The Fragility of Our Reality: A Conversation with the Brain Behind PBS Miniseries on Neuroscience

David Eagleman holding a brain

When you get down to it, neuroscience is just brains studying brains. One upshot of this reflexivity is a funny kind of loop: studying the brain tells you about being a self; being a self offers up questions about the brain. More, perhaps, than participants in any other scientific field, neuroscientists can oscillate between the hard data of the physical world and the loftier questions of self and soul.

That kind of back-and-forth has been central to the career of David Eagleman, a neuroscientist at the Baylor College of Medicine. As an academic researcher, Eagleman has studied time perception, synesthesia, sensory input, and decision-making. But that more traditional work has included some less-than-traditional research techniques—Eagleman has dropped research subjects from a 150-foot-tall tower to study their time perception under duress—and some more wide-ranging intellectual explorations, including a popular study of the subconscious brain, a book about the internet, and an experimental novel, Sum, in which Eagleman imagines 40 possible versions of the afterlife.

This intellectual energy is on display in The Brain With Dr. David Eagleman, which premieres on PBS this week. Over the course of six hour-long episodes, Eagleman dives into issues of mind, identity, perception, and reality. Each episode is titled with a question: “What is reality?” “Who is in control?” “How do I decide”? What emerges is less authoritative tour than nod toward the unknown. Our experiences of reality are delicate, and conditioned by a brain that remains, to a large extent, unmapped: the terra incognita in our skulls.

Over the phone, Eagleman spoke with The Cubit about traumatic brain injuries, the idea of possibilianism, and the language we use to describe our brains.

This interview has been edited for clarity and length.

In The Brain, you do a good job of depicting the fragility of our experience of reality. Am I right to be a little scared by this instability?

[Laughs] Well, you know, it’s one of these things about knowing ourselves, right? We are so utterly dependent on the integrity of this three pounds of tissue in our skulls. When that changes, you change too. When it comes to these questions of who am I?, that’s got to be a part of our understanding. And yeah, it is a little scary, I agree.

We have this illusion of continuity, that we are a single individual that lasts through time. This is, of course, the very natural intuition that led to ideas about an immortal soul. But in fact we’re completely tied in to what’s happening with our brains. Any sort of discussion about the soul or something at the center of us has to be integrated with this clinical knowledge.

Plenty of philosophers have critiqued our perception of the self as an autonomous, continuous thing. Is it different when it’s science making the point, instead of philosophy?

I think science and philosophy do and should go hand in hand. What the science gives are very clear, stark examples that are, for better or worse, unarguable. When you walk down any standard neurology ward, and you look at patient after patient—at people who have had a stroke or a tumor or a traumatic brain injury—what you see is that they’ve changed. They can change entirely: their decision-making, their risk aversion, their personality, their capacity to name animals or see colors or understand music. That clarifies the whole picture about the relationship that we have with our brains. Philosophical arguments are always subject to debate, but the scientific observations just are what they are. 

You’re talking about the relationship that we have with our brains. Even in this conversation, we’re speaking of a self that’s distinct from the brain.

We’re linguistically limited. We don’t have, built in to our language, the right kind of tools to talk about this in a natural way. That reveals something even deeper, which is the strength of our intuitions about our conscious experience. I mean, it really feels like the you that wakes up in the morning is the one that’s in charge and driving the boat—and oh, by the way, you happen to own a spleen and a liver and lungs, and a brain also.

That’s such a powerful experience. Obviously our langauge just reflects that.

Neuroscience very quickly gets to these big questions: Who am I? What am I doing here? What is the self? Is there a soul? It seems to cut to these politically and culturally charged questions more than most other fields.

I feel very lucky about that, because if I were an expert in soil mechanics or something, my work would be important, but nobody would care about the questions I’m asking. What attracted me to this field is the centrality of the brain to our identities.

It’s interesting that you said that the questions it touches are charged. You’re right about that, and yet I hope in some circumstances that neurosciece will be exactly the thing to “uncharge” the question. If you can actually have a way of testing those questions, and coming to a conclusion, that releases the charge from the question.

Then it doesn’t have to be a hundred cultures raising swords against each other, because science is an international fellowship. This is one of the things that I love the most about science: in my lab or any lab, there are people there from all over the world. But they’re all there speaking exactly the same language. It’s a very clear set of rules about what flies and what doesn’t fly.

These are deep-seated cultural ideas about self and identity, though. I wonder if this is how evolutionary biologists were talking in, say, 1910, before evolution became such a full-blown cultural battleground.

