña-Guzmán,
Ellie: 0:09
and I'm Ellie Anderson. Welcome to Overthink,
David: 0:11
The podcast where two friends,
Ellie: 0:13
who are also professors,
David: 0:15
put philosophy in dialogue with the everyday.
Ellie: 0:18
Because big ideas are within everyone's reach.
David: 0:30
Ellie, have you heard about the infamous Italian head transplant doctor?
Ellie: 0:36
No. Tell me more.
David: 0:37
So it's this neurosurgeon by the name of Sergio Canavero who became-
Ellie: 0:42
A real person?
David: 0:43
Yes, it's a real person.
Ellie: 0:44
Living today?
David: 0:45
Yeah, he's still alive, a real Italian who exists in the world. Um, and he became famous in 2015 when he claimed that it was his plan to perform the world's first ever head transplant, like literally cut the head off of somebody's body and then attach it to somebody else's body. And this of course ruffled a lot of feathers, not only in the scientific community, but in the bioethics community.
Ellie: 1:15
Send a lot of heads spinning.
David: 1:17
Oh my gosh. Well, thankfully not yet. And that's part of the story here, but then two years later, he once again made international headlines when he made the claim that he had successfully made a head transplant and people were like, how in the world did this happen? Because in the interim, he looked for people to help him, cause you need a lot of people, I guess, to chop a head off and reattach it to another body. And-
Ellie: 1:42
And a lot of grant money.
David: 1:43
Yes, it's supposed to cost over $10 million for this one surgery. Anyway.
Ellie: 1:48
Oh, wow.
David: 1:49
Basically everybody in North America and everybody in Europe was like, eh, not interested. Thank you. And so he then went to China where he found a team of experts that were like, we got you, we'll help you do this. And so he performed a head transplant, but it was on two dead cadavers and he then wanted to claim to be the first person to have made a successful head transplant. Yeah. And so-
Ellie: 2:15
But he basically just did taxidermy.
David: 2:17
Did advanced human taxidermy. But he has said that his next step is to make the real thing, to actually take the head of a living person, attach it to the body of another living person, as a way of reaching what he thinks is the acme of modern day surgery. What do you think about this? Okay.
Ellie: 2:43
I mean on the one hand, like, let's go, let's see what weird heights of human experience we can reach. On the other hand, $10 million going to just this head transplant surgery really rubs me the wrong way. There are so many better things we can use that money for. And also, I think this guy probably watched too many horror films. He's just like leaning into the mad scientist.
David: 3:05
Yeah, his life is a horror film. And I mean, he is convinced that he will succeed at taking a brain in reattaching it to an entirely different body and-
Ellie: 3:16
Muahaha.
David: 3:18
produce a new kind of human experience, really.
Ellie: 3:22
New kind of human experience? Okay. I don't know about that, but I do think that theme of head transplants is a really common one in horror. And in fact, when I was- I was researching a paper that I never ended up writing a few years ago, classic academic.
David: 3:37
Story of our lives. It's the dark CV. Here are all the drafts that I never published.
Ellie: 3:42
Exactly. And it was on our obsession with the brain as a culture. And I actually came across this entire wiki website that's a list of horror films that have brain transplants in them. But I think one of the more interesting recent examples of this is in the film Get Out, um, where the film Get Out features a brain transplant surgery where basically old white people are getting their brains put into the bodies of like strapping young Black folks who will then allow the white people to live on through their consciousness. And the idea is that when you're replacing the brain, you're also replacing their consciousness. And there's a little bit of the consciousness of the Black person whose body it is that remains. And Jordan Peele, the creator of the film, has this whole story within it about why that is, right. There's like, at the brainstem, that's where the seat of consciousness, that kind of glimmer of it still remains. But actually he got this idea for the brain transplant in the film partly through an internet research rabbit hole in 2016 about Italian surgeons, is always the Italians, who had successfully grafted the head of a chimpanzee onto another- oh, wait, is it the same?
David: 4:56
Well, no, it isn't. I don't know if-
Ellie: 4:57
Maybe it's the same guy.
David: 4:59
So I don't know if it's exactly the same guy, but I do know that Canavero has done experiments, not, I don't know if with chimpanzees, but definitely with mice where he has taken the head of one mouse. He cuts it. And then he sort of grafts it onto another mouse that has its own head creating this sort of like two headed mouse-Hydra monster as a way of testing whether the body would reject a different head. So there's definitely a connection here. So if Jordan Peele fell into that rabbit hole in 2016, I pretty much guarantee that he ran into the research of Sergio Canavero, because this is exactly when Canavero made international headlines.
Ellie: 5:41
I think there's- there's almost certainly a connection here. And, you know, I think all of this, whether it's the brain transplants that we see in horror films or whether it's Canavero's quest to do a real live head transplant between humans, I think what we see is this assumption in our culture that the brain has a special relationship to conscious experience relative to other organs. A lot of philosophers will describe the fact that I can imagine losing basically any limb except for my brain and still thinking about myself as the same person. And obviously I don't think people would dispute the fact that the brain is a very special organ of the body. It has a kind of privileged relationship to our sensory awareness, to our movement, to our thoughts and feelings. But you know this idea that the brain is suddenly the stand in for the mind requires a lot of unpacking. It's not at all evident.
