“Mysteries Abide”: A conversation on consciousness with author Michael Pollan

The following post from Rachael Petersen, MDiv '24 is an ongoing series from affiliates of the Thinking with Plants and Fungi Initiative.

This interview was edited for clarity and length.

For more than thirty years, Michael Pollan has been writing books and articles about the places where human and natural worlds intersect: on our plates, in our farms and gardens, and in our minds. Pollan is the author of eight books, six of which have been New York Times bestsellers. He is a professor of the practice of non-fiction at Harvard. His forthcoming book explores the science and philosophy of consciousness.

 In fall 2022, Pollan participated in CSWR’s ongoing Plant Consciousness Reading Group, where we explored contemporary debates on whether plants are conscious. He explored this question and more in conversation with Rachael Petersen, MDiv ’24.

This interview was edited for clarity and length.

Rachael Petersen (RP): In fall 2022, your participated in the CSWR’s Plant Consciousness Reading Group co-led by myself and Natalia Schwien. What ignited your interest in that group?

Michael Pollan (MP): It was a really interesting experience and a great group. I loved the mix of perspectives. Our conversations renewed my interest in questions that I’m looking into for my forthcoming book on consciousness. Part of that is I'm trying to drill down to the most basic place where you have at least sentience, or awareness or responsiveness, such as you might ascribe to plants. One of the most productive paths to study consciousness is to work from very simple cases. That’s why I think plants are interesting. You say, “okay, we have plants over here and, say, brine shrimp over here. Why doesn’t consciousness cross that bridge?” Or maybe it does. And as you go from brine shrimp to pigs, or dogs, or primates-what's happened? These building blocks help us understand consciousness. That's why it's important to study plants and bacteria and simple organisms, though I’m not comfortable ascribing consciousness to plants.

RP: What evidence could convince you that plants are conscious?

MP: My take has always been that plants don’t need consciousness to do what they do. You have to think of consciousness not as this ultimate achievement, but as a tool for living. Consciousness makes a lot of sense for animals, especially because we have to move around. But, as I wrote in Botany of Desire, plants are stuck in place, which made biochemistry the more important thing to develop. They can’t run away. They need to defend themselves by other means, such as toxins that mess with the minds of conscious beings.

I'm much more comfortable ascribing intelligence to plants. They have effective, flexible responses. They have an awareness of their environment. But I haven't yet seen anything that made me think we should consider them conscious, even though we had a “Plant Consciousness” reading group [laughs]. It’s a provocative idea that gets people in the tent to explore what cognition, intelligence, and sentience are.

RP: Part of the problem, which we often discuss in our group, is terminology. Key terms like intelligence, consciousness, and sentience are poorly defined or used in different ways by different people.

MP: I try to argue for precision in language. The world of artificial intelligence is teaching us–or should be teaching us–that we need to make a distinction between intelligence and consciousness. The two often get confounded in ways that don’t make sense. I think you can be highly intelligent without being conscious, if you define intelligence as solving problems or dealing with changing circumstances–see, for example, lots of machines and large language models.

But consciousness is something else. I see consciousness as a more self-reflexive, more recursive phenomena–as philosopher Thomas Nagel put it, there is “something it is like” to be a conscious being. And I do think it’s rooted in particular biology that animals have, possibly down to a very low level. There are interesting arguments now that brine shrimps are conscious. I think the philosopher Peter Godfrey Smith is making the point that there’s “something it is like” to be a shrimp. There may well be “something it is like” to be a mosquito. And that's going to pose all sorts of issues for people concerned about animal rights, but there it is.

There are writers who use sentience and consciousness interchangeably. But I don’t. To me I can imagine a sentient being who takes in information about the world, makes predictions based on sensory information, has a sophisticated awareness of what's going on, and perhaps has a repertoire of responses that are not automatic or automated. So, I see sentience as a kind of proto-consciousness.

RP: With that distinction, it sounds like you’re comfortable attributing sentience to plants but not consciousness.

MP: Well, I'm not yet comfortable, but I'm open to the idea. I mean, who am I to say? I'm not a scientist or a plant [laughs].

RP: My colleague Dr. Christine Webb often points out that the presumed scientific burden of proof rests on demonstrating that non-human animals and plants are conscious. She wonders what would happen if we instead assumed other beings were conscious, and then our task became to prove that they weren’t.

MP:  I think the biggest assumption that would have to be overcome is that brains produce consciousness. We have to realize it's just an assumption. We have to be open to other ideas. The spell of scientific materialism is powerful, even though it really has nothing definitive to say about this crucial phenomenon [consciousness].

One of the most interesting things going on in biology right now is the growing recognition of our neurocentrism. For example, Mike Levin, a biologist at Tufts, studies bioelectric fields. He builds these creatures from cells called xenobots and has shown that they can learn and be taught things even though they don’t have a brain. He has also experimented with planarian flatworms. He will teach the worm something, then cut off its head. He’ll wait for it to grow a new head and–lo and behold!–the worm remembers what it had been taught. It lost its neurons so must have stored the information somewhere else. Levins thinks it’s in the bioelectric field. His work demonstrates that you don’t need a brain for intelligence or memory.