I actually think one wouldn’t need neuroscience at all to notice some very basic things, such as that we all come to know and love and accept whatever our cultures pour into us. Part of the process of becoming a worldly adult is to recognize that, whatever you grow up with, you tend to think is the correct sort of answer.

You don’t have to be an anthropologist to realize that there’s not a blossoming of Islam in Springfield, Ohio, and there’s not a blossoming of Protestantism in Mecca. If there were one truth, you might expect that it would spread everywhere equally, but obviously it doesn’t. It’s all culturally conditioned.

It is the case that neuroscience is squarely in the middle of the arena in all these discussions, but I can imagine that a hundred years ago, before neuroscience was really a deal at all, it wouldn’t take much for one to realize the degree to which we’re culturally conditioned. That simple fact, I think, also discharges some of these questions.

So is neuroscience a way to codify that realization, or to understand it more deeply, or to give it context?

Part of what’s so stunning about neuroscience are the individual patient cases, where somebody gets a small amount of brain damage and it completely changes [some] aspect of their system of beliefs. Many people have had this in their family in one way or another, whether it’s their beloved grandparent who gets Alzheimer’s, or somebody that they know and love who gets a traumatic brain injury, or a tumor or a stroke.

It’s the more local version of what an anthropologist might realize: “Wow, we absorb our cultures.” What neuroscience offers is the closeup. “Okay, we absorb [knowledge] into our nervous systems, but boy, our nervous systems are fragile, and when they change a little bit, the identity changes with them.”

In the show, you emphasize the degree to which our experiences of reality are constructed inside our heads. But there are also these cultural or external ways to organize reality, too.

Einstein said that theory determines what we can see. What he meant, of course, is that when you step in any situation with some framework in your head, you’ll see certain details and you won’t see other details, because of what you’re looking for. Culture does this to us all the time: the things we notice, the ways we respond.

In terms of religion and cosmic belief, you’ve described yourself as a “possibilian.” What does that mean? How is that different from an atheist or an agnostic?

My personal view is that we know far too much at this particular moment in history to buy into the details of anybody’s particular religious story, and yet we know far too little to commit to a version of strict atheism, where we pretend like we have it all figured out, and that science gives us all the tools that we need to have a full understanding of what is going on in the enormous cosmos.

Possibilianism is an active exploration of different hypotheses. That’s what science is all about. The scientific temperament is a tolerance for holding multiple ideas in mind at the same time, and then gathering evidence to find support in favor of some of the ideas over others.

I just feel like the [question] Is there God or no God? is too limited for a modern discussion. My interest is in saying, “Well, how could we even get a sense of the structure of the possibility space, so that we can start trying to rule things in or out?” Sometimes what science does is open up new folds in the possibility space—new ideas that we hadn’t thought of.

The cosmos is so much more vast than we’re capable of wrapping our minds around, certainly in 2015, certainly in our brief lifetimes.

In Sum, you play these kind of cosmological games—what if an afterlike looked like this, or like this, or like this?

In some sense [Sum] is a possibilian manifesto. None of those stories were meant to be taken seriously, of course, but the serious part is the meta-message of the book, which is, “Hey, you know what, we can start shining a flashlight around this possibility space.” If I can sit down and make up 40 completely different versions [of the afterlife], then we could, as a community, make up many hundreds and thousands of versions of what might be going on. The important part is the exploration, instead of the pretense to certainty.

You have this philosophical commitment to possibility. But there are people trying to get specific moral messages out of neuroscience, too—specific statements about how we should live, how we should blame, and so forth. Is that going too far, or can these conclusions coexist with that openness to possibility?

I actually think it’s extremely important to figure out what we can learn, including in terms of morality and social policy, from neuroscience. I direct the Initiative on Neuroscience and Law, about the intersection of what happens with criminal justice and what we know from neuroscience.

Just as a quick example, one issue is our prison population has quadrulpled in this country, almost entirely because of the war on drugs. The issue about drug addiction is that the War on Drugs has always been attacking drug supply, but if you really want to have an impact on people whose lives are getting ruined by drugs, you have to understand drug demand, not supply, and that’s the brain of the addict.

There are [other] issues about juveniles and how you punish juveniles—their brains are really plastic. I think that it’s actually very important to leverage what we know in neuroscience to crafting social policy that’s more aligned with testable evidence.


Also on The Cubit: Why Science Needs Neurodiversity


  •' Jim Reed says:

    If neuroscience is brains studying brains, doesn’t that imply that the work at CERN is subatomic particles studying subatomic particles? (that would be both at the level of the machinery, and the theoretical physists working on explanations)

  •' Jim Reed says:

    I think he might be on to a key universal truth here:

    there’s not a blossoming of Islam in Springfield, Ohio, and there’s not a blossoming of Protestantism in Mecca. If there were one truth, you might expect that it would spread everywhere equally, but obviously it doesn’t. It’s all culturally conditioned.