David: 6:33
Yeah. And it's not just that it's special or that it's important, but rather that it is the seat of consciousness, right, that that's where consciousness is geographically located to the point that you can take it from one spatial temporal location to another without losing something fundamental about the consciousness that it houses. I think that's the key here. That's the assumption that motivates this research and these horror films.
Ellie: 6:57
Exactly. And that leads us to what we want to talk about today, which is a thought experiment that a lot of folks encounter as undergraduate philosophy students. I it intro. And that is a thought experiment known as Brain in a Vat, which basically is a mental exercise in imagining what if you are actually just a Brain in a Vat, in a laboratory somewhere, and all of your conscious experience is simulated.
David: 7:26
Yes, I have taught and been taught the infamous Brain in a Vat experiment, uh, as a philosopher, and it's a mental exercise that has obsessed philosophers for decades by suggesting that we might be living in a simulation and that because of that, we might never attain genuine self knowledge, because one of the questions that emerges from this thought experiment is that if you are a brain in a vat, how could you ever know that you are a brain in a vat? And so is self knowledge an illusion that will forever allude us?
Ellie: 8:01
How do I know that this closet from which I'm currently recording isn't a simulation of a closet? Today. We're talking about the Brain in a Vat.
David: 8:17
What does this thought experiment tell us about human consciousness and our culture's obsession with the brain?
Ellie: 8:23
And can you ever really be sure that you're not a brain in a vat, living in a simulated reality? The thought experiment known as the Brain in a Vat was first formulated by philosopher Gilbert Harman in 1973, who invited his readers to imagine that you might actually be a brain living in a laboratory, hooked up to all kinds of sensors that are making it seem like the breeze you feel is an actual breeze outside, or the trees you see are actual trees in the world. Then philosophers latch onto this idea, because Harman encourages us to be skeptical about whether or not the reality we perceive is actually real. And when he first devised this thought experiment, he did so because he wanted to update classical philosophical exercises, inviting skepticism by saying, Hey, we're living in the age of the brain now, so let's make this all about the brain.
David: 9:28
Philosophers love their thought experiments because they allow us to test our intuitions about various things. So one of the things that I love about teaching thought experiments, such as the Brain in a Vat, is that students are always in shock when they realize that not everybody in the room has the same intuition that they do. Yeah. And in particular with the Brain in the Vat, you really see this where some students will be like, oh yes, if I am a brain in a vat, I would not be able to tell the difference and it would be almost as if I am in the matrix, right. Like nothing about my experience would change. And so we can never know. And other students are like, absolutely not. This is impossible and inconceivable.
Ellie: 10:07
Yeah. And so I think that's interesting because thought experiments are basically philosophical stories that we read or talk about in order to find out that we already hold implicit beliefs about philosophy. Honestly, I think a lot of times people are like, oh, I don't know anything about philosophy because I've never taken a philosophy class, but then once you give them the Brain in a Vat story, then you realize that they actually have a lot of implicit beliefs about the relation of consciousness to the body, about the nature of the brain, and those are philosophical beliefs, right? So maybe we can give our listeners a little summary of what the Brain in a Vat thought experiment is. And I suggest that we take probably the most famous formulation of it, which comes from Daniel Dennett in the late seventies, in an essay called, "Where Am I?"
David: 10:54
In this essay, Dennett begins by telling a fictional story about how the Pentagon knew about his research, because he's a really famous philosopher of mind, and then the spending on officials were like, Dennett, we have a mission for you. We need you to go and retrieve some weapon that is stuck underground somewhere. But, because of a lot of complications, long story short, you have to leave your brain to the side.
Ellie: 11:20
Because there's like radioactive material underground that would destroy the brain, but wouldn't destroy the other parts of the body.
David: 11:28
Magically, but it's a thought experiment, so let's roll with it. And so Dennett is like, oh, should I do it? Should I not do it? He decides to do it. And what follows is that effectively, his brain is surgically separated from the rest of his body. It is envatted, it is put in some container, you know, with the cerebral spinal fluid or something. And-
Ellie: 11:48
And then it has like all these hookups to, uh, different wires that simulate sensory perception, that simulate embodied affect, and that allow him to think.
David: 11:57
Yes. And that allow him also to control his body from a distance, his muscles, his arms and legs, so that his body can actually go down to the underground area where he has to retrieve this weapon without the brain actually being there and being exposed to the radiation.
Ellie: 12:14
And then actually what happens is that while his body is underground, trying to retrieve this nuclear warhead, it gets disconnected from the brain, which means that the body dies because it can no longer support itself. And so then he's just a brain in a vat with no body, but then the scientists are like, oh, don't worry, we'll get you a new body. And then he gets a new body whom he takes care to mention is pudgier and a little bit more sloppy looking than he is.
