A neuroscientist's search for the human essence

There’s a struggle going on inside the brain of David Eagleman for the soul of David Eagleman.

That is, there might be such a struggle if Eagleman’s brain believed that Eagleman had a soul, which he is not sure about. In fact, Eagleman’s brain is not completely sure that there is an Eagleman-beyond-Eagleman’s-brain at all, with or without a soul, whatever a soul might be.

Welcome to the world of “possibilian” neuroscientist and writer David Eagleman. You can find him in Houston mapping the brain’s circuitry and teaching classes at the Baylor College of Medicine. But Eagleman really lives in the space between what-is and what-if, between the facts we think we know and the fictions that illuminate what we don’t know.

Eagleman the scientist would love to rev up his high-tech neuroimaging machines to answer the enduring questions about the body and the soul. But Eagleman the writer knows that the machines can’t answer those questions.

So while he reports on the questions he can answer in scientific journals, he also ponders the what-ifs in books. His latest is Sum: Forty Tales from the Afterlives, a playful series of short philosophical imaginings of life after death. And, if things work out the way Eagleman hopes, he will fulfill his childhood dream of becoming the Carl Sagan of the brain, explaining the billions and billions of neurons in our head to a curious public. Like Sagan, the youthful Eagleman has both scientific expertise and a gift for translating complex ideas into everyday language.

Eagleman’s scientific and popular endeavors are part of the same creative project to deepen our understanding of a complex world. Science is always just storytelling. In the last 400 years, the earth has been pushed out of the center of the universe, Newtonian physics nudged by quantum mechanics—science marches on, with lots of “facts” left by the side of the road to rust.

Throw a stone into any contemporary university English department and you’ll hit at least one postmodern literary theorist who will talk about science as narrative. But it’s rare to hear it from a scientist who is as committed to the scientific project as Eagleman. Here’s someone running a lab with five high-test fMRI machines, 16 employees and a half-million-dollar annual budget. And it’s all just stories?

“I don’t want to say ‘just stories.’ These are the best stories we have on the planet,” he says. These are stories that cure disease and make space travel possible. The awareness that there is always a potentially game-changing discovery around the corner is, for Eagleman, the allure of science. “You go in because you think, ‘I want to kick over the whole fucking chessboard.’ That’s what makes a good scientist.”

In the spiritual realm, Eagleman rejects not only conventional religion but also the labels of agnostic or atheist. In their place, he has coined the term “possibilian”: those who “celebrate the vastness of our ignorance, are unwilling to commit to any particular made-up story and take pleasure in entertaining multiple hypotheses.”

Since scientists mostly talk about knowledge, Eagleman’s emphasis on ignorance is unusual. So it’s time for an analogy. Eagleman likes analogies.

The work of science is akin to building a pier out into the ocean, he says. We excitedly add on to the pier little by little, but then we look around and say, “Wait a minute, I’m at the end of the pier, but there’s a lot more out there.”

The ocean of what we don’t know always dwarfs what we do know, he says. “During our lifetimes, we will get further on that pier. We’ll understand more at the end of our lives than we do now, but it ain’t going to cover the ocean.”

Eagleman’s small office at Baylor offers no indication of what’s going on in his head; it’s a rather bland space, with little on the walls or the bookshelves. The collective lab space, however, is more eccentric. The whiteboard walls (which are actually a light blue) sport a kind of scientific graffiti—ideas for projects, questions about projects, lists of things to be done on projects—that reflects the serious but anarchic spirit of the lab. It’s clear that Eagleman’s possibilian sensibility affects the spirit of the place.

As he finishes up a task on the computer, he is calm and focused. But once Eagleman starts talking, things take off quickly. Swiveling 180 degrees in his chair, his foot pushing off the various pieces of office furniture to propel him around like a wind-up machine, his verbal velocity accelerates as he describes his ideas. Those range from the experiments he’s running to age-old philosophical questions about free will.

His first book, the co-authored Wednesday is Indigo Blue: Discovering the Brain of Synesthesia, explored the condition in which one sense, such as sight, is simultaneously perceived by another sense, such as hearing—“hearing a color,” for example. His third book, the forthcoming Dethronement: The Secret Life of the Unconscious Brain, explains for a general audience how the human brain constructs reality.

In between those two books came Sum, which spawned a theatrical adaptation staged at the Sydney Opera House in Australia with an original score written and performed by avant-garde musician-producer Brian Eno. Just out in paperback, the book’s speculative musings have captured the imagination of a small but lively group of people who claim the possibilian label, leading Eagleman to begin writing Why I’m a Possibilian.

In his thinking about religion, Eagleman takes seriously the old saying “the absence of proof isn’t the proof of absence.” Eagleman recognizes that people who don’t believe in God can never say with certainty that one doesn’t exist; he’s not trying to support or rule out any particular claim but simply suggesting that it’s healthy to imagine possibilities.

Sum is a series of 40 what ifs: What if there is an afterlife where we relive all of our experiences, but shuffled into a new order? What if in the afterlife we confront all the possible versions of our self that could have been? What if we experience death in stages: when the body stops functioning, when we’re buried, and the moment when our name is spoken for the last time?

