Andrea Miller: What is consciousness? In what way is the soul a good definition for it, and in what way is it not?
Michael Pollan: Consciousness and the soul have an old relationship. The people who talk about the soul are often doing it in a religious context, and it has supernatural implications that consciousness doesn’t always have. But soul talk has infiltrated consciousness talk in lots of interesting ways. Consciousness is sort of the modern substitute for the soul.
My definition is very simple. Consciousness is awareness. Experience is another good definition. And [American philosopher] Thomas Nagel came up with a definition or formulation back in the seventies that a lot of people in the field still rely on. He wrote a famous essay called, “What Is It Like to Be a Bat?” His conclusion is, if it’s like anything to be a bat—if we can imagine that a bat has experience, and that that experience has some qualities of any kind—then that bat is conscious. So, your toaster doesn’t have that quality of what-it-is-likeness, but your cat or dog may well. And, in fact, I think your plants may well.
What does the Buddhist concept of no-self teach us about consciousness?
No-self is really significant for consciousness research. [In the West,] there has been an assumption that the self and consciousness are very closely allied and that when you lose your self or your ego, there’s nothing left. What Buddhism teaches is that there is still something left. There is still consciousness. It doesn’t depend on a self. And I think the research bears that out.
There’s an interesting book written by a German philosopher named Thomas Metzinger, who’s a big meditator. He’s collected thousands of examples of people describing consciousness without a self, and he points out that we all experience it every morning when we wake up. In the first milliseconds before our self reconsolidates and we realize who we are and where we are and what time it is, there’s a moment of selflessness. We all have this experience. The other way we have it, of course, is on psychedelics.
My book How to Change Your Mind was about that. I’ve had psychedelic experiences in which the self was completely dissolved, but I was still conscious.
[Scottish philosopher] David Hume said something very similar back in the 1700s. He said, “I went looking for the self in my mind, and all I found there were perceptions and thoughts and feelings and emotions, but no perceiver of those perceptions, no feeler of those feelings.” And he raised questions as to whether the self was a real thing. Indeed, if you do go looking for the self, good luck. You’re not going to find it.
This passage in Hume is incredibly Buddhist-sounding, though it came before anyone in the West knew what Buddhism was. But one researcher suggested that Hume might have come in contact with Buddhist ideas. Hume did some work at a college in France, where a missionary who had been to Asia had written and left a treatise about Buddhism. So, it may be that Hume was exposed to it there.
You wrote in your new book, A World Appears: A Journey into Consciousness, “Why do we cling to the idea of a self, placing great value on self-confidence and self-esteem, while simultaneously spending so much effort on self-transcendence, whether through meditation or psychedelics or experiences of art, awe, and flow?” What answer to that question can you offer?
I think the question is as important as the answer—just pointing out this paradox. In a society as complex as ours, you need a self as a unit of social currency. I need to assume you have a self that I’m addressing right now, and likewise, you’re assuming I have one that you’re addressing.
Selves are very useful. Ego, which to me is a synonym for the self, is very useful. It got my book written, and it gets your magazine produced. It drives us in various ways. It’s kind of the unit of social life and the unit of evolution; we act as selves in terms of survival and reproduction.
On the other hand, the self is also the source of great suffering. Our selves can be injured. People can hurt our feelings. We get banged around a lot. Our ego also can assail us with doubts, with rumination, with the critical voice. It internalizes judgment. So, we’re also very happy to get away from it. And we do all sorts of things to shrink the self.
When we shrink or lose our selves, we become more connected to other things. Dacher Keltner, who’s a colleague of mine and a psychologist here at Berkeley, has done these experiments where he studies awe. He has people draw themselves as a stick figure, then gives them an experience of awe, like beautiful footage of Yosemite or something like that. Then he has them draw themselves again, and they draw themselves at like half the size. So, awe is a very collective, prosocial emotion that diminishes our sense of self as a separate entity.
What is the relationship between consciousness and the brain, and is it possible for something that doesn’t have a brain to have consciousness?