David: 12:44
Now, according to Daniel Dennett, what's really interesting about this thought experiment, which is almost absurdist in its metaphysical assumptions, is that it raises fundamental questions about the nature of the self, and in particular, he reflects on the question of where his identity is, because even before his body is disconnected, he asks the question, now my body is separated from my brain. My body is here. My brain is there. Where am I? Where is the locus of my consciousness? Do I experience myself as being my body or do I experience myself as being my brain? So which object is looking at the other? And as the story unfolds and he's given different bodies after the first one exits the picture, the same question returns in various iterations.
Ellie: 13:33
Yeah. So when his body is still alive, he says that he feels that his eye is located in his body and not in his brain. He's like, no matter how much I try, I can't really think about myself being that brain. I am that body. And he has a passage where before he goes to retrieve this nuclear warhead, he goes, or his body, rather, goes into the laboratory that has his brain in a vat and his body looks at his brain. And I want to just read a passage from that because Dennett is a pretty colorful writer, for a philosopher.
David: 14:07
I love that you say "for a philosopher." Which is true.
Ellie: 14:11
I mean the pretty low bar there let's be real. Okay.
So he writes: 14:15
"Well, here I am sitting on a folding chair, staring through a piece of plate glass at my own brain, but wait, I said to myself, shouldn't I have thought, here I am suspended in a bubbling fluid being stared at by my own eyes. I tried to think this latter thought. I tried to project it into the tank, offering it hopefully to my brain, but I failed to carry off the exercise with any conviction." So what he's talking about here is his inability to imagine his brain as the locus of his conscious experience, and he really associates with the body, but then once his body dies, suddenly his consciousness snaps back and he associates himself with the brain in a vat. Now his eye is located in the vat.
David: 15:04
And so by this point, he's just literally a brain in a vat. Now in the thought experiment, he adds a number of complications to the story, like then there is another body and another brain.
Ellie: 15:15
Yeah.
David: 15:17
But for our purposes, what matters here is that when Dennett finds himself in that state, identifying with his brain floating in this fluid, he's giving us, I think, the purest expression of the thought experiment of the Brain in a Vat. And of course there are many versions, but this is one of the most famous ones. So what are philosophical questions that come out of this thought experiment for you?
Ellie: 15:42
The major one is if you are indeed a brain in a vat, how would you know it? That's really what Gilbert Harman was doing with his original formulation of this. And I think so, let's imagine right now that, you know, you're not Dennett, you don't know that your brain was surgically removed from your body, um, and you find yourself sort of living in space. You're listening to this podcast right now. Maybe you're on a walk in your neighborhood or you're driving in your car, and you see things around you, you see the sky above you, you feel the weight of your feet on the ground or on the brake. Of course I use brake because I live in Los Angeles where you're stuck in traffic all the time. I'm hoping that if you're listening in the car, you've got your foot on the gas pedal.
David: 16:25
Unless you're at a red light.
Ellie: 16:27
Yeah, touche. But yeah. So how do you know right now that the world around you is indeed real? What if it's the case that Jeff Bezos has actually harvested all of our bodies and put them in some version of the matrix and you are actually in some laboratory underground in Nebraska right now.
David: 16:50
Yeah.
Ellie: 16:51
Having all of this sensory stimulation directly put into your brain that makes you feel like you're having these experiences.
David: 16:59
Yeah. And I think for a lot of philosophers, that epistemological question of knowledge, how do you know who you are, in this case, is primary. Now what's interesting about this epistemological dimension of the thought experiment is that it's really tricky to answer, right? How do you convince somebody that you are not a brain in a vat because whatever arguments you make about your experience are drawn from an experience that in theory could be simulated by the scientist in the laboratory where you as your brain are located. And-
Ellie: 17:28
Absolutely. So like you have the thought, David, I am not a brain in a vat, but what if that's just one of Jeff Bezos' henchmen putting that thought into your head by means of this chord going straight to your brain?
David: 17:39
Well, that's right. And I want to emphasize that there are a number of neuroscientists who kind of abide by this belief that you could generate human experience by tinkering with the right parts of the brain, a little sensory input here, a little motoric output over here and voila, you get a lived experience out of that. And so how you prove that your experience does not come from being a brain in a vat is very difficult. Dennett makes a couple of points in his essay that I find really interesting and that make me feel like I can say relatively confident that I am not a brain in a vat.
Ellie: 18:16
Oh, okay. So what are they?
David: 18:17
Well, at some point, for example, he mentioned that as a brain in a vat, it would be really odd to have certain experiences that are embodied, right? So for example, what is anger if not the feeling of blood rushing through your body? Of course you could say that that can be programmed into the brain. And so this is where you get the circularity. But that's where I think we cannot separate the epistemological question from almost the more practical consideration of whether a brain can really have these experiences all by itself.
Ellie: 18:52
Okay. So the epistemological consideration being, how do I know that I'm not a brain in a vat? And you're saying, David, that, well, that question of how I know I'm not a brain in in a vat, it maybe only is intelligible when we're really removing ourselves from the everyday landscape I've experienced.
David: 19:10
To me, this is equivalent or at least comparable to the claim how can you prove that there isn't a unicorn flying around the universe, always located where you're not looking, right. The burden of proof is on the other side. What reason could I possibly have to believe that that's possible in the first place? It's one of those cases where philosophers want an answer purely through armchair philosophy, like I'm going to come up with a reason that will break this thought experiment without any considerations of the real world. And that's where I kind of jumped off the bandwagon.
