What Humans, Animals and Plants Tell Us About Consciousness | Michael Pollan

Huberman Lab

In this episode of Huberman Lab, Andrew Huberman hosts Michael Pollan for a deep dive into the nature of consciousness and biological interc

Key takeaways

• Michael Pollan explores the hypothesis that the brain may act as a receiver for consciousness rather than its sole generator.
• A distinction is made between sentience, which involves basic environmental awareness, and consciousness, which includes metacognition.

Main topics

• Theories of consciousness
• Plant intelligence and sentience

Notable quotes

Brains are like radio receivers or TV receivers.

Conclusion

The episode highlights the profound, often invisible, biological dialo

Transcript preview

Speaker 2 (0:00) I came out of this experience of studying consciousness and looking at all the theories of consciousness. I don't want to give it away, but we have no idea about consciousness, really, how brain matter generates consciousness, if indeed that's how it happens. And there are people who doubt that's how it happens. It could be that the brain channels consciousness, right? I mean, that if you conceive of consciousness as like electromagnetic waves. Brains are like radio Speaker 1 (0:27) receivers or TV receivers. You wouldn't Speaker 2 (0:29) look in the TV set for the woman who gave you the weather report. She's not there. She's somewhere else. So I don't know that that's true, but coming out of this experience of studying this, I don't dismiss an idea like that. You have to keep an open mind because our presumption that consciousness is an emergent property of brain complexity, that idea doesn't have much traction. Speaker 1 (0:54) Welcome to the Huberman Lab Podcast, where we discuss science and science-based tools for everyday life. Speaker 1 (1:03) I'm Andrew Huberman, and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. My guest today is Michael Pollan, author of landmark books including How to Change Your Mind, which is about psychedelics, The Botany of Desire, which is about how humans and plants co-evolved and collaborated to thrive, and The Omnivore's Dilemma, which is an incredible book about food and nutrition. And most recently, the book A World Appears, A Journey into Consciousness. Michael Pollan is considered by many, including me, to be one of the most learned and thoughtful people on topics that matter to all humans and the things that we can do to improve the human experience. Today, we talk about many topics, but mostly we focus on consciousness. And Michael brings forward a new perspective that integrates the best science on this topic, as well as philosophy and beyond. And we get deep into this notion of the ego, meaning our notion of self and how the ego is both important for and limits our understanding of ourselves and life. I should emphasize that the conversation is not as abstract as I'm making it sound. What I love about Michael Pollan is he makes these topics very clear and very concrete, and in many cases, actionable. Thanks to Michael, by the end of today's conversation, you will be placed at the front edge of the conversation and the data on this thing that we call consciousness. You'll also be versed on the latest of plant, or what is sometimes called psychedelic medicine, and perhaps most importantly, what you can do in your life to gain new perspective on yourself, others, and the planet at large. Before we begin, I'd like to emphasize that this podcast is separate from my teaching and research roles at Stanford. It is, however, part of my desire and effort to bring zero-cost to consumer information about science and science-related tools to the general public. In keeping with that theme, today's episode does include sponsors. And now for my discussion with Michael Pollan. Michael Pollan, welcome. Thank you. Good to be here. Longtime fan of your books, of you. I've had the privilege of speaking on stage next to you, although... Mostly I was just listening to you because you are this amazing intersection of science writer. You've written about food, psychedelics, now consciousness. You'll tell us about your new work on microbiome. I feel like there's also some Wendell Berry woven in there. Speaker 2 (3:16) Big Wendell Berry. Good. I didn't insult you. I didn't check out that. Not Speaker 1 (3:19) at all. Speaker 2 (3:19) We just lost him too. Oh, is that right? He died like two weeks ago. Oh my goodness. Speaker 1 (3:24) I know. I'm like a huge Wendell Berry fan. Really? Me too. He Speaker 2 (3:28) taught Speaker 1 (3:28) me how to write and he Speaker 2 (3:29) taught me how to think about certain things. But he had a huge influence on me. I was very fond of him. Did you ever meet him? Speaker 1 (3:37) Oh, yeah. I Speaker 2 (3:37) interviewed him on stage a few times. He interviewed me in Lexington, Kentucky about one of my books. And I went to his house and saw the