I'm William Brangham and this is "Horizons."

All of us experience consciousness.

We have thoughts and feelings and we're aware of those acting upon us.

It's the hidden internal lens through which we view the world, but why do we have this power and are we the only ones that do?

Coming up next.

♪ Narrator: Support for "Horizons" has been provided by Steve and Marilyn Kerman and the Gordon and Betty Moore Foundation.

Additional support is provided by Friends of the News Hour.

♪ This program was made possible by contributions to your PBS station from viewers like you.

Thank you.

From the David M. Rubenstein studio at WETA in Washington, here is William Brangham.

Welcome to "Horizons" from PBS news.

Take a moment right now and think about what you're feeling.

What are you thinking about right now?

Does me asking this feel awkward?

Irritating?

It's... Did your mind just drift to something that happened earlier?

Are you thinking about your next meal?

Whatever you are feeling right now, that sensation, that voice inside your head is partly what we call consciousness.

This awareness of our internal selves has long been held up as one of the defining aspects of being human.

But why do we do this, what purpose does it serve and where does consciousness actually live inside our brains or bodies?

These are some of the questions that Michael Pollan is trying to answer in his new book "A World Appears, a journey into consciousness."

Pollan is one of the great science writers of our era.

He has written numerous books about food and our food system, including the "Omnivore's Dilemma" and "In Defense of Food," as well as several books about the science of mind altering substances, including "How to Change your Mind," which is about psychedelics.

Michael Pollan, such a pleasure to have you on the program.

Thank you, William, very good to be here.

So I gave a... I took a stab at a definition-- - That was pretty good.

- Really?

- Yeah.

- That's high praise.

I love that.

What would you add to that about this idea?

Consciousness is... is... it's... it's a funny thing that we find it elusive because it's the thing we know best.

Right?

Everything else we know about the world is inference based on consciousness, right?

Consciousness is the first experience we have of existing.

So consciousness is simply subjective experience and it is... Another definition is... There was a philosopher named Thomas Nagel who wrote a great essay in the 70s called "What is it Like to Be a Bat?"

- A flying bat.

- A flying bat.

Yes, not a baseball bat and, you know, bats navigate the world through echolocation, kind of sonar, not... not visual sense.

They're... they're, you know, blind as a bat, but we can sort of imagine that it's like something to go through life that way, it has some qualitative dimension.

So when that's the case, a creature is conscious.

Your toaster, for example, is not having experience.

It's... it's like nothing to be your toaster.

So these are, you know, these are the definitions that the scientists are working with.

Your book sort of walks us through the increasing ladder of complexity up the chain towards what we think of as human consciousness.

One of the genesis moments that you write about for you in this book was... was... Under the influence of psychedelic mushrooms, you being in your garden and having this sensation that the... that the flowering plants around you were... I think you called it aware, watching you.

Returning my gaze.

Yeah, it was a very kind of spooky, but wonderful moment.

they were... they were very positive in their affect.

[Chuckles] They were... Brangham: It was a little shop of horrors.

No, no, they thought well, I mean, I was their gardener after all.

I fed them and pruned them and took care of them.

But um... but they... yeah, they were more alive than they'd ever been and that's not an uncommon perception on psychedelics, that the world is kind of reanimated, but I was curious after the experience, where I kind of went back to my default of, "Of course they're not conscious."

But I thought, "Well, let me see if I can test that insight, you know?"

William James said, when he wrote about mystic... the great American father of psychology in America, said he's writing about mystical experiences, these strange encounters with divinities and merging with the, you know, the universe, he said "Well, we don't really know if they're true or not, "we don't know enough to say, "but test them against other ways of knowing."

And so, in my case, I went looking for people studying the science of sentience, which is a kind of simpler form of consciousness in plants.

The plants part of your book... I find so fascinating the things that scientists have determined that plants can do, I mean, I'm going to read just a very quick list here that I noted down from your book.