Ellie: 19:44
Yes. And I know we'll have a lot to say about why we think that this kind of armchair philosophy is wrong-headed, um, a little bit later in the episode, but I want to say, I don't think it's fair to compare the brain in a vat to the unicorn flying around space. I agree with you that there is a burden of proof fallacy going on where it's like, prove to me that I'm not a brain in a vat, prove to me that there's not a unicorn flying around the sky that moves out of my line of vision every time I turn around. But I do think that the Brain in a Vat is a more interesting, potentially also more plausible, but I don't know, maybe not, example then the unicorn example, because one of the reasons that people find this experiment interesting is that there are so many things that happen by virtue of our brain, right. So much of conscious experience is dependent on the brain if not caused by it. And you can really simulate a lot of experience. Think about hallucinations and delusions. Those are dependent on the brain and they happen all the time.
David: 20:44
Well, yes. And the history of neurosurgery in the 20th century shows that you can actually produce really complex thought processes like memories of childhood or hearing entire melodies by tinkering with parts of the brain. And so you're right. That we have some reason to believe that the brain causes some phenomenal or cognitive experiences, but we have no reason to believe that a brain in a vat would do that, right. So that's the important thing, because what is essential to the Brain in a Vat thought experiment is the exclusion of the body. And that's what we have no reason to believe could ever lead to the generation of subjective experience on a scale comparable to the one that you and I have.
Ellie: 21:27
Or let's be careful here. It's not the exclusion of the body. It's the exclusion of the rest of the body. The brain is a part of the body. This is what really gets me about this, is that the brain is a bodily organ.
David: 21:37
Yes, but not if you buy into the logic of the thought experiment, because the brain is by definition not the body, which is why it's separable from it. But yeah. This is what's at stake here, right? Like, is the brain part of the body, is it dependent on the body, or is it really the seat of consciousness such that we can change the encasing without losing anything significant?
Ellie: 22:01
Well, I think you just hit on something, David, that will remain a theme for the rest of this episode, which is what I call brain body dualism. This idea that for thousands of years, philosophers in the so-called Western tradition have held the view that the mind is separate from the body. Not all philosophers, but a lot, right? You see it in Plato, you see it in Descartes. Those are probably the two most famous examples. And this idea is that there is something like the mind, our consciousness, our power of thinking that transcends the body and that is actually separate from it. Today, most people don't believe that, we recognize that consciousness is embodied, but it's almost as if we've transferred our views of dualism away from mind body dualism and onto brain body dualism, where we're suddenly talking about the brain as if it is consciousness, as if it is the soul, rather than being a part of the body that has a special relationship to consciousness.
David: 22:55
And the Brain in a Vat thought experiment can be traced to Rene Descartes' Meditations on First Philosophy from 1641, where he very famously engages in a project of doubt, asking himself what is true? What is certain? What can I know for sure? And in one of the stages of his analysis, he raises this question, which is how can I know that I am not being fooled by an evil demon who is putting thoughts in my head and making it such that I think things that are unreasonable, right? Like maybe the evil demon tells me that two plus two is five. And I really believe How would I know that that's not true? And it's an early sort of 17th century Age of Reason version of what later becomes this neuroscientific Brain in a Vat thought experiment.
Ellie: 23:47
Exactly. Brain in a Vat is an updated version of-
David: 23:50
demon.
Ellie: 23:51
Evil demon. It's the malin genie. Now it's just Jeff Bezos that I'm imagining behind our existence as brains
David: 23:58
Yeah.
Ellie: 24:21
in vats.
David: 24:26
Even though this proving the thought experiment of the Brain in a Vat is trickier than most of us imagine, at least from a philosophical standpoint, a number of experts in the philosophy of mind, in cognitive science, and embodied perception theory have argued that we aren't and never will be brains in a vat.
Ellie: 24:47
Yeah. A common line of reasoning here, which I- I mean, I'll just put my cards on the table here, totally agree with,
David: 24:53
Surprise.
Ellie: 24:54
is the idea- is the idea that what the Brain in a Vat experiment shows us is not that consciousness could be simulated in a laboratory outside of a body, but actually that it shows us surprisingly, and, you know, against Harman and Dennett's wishes, just how much we need a body to have perception. So think about the vat. You said, David, earlier that in Dennett's version of it, he says that there's an artificial version of cerebral spinal fluid that fills the vat, right? So the brain is suspended in this fluid, that simulates exactly the kind of fluid that we-
David: 25:35
In our real bodies. Yes.
Ellie: 25:37
Right. And then all of these things have to be hooked up to the brain in order to simulate sensory perception and embodied movement. And this is a point of view that has been articulated by the philosopher, Alva Noe, the philosophers Sean Gallagher and Dan Zahavi, and also the neuroscientist Antonio Damasio. So Gallagher and Zahavi say that even the pure brain in a vat needs absolutely everything that the body normally provides. Basically in order for the brain and Nevada experiment to work, that would have to be something like a living body. So it's teaching us what we already know, which is that perception needs embodiment, goodbye, global skepticism. You are not living in a simulation.