long-legged house where he writes on the river. He was always trying to convince people like us about the beauty of the tobacco culture. And he kind of bracketed the cigarette piece and the lung cancer piece. But the culture was so beautiful. And it was the one time where the whole community got together and racial lines were crossed. And the barns are gorgeous, the tobacco barns with the slots for drying. So he wanted me to see those when I came Speaker 1 (4:20) there. Amazing. Yeah, I was feeling a little anxious about bringing in that reference in case you weren't a fan or you didn't like his work, but clearly he was calling in because... He Speaker 2 (4:30) was. Speaker 1 (4:30) And for those who don't know, Wendell Berry is this just magnificent poet who... And farmer Speaker 2 (4:35) and essayist. Yeah. And he, you know, actually when I was writing my first book, Second Nature, I was trying to figure out how to behave in the garden. which is a microcosm of how do we behave in nature, right? In other words, I had pests. I had problems. I had fertility issues. And the American tradition of thinking about nature, which goes back to Thoreau and John Muir and Emerson, is all about celebrating the wilderness and being a spectator in nature. And of course, the gardener can't afford to do that. You have to act or you're not going to have anything to eat. I had a head full of... Thoreau and Emerson from college and graduate school. And I was kind of stymied about like, what do I do about weeds? Thoreau's telling me weeds have just as much right to be in your garden as the bean plant, which is crazy. But it was Wendell who would write these essays and he convinced me, he said, we have a legitimate quarrel with nature and that our relationship is, we do have to make changes in nature for us to survive. And that's kind of who we are. is the species who remakes nature in various ways. But it has to be done sort of more like a marriage than a domination. And so he just had a new way of thinking about how to relate to nature that really helped me and clarified my whole view of environmentalism. So, yeah, he's a great hero. Speaker 1 (6:05) Amazing. Saddened to hear that he passed, but he certainly left behind amazing. I Speaker 2 (6:10) think he was 92. Speaker 1 (6:10) Well, that's a pretty good run. Yeah, he had a very good run. We will put some links to his work for those that aren't familiar. And I encourage anyone listening to just, and even those who are familiar with Wendell to go read some of his poems. They're an incredible journey and full stop. Yeah. Yeah. I'm with you. Let's talk about consciousness. As a neuroscientist, I was taught to avoid this issue. I hear it was the kiss of death at a certain point, right? Neuroscientists who had... were already very accomplished and famous in some specific domain, like memory or neuromuscular junctions or whatever, could talk about it. They had permission once they had their prizes and their stature. But some people have died on the... bed of nails that is the consciousness discussion. I almost did. Clearly not. But yeah, but maybe you can tell us why it's so precarious. But it's hard to define, I think, is part of it. And kudos to you for jumping in with both feet on this one. So after having written a book about consciousness, essentially. Do you think that we can describe it in a sentence? Can we give it an operational definition? It's such a strange phenomenon because there is nothing Speaker 2 (7:24) we know with more certainty than the fact that we're conscious. It's the only thing we can be sure of. Everything else we know through consciousness, right? Everything else is an inference. But we have this thing that we know we have. But defining it is difficult. So there are some very simple definitions like subjective experience. That's pretty good. Your toaster doesn't have subjective experience. And I would argue AIs don't have subjective experience, but we can talk about that later. Another popular, I don't know if it's a definition exactly, is Thomas Nagel, the philosopher in the 1970s, wrote a brilliant essay called What Is It Like to Be a Bat? And his point was, if it is like anything, then you're conscious. So even though we don't know exactly what it's like to be a bat, we can kind of imagine a creature that navigates the world through sonar, through sound waves instead of light photons. And so, okay, we can imagine that. So yes, bats are conscious by that definition. So is it like something to be a computer is a real question that I think we're going to have to face. That's kind of what I use as a definition. There's Speaker 1 (8:37) a lot of bells and whistles that human consciousness has above that. We're not just aware, but Speaker 2 (8:42) we're aware that we're aware. We have self-reflection or metacognition. Emotion, you know, add that in. So I think humans have a very elaborated... kind of consciousness compared