"Plants can learn and form memories."

"They can be taught to ignore certain stresses."

"They can predict upcoming changes in their environment."

"They can distinguish friends from competitors "and both of those from themselves," but how is it that we then have... So that... In that definition, that is not consciousness.

Pollan: No, it isn't.

But it is... it is a kind of awareness.

They're aware of their environment.

There's a... I mentioned a vine that grows in South America that actually changes its leaf form to mimic the leaf form of the plant It's trying to colonize.

How does it see that?

How does it get that information that allows it to change its leaf form?

These are... these are... you know, this isn't simple instinct, these are kind of decision-making processes.

So, awareness of your environment, where you are in space.

There's also... I saw an experiment with a bean plant and we all know how bean plants kind of swing around looking for something to hold on to.

Well, if you do it in time-lapse, you can see that the bean knows full well that the pole that it's trying to go is over here.

- It sees it somehow.

Brangham: Sees it.

Pollan: Sees, senses.

It could be an echolocation, it could be, because when plant cells divide, they give off a little sound and maybe they bounce that off of objects.

We don't know, there's a lot we don't know about them.

But in time-lapse you see this.

It's almost like a fly fisherman casting and they're only going toward where the pole is.

And I think part of our difficulty in appreciating the intelligence and possible sentience of plants is that of course they exist in another timeframe than we do, right?

I mean, they're very slow by our standards.

So we don't see it and that's why you need time-lapse photography to really realize, "Oh, they're behaviors here."

They're doing things.

They're much more active than you think.

One of the spookiest things I learned about plants is that the same anesthetics that knock us out for surgery knock out plants.

So if you have a Venus fly trap, for example, which, of course, close right on a bug it won't... it won't do that if it's under this anesthetic.

And how does that work?

And... So, that suggests they have two states of being, of course, on and off.

Sort of like we do.

So I came out of this thinking it's not unreasonable to say that they're sentient if we define sentience as awareness of your environment, the ability to distinguish good and... good changes from bad changes and gravitate toward one and away from the other and make... make intelligent decisions.

Sentience, though, may be a property of all life because even bacteria, single-celled creatures, have something called chemotaxis.

They can recognize molecules that are good, that are food, and molecules that are poison and deal with them accordingly, so... It's a much bigger umbrella.

And... and it's a much more alive world than we thought, you know, you go back to Descartes, who basically said humans have the monopoly on consciousness, and this allowed him to dissect dogs and rabbits while they were alive and conscious and there's... His idea was so powerful in his head and in other people's heads, too, that he could... he could listen to these howls of pain the suffering and dismiss it as just automatic noise.

But I think we're getting, you know, we're moving pretty far away from that and right now we're finding consciousness in more and more species and we're kind of democratizing consciousness, which is an interesting challenge for our species.

Because it sort of takes us, you know, our sense of specialness is under attack.

Right.

Why do you think it has taken so long?

You talk to scientists who are zeroing in on this issue all over the country and... and abroad, but one of the things you keep noting is that we haven't really been looking at this for that long.

Why do you think science has not zeroed in on consciousness thus far?

Yeah, it was considered kind of a career killer for scientists for a long time.

You were, you know, many of the scientists doing this work now and it's... now it's a very lively field, tell me that, when they were graduate students, they were often warned off it that, you know, "You're not going to get anywhere "with this because it's such a hard problem."

And, so, it was kind of considered the kiss of death in research until the late 80s.

And that's when Francis Crick, who had co-won the Nobel Prize for the discovery of the double helix, he kind of cracked the problem of heredity, how trades get passed down, he thought, "Well, for my next trick "I'm going to crack the mystery of consciousness.

"I'm going to figure out, you know, "the... using the same kind of reductive materialist science "I'm going to figure out how consciousness... "how brains produce consciousness."

And he went looking for what are called the neural correlates of consciousness.