David: 26:16
Yeah, I think the only way for the Brain in a Vat experiment to really work is if it's literally a brain in a vat and nothing else, like literally just take a brain and put it in a glass and see what it can do. No input, no liquid, it doesn't get cleaned. It doesn't have any kind of circulation. And once you think about it in that way, as literally a brain in a vacuum, rather than a brain in a vat, you realize just how incoherent the idea motivating the thought experiment is.
Ellie: 26:46
Yeah, that brain is just a piece of meat at that point, right? It's about as alive as the corpse in China that Canavero did a head transplant on.
David: 26:53
Oh my God. Um, I mean, but in a way you are right. And the neuro phenomenologist-
Ellie: 26:58
I am right.
David: 27:00
Um, well, this is an argument that is presented in quite some detail in an essay entitled "Brain in a Vat or Body in a World?" by the neuro phenomenologists Evan Thompson and Diego Cosmelli, where they say, look, if you really want to make this thought experiment work, you need a few things. First, you need to keep the brain alive, right? It has to be a living organ. In order for you to do that, you have to give it nutrients and get rid of waste. That means that you need a circulatory system. That's already something external to the brain itself. You need to deliver blood to the parts of the brain where activity is going to happen. And then you need to take out the blood that's already been used up for mental activity. You also need a vat or a body that is responsive to the brain. Otherwise the brain doesn't do anything. And if the vat that you're dealing with is entirely passive, then you will never have the kind of brain-vat coupling that is essential for experience. So then this raises a real question, right? In these thought experiments, we can ask a lot of questions about the brain. But we also need to ask questions about the vat. Is the vat literally just a passive physical object that contains the brain in the same way that my glass of water contains the water that I drink, or is it something that is under the dynamic control of the brain itself? Can the brain move the vat? If it can't, it will never give you experience..
Ellie: 28:34
Yeah. To what extent is consciousness tied up with our ability to move?
David: 28:41
Yeah. And I mean, this is what the field of embodied perception argues, that for a long time, we've had this mistaken assumption that experience sort of just happens. It's a given. We just open our eyes, for example, and we perceive a visual. In reality, we arrive at that complex perception by literally moving our body, which can include moving my eyeballs to scan the field, or moving my neck in order to get a sense of the layout of the land and embodied perception theorists make the argument that it is through the movement, through the bodily movement that the perceptual field actually comes into presence for me as a subject. And there is some research that shows that, for example, if you prevent subjects from moving their eyeballs, that the field in front of them stops making sense because they can't scan it. They can't synthesize it. And so the movement is essential.
Ellie: 29:42
Yeah. And this brings up locked in syndrome for me, which is a condition brought about by brainstem injury typically caused by a stroke where you cannot actually move your body at all, but you're still conscious. But Alva Noe talks about this in his book Out of Our Heads and says well generally locked in patients will still have the ability at least to move their eyes, which is one of the examples that you mentioned. Going back to Aristotle, Aristotle's ancient Greek conception of the soul was that animal and human souls are in part defined by their ability for movement.
David: 30:17
Yeah as opposed to plants.
Ellie: 30:17
I think it's in contrast with-
David: 30:19
W- which are rooted. And modern day scientists, perhaps building on this Aristotelian line of thinking, they will talk about what are called PAM loops, which are perception-action mechanisms, where, in order for you to have a perception, you need the P and you need the A. You need the perception and the action because the action brings about the perception. Otherwise you just don't have that.
Ellie: 30:46
Yeah. The idea that we as perceivers are just passive recipients of sensations from the external world I think runs really deep in our folk psychology in the contemporary world, but actually is not at all what's going on in perception. It's like thanks John Locke and David Hume for giving us that sense of what's happening in perception, but contemporary neuroscientists would beg to differ as would phenomenonologists.
David: 31:12
A lot of this depends on which sensory modality you'd take to be sort of characteristic of experience. For a long time we've known a lot about vision and we tend to think that vision works like that, right? You just like- your eyes just register what's there and then you act, but the perception predates the action and embodied perception theorists will say, well, what if we get rid of this privilege that we give to vision, and we start thinking of experience as sort of modeled on touch rather than vision? And if you think about touch, you cannot really touch the texture of something simply by putting your hand on the surface. You have to put your hand on the surface and then slide your hand across the surface in order to know whether it's rough or smooth. And it's that action, that scanning movement, that produces the perception. This is what embodied perception theorists mean when they say that all experience is touchy in the sense that it has this quality that it needs the movement in order to be real.
Ellie: 32:19
Well and another key component of touch is that anything you touch is also touching you. There's a more immediate reciprocity in touch than there is in, say, vision where you are at a distance from what you are seeing. In touch, you have to be right up against what you are touching such that you can say that it is touching you. But I'm also thinking here, David, I'm so glad you brought up vision because I'm thinking here about how deep our assumption goes that the seat of consciousness lies somewhere behind the eyes. I think a lot of us, if you close your eyes right now- don't do this if you're driving, unless you're on that brake pedal- um, if you close your eyes and you think about yourself, where would you say it is? And a lot of people will say, it's somewhere behind my eyes. And I think that has a lot to do with our privileging of vision, but in a lot of human cultures, there have been other hypotheses. And one of the most influential of these is the cardio centric hypothesis, which is the belief that the heart is actually the center of conscious experience. The heart is what controls bodily movement. And this was a view that was prevalent in ancient Egypt, as well as in ancient Greece.