Possibly. The default position in the scientific world for many years has been that brains surely produce consciousness—that consciousness is an emergent property of neurons arranged in a certain way.
We have found no evidence that this is the case. The search for what are called the “neural correlates of consciousness” has really come up empty, so that has opened people to more mystical ideas of consciousness—that perhaps it comes from outside us and that what our brains do is not generate consciousness but channel it. They’re like radio receivers. That’s one whole theory of consciousness.
The brain is obviously involved. If you knock out the brain, you can knock out consciousness, and you can change consciousness by changing the brain, as we do with psychedelic drugs and other kinds of drugs, too. But to go from that to the idea that consciousness is a production of brains, you can’t do that. No one has really succeeded in showing that.
What you’re describing is how you get from brains to minds. It is a hard problem, because we don’t really have the best tools. Our scientific tools were designed for the objective, measurable world. And consciousness, by definition, by its nature, is subjective. We don’t have very good tools, at least in the physical sciences, for studying things that are subjective, getting into the mind of any other person.
So, there are a lot of theories. One paper I read said there are twenty-two different theories of consciousness, which should tell you that we’re kind of lost and that we may have to content ourselves with not knowing exactly how brains produce consciousness, if they produce consciousness.
This brick wall we’ve run up against has led to some unconventional theories. I mentioned one—the radio receiver theory. It’s called a “transmission theory” of consciousness.
But there are others, like panpsychism that argues that everything—all matter, all particles—has some teensy-weensy bit of consciousness, that even particles have experience, and that somehow the experience of these great many little bits and pieces combines to create the kind of consciousness we have. It’s not that those particles have interiority or anything, but they have the building blocks of consciousness. This theory certainly solves the problem [of how consciousness is created] but at a pretty high price: You’re adding a whole new physical law. But we’ve done that before. How long ago was it that we didn’t know about electromagnetism, the fact that there are all these waves in the air that can carry information? That’s pretty mind-blowing, too.
I understand that we can’t pinpoint a part of the brain where consciousness exists. But why couldn’t it exist throughout it?
It could. The more we understand the brain, the more we see that there are some discrete areas that have specific jobs. There’s a language center, for example. There are memory centers. So, it’s possible that consciousness could be a networked effect.
This is a theory called “integrated information theory,” which is one of the leading but pretty controversial theories of consciousness. The idea is that if you arrange neurons, or even something like transistors, in a sufficiently intricate, recursive way, with lots of feedback loops, that system could be conscious, whether it’s a brain or something else.
How do we prove this? It’s very hard. The theory predicts that a part of the brain with the proper wiring should be active when something becomes conscious to us. There have been studies looking for that, and the results are equivocal. Honestly, we’re kind of lost in this quest.
Do you think that AI could become conscious?
Many people do, especially many people here in Silicon Valley near where I live. But that belief is based on what I think is a faulty assumption—that brains are computers.
We go through history, and we always think, whatever the cool new technology is, that’s the right metaphor for the brain. So, in Renaissance times, it was the clock, and then for a while it was the loom, because looms were very high tech. And it was a mill, you know, a grinding mill, and now it’s the computer. It sounds superficially correct—we know that the brain does do computations. Neurons fire or don’t fire the way transistors can fire or not fire. They’re binary like that. But if you think about the metaphor, it falls apart completely.
The key to computers is that there is a firm distinction between hardware and software. The beauty of that is that you can run many different programs on the same hardware, and when the hardware dies, the software can live somewhere else. The belief is that consciousness is essentially software. It’s kind of an algorithm.
But look more closely, and you realize that, in brains, there’s no distinction between hardware and software. Every memory corresponds to a physical pattern of neurons connected in a certain way. Also, in addition to being on or off, neurons are influenced not just by electricity, but by chemicals. Hormones, neurotransmitters, drugs—all these different things affect neurons and whether they fire or not and how strongly they fire. There’s just a bath of chemistry involved as well. So, this easy analogizing between brains and computers doesn’t hold up.