    There are areas where there is one truth spread everywhere. Mathematics is the same around the world, and even going back in time. Electronics is the same. Computer programming and Windows development is the same in the US and India, and interchangable, even if English as the main language is not quite interchangable. Does this mean universal truth is real truth, and truths like Islam and Protestantism that vary from place to place are not real truth? Clearly those variable truths must be false in many places, and maybe they are false everywhere. Maybe only truths that societies around the world can agree on are really true. Maybe this is the key to global society taking the next step up the ladder of human development.

  •' Rmj says:

    “Philosophical arguments are always subject to debate, but the scientific observations just are what they are.”

    Which is why the observation that neutrinos had no mass has been replaced with the observation that the bulk of the mass of the universe is in neutrinos.

    Because scientific observations are always just what they are. Or something.

  •' nightgaunt says:

    That is brains studying sub atomic particles. It all goes through our brain and neurosystem first. With its built in delay and the limitations of perception we each are born with and attention shunning via bias. Both in the hard ware and filtered through our soft ware. However the brain is and isn’t mind. Mind is the play of electrical fields generated by our neurons firing in various changing coruscations of sequences an patterns in different parts of its structure as it functions. Some people get metaphysical there and call it “soul”. But you can’t have one without the other which ends that analogy.

  •' Jim Reed says:

    It is a collection of sub atomic particles, and it all starts there. If you could step back and look at it, the giant machinery is also a collection of particles, and therefore subatomic particles, and the measurements come out of it.

  •' Jim Reed says:

    The bulk of the mass of the universe is in dark matter. They do not yet know what that is.

  •' Rangiora says:

    I have a question. It’s serious for me, and I’d like only informed answers please. It’s the first question I’d ask Dr Eagleman if I met him.

    When I was a kid I had a small transistor radio. It picked up exactly three stations (this was in a remote part of NZ in the 1960s) One day I dropped it on the concrete floor of the shearing shed. Thereafer it picked up only two stations. What happened to the third station? Either it was housed in the part of the radio that was damaged on impact with the floor and stopped functioning, or the radio’s ability to transmit that particular frequency was impaired. Well, we all know the answer. So when neuroscientists say that memory, for instance, is housed in a specific part of the brain, and when that part of a particular brain is damaged it is said that the person has ‘lost’ their memory, how do we know that the memory doesn’t still exist (in the universal ‘cloud’, say, or the one and only Mind) and what has been lost is the person’s abillity to access it?

    We live in a physical world full of large, fast-moving objects armed with teeth and claws, and so our physical capabilities have evolved to cope with such immediate dangers and our perceptions are necessarily physical first so that we see ourselves as ‘housed inside our bodies’. This is a useful bias for surviving in a physical environment, but is it reality?

  •' Camera Obscura says:

    Oh, but no one has seen or defined what “dark matter” is, they’ve merely theorized it because their equations don’t come out right unless it’s there. But there isn’t any observation of it, or at least there hadn’t been the last time I looked. It’s not even really known to be there, though if, for some reason the equations go out of wack they’ll just create or uncreate dark matter or dark energy to make them balance again. Though, conisdering they’ve invented jillions of universes that’s a piece of cake made of dark matter and cooked with dark energy.

  •' Rangiora says:

    I have a book called ‘Fact and Faith’ by a scientist called Haldane, the early twentieth century equivalent of Richard Dawkins, in which he proves how science is superior and religion inferior because the first is based on fact and the second on mere faith. The irony of course is that scientists are the worst people in the world for confusing fact and faith, as they present articles of their faith (i.e. working hypotheses they’ve become emotionally attached to) to the public relying on their scientific credentials to cause the public to believe they are facts.

  •' Jim Reed says:

    The good thing about science is they are making progress. So far religion hasn’t made any.

  •' Jim Reed says:


  •' Camera Obscura says:

    If Haldane said that science was based on fact, he was remarkably ignorant of the epistemological basis of science.

    The fact that published science, science which is accepted by scientists as science, taught and built on by other scientists but which, then, is overturned is a definitive refutation that that idea.

    Haldane was an atheist nut case as well as an accomplished scientists, who was an ardent Stalinist in the worst years of Stalin’s rule, one who refused to speak out against the oppression of his fellow geneticists in the Soviet Union who were being murdered for refusing to tow the Lysenkoist line that Stalin had deemed was scientifically correct. Scientists in the Soviet Union, in the countries it occupied after WWII, China and elsewhere held that Lysenkoism was science, though other scientists said it was nonsense.