to some other creatures. I make a distinction in the book between sentience and consciousness that some scientists make and I find really useful. Sentience being a more basic kind of ground floor of consciousness that... Speaker 2 (9:12) includes awareness of your environment and a recognition of changes and whether they're good or bad. And that may be universal. I mean, that may be a property of life. You can make a case that plants have sentience, that single-celled creatures have sentience, and it may be something you need to survive in an environment that's constantly changing, that you can't program instinctually everything you need to know so that this would be very useful. Speaker 2 (9:41) Consciousness is how we do sentience. You know, we've added on all these things and every creature has its own version of sentience based on their body type, their sensorium, the scale at which they live in time and space. Because it's kind of to take our version of consciousness and make that the standard for everybody seems kind of crazy. This thing about Speaker 1 (10:04) being able to respond to the environment being some... key component of consciousness. A plant can respond to the environment. A barnacle can respond to the environment. A bacteria can. Bacteria can. They can light sense. They actually know the difference between morning and evening. And they have Speaker 2 (10:21) hemotaxis. They know between the difference between something that's good to eat and something that's toxic. Speaker 1 (10:26) Do you think they know they know? This is the piece that I feel like the responding and the awareness that one is responding is maybe where, in my mind, I want to draw the line for some reason. A plant will, you know, you know, furl and unfurl in the presence of light, but does it know it's responding and why? I mean, I suppose we all the time respond to things and don't know why, but usually like if I take a sip of this tea and it's too hot, I have some sense of what I'm going to do next and why. Whereas I feel like the other stuff is just reflexive. Speaker 2 (11:00) Yeah, it's reflexive, but I don't think it's, it's. always programmed. I think that there are novel situations that even a plant confronts where they have to have an intelligent response that isn't necessarily something programmed in their genes. I mean, I took a deep dive into this field of plant intelligence, which is fascinating. I mean, the things we're learning that plants can do that you would not have guessed. I mean, you can take a corn plant. And it can navigate a maze. You can give it a maze and put some fertilizer, some ammonium nitrate in one corner of it, and the roots will find the fastest path to that ammonium nitrate. That's not a situation it really experiences in nature. That takes a certain kind of intelligence, problem-solving ability. If you play the sound of caterpillars chomping on leaves for a plant, they will react to the sound and send either toxins or bad taste and chemicals to that leaf to defend themselves. They can respond to the sound of water and if they hear water running through a pipe, they will... They have like 20 senses. We have five or six. They can sense gravity, which we can't do. They can sense pH. They can sense whether nutrient levels are on a positive gradient or negative gradient. I mean, it's remarkable. One of the, to me, most curious things about plants is that they respond to the same anesthetics we do. Now, you might think, What does it mean to put a plant out? Aren't they already out? But actually, they're just slow. They have behaviors. They're just very slow. So you take a plant with a really fast behavior, like a Venus flytrap, and you put it in a bell jar, and you put some anesthetic gas in, xenon gas, or any number of, you know, anything you can put in gas form, and they will not respond to an insect crossing their threshold, where normally they would. clamp down. So that raises a really interesting question. What exactly are they losing when they are under? We would say consciousness, but that's a long way to go. I mean, I don't use the word consciousness for plants, although I met scientists who do, but I would say that's sentience, that there's a loss of sentience that's happening when they are anesthetized. But As you know, anesthetics are really weird. We don't even know how they work on us, right? I mean, xenon gas is inert gas, and it puts you out. Speaker 1 (13:43) How does that work? Does it scare anyone going in for surgery? The anesthesiologists have gotten much better. Yes, they know what Speaker 2 (13:50) they're doing. They know what they're doing. Speaker 1 (13:52) I'd like to take a quick break and acknowledge our sponsor, 8sleep. 8sleep makes smart mattress covers with cooling, heating, and sleep tracking capacity. 8sleep just launched the Pod 6, which is their most advanced sleep system. The Pod 6 is half the size of their previous models, it's 20 % faster with its cooling and heating, and it has nine times as many sensors for tracking your sleep. 