If you talk to the people who think that consciousness can be created in a machine, what they all have in common is a belief that consciousness is a matter of computation, and just like software, it can be run on different substrates. I could be proved wrong, but I don’t think so.
The other problem I have with the idea of conscious AI is that there’s a lot of reason to believe that consciousness begins with feelings rather than thoughts and that feelings are a particular kind of thought, but they’re very based in the body. There’s research that suggests that consciousness, to the extent it begins anywhere, begins in the brain stem. It’s the body sending information to the brain in the form of feelings to tell the brain, “We need to eat, we need to get warmer, we need to sleep.” The idea that consciousness starts with feelings makes a lot of sense. And feelings really have no weight unless you’re vulnerable, unless you can suffer, unless you’re mortal, and I don’t think computers are or will be those things anytime soon.
Can you say more about blind spots that Western science has about consciousness and how these blind spots have affected the way we see the world and interact with it?
The main one is this metaphysical assumption that everything is or can be reduced to matter.
It’s very hard to reduce consciousness to matter. It’s very hard to reduce a poem to matter once it’s circulated in the minds of humans. I mean, yes, there’s the poem on the piece of paper, but a great poem exists in another realm, and it’s real. Mathematical formulae and ideas are real. They’re not matter. So, I think we have to expand our sense of what the universe is made of.
What about consciousness? What is that? It’s confounding in a way that’s very healthy. I don’t think it’s bad to have mystery.
The other problem with studying consciousness is that the only tool we have to study consciousness is consciousness. The world we behold is very much the product of our particular senses, the frequencies of sound and light that we can see, and the dimension of time in which we live, which has something to do with our mortality and how long we live. Compare us to plants—you have to speed them up with time-lapse photography to see that they’re actually pretty active, but they live in a different dimension of time than we do. Consciousness could be substantially different for different kinds of creatures. So, I think we have to realize that we can’t get outside consciousness to study it. And that’s a problem. If objective measurement is the goal, from what vantage do you study consciousness? Any vantage you pick is a product of consciousness.
Are plants sentient beings? How can we know whether they’re sentient or not?
Well, we can’t know whether each other is sentient or conscious. We kind of infer it based on behavior and likelihood, since we’re made of the same stuff, we’re the same species. But it gets harder and harder the further away from humans and primates you go.
And plants are an interesting case that forces you to refine your terms. I make a sharp distinction between sentience and consciousness.
I see sentience as the most basic form of consciousness. I think consciousness probably begins with sentience. Sentience I define as the faculty of sensing your environment, as the word implies, but also having a sense of what is a positive valence and a negative valence—that this is good for you, this is bad for you—and having some agency, some ability to move toward the good and away from the bad. That’s sentience. There’s a kind of primitive experience there and a primitive awareness. But there’s no self-consciousness. There’s none of the bells and whistles we have, but it’s very important.
I would argue that everything alive has sentience. I think it needs it to survive. It’s very hard to automate everything in a world where things are changing so quickly. I don’t think you survive evolution if everything you do is automated. I think you have to be a problem-solving machine to some extent to survive, and that’s what evolution gives us. So, that’s sentience.
Plants have one way of doing sentience, very much involving their mastery of biochemistry. They’re very sensitive to chemicals. They smell. If something’s threatening them, they use smell. They have these volatile chemicals they release, sometimes to summon a predator insect to take care of another insect problem. They have like twenty different senses.
They can hear, in some way we don’t understand, some kind of echolocation. A plant root will seek out a pipe in which there is running water, even though the pipe is not wet—there’s no condensation, no water between it and the pipe. Presumably, it’s hearing the vibrations of water passing through it. Also, if you play the sound of caterpillars chomping on leaves next to a plant, it will produce chemicals that change its taste and make it less appetizing to a caterpillar.
They can see. They know when they’re being shaded and take steps to deal with it. There’s a lot of mystery about how plants do what they do. Plants have memories. Plants show that you can, in some sense, be a cognitive being without a brain. So, that raises significant questions. Can you be sentient without a brain? I would say you can. Can you be conscious without a brain? Maybe not.