David: 33:28
Yeah this is a common theme, for example, in Homeric literature, where most of the characters would point to the chest as the source of their identity, because what was called thumos, which is the sort of animal strength or animal spirit was located just right in front of your stomach, really, in front of your chest. And so this notion that we feel ourselves as being in our heads because that's an objective feature of our lived experience is not quite right. And in fact, it might be just modulated by our cultural values and our assumptions about the way in which the body produces that experience.
Ellie: 34:08
Yeah. Yeah. And I'm not suggesting that, oh, we're wrong in imagining that the brain is the center of consciousness, let's go back to this cardio centric hypothesis. But I do think that what we see, I think what we see in both of these though, is the desire to locate consciousness in one specific part of ourselves. And that's what the philosophers Harry Smit and Peter Hacker call the Mereological Fallacy, which is such a fancy name. I love it. Um, but really indicates a pretty basic concept. The Mereological Fallacy is the logical error of ascribing psychological predicates to a part of an animal that actually only applied to the animal as a whole, right. And so consciousness extends throughout our entire body, but we want to locate it in the brain or in the heart.
David: 34:57
And this is an argument that Alva Noe makes in that book Out of Our Heads, where he says, look, we make a mistake when we do that with the brain, because brains don't experience things, organisms do, right? Because if you say that the brain experiences something, then you in theory could say that neurons experience. And yet we know that that doesn't cohere anymore with our intuitions about what experience is. And so I think it's very important to note that for people like Evan Thompson or Alva Noe, experience requires three things, it requires yes, a brain or more specifically a nervous system, whether that's centralized like ours or distributed like an octopuses. So you need that. You need a nervous system. It's really important. Without it, you can't really have complex experience. You need a body in which it is integrated. And finally you need a world that enables action. If you take any of those three components out, they argue experience will just evaporate.
Ellie: 35:56
Yeah. And so we just have this kind of fallacious notion that we can isolate the brain and we'll still have consciousness. And that's what some philosophers have called neuro-essentialism or neuro-enthusiasm. We're-
David: 36:10
Curb your enthusiasm. Curb your enthusiasm.
Ellie: 36:12
Yeah. That- that term comes from Owen Flanagan.
David: 36:14
Um, well, and Evan Thompson uses a version of that term. He introduces a concept which is neuro-nihilism, which is when you don't believe in anything other than neurons.
Ellie: 36:26
Oh my God. Well, and I also just want to point out that even those folks who aren't neuro-nihilists, who aren't neuro-essentialists still share neuro enthusiasm a lot of times. For instance, a couple of recent books that have been super influential in kind of an affective neuroscience and that have really put pressure on mind-body dualism, still to my mind, talk about the brain and the body as if they are separate, right? So they still have brain body dualism. For instance, there was an influential book called The Body Keeps the Score by Bessel van
David: 36:58
der Kolk. Oh, yeah, we, we disagree about this book.
Ellie: 37:01
Yes! We brought that up in a di- different episode. And then there's also How Emotions are Made by Lisa Feldman Barrett. And both of those books are really trying to resist the idea that the brain is isolated from the rest of the body, but they talk about brain-body connections all over the place in those books, suggesting to me that they're still not adequately recognizing the extent to which the brain is a part of the body.
David: 37:27
Well, but if they talk about the connections, then it's a part of the body.
Ellie: 37:31
Well, yeah, but then just say like brain-foot connection or brain-liver, right.
David: 37:37
Um, no but I agree with you that most people think of consciousness as brain bound, and that's the point here, right? And that's what motivates, not just a lot of contemporary research in hardcore neuroscience, but even these kinds of thought experiments that philosophers like to play with as a way of testing our intuitions about who we are and where we are.
Ellie: 37:58
Yeah, and testing our intuitions is wonderful. It's fun. And it's really instructive, but I don't think it can replace actual research and a broader picture of philosophical and neuroscientific view of what's going on in perception.
David: 38:11
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Ellie: 38:41
Whether or not you've heard about the Brain in a Vat thought experiment before, it's likely that you have some neuro enthusiastic tendencies. This type of thinking continues to exert real power over scientists and technocrats who imagine a potential future of brain in the vat or the infamous head transplant. But it actually has a longer history than most academic philosophers think. The idea of a brain and that preexists Harmon and Dennett's versions in the 1970s. David, tell us about this.
David: 39:12
Yeah. So I always thought the Brain in a Vat thought experiment really began in the 1970s. That's when somebody sort of reinvented the thought experiment of Descartes with the evil demon or the evil genius and put this neuroscientific twist on it. But then I got lost in a rabbit hole of history of science research. And I came to find out that the idea of a brain in a vat actually predates it's use by philosophers. And there are two main narratives about where this idea comes from. The science studies scholar Bronwyn Parry recently published an article in which she argues that the origins of this idea ought to be traced back to a 1929 book written by the Irish scientist John Desmond Bernal entitled The World, the Flesh and the Devil.