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The Environmental Working Group has also shown that over 122 million Americans drink tap water with high levels of chemicals known to cause cancer. It's for all these reasons that I'm thrilled to have RoRa as a sponsor of this podcast. I've been using the RoRa countertop system for almost a year now. Rora's filtration technology removes harmful substances, including endocrine disruptors and disinfection byproducts, while preserving beneficial minerals like magnesium and calcium. It requires no installation or plumbing. It's built from medical grade stainless steel, and its sleek design fits beautifully on your countertop. In fact, I consider it a welcome addition to my kitchen. It looks great, and the water is delicious. If you'd like to try Rora, you can go to rora.com slash Huberman and get an exclusive discount. Again, that's Rora, R-O-R-R-A dot com slash Huberman. Can we? Go at self versus other as maybe one potential window into this I don't want to make any assumptions But when I think about the consciousness problem, I I think most people know that they are them and they know what's not them and Maybe a decent analogy is when nerve cells grow They know the difference between them and other cells. So at the cellular level, you know, this is already set up and in fact I love your example of the root growing towards the fertilizer because you can give a nerve cell a simple rule, all nerve cells a simple rule, which is essentially grow out as far as you can and connect with as many other nerve cells as you possibly can and know the difference between you and other. And if you do that- Speaker 2 (17:26) Even Speaker 1 (17:26) within the same Speaker 2 (17:27) species. Speaker 1 (17:28) Yeah. So, you know, and there are some exceptions to this, but it turns out to be, it's not straightforward to build a brain, but- You don't need a ton of signals. You need signals that say grow here and you need signals that say you may not grow here. What we call chemoattractance and chemorepellance. And then if you think about the dendrites and axons, the branches of the neurons, they often have these beautiful architectures. Speaker 2 (17:49) Those Speaker 1 (17:49) are set up by a simple rule of self-avoidance. Speaker 2 (17:52) The Speaker 1 (17:53) branches know that they are. that they're of the same neuron, and they just keep growing, and they keep branching every time they get too close to one of their own. And then you end up with these beautiful architectures, depending on what other cells are doing that around you. That's how you get all these different cell types. And there's other features to it, too. And I was shocked and excited to learn that that's kind of how tree roots do it, too. Yes, I was Speaker 2 (18:15) going to say. So Speaker 1 (18:16) simple rules can build immense complexity. That's the point. And the self, recognizing self versus other. And then a simple rule of get as much stuff as you can. It sounds very selfish, right? Sets up a great system, actually, because then everyone's doing that and you end up with essentially a tiled system. No tree, no neuron gets too much space. And while this is all very cellular and we're literally talking about the branches of cells, it's not, you know, thinking. I feel like. When you get up to the whole organism, I know the difference between me and you, me and the microphone. These plants seem to know the difference between them and the fertilizer. So this lack of confusion about what's me and what's not me seems to be like the most important rule that perhaps builds up to the consciousness thing. perhaps. It's Speaker 2 (19:04) really an important rule. And you see it in plant roots too, because if you put two plants that are related to one another, have some genetic connections, but are separate plants, they will share soil and grow together. But if they're not related, even if they're the same species, they will compete. Ditto the plant that, when plants are shaded by another plant, they grow fast to get above it. But if they're shaded by themselves, closer to your example, they don't. They know. Like, well, we're getting the light over there, so I don't have to go there. But yeah, I think the self and other is a key rule. And I completely agree that you can take a set of very simple rules and build a very complex creature from it. How that gets you to consciousness, I mean, self and other is an important part of consciousness. Although, And I talk about the self as kind of the most elaborate or advanced manifestation of consciousness. It turns out you can have consciousness without a self. And that's, you know, I mean, meditators know this. Psychedelics can give you an experience of consciousness without a self. I think we have it every morning when we