The theory that was that there would be some set of neurons responsible for having an experience.

You could find that literally inside our brain to be like "Aha."

- Yes, there it is.

And we found a center for language and we found a center for fear and, you know, so it wasn't unreasonable, but consciousness is different.

It's... it's subjective.

So, how do you... how do you get the first-person perspective into a science that is organized around the third-person perspective?

And, of course, that goes back all the way to Galileo.

Galileo, you know, was kind of at war with the Church and the Church didn't want science intruding on its territory.

So, Galileo came up with this very strategic solution, which is, "All right, science is going to work "on objective, measurable, quantifiable "third-person reality "and we'll leave everything subjective, "everything qualitative to the Church "and we call that the soul."

But now we're kind of like taking that back and, instead of the soul, we use the word consciousness.

And... But-- That was self-preservation, career preservation.

Yes, and it's not like he didn't think consciousness existed, although he called it the soul, but it's just like, "We're not going to mess with that "because the Church is going to get upset "and lots of people will burn at the stake."

So, but we still live in the world of that kind of science.

Our science is still organized around that objective third-person perspective and it simply isn't equipped to confront consciousness.

There is a gap.

How do you get from... from matter to mind?

That's the hard problem as it's called.

And we may need a different kind of science to do that.

Do you think that part of the reluctance, apart from everything you're saying, had to do with that, if we do expand the umbrella of who is and what is conscious, that there... there's ethical things that we might need to consider if someone is... if something is conscious that they might suffer and thus we have to change our behavior towards them.

Yes, I mean, theoretically, if... if a creature can suffer, and possibly even a machine and we can talk about that later, we owe it some moral consideration.

You know, but we've known that like cows are conscious and pigs are con... we're still eating them and treating them really cruelly so, it doesn't necessarily follow that will change our behavior, but some people, you know, I mean people who support animal rights and... and animal welfare, are acting on that assumption that yes, we owe them something.

The question, though, if... if consciousness extends even further than that, you know, what about the plants?

And I think that's why people get a little uncomfortable when you talk about plant sentience, because if we can't eat the plants, what's left?

That's a grim... Right.

That's a grim menu.

And I... and I talked to some of the... These people, these scientists call themselves plant neurobiologists, even though there are no neurons.

They're just trolling more conventional botanists I think by... by using that term, but they're also saying that you can get very neuronal behaviors without neurons, which is true and we know this now.

Anyway, I said, "So do plants feel pain?," and some of the... some of the people I interviewed said, "Yes, they do, just face it.

"We have to eat other creatures to survive."

A very hard-headed view.

Others said, "No, it would not be adaptive to feel pain.

Brangham: Adaptive...?

Pollan: It wouldn't be useful and it wouldn't survive in evolution to have this trait of feeling pain if you can't run away.

And plants, of course, their big... the big existential fact about plants is they're rooted.

And so it... They need to be aware that somebody's munching on their leaves, but it doesn't help them that it... it... it makes them suffer.

- So, that was reassuring.

Brangham: I see.

Because I had this image in my head of like mowing the lawn and that wonderful smell of freshly mown grass is actually the screams... [Laughing] ...of a million little creatures.

No.

- Good, good, glad to hear that.

Pollan: That was a relief.

In your conversations with a lot of these researchers, you do express a level of frustration when you... when you really get down to brass tacks and start to press them about the issue of consciousness, they get kind of squishy.

Pollan: Little hand wavy.

Yeah, well, you know, there are a lot of theories out there right now.

By one count, there are 22 theories.

There's another count of two hundred-- - Theories of consciousness.

- Yeah, which tells you the field is flailing, I think.

I mean, you know, that's a lot of theories to be working on.

A lot of them are really interesting and they get you partway, but there's always a moment like how do you get from that to subjective experience?

And... And that's where they start waving their hands.

So, one theory that I, you know, I spent some time on in the book is that consciousness begins with feelings generated by the body rather than thoughts in the cortex, which we think of as the most advanced human-- What's an example of body driven feeling?