Ellie: 40:02
Oh my God. I love that name.
David: 40:03
Yeah, the title is amazing. Um, and this is a really fascinating book because it's written by a scientist, but it's not really a book of science or of science fiction. Rather, it's a book of scientific prediction, which was a genre at the beginning of the 20th century. And so in this book, he comes up with all these predictions about what our scientific future will look like as he interpreted it in 1929. He has a chapter called "The Flesh" in which he says, we are going to be brains in a vat. Scientists will figure out that they can remove the brain from the body and they will have to figure out all the technical details. So he says that it will have to be connected to sensors and maybe we'll have to like put some eyes on it so that it can see.
Ellie: 40:48
He really got there.
David: 40:49
Oh, yeah. And he comes to the conclusion that in the future, this will be the new normal for humans. And it means that human life will be divided into two phases. We will have our bodily life, you know, the period of 60 to 80 years in which we live with our body. And then after that, we will have our post bodily life, which is where we just live as brains in a vat. Well, no, because it will be in a really controlled environment. He also talks a lot about cryogenics where it's like, it has to be really cold so that it slows down the aging process.
Ellie: 41:25
Oh, well then I'm just like, why don't we pull an Austin Powers and just like freeze our entire bodies, why just the brain?
David: 41:30
Yeah, no, fair enough. And it's really funny because he actually says, look, you should enjoy your bodily life. So for the first 80 years of your existence, you should do things like dance, because you won't be able to do it after you lose your body.
Ellie: 41:45
The brain's not going to be dancing little vat.
David: 41:47
Because they cannot move. And he says don't bother learning like mathematics for the first 80 years, because you'll have plenty of time to do the purely cognitive things afterwards.
Ellie: 41:58
Maybe I missed this. Would the brain in a vat have a simulated experience? Like, would I be able to think that I'm dancing?
David: 42:04
Yeah, maybe. So, so he doesn't talk about the illusion, which is then the philosophical kind of twist on it. That's the question that the-
Ellie: 42:11
So he doesn't get to the simulation.
David: 42:12
No, and he doesn't think it's a thought experiment. He thinks it's a scientific prediction. And this book has been called by a number of people, the most influential science work for science fiction. So this is where a lot of science fiction writers go to take ideas in order to envision-
Ellie: 42:30
20th century Ted Chiang.
David: 42:32
To envision like dystopian or utopian scientific futures. So that's one narrative, that it begins with this Irish scientists who actually made some really important contributions to x-ray technology. Yes. It's kind of like a legit scientist just feeling entitled to predict the future, which includes the brain in a
Ellie: 42:51
vat. Book called The World, the Flesh and the Devil.
David: 42:54
The Devil. Yeah. I love that it's not just the world in the flesh, but also the devil. Maybe a connection to Descartes.
Ellie: 43:01
Oh, I gotta read.
David: 43:02
Now the second narrative about the historical origins of the brain in a vat experiment trace it to French literature. This narrative is defended by the historian of science John Tresch, who argues that the first image of a disembodied brain sort of floating around a fluid is found in a novel that was published in 1914 by the French surrealist, Raymond Roussel, who became a very influential figure for a lot of 20th century French philosophers, like Deleuze and Foucault. Foucault wrote an entire book about Roussel.
Ellie: 43:35
That's where I'm like, where does that name sound familiar from?
David: 43:37
Yeah. It's from that. And so he wrote this novel called Locus Solis, and it's a story about an eccentric scientist who inherits, from his father, basically the severed head of a French revolutionary. So there was this guy who was a revolutionary, but whose head rolled up during the Reign of Terror for some reason. And well, yeah, but I don't know why the revolutionary would have been guillotined. That's my point.
Ellie: 44:06
Oh, he wasn't a left-wing Jacobin.
David: 44:08
Yes, that's it. That's exactly right. And so he, the scientist inherits this head that's just like a family heirloom. And then he has this tank with electrified water where he puts the head and because of the electricity- and at this time we should know there's a lot of research on animal magnetism- and so his idea is that you could bring this brain back to life. And at some point he says, you know, like the rest of the face, like the face muscles would fall out, they would fall away, leaving nothing more than a brain that is able to sort of tell you stories about the revolution. Yeah. And John Tresch makes the argument that we need to understand the Brain in a Vat idea in the context of its origin, which is the context of this weird French ambivalence slash infatuation with decapitation. And everything that that signifies. And so it raises questions about politics. It raises questions about philosophy and it raises questions, of course, also about just the symbolism of the head.
Ellie: 45:18
Ah, well, yeah, and you know, one thing that I was really struck by in looking at that wiki of all of the brain and/or head transplant horror movies is just how many of them, and this is a totally different point from what you were just saying, David, but, um, it's just, how many of them are brain transplants between beautiful women and ugly women.
David: 45:39
Oh.
