I’m writing a book on the mind-body problem, and one theme is that mind-theorists’ views are shaped by emotionally traumatic experiences, like mental illness, the death of a child and the breakup of a marriage. David Chalmers is a striking counter-example. He seems remarkably well adjusted and rational, especially for a philosopher. I’ve tracked his career since I heard him call consciousness “the hard problem” in 1994. Although I often disagree with him—about, for example, whether information theory can help solve consciousness—I’ve always found him an admirably clear thinker, who doesn’t oversell his ideas (unlike Daniel Dennett when he insists that consciousness is an “illusion”). Just in the last couple of years, Chalmers's writings, talks and meetings have helped me understand integrated information theory, Bayesian brainsethical implications of artificial intelligence and philosophy’s lack of progress, among other topics. Last year I interviewed Chalmers at his home in a woody suburb of New York City. My major takeaway: Although he has faith that consciousness can be scientifically solved, Chalmers doesn’t think we’re close to a final theory, and if we find such a theory, consciousness might remain as philosophically confusing as, say, quantum mechanics. In other words, Chalmers is a philosophical hybrid, who fuses optimism with mysterianism, the position that consciousness is intractable. Below are edited excerpts from our conversation. —John Horgan


Chalmers, now 50, was born and raised in Australia. His parents split up when he was five. “My father is a medical researcher, a pretty successful scientist and administrator in medicine in Australia… My mother is I would say a spiritual thinker.”

“So if you want an historical story, I guess I end up halfway between my father and mother… My father is a reductionist, and my mother is very much a non-reductionist. I’m a non-reductionist with a tolerance for ideas that might look a bit crazy to some people, like the idea that there’s consciousness everywhere, consciousness is not reducible to something physical. That said, the tradition I’m working in is very much in the western scientific and analytic tradition.”

Chalmers was a “math geek” who pursued a graduate degree in mathematics at Oxford. But he started thinking about the mind-body problem when he was 10 and was diagnosed as nearsighted. “I got glasses and suddenly… the world was deeper and more three-dimensional than before…. I kind of understood in principle about the objective mechanisms of binocular vision, how information from one eye and another eye gets put together, and that will allow me to… catch a ball better. But why did that lead to this subjective brilliance, the world kind of popping out into 3D? Where is that in this processing story? I didn’t think of it that way at the time, but that was basically a story about consciousness.”


Within months after arriving at Oxford to study math, “all I was doing was thinking about consciousness… I started thinking seriously about switching to philosophy in order to work on this.” Taking a break from his studies, Chalmers traveled around Europe. He read Zen and the Art of Motorcycle Maintenance and other books with philosophical themes, and wrote down thoughts about the mind in a notebook.

He decided to switch to philosophy. He thought he would have to get an undergraduate degree before pursuing a graduate degree, but a philosophy advisor said that wasn’t necessary. His initial reaction was incredulity. “I thought, ‘What kind of a Mickey Mouse field is this!' You can go straight into the graduate program without an undergraduate degree? That would be totally impossible in mathematics, but it turns out this is something people do.”

The philosophers were delighted that someone with mathematical training wanted to switch to their field. “So I wrote up a couple of articles and they let me in philosophy.” He sought out philosopher Colin McGinn, who later became renowned for arguing that consciousness is unsolvable. “I knocked on his door, and to his credit he talked to me for an hour.” McGinn told Chalmers his ideas about consciousness were “a load of crap. Little did I know at the time that to Colin almost all ideas about consciousness are a load of crap.”

Chalmers transferred from Oxford to the University of Indiana to pursue a doctorate under Douglas Hofstadter, who had spelled out his radical ideas about the mind in The Mind’s I, co-written with Daniel Dennett, and Godel, Escher, Bach. Chalmers’s Ph.D. thesis became his first book, The Conscious Mind.


When I asked where “hard problem” came from, Chalmers replied that in the early 1990s, he started distinguishing consciousness from cognitive functions, like “self-monitoring.” “I’d say, ‘That’s the straightforward stuff. We’ve really got to worry about this.’ And at some point it just became useful to say, ‘That’s the easy stuff and this is the hard problem.’” He used the phrase "hard problem" in a talk he gave at “Toward a Scientific Basis of Consciousness,” a meeting held in Tucson in 1994, and it caught on. “I had no idea this whole ‘hard problem’ thing would blow up the way it did.”

Chalmers has never claimed to be the first person to point out that consciousness is a special kind of problem. He noted that Descartes and Leibniz, among others, thought along similar lines. So did Herbert Feigl, who in the 1950s separated the mind-body problem into the sub-problems of sentience, sapience and selfhood. “It was pretty clear that by the problem of sentience he meant what we now think of as the hard problem.”

Thomas Nagel also famously asserted in his 1974 essay “What is it like to be a bat?” that “consciousness is what makes the mind-body problem really difficult.” Chalmers agrees with Nagel that “we need radical ideas” to solve the mind-body problem. “When it comes to the mind-body problem, you’ve got to have a tolerance for some kind of craziness.”


Chalmers has never been tempted by mysterianism. (Although Colin McGinn is most closely associated with that position, Owen Flanagan coined the term.) Chalmers has always believed that “there’s a solution out there somewhere and we ought to be able to find it. Or we ought to try. We’re not going to know if there’s no solution there until we try and try and try.”

Does he ever waver from that optimistic belief? “Of course,” Chalmers replied. “I think there is some true story about why there is consciousness in the universe. There is some basic set of laws or something that explains it as well as it can be explained.... Whether we are going to be in a position to come up with that really great story is a further question.”