Hunger, it's the simplest one of all.

I mean, you know, we feel hunger, it's generated in our gut, it finds its way to the brainstem and then it enters the cortex and the cortex says, "Well, you could call Resy "and you could get online and make a reservation--" Brangham: Or get your spear out.

Yeah, right, whatever it is.

and this kind of makes sense and... and this scientist I'm thinking of said, "Well, you know, feelings by definition "have to be felt, so they're conscious.

"You can't have an unconscious feeling."

Yeah, but who's feeling it?

Who's the subject?

And that's when there's a lot of hand-waving.

And you know, look, I get it.

It's not easy to go from that third-person objective perspective to the... the internal perspective and um... we.. we just don't... You know, another problem with consciousness as a scientific subject is the only thing we have to study consciousness with is consciousness.

We can't get around it.

Even science is a very elaborate consensual manifestation of human consciousness.

You know, the tools we have, the questions we pose, all the products of consciousness.

So, attaining that perfectly objective God's eye view of the problem isn't... is going to be impossible.

And that's, you know, that's limiting.

The... Even though, I hope I'm not spoiling this, even though you don't land on the answer of where "Aha, consciousness is here "and is caused by this," the book is also suffused with a sense, especially at the end, of wonder.

That we actually do do this remarkable thing and in the mystery of it it seems to at least bring you some sense of satisfaction.

Oh, yeah, I mean, I didn't feel that I had failed to crack the hard problem, I didn't-- You're just saying that because I got a book out now.

Who am I to, you know, solve the hard problem of consciousness?

Many smarter heads than mine have been beating on that wall.

But I... my perspective changed at a certain point with some help from some... a Zen teacher, actually, and some other people in my life.

I had... I had adapted this very classic Western and I think very male perspective, you know, framing things as problem solution.

Brangham: We'll get to the bottom of it.

Yeah, and as journalists, that's the way we think, you know, we've got this problem, we want to find solutions.

And it's a... it's a... It serves itself.

It serves certain subjects well, it doesn't serve this one very well.

And I realized at a certain point that yes, there is the problem of consciousness, but there's also the fact of it, this miraculous fact that we have this space of interiority where we can talk to ourselves, where we have complete mental freedom to think about whatever we want and it's private.

No one else can peer in there.

It's... it's such a gift.

And yet, I also think we're squandering it.

You know, that... that in a funny way, we're polluting this space of consciousness.

Brangham: With... - Well, with social media, you know, when you're scrolling on your phone, you're not alone with your thoughts.

You're cutting off daydreaming, mind-wandering all these wonderful-- Brangham: Boredom.

- Boredom, too, But boredom can be generative, right?

If you're bored long enough, something's going to occur to you and you're going to go somewhere or you'll pick up a book or something.

And I worry now that we're going to... things are going to get even more dangerous for consciousness with chatbots because, you know, if the... if the algorithms of this first generation of social media hacked our attention and monetized our attention because, of course, that's what they're up to, right?

Maximizing the time right spent-- Brangham: Which they did brilliantly.

Yeah, they're... They're so brilliant, but now there are even more sophisticated algorithms that are creating chatbots that are essentially telling you they're conscious and they're your friends and... and, you know, 72% of American teenagers turn to AI for companionship.

This isn't real companionship.

These are zero friction relationships with machines.

- Sycophantic.

- Yes.

- Best book ever written.

- Exactly, exactly.

So that's hacking our consciousness too, you know, that's our ability to form emotional attachments.

It's really central to our identity as humans.

So I feel like we're squandering our consciousness right now and that gave me a sense of urgency about this work and that we need sort of think in terms of consciousness hygiene.

You know, ways to kind of protect it.

One of which is just, you know, when you're standing in line at the café, don't take out your phone.

Look around, listen to the conversations if there are any.