Ellie: 45:40
That speaks to a slightly different dimension of this kind of symbolism of the head that you're talking about here, right? It's not the French guillotine revolutionary dimension, but it's like the very American obsession with beauty norms. And I think back to my childhood, because I spent a lot of my childhood watching random old films. My mom and I share a passion for old B movies. And so, you know, it's like, these are childhood memories of like a weird, beautiful woman's head in some sort of vat. I don't even remember the film. But yeah so I think there's that in the kind of more recent past, and then there's also the future too of the kind of tech bros who are obsessed with living in a simulation and trying to figure out how to make that happen.
David: 46:25
Yeah. With the tech bros, it's really interesting because there are two kinds, as far as I can see it. There's probably a ton, it's a very diverse field, except racially, you know, it's not very diverse. They're very diversified in the fantasies that they harbor about the future. So you have like the cryogenics bros, right? They are like, I'm gonna cut my head off and freeze it so that in the future I can be thawed and live again once maybe that Italian guy can reattach me to a new body. I mean, this is the idea. And there are already businesses, I should say. There are a few in San Francisco that will cryogenics you. So there are businesses that already have-
Ellie: 47:04
Wait.
David: 47:05
Frozen heads of people in store. Yeah. You pay a lot of money and basically you sign a contract where it's like, you're going to keep me frozen for a few decades until the science gets there and they put the money in an escrow account so that they can't get ripped off. They've thought about this.
Ellie: 47:21
God.
David: 47:22
And so-
Ellie: 47:23
Oh my God.
David: 47:23
yeah, so you have the cryogenics bros and then you have the singularity bros, right? The ones that are like upload me to the cloud ASAP. And it's the same fantasy. It's the fantasy of being a subject without all the vulnerabilities of the body.
Ellie: 47:39
And the fantasy of immortality, right? Because the earliest iterations of mind body dualism are stories about the immortality of the soul that we find in Plato's dialogues, right. Or Pythagoras. Pythagoras was actually a rare ancient Greek who thought that the center of the soul was in the brain rather than in the heart, but in any case, same idea that there was an immortality of the soul that will kind of break off after death, which is also really funny to me because both cryogenics bros and singularity bros tends to be new atheist bros as well.
David: 48:11
Well, but this is where the line gets really kind of blurry. And a couple of years ago, I taught this book by Ray Kurzweil called The Singularity is Near when humans transcend biology and he's a new atheist who believes in the power of science and especially computer science. But yet, if you read his 850 page long book, he has-
Ellie: 48:33
Vanity project if there ever were
David: 48:35
one. Oh my gosh yes, but it has all thistheologicall language that he doesn't even seem to realize is there where he talks about how, once we upload ourselves into the cloud and we reached sort of maximum computing power, our consciousness will spread out throughout the universe and we will become one with the universe itself. And he about reaching a moment of judgment in which the universe becomes aware of itself through us and then has to decide its own future. So literally like a day of judgment.
Ellie: 49:08
And this is like also fully a Black Mirror episode, right? Black Mirror, which like tries so hard, but has so many terrible philosophical underpinnings to basically every- every episode.
David: 49:20
Well, and you know, there's also another connection here to be made between him and that Irish scientist, Bernal, who wrote that science prediction book, because Kurzweil loves making these predictions. So in that book, he straight up says, this singularity will come in this particular year. I think he said 2034 or something like that. So he- he engages in this kind of prophesizing activity that will always get you into trouble. And it's because again, that line between the scientist and the prophet has been blurred because as a singularity bro, he doesn't see himself just as a scientist, he sees himself as a deity, as a sort of secular God-like figure.
Ellie: 50:03
Oh, sheesh. Well, and I will say, I mean, I think if you separate the deification of somebody like Kurzweil from it, there's something really cool about scientists having something to say about predicting the future. Science and philosophy, I think, are symbiotic. Although what really rubs me the wrong way, and this is a story for another time, is just how many scientists will knock philosophy while also making philosophical predictions and involving a ton of philosophical assumptions in their work. But I do think that there's very much a place, to my mind, for scientists making predictions about the future. Of course, they're doing that already with the development of technology, but I think we have to be very careful about recognizing what philosophical beliefs, we are importing into our predictions. And one of the philosophical beliefs that I would really counsel that all of us move away from is this idea that the brain is the center of consciousness, as Noe says in his book. The really astonishing hypothesis here is that you are not your
David: 51:00
Yes. That's exactly right.
Ellie: 51:02
Like we think it's all cool and you know, progressive to be like, oh, you are your brain. You're not an immortal soul, but actually it's way cooler that we are not our brains.
David: 51:11
Well, and you know what we should bring back instead of all the scientific predicts? We should bring back philosophical predictions where philosophers take the reins over predicting what the future will look like and in the future.
Ellie: 51:23
They never just that they stopped having an impact in the public sphere in the way that they once may have.
David: 51:28
But philosophers never make predictions about the future with the same conviction that scientist. And I kind of want us to start doing that, like in the future by 2034, nobody will be a mind body dualist. That's the inevitable reality.
Ellie: 51:44
I look forward to your book of philosophical predictions, David.
David: 51:47
You know an unexplored terrain if there ever was one. We hope you enjoyed today's episode. Please rate and review us on Apple podcasts, Spotify, or wherever you listen to your podcasts.
Ellie: 52:01
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David: 52:08
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Ellie: 52:18
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