June 27, 2023. I first posted this profile of philosopher David Chalmers, famous for calling consciousness “the hard problem,” in 2015 on ScientificAmerican.com. I’m republishing this edited version here on my free journal “Cross-Check” to supplement my report on a highly publicized bet between Chalmers and neuroscientist Christof Koch. –John Horgan

David Chalmers, whose career I’ve tracked since I heard him call consciousness “the hard problem” in 1994, is an admirably clear thinker and writer, especially for a philosopher. He doesn’t oversell his ideas (unlike, say, Daniel Dennett when he insists that consciousness is an “illusion”). Chalmers's writings and talks, and meetings he’s organized, have helped me understand integrated information theory, Bayesian brains, ethical implications of AI and philosophy’s lack of progress. I interviewed Chalmers in 2015 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. Below are edited excerpts from our conversation.

REDUCTIONIST DAD, SPIRITUAL MOM

Chalmers was born (in 1966) and raised in Australia. His parents split up when he was five. Chalmers ended up as a blend of his “reductionist” father, a medical administrator, and his “spiritual” mother. “I’m a non-reductionist with a tolerance for ideas that might look a bit crazy to some people, like the idea that… 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 obsessing over the mind-body problem when he was 10 and diagnosed as nearsighted. “I got glasses and suddenly… the world was deeper and more three-dimensional than before…. I kind of understood 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.” 

FROM MATH TO PHILOSOPHY

Soon after arriving at Oxford to study math, “all I was doing was thinking about consciousness.” 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 he wrote down thoughts about the mind in a notebook.

He decided to switch from math to philosophy. He thought he would need an undergraduate degree before pursuing a graduate degree, but a philosophy advisor said that wasn’t necessary. Although appalled by philosophy’s “Micky Mouse” standards, Chalmers “wrote up a couple of articles and they let me in philosophy.” He 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 Godel