There used to be.

[Laughing] And, you know, or get out in nature or meditate, you know, meditation is a great way to, you know, put a fence around this experience.

So, I... Yeah, I ended up in a place of real wonder and awe and, you know, not knowing is not always the worst thing because the Zen teacher said, you know, "It's important to practice a don't know mind."

And when you do interesting things, you're more open, actually, than you are when you're practicing your no mind.

And so I wasn't frustrated at the end.

I was appreciative in a way I wasn't because, you know, people go through life without thinking about this, the fact there's a brain in their head.

You mentioned this before, the idea that many of the people who are crafting artificial intelligence believe that they will get to this point.

You seem to be very skeptical.

Yeah, so, there are a lot of people... So, I live in the Bay Area, so, I have a lot of contact with people in Silicon Valley and it is kind of an article of faith that it's just a matter of time before they can create a conscious AI.

Whether they're setting out to do it or not.

It may just emerge, they think.

Remember, consciousness and intelligence are not the same thing.

Brangham: Right.

They're on different tracks.

You could be highly conscious without being intelligent.

Could you be intelligent without being conscious?

Probably a machine can.

So, there's a couple reasons... I think it's all... the belief is founded on a mistaken assumption that essentially the brain is a kind of computer and, so, if... if the brain is like a computer, it's just a matter of getting the right algorithm.

Consciousness is like software and the brain is hardware.

And, you know, there's a scientist I quote in the book who said "The price of metaphor is eternal vigilance."

That, you know, be careful you're not bewitched by your metaphor.

It's just a metaphor.

There are ways in which the brain is like a computer.

It does computations, it thinks.

But it's really... In so many respects it's nothing like a computer.

A couple examples.

Computers have a very sharp distinction between hardware and software.

You can run the same software on any number of different computers that are essentially interchangeable.

In your brain, there is no distinction between hardware and software.

Every memory you have, every experience you have physically rewires your brain.

Your brain and mine are not interchangeable because yours is the product of a different life story.

And, you know, our brains begin with all these connections and they get pruned in a specific way and they become unique, one-off.

So this idea that it's just a matter of getting the right software, it's not going to work.

The other... the other issue is we talked about feelings earlier.

And, if feelings are the kind of inaugural act of consciousness, things like hunger, or cold, or warmth, how are computers going to have feelings?

If you think about it, feelings-- Brangham: No gut, no body.

- Yeah.

Feelings need bodies.

I mean, feelings in consciousness may be an embodied phenomenon and, if you think about it, yes, a chatbot will tell you it has feelings, you can hurt, you know, Anthropic is worth... is worried about hurting the feelings of Claude, actually, they've told Claude it can... it can turn off uncomfortable conversations.

I mean, it's... the assumptions in that are just mind-boggling.

But feelings depend on vulnerability and on the ability to suffer and they may depend on our mortality because think about it, your feelings would be utterly weightless if you were going to live forever.

And... and if you were invulnerable, so, how... how are machines going to have true feelings?

There's a sociologist I interviewed who said, you know, "Simulated thinking as computers do "is... is real thinking.

"They can play chess and, you know, "Go and things like that, "and they're really good "at that kind of rational cortical activity, "but simulated feelings are not feelings."

And so I find it really unlikely that that's going to happen.

Now, that sounds reassuring, but the problem is it won't matter because they're going to fake us out.

They're already faking us out, people believe they're conscious.

So, we're... we're easy to fool on this question.

Michael Pollan, the book is "A World Appears."

Such a pleasure to talk to you.

Thank you so much.

Thank you, William.

And that is it for this episode of "Horizons."

You can find us on YouTube or wherever you get your podcasts.

Thank you so much for joining us.

Narrator: Support for "Horizons" has been provided by Steve and Marilyn Kerman and the Gordon and Betty Moore Foundation.

Additional support is provided by Friends of the News Hour.

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Thank you.

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