In 2000, 43 years after going totally blind at the age of three in a freak accident, a California man named Mike May had his sight restored in one eye by a pioneering stem cell procedure, coupled with a cornea transplant. A camera was on hand to record him seeing for the first time in his adult life, but the result was disappointing—despite a fully functional eye, all May could see was a blur of shapes and colors.

David Eagleman, a neuroscientist at the Baylor College of Medicine in Houston, recounts May’s story in his new, six-part television series The Brain, which premieres this evening on PBS. According to Eagleman, May’s brain had never learned to interpret the visual signals that are usually sent by our eyes; when those signals suddenly resumed, the data seemed random and meaningless. Blind, May was an expert downhill skier; sighted, he couldn’t tell his children apart. The lesson is that reality isn’t something we passively observe but rather something that our brain continually fabricates out of the myriad signals streaming in from our sensory organs. As Eagleman puts it, “What we experience isn’t what’s really out there, but a beautifully rendered simulation.”

The Brain is Eagleman’s attempt to unravel one of science’s greatest mysteries: how consciousness emerges from the three-pound lump of pink tissue inside our skulls. Rather than organize the documentary according to the parts of the brain—a division that makes little sense, Eagleman said, because nearly all parts are involved in nearly every brain function—Eagleman devotes each episode to a philosophical query like “What is Reality?” or “What Makes Me?”

Although the answers he provides are solidly grounded in science, the show is informed by the 43-year-old researcher’s polymorphous curiosity and sense of adventure. As an undergraduate at Rice he majored in English literature (“my first love”), volunteered in the Israeli Army for a summer, studied abroad at Oxford, and, at one point, dropped out and moved to Los Angeles to pursue screenwriting and stand-up comedy. When those careers didn’t pan out, he returned to Rice in 1992 to finish his degree. One day he picked up a special issue of Time or Newsweek—he can’t remember which—about new research on the brain.

“For me it was a moment in time when I realized, wow, this is the greatest thing that I’ve ever come across,” Eagleman told me as we talked in a small, immaculate conference room in TMCx, a business incubator in Houston’s Texas Medical Center where Eagleman oversees two start-up companies based on his research. Housed in a former Nabisco factory, the offices have the casual feel of a Silicon Valley start-up. “Back [in 1992], there was very little written as far as popular neuroscience. I went to the Rice library and checked out all the books on the brain. Then one of my friends said to me, ‘Why don’t you become a neuroscientist?’”

“And this seemed like a realistic plan?” I asked Eagleman.

“Sure,” he replied. “We all have to pursue our passions, right? And this was the coolest thing I’d come across.” So the former stand-up comic, screenwriter, soldier, and English major entered the doctoral program in neuroscience at the Baylor College of Medicine, only a few blocks from Rice. After earning a Ph.D. with a dissertation demonstrating a new way that brain cells exchange information, he completed a post-doc at the Salk Institute in Southern California, working under Nobel Laureate Francis Crick, the co-discoverer of DNA, before returning to Baylor as an assistant professor.

In between conducting research and publishing scholarly papers in journals like Science and Nature, Eagleman was secretly working on a side project—a work of speculative fiction titled Sum: Forty Tales from the Afterlives. Published in 2009, the hard-to-classify little book comprises a series of thought experiments about what might await us on the other side of death. In one chapter, the dead are cast as background characters in the dreams of the living; in another, they are pressed into service as ten-thousand-kilometer-tall creatures who hold up the cosmos. “Often I would come home at night from the lab and just write all night until I fell asleep on the keyboard,” Eagleman said. “Of course, that was in my bachelor days,” he added with a laugh.

Sum attracted a broad spectrum of admirers, from children’s novelist Philip Pullman to actor Hugh Laurie to string theorist Brian Greene. Musician Brian Eno collaborated with Eagleman to turn the work into a full-scale opera, which has been performed at the Sydney Opera House and London’s Royal Opera House. Eagleman has also written two more conventional works of popular science: Wednesday is Indigo Blue: Discovering the Brain of Synesthesia (with Richard Cytowic) and Incognito: The Secret Lives of the Brain. He’s working on a fictional follow-up to Sum, although his staggering workload, combined with the responsibilities of family life—he’s now married with two young children—have slowed its progress.

While promoting Sum in 2009, Eagleman inadvertently created an intellectual movement. During an interview on National Public Radio, Eagleman was asked about his religious beliefs. He replied that he considered himself a “Possibilian,” which he defined as someone willing to entertain multiple hypotheses about, say, the feasibility of creating a conscious computer or the existence of some sort of Creator.

“The cosmos is so much bigger than we can even comprehend a shadow of,” he told me. “What we do in science is try to collect evidence to support a certain idea, but we don’t go running around screaming with certainty before anything’s been done.” When Eagleman first Googled the term Possibilian, no results came up; now the search returns over 8,000 hits, including Wikipedia and Facebook pages dedicated to Possibilianism.

The rise of Possibilianism notwithstanding, popularizing science among general interest audiences—especially television audiences—remains a challenge. The successful template for bringing science to the masses is still Carl Sagan’s 13-part PBS series Cosmos, which aired in 1980. The broadcast, the most widely watched series in the network’s history, made a profound impression on the young Eagleman, as it did on many other future scientists. “When I was a kid, my parents wouldn’t say stuff like, ‘You’re going to be the president of the United States.’” Eagleman told me. “They’d say, ‘You’re going to grow up to be Carl Sagan’,” evidently a more exciting prospect to the young boy. Eagleman had long dreamed of making a Cosmos-style series on the brain, but producer after producer told him that television audiences no longer had the patience for such a show. (They were proved wrong when Fox scored a surprise hit last year with Cosmos: A Spacetime Odyssey, a follow-up to Sagan’s original series, this time starring rock star astrophysicist Neil deGrasse Tyson.)

Eagleman finally found a willing partner in Blink Films, a London-based production company that specializes in science documentaries. “I wanted to do a landmark series on the brain, but one of the difficulties is that the brain is very difficult to see, so traditionally people tend to do stories about people with unusual brain disorders,” said producer Justine Kershaw. “What it really needed was an amazing neuroscientist at the heart of it, and they are not easy to come by. Then I stumbled across David a few years ago, and I thought, at last, the perfect person to take us through this world.”

The show’s full title is The Brain with David Eagleman, and, indeed, Eagleman is front and center, introducing each episode, conducting interviews, and subjecting himself to various scientific experiments. Around two-thirds of the show was filmed at various locations around Houston, with the rest shot as far afield as Switzerland and Bosnia (the latter to illustrate the cognitive foundations of genocidal violence.) The youthful Eagleman is a charming, charismatic presence, effortlessly breaking complex ideas into bite-sized aperçus.

“He’s a brilliant communicator,” Kershaw said. “It helps that he was an English major before he was a neuroscientist, because he’s got an amazing ability to tell a story. So often, scientists lack the ability to do that.”

How, I asked Eagleman, did he find time to film a major television show while overseeing a lab, managing two start-ups, writing books, and delivering talks around the world—to say nothing of raising two children? “I’m never not working,” he explained. “I’m constantly rolling at full speed until the moment I fall asleep. And even then I’m sending off a last few emails on my phone.”