    What I doubt Haldane knew much about, as well, was religion which, as a typical Brit-atheist, he discounted as worth his time to study.

  •' Jim Reed says:

    Is there God or no God? is too limited for a modern discussion. My interest is in saying, “Well, how could we even get a sense of the structure of the possibility space, so that we can start trying to rule things in or out?”

    There might be a better question you could ask if you want to start ruling things in or out. The God question might be a way to hide from the issues. The right question to ask here might be is there a real Jesus or not? This question is key because it is central to 95 or 99% of our religion here in America. If we can establish there is no Jesus, the consequences are immense for us, and the fallout probably goes beyond what we could even imagine at the moment because the response might even spread from Christianity to other religions. Avoiding this question would probably mean you don’t really want to start ruling things in or out. I could see how a lot of people wouldn’t want to because it is such a sensative area. On the other hand, it is a question that can’t be avoided for long because the question is now out there, and it is not going away. The question you probably have to ask yourself is do you want to get involved in this question before the shit hits the fan, or after.

  •' Judith Maxfield says:

    This read seems to rule out what R. Dawkins defines as science; that you can’t study as science questions regarding the “why” or meaning of human activity beyond chemical presence in the body. I’m quesy over the title description of neuro”science”. What gives? Would love to know how Dawkins would reply to this one.

  •' andrew123456789 says:

    I’m not convinced that neuroscience renders the “immortal soul” or “separate self” illogical or a necessarily false thing. That science has no explanation for something does not render that something untrue.

  •' Camera Obscura says:

    Yeah, geology leads to global warming, physics leads to nuclear weapons and pollution, a mix of chemistry and GMO leads to things like the collapse of honey bees…. Yeah, real progress.

    Science can make absolutely no progress in getting people to behave morally because science was exempted from doing that. It can’t do much but deny that things like morality are real and there is a moral requirement to act morally. Even though the continued existence of human beings depends on that, science can’t even come up with a reason some scientist shouldn’t create a virus or a bomb that would kill us all.

    You have a ridiculously romantic, 19th century view of science that wasn’t even accurate in the 19th century. It is PR not fact.

  •' Jim Reed says:

    That is true. But the fact that the immortal soul is total speculation by religions that are just trying to give people something to believe and create value by offering them eternal life when they have nothing to offer, that makes it seem unlikely. Of course since the religions are not based on anything factual, you can’t know for sure, even if the God they invent is crazy from any logical way of looking at it.

  •' andrew123456789 says:

    I don’t buy into this way of thinking, because it assumes that the scientific way of determining logic and fact is the only valid way. I do place credence in things like intuition and direct mystical experience. Yes, some of it is invention, but the strokes you paint with here are simply too broad.

  •' Jim Reed says:

    The point of the scientific way is it can be the only valid way. The alternative is to assume you don’t need science because you can work with intuition or direct mystical experience. We had those before, and science came along because those others were leading in bad directions.

    Perhaps we should compromise and say science is the only valid way to determine truth, but intuition can be an alternate way to determine mystical experience.

  •' Rangiora says:

    Thanks for your attempt at answering , but I can’t have made myself clear: I wrote ‘informed answers’.

  •' Jim Reed says:

    When you were a kid, there were a lot more stations than the three you could pick up. The reason is the others were farther away, out of your range. When you dropped your radio it got a little bit misadjusted, and the range that you could pick up might have dropped to where you had only 2 stations left in your range.

    When you post on RD, you can’t control what kind of answers your comment will get. It is a blessing and a curse.

  •' apotropoxy says:

    You seem to be confusing observation with the reality of what is observed. As new insight into reality takes place, the observation adapts to it. Religious belief holds a categorical rejection of reality when it contradicts doctrine. Change in doctrine can take a VERY long time.

  •' Rangiora says:

    We’ve had these jousts before and I’m fine with them. You write ‘When you dropped your radio it got a little bit misadjusted’ so that it couldn’t acquire the same signals as previously. So if that’s the case with the radio why not with the brain? My point is, that a person can assume the brain is different to a radio in that it produces its output, or they can assume that the brain is the same as a radio in that its output passes through it from elsewhere, and these assumptions are equally rational and equally non-scientific. Unless a reader with scientific credentials can point me to hard evidence to support one or the other assumption.
    Unless you do so your bold assertion ‘Yes’ is merely a statement of faith.

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