The stories aren’t meant as serious proposals. They are merely vehicles for Eagleman’s ruminations on vexing philosophical questions. Eagleman’s most basic concern is the mind: Is there anything beyond the physical brain? If there is something beyond, is that what we should call the mind? What does all this mean for the concept of the soul?

These are the questions Eagleman wants to answer.

In the lab, Eagleman says that he and other neuroscientists work under the assumption that “you are nothing but your brain.” Many scientists and philosophers come close to suggesting that this is not an assumption but a fact. These scientists reduce the mental to the material. That could be the case, Eagleman says, but he’s not certain.

His first hesitation is standard; no one could really look at humans as “just a bunch of atoms, or just a bunch of neurons” because of a concept known as emergent properties. Here’s the classic example of that notion:

At room temperature, hydrogen and oxygen are gases. Combine one oxygen and two hydrogen atoms and you get water. Liquidity is an emergent property, which no chemist could have predicted by analyzing the individual atoms. The same can be said of us— we are made up of material components, but what’s interesting about humans are the emergent properties. Consciousness couldn’t be predicted from a list of the elements that make up each one of us.

Eagleman’s second hesitation is more intriguing, and it’s one he doesn’t typically discuss at scientific meetings. We shouldn’t presume, he says, that we know about all the pieces of the puzzle, or all the forces that structure the world in which we operate. Enter the possibilian.

“How do you put together a bunch of physical pieces and parts, and get private subjective experience out of that? How do you get the taste of feta cheese or the

redness of red or the feeling of pain?” he asks. Those questions suggest that scientists are missing giant pieces of the puzzle. In physics, it would be like trying to explain the universe without first understanding gravity.

“We’re stuck with this very deep problem, this 800-pound gorilla: If it’s all just mechanical stuff everywhere we look and if every part of the brain is connected to, and driven by, other parts of the brain, then where’s consciousness?”

For most folks, the answer might be, “Well, it’s in my mind.” But that begs the question: What is a mind?

Long before fMRI machines, philosophers have been debating these questions. David Sosa, a professor and chair of the philosophy department at the University of Texas at Austin, says materialists dominate the field these days. Sosa remains a dualist, believing that the mind and the brain, the mental and the physical, are different things. Sosa is respectful of the work of neuroscientists like Eagleman and agrees philosophers should be engaging their findings, but he’s unwilling to rush to judgment about this age-old question.

Eagleman shares that caution, but refuses to take sides, hence the term possibilian. He has no glib response to the question of consciousness. “There’s no equation that can give us the taste of feta cheese,” he says.

What could the missing pieces be?

Imagine people with no exposure to modern gadgets find a radio. They hear a human voice coming out, yet there’s no one speaking. They fiddle with the radio, remove the back cover, pull on a wire, and observe that the voice stops. They reconnect the wire, and the voice is back. They touch other parts and the voice changes. Not knowing about the electromagnetic spectrum, these tinkerers would be tempted to assume the voice is coming from the radio itself.

This is where the concept of emergent properties is important. It might be tempting to conclude that the voice is an emergent property of the radio, of the way the parts and pieces are arranged, but that would miss the invisible radio waves. “The physical integrity of the radio is necessary for its proper functioning, but it’s not about the physical thing. That’s just a receiver for things coming from elsewhere,” Eagleman explains.

It’s plausible, he concludes, that we could be waiting for the neuroscience equivalent of the law of gravitation, “whole new—I don’t even know what to call them—forces or dimensions or whatever. A hundred years from now people might say, ‘those poor assholes in the 21st century were trying to solve the consciousness problem and they didn’t even know about force X.’”

Eagleman is quick to make it clear he’s not saying there is a force X. He just wants to keep an open mind.

Growing up in Albuquerque, New Mexico, with a psychiatrist father and a biologist mother who both loved books, Eagleman recalls being “immersed in biology talk” while his father, who spoke eight languages, would routinely recite poetry and prose from memory. When he went off to college to major in literature at Rice University in Houston, he dabbled in space physics and engineering but avoided biology. His last biology class had been in the 10th grade, at which time he pronounced the subject “gross.” But late in his undergraduate career he found himself drawn to questions about the brain, and once he started reading he was hooked.

After doctoral work at the highly rated neuroscience program at the Baylor College of Medicine, he spent five years in San Diego at the Salk Institute. He returned to Texas to take a faculty job at the University of Texas Health Science Center at Houston, and three years ago Baylor lured him back.

Research assistant Elyse Aurbach, a Rice University grad, calls Eagleman and the lab “genuinely scientific.” Any idea that is intriguing is worth discussing, she says, no matter who proposes it. The emphasis is on innovation and collaboration. Don Vaughn was a high school student in San Diego when he met Eagleman on a Science Day. After graduating from Stanford and working in investment banking for a summer (“Banking really wasn’t for me,” says the mohawked Vaughn), he bugged Eagleman to give him a job. Now Vaughn is working on understanding what goes on in the brain when we feel empathy, and is pondering graduate school.

For all Eagleman’s talk of intellectual limits, there’s no doubt he believes deeply in hard science.