All this raises questions of what an organism can do without neurons. What can you do that seems brain-like? We have this idea that there has to be a locus of intelligence where signals flow in and action flows out. Darwin said that in plants it was the radical or the root tip. In her new book on plant intelligence, The Light Eaters, author  Zoë Schlanger considers the whole plant a brain. But then what does that mean, exactly? What is a brain?

We have this notion of a brain in a vat, which many of us don’t even question. But all our understanding of brain anatomy has changed. Brains are nowhere without sensory organs. Brains are irrelevant without a body. We used to think “there was a center for this and a center for that.” But then we started thinking about networks. And now we’re moving beyond networks. There are all these global functions. There’s no center, even at the center! It’s all a mystery!

RP: “There’s no center even at the center” is a great note to start or end your book.

MP: Mysteries abide! [Laughs]

The point is we've had scientific paradigms before that fell apart, and neurocentrism could fall apart. All centrisms ultimately fail. Regardless, I do think we should see consciousness as somehow rooted in biology—It’s deeply implicated in life.

RP: This field is dynamic and complex. When I heard you were writing a book on consciousness, I thought to myself, oh boy.

MP: I know! Everyone takes pity on me. I take pity on me!

RP: What have you learned in researching your book?

MP: One of the things that strikes me in researching this field–and this is the first time this has happened in all the fields I've researched–is that nobody knows anything [laughs]. I mean we've learned things about perception, mostly visual perception. But if you read most books by consciousness, researchers make huge promises in the introduction that they're going to explain interiority or subjectivity or thoughts. But they never get quite there. They get stuck on perception, which is hard enough. They give a lot of information about visual illusions and predictive coding but don’t dig very deep into consciousness as most people understand it. So that's been a main finding—and a disappointment.

Part of the problem is methodological. We're trying to understand consciousness using consciousness. It's the only way we can operate. We can't step outside it. There's no view from nowhere, right? It’s a hard problem, as they say, and gets into metaphysics really quickly.

As mentioned, another important debate is this whole question of whether consciousness requires a brain. Some theories, such as Integrated Information Theory, don’t necessarily depend on brains. Then there's panpsychism, which suggests consciousness may lie outside of brains and is a property of the universe. Panpsychism is really an attempt to save materialism because consciousness is a tremendous challenge to scientific materialism. One way to save it is to add a new fundamental force, “consciousness,” and make it inherent to matter, just like mass, gravity, spin, whatever… I don’t think there’s a lot of evidence to justify that, and it creates new problems. But it’s one attempt at a fix.

There's a surprising revival of idealism going on, led by people like Donald Hoffman at UC Irvine and Bernardo Kastrup in the Netherlands. This may be a symptom of the fact that no one's really getting anywhere with consciousness under the materialist paradigm. There is an effort to think outside the box, and some people are wanting to go pretty far outside the box. Idealism can be linked to the predictive processing model of the brain, which says we infer and predict what we see, rather than take in information about the “real world.” Our perceptions have been refined by evolution not to be accurate, necessarily, but rather merely helpful for survival. What we perceive is adaptive, but it may be completely “wrong.”

One of the more striking quotes I got was from the scientist Christof Koch when I asked, “what would the world look like if there were no consciousness in it at all?” He didn't hesitate long. He said, “Dust! Just dust!” When I asked him the question again more recently, he said, “Particles and waves.” That's what he thinks the world is without consciousness. But I find that sort of hard to imagine.

I think psychedelics are telling us some interesting things about consciousness. I've been struck by the fact that so many consciousness researchers, whether they're philosophers or scientists, are personally dabbling in psychedelics right now. Christof Koch writes a lot about his psychedelic experiences in his latest book. He has found them very interesting tool, although his experiences don’t always accord with his scientific beliefs. So, it can create interesting tensions that could prove productive.

It could well be that consciousness is not just one thing. I interviewed somebody who described herself as a “pluralist of consciousness.” The idea that it's one thing that we're looking for is a kind of heroic narrative that in my experience is shared more by the men in the field than the women. Women are willing to entertain a more pluralistic view, and that doesn’t surprise me at all.

RP: I love that. It parallels a conversation we’ve had in our reading group around intelligence. Intelligence isn’t a monolith. My dog would beat me at a test to sniff out truffles in the forest; but I’d score better on a math test. So maybe we should talk about different types of consciousness just as we think about different types of intelligence that have adaptively evolved differently in different species.

MP: Yeah. I think of consciousness as a tool. I do think it's rooted in our biology. I accept this idea that the brain exists to keep the body alive, and not the other way around, which most of us implicitly believe in our neurocentrism. This involves elaborate mechanisms for maintaining homeostasis and resisting the second law of thermodynamics. That's what the game is about.

I came at the field thinking of consciousness as a very ethereal thing removed from the materiality of the world. I guess started out as a dualist, without knowing that term. But the more I examine consciousness, the more rooted in nature and biology it seems to be.

RP: So you were a unwitting dualist when you entered this field. What are you now?

MP: I don't know what I am. I don’t have a label. I’m very much up in the air, AKA confused. But I'm getting comfortable with my ignorance. The weird and either alarming or interesting thing about this book I’m writing is that readers will know less at the end of it than they did at the beginning [laughs]. Whether that value proposition is appealing to people or not will be a dilemma for me and my publisher to navigate.

RP: Well, I appreciate the humility you’re bringing to this daunting subject, and I look forward to reading your book.