Consciousness is the way that the primates and higher vertebrates do sentience. We do it differently from plants. It would not be of any benefit to a plant to have self-consciousness or interiority. So, their energy went into making chemicals and reading chemicals. For us, who are very social beings, who depend on other people for our survival, consciousness is very useful in that it allows us to read minds and converse. We have a theory of mind. So, I can anticipate what you might say, and you can anticipate what I might say, and then when we’re surprised, we know how to deal with that. It would be very hard to automate human social interaction.
Let’s talk more about animals. What are the most recent discoveries about animal consciousness?
There was something called the Cambridge Declaration of Consciousness in 2012 where a bunch of animal scientists got together, and they said, it appears to be likely that all mammals and birds, as well as many other animals, including octopuses, are conscious. Later, experts went much further. They said, insects and possibly insects and other invertebrates are also conscious.
So, as time goes on, we’re going further and further down the evolutionary tree and finding consciousness. We’ve come a long way from René Descartes, who basically said humans have a monopoly on consciousness. He was constantly dissecting animals without anesthesia, interpreting their cries as just automatic sounds that don’t connote any kind of awareness or consciousness.
So, we’ve come from “we are the only conscious being” to “we are one of many, many conscious beings,” but it would be arrogant to say that everybody’s consciousness is like ours. And then the question is, what are the implications? Do you have to extend moral consideration to any being that’s conscious? I don’t know. That would leave us with a lot less to eat.
I was going to ask you about the moral considerations.
I do think we have ethical obligations to creatures we can see suffer. This is an idea that goes back to [English philosopher] Jeremy Bentham. It’s a good place to draw the line, and it is a definition of consciousness some people have, which is that a conscious being is one that can suffer. It’s not a bad definition.
It implies feelings, as I was talking about earlier, but it also implies there’s a difference between pain and suffering. Pain is very direct, in the moment, physiological. Suffering can have a whole other dimension. When we’re in serious pain, we know we can die in a way that other animals don’t, and I think that that increases suffering. You add fear to pain.
If you draw the line at all sentient beings—that you shouldn’t eat them—then you’re left with salt, as far as I’m concerned. One of the reasons people get very nervous about this idea of plant sentience is that it raises issues about their diet.
I looked at this question: “Do plants feel pain?” And I talked to two different scientists. One said yes, you gotta man up and face the fact that these plants you’re eating are suffering or feeling pain. And the other said, no, pain makes no sense if you can’t run away. There’s no good reason to evolve pain. Plants are aware of what’s happening when somebody’s chomping on their leaves, but it doesn’t hurt them in the sense we understand.
You’re a meditator. What has meditation taught you about consciousness?
Meditation is one of the reasons that I got interested in consciousness. One of the things that happen in meditation is that you look at your own consciousness and you get a sense of just how strange and uncontrollable the mind is. You have thoughts that come from nowhere that you didn’t decide to think. Images come from nowhere.
So, meditation has a way of defamiliarizing consciousness. You see it in all its strangeness, and I think it acquaints you with some mysteries of the mind that you’ll want to unpack. It also becomes an investigation of the self, if you’re meditating seriously. I have a meditation teacher who sometimes says, “Go look for your self. Go look for the thinker of your thoughts. Go look for the one who feels the discomfort you feel sitting on the cushion after an hour. Who is that?” You can’t find it, so it’s a very interesting exploration.
There were two inspirations for this new book, A World Appears. One was my experience meditating, and the other was my experience with psychedelics. Psychedelics also smudge the windshield through which we usually perceive the world and make us realize that there is a windshield and that it’s this way and not that way, and that you can change it—the drugs change it somehow. That too raises all sorts of questions about consciousness.
I see meditation and psychedelics as very closely related. Both are meditative states of different kinds. Both take us out of the present world and deep into our own minds. Meditation has been very important to my education about consciousness.