Back to the radio analogy. Even if there is an undiscovered force that would change the way we think about consciousness, Eagleman points out that we have to know how the radio works. And he wants to know how the brain works. “Understanding the machinery is not a bad pursuit at all,” he says. “It doesn’t rob the myste … doesn’t rob the awe from everything.”

Why does he stop himself from saying “mystery”? Why replace it with “awe”?

Eagleman explains that Frances Crick, the Nobel laureate biologist at the Salk Institute, once told him, “What we lose in mystery we gain in awe,” and the phrase stuck.

“Our goal in some sense is to reduce the mystery, but that doesn’t reduce the awe,” he says.

Eagleman doesn’t believe there are things we humans can’t understand, or problems we can’t solve. He doesn’t think a soul is something mystical, if it exists, it’s just something we don’t understand yet. Eagleman acknowledges that in his lifetime we won’t come up with the theories to explain it all, and that some of science’s stories may turn out to be wrong.

I poke a bit. Eagleman flies the possibilian flag, rejecting fundamentalism. But might he be a technological fundamentalist—someone who believes that humans, using science, will always find high-energy and high-technology solutions to problems, including to the problems created by those processes? Eagleman is intrigued by the concept but rejects the label. He has considerable confidence in the species, and confidence in himself.

When I asked him about his admiration for Sagan, he explained that he “would love to turn people on to the big ideas” the way Sagan did through books and the 1980 PBS series Cosmos: A Personal Voyage. Although he’s a boyish 38 years old, Eagleman doesn’t hesitate to acknowledge that he wants to carve out that kind of special public place for himself.

“Growing up, me and my parents, we never said ‘Someday you can be the president of the United States.’ We always felt like, ‘Someday you can be the next Carl Sagan.’”

Why such respect for Sagan? “He took the most beautiful ideas that we have in science and laid them out there in a way that any eighth-grader could understand, and that could bring tears to the eyes of any adult.”

Eagleman’s clarity and confidence would translate well to television; it’s fun to listen to him talk about all that he knows about science. But the more interesting side of Eagleman emerges when he’s stopped cold by the overwhelming complexity of the world—both outside and inside us—and the limits of human intelligence. He slows down and reveals the struggle inside Eagleman, between the confidence-bordering-on-hubris of a neuroscientist and the humility-that-produces-doubt of a writer. He knows he’s chewing on age-old questions.

In five hours of interviews, we ran into those walls a handful of times, most notably when I asked whether our big brains might make humans a tragic species. Might our intellectual capacity to achieve great things contain the seeds of our own destruction?

“That’s interesting. I would say…” he starts before pausing for 20 seconds, an eternity in Eagleman-time. He reframes the question: “Do we hit the solution or the disaster first?”

Here’s Eagleman’s upbeat answer: “My biggest place of hopefulness is in the fact that we’re leveraging human capital more than we’ve ever done before. So I feel like that makes it even more likely for solutions to come along. I don’t mean to be a Panglossian scientist and say that science progresses, it’s always going to lead to solutions, but yeah, I …”

His voice trails off. Eagleman may be an upbeat possibilian, but he remains true to possibilianism. Are there any possibilities that scare Eagleman-the-scientist?

“I’ve been doing this for 18 years, and I sometimes feel like, oh my God, what if I’ve gone just a little too far? When you reach your arms down into it, sometimes I feel like I’m seeing the matrix in a sense. Oh my God, this is all a construction.

“So the same question that excites me [how does the brain construct reality?] can also scare the shit out of me a lot of times. Because it’s much more comfortable to imagine that you open your eyes and the world is full of color and things just exist and time flows like a river,” he says. “But when you start breaking all that down and seeing that it’s a construction of the brain, it’s kind of awful, I guess because it makes you feel so alien to everything you’ve ever known and loved.”

Does that mean Eagleman-the-writer wants to believe that he has both a brain and a soul? He pauses again.

“Internally, I have felt as I’ve gotten older that I am not the same as my body, despite all of the neuroscience. How do I put this? What’s clear is that I depend entirely on the integrity of my body. As things in my brain change—if I were to develop a tumor, for example —that could completely change who I am, how I think. So I’m somehow yoked to my brain in a very strong way, and the question for all of us is, are we yoked to it 100 percent or is there some other little bit going on?

“From the inside, I have an intuition that I’m not just equivalent to my body. That said, intuitions always prove to be a very poor judge of reality. So, if you ask me, ‘Do I have a soul?’ I would say, ‘You know, I kind of feel like there’s something about me that’s a little separate from the biology.’ But I have no evidence for that.”

The struggle between the brain of a scientist and the soul of a writer continues. Maybe the brain allows itself to imagine a soul to take the sting out of mortality. Maybe the soul allows the brain to pretend to be in control, secure in the knowledge that the soul is immortal.

Hard to say, but in the space between the materialist and the mystic, anything’s possible.

Robert Jensen is a journalism professor at the University of Texas at Austin. His latest book is All My Bones Shake: Seeking a Progressive Path to the Prophetic Voice (Soft Skull Press, 2009).