“I’d be happy if we got to the point where, say, in 50 or 100 years we at least have some candidate theories, serious, well-developed mathematical theories that are consistent with the data… But we’re not even close to that point yet. I guess I’m inclined to think we can always make a lot of progress. Whether we get all the way is an open question.”


One huge advance would be the invention of a “consciousness-meter,” which could provide a “precise readout of the state of consciousness” of any given object. “I could point it at your head and get a read-out of your state of consciousness. Point it at this flower and see if it’s conscious or not. Point at a dog to see if anything might be going on in it. We don’t have that.”  Such a device would “basically give you the data you need to formulate, let’s say, a semi-mathematical theory of consciousness,” which correlates a given physical system with a given conscious state.

A theory of consciousness might have practical applications, such as determining whether non-communicative patients are in fact conscious. “But I suspect we would end up having some of the same metaphysical arguments” about consciousness. “You would still have all the philosophical argumentation over materialism or dualism. Is consciousness fundamental, are consciousness and the associated physical state identical, or are they two distinct things?”

Philosophers would probably debate the meaning of a final theory of consciousness, just as they debate the meaning of quantum mechanics. “But there would be this core of science that everyone would recognize and use, as there is with quantum mechanics.”

A final theory of consciousness, Chalmers said, might not trigger an “Aha!” reaction. It might not have the “pleasing-ness” of, say, “an explanation of chemistry in terms of physics, or biology in terms of chemistry, where you see, it had to be that way. There had to be life, at least given that the atoms are arranged this way.”

On the other hand, the fundamental principles of physics have this same quality. “You never see why they have to be that way… The connection between, say, physical processes and consciousness may be analogous to fundamental laws in physics. If that’s right, then at least we have a story, an explanation, of why you’re not getting that ‘Aha.’ It’s analogous to the lack of an ‘Aha’ in the theory of gravitation or quantum mechanics.”

Some physicists, I noted, still hope they will discover a theory of everything that resolves the paradoxes of quantum mechanics and explains why the fundamental laws are the way they are. Chalmers looked skeptical. If you explain space-time in terms of strings, he pointed out, you’re still left with the question, Why are there strings?


Does philosophy help him deal with personal problems? “I’m not sure how deep an integration there is between what I think about philosophically and the way I live,” he replied. “I’d love to be able to say, ‘Here is how the insights I’ve had about consciousness have transformed my life.’… I’ve basically lived my life the way I want to live it without necessarily being all that reflective at the practical level.”

Chalmers suspects this disconnect is common among philosophers. Eric Schwitzgebel, after studying ethical philosophers, concluded that they are “no more ethical than the rest of us” and that “thinking about ethics doesn’t make any difference to their actual lives.”


Chalmers is not religious. “I can’t take seriously the idea that there is any being in the universe worthy of worship." He has resisted jumping on the Buddhism bandwagon. He has “never had the patience” for meditation, and he has doubts about basic Buddhist claims, such as anatta, the doctrine that the self does not really exist.

“Deep down,” he says, “I’m a Cartesian,” who believes “there is a self.” On the other hand, belief in anatta can perhaps help us become less selfish and more compassionate toward others. “As a moral view, I find a certain appeal in that.”


Chalmers is writing a book about virtual reality, which Oculus Rift and other consumer products are bringing to the public. Soon, “we’re going to have the option of spending more and more of our time in a virtual reality.”

Philosophers should reflect on “the status of life inside a virtual reality in order to make good, informed decisions about whether we want to have virtual lives or non-virtual lives.” His book will argue that “simulated reality is not a second class reality.” Virtual reality “is actually a perfectly good way to be real.”

Chalmers rejects the idea that virtual reality is immoral because it distracts us from real-world problems. “You might as well say, ‘Don’t read a novel because of all the bad things in the world.’” If real life is “crap,” we can “choose to go into a virtual analog like Second Life, and it’s amazing! We can do so much!” he said. “We need to be at least reflecting on the status of virtual lives.”


Chalmers, to my surprise, does not have strong feelings about free will. “If it just means you can do what you want to do, then, well, that seems pretty straightforward. If it’s the ability to do something completely non-deterministic, well, I don’t know if we have that.”

“In the context of consciousness, some people who believe in free will look for a causal role for consciousness in the physical world. I’m somewhat agnostic on that.” Chalmers has been accused of claiming that consciousness is an epiphenomenon of mental functioning, which has no causal role. Actually, he’s “interested in speculations about how it might play a causal role.”

Chalmers likes the idea that consciousness can serve as the basis for morality and value. “A system has to be conscious to have any value. The more consciousness, the more value. But beyond that, and how they are connected, I really don’t have any clear idea.”

In the same way, Chalmers suggested that consciousness is the key to our sense of meaning. “What gives life even the potential for meaning in the first place is, I guess, consciousness. It takes somehow all this activity in the brain or body and turns it into meaning, like water into wine.”

Further Reading:

The Mind–Body Problem, Scientific Regress and "Woo"

Dispatch from the Desert of Consciousness Research, Part 1

What Is Philosophy's Point?, Part 1 (Hint: It's Not Discovering Truth)

Is Scientific Materialism "Almost Certainly False"?

The Rise of Neo-Geocentrism

Why information can't be the basis of reality

Can Integrated Information Theory Explain Consciousness?

My Bunk-Bashing Diatribe at a Deepak Chopra Conference

Is Consciousness Real?

Christof Koch on Free Will, the Singularity and the Quest to Crack Consciousness

World's Smartest Physicist Thinks Science Can't Crack Consciousness

Are Brains Bayesian?

How Would AI Cover an AI Conference?

Meta-post: Horgan Posts on Brain and Mind Science