wake up. There's that 500 milliseconds, you know, when you're reconstituting, like, who am I? Where am I? Oh, you know, here I am. And it's 750 milliseconds if you're in a hotel room, as I realized this morning. That's kind of weird that you can have, that there is a consciousness that is not organized around a self. And Buddhists have known this for a long time, but it's a strange idea. Going Speaker 1 (20:49) back to the plants and their intelligence, I spent a little bit of time with people in the plant medicine community. Not a lot. I'm not like a heavy psychonaut or anything. There does seem to be this understanding there, and I don't think it's just conjecture. I think it's a real understanding of people who spend time in the jungle, who spend time with plant medicines. Even pharmacists in this country will tell you that most drugs were bioprospected from the jungle. Big pharma are isolated compounds synthesized, as you know, from jungle plants and other plants. So there's this notion that the plants actually can sense us. and that they're communicating with us. I know this sounds really wacky, but we can certainly see them. We can smell them. They can have, you know, odor effects on us. Some are poisonous, some are delicious and wonderful for us. They're nourishing. What do you think about this sort of cross-species communication? Do you think it's a real thing? Having spent some time, you spent a lot of time on about- Yeah, Speaker 2 (21:51) I Speaker 1 (21:51) think about plants and Speaker 2 (21:52) my Speaker 1 (21:52) garden and all these things. Yeah, Speaker 2 (21:54) like Speaker 1 (21:54) my mom gardens. And she is convinced, and she's Speaker 2 (21:57) a Speaker 1 (21:57) very rational person. She is convinced that talking to the plants while she plants them has a real effect on the relationship between her and these plants. I mean, she's not thinking that they can hear and understand the language, but that there's some sort of energetic transfer there. And I don't think she's alone. People who garden have a relationship to the plants. And I certainly feel this way about my dog, to some extent, my fish, although to a lesser extent. I don't think it's entirely crazy. Speaker 2 (22:25) I don't think it's crazy. I think that I haven't had that experience myself. I did have an experience, and this was talk about plant medicine on psilocybin that I described in my book, of feeling that the plants in my garden were conscious and aware and returning my gaze. And they were very benevolent. I took good care of them. That's good. Otherwise, it could get scary. Yeah. Yeah. And I didn't know what to do with that. I mean, there's a whole question with insights you have on psychedelics, like, do they have any value? And how do you judge their value? And in my case, I thought back to William James, who had written in Varieties of Mystical Experience, that you can't really judge the veracity of a big insight on a mystical experience because we don't know enough. But there are two ways to think about it. Is it a useful thing? Is it pragmatic to believe that? And that's one argument in favor. And the other is treat it as a hypothesis and see if you can find other ways of knowing, scientific or otherwise, that could support that idea. And that's what got me into plant, you know, learning about plant intelligence and plant sentience. We are in relationship with plants, domesticated plants in particular. I think they manipulate us in various ways. But it's not at the level of the individual plant. It's at the level of the evolution of the species. So, you know, corn came to dominate the landscape in much of the world because it figured out what we wanted from it. And when I say figured out, I mean purely by trial and error. Cannabis, too. Cannabis was, you know, this plant, you know, located in western China, I guess. And now it's everywhere. And the reason it did is... it learned that we respond, if it produced this chemical called THC, it was going to get carried around the world and reproduced. And so I think we're in this symbiotic relationship with plants in that they do manipulate us. They're geniuses at biochemistry, as you suggest, you know. And that's a function of the fact that they can't get up and run away, right? They're rooted. They're sessile, as it's called. And so instead of consciousness like we have and the ability to move around, they develop chemicals, this incredible suite of chemicals. And they hit on some chemicals that happen to change our consciousness. And this has been one of the most successful strategies. Coffee and tea are great examples. They didn't originally make these chemicals for us. They're probably defense chemicals. But what's interesting about the defense chemicals that they produce is that they're not, they don't kill anything. I mean, caffeine might kill insects, some insects. But somewhere along the line, they learned that it was better to just kind of fuck with your mind than kill you outright. Because if they killed you outright, you would very quickly develop resistance, right? You'd select for resistant members of the species. The way I learned this, it was courtesy of my cat, Frank. Frank had a real catnip problem. And every night, Frank, I would go down to my garden to harvest some lettuce or something like that. And I had a catnip plant, and this is in a fenced garden. And Frank would follow me and look at me. And he needed to be reminded where the catnip was. It's like, you know, why don't you know where it is? because he would get so wrecked on catnip that he would forget. And I'm like, that's a brilliant strategy on the part of the plant to get your predator Speaker 1 (26:20) to forget where you are. Amazing. Speaker 2 (26:22) And the other thing they do, of course, many plant chemicals, psychoactive chemicals, diminish your appetite. Another brilliant strategy. So I have enormous respect for what they do and what they do to us. And I really see them as active players in this drama. I wrote a book called Botany of Desire, which really looked at how plants have mastered our desires as their evolutionary strategy. Desires for beauty in the case of flowers, desires to change consciousness, desires for food. So I have ultimate respect for their ingenuity. Speaker 1 (26:58) When you say that plants have figured out, do you mean that sticking with the rule of evolution, you just want to make as much of yourself as you possibly can in species that nurture young, nurture young, protect young, proliferate, die, repeat, right? I mean, that's like a harsh way of thinking about it, but those are essentially the simple rules of evolution. Try not to die, try to at least live long enough to proliferate and make sure that the young make it. And in retrospect, Speaker 2 (27:25) it looks like you figured something out. But in fact, you're just trying things and certain things work. And the plants that, you know, had the most caffeine, say, proliferated in a way the ones that had the least caffeine did not. Speaker 1 (27:38) I mean, I think about dogs a lot because I love them. And I'm told that dogs descended from wolves that figured out that if they were kind enough. and they were patient enough, they might get scraps of food. And eventually that led to the domestication and the expansion of all these different breeds of dogs. I mean, I think that's essentially the story. So they're not getting together and having a little, you know, backroom conversation like we've almost got them. And that's certainly been advantageous for the domestic dog. They're very well treated, better than some humans, in fact. And Speaker 2 (28:12) there are only 50,000 wolves left in this country. And how many dogs are there? It was a Speaker 1 (28:17) good strategy. Right. Yeah. And I feel like more people have dogs now than when I was growing up. Well, Speaker 2 (28:22) COVID Speaker 1 (28:22) led to a lot of people getting dogs. Yeah. So it's, it's, uh, most people don't get dogs to do work. They get dogs to be family members. Right. And so they're really, they're really figuring stuff out. They got us. They got us. Um, but this figuring stuff out thing is, is as it relates to consciousness is, um, maybe it brings us back to the definitions. So does that mean that you don't have to have self-awareness that you're doing it? plants probably don't realize they're doing this. They're just following a rule that's scripted into their genome. Try and get resources, feel good, not pain in the moment and proliferate, take care of young and so forth. Speaker 2 (28:57) So Speaker 1 (28:58) do you think that this consciousness of plants or of dogs or of humans can emerge through the simple flipping of switches that are hardwired into us? Or do they have any say in this? Do they realize that they're doing better for the next generation because plants don't get to see what happens to their seeds in most cases. Dogs don't really know what happens to their puppies once they're adopted out. Yeah. Humans are unique in this way. Speaker 2 (29:28) Oh, I think we are. I mean, I think we have an awareness, a self-awareness, and a sense of, you know, we can time travel. You know, your dog probably can time travel a few minutes or maybe a half hour if it's really hungry. you know, but we have the ability to imagine the future, even a future we're not in. That's one of the things that's special about our consciousness. I mean, you know well that our brains are doing a lot more than we're aware of, right? I mean, 24-7, they're monitoring our body, you know, reading these interoceptive signals and making adjustments and taking in things from the environment without our awareness. So the question is, Why does anything have to rise to the level of awareness? Why wasn't it all automated? I think that's one of the mysteries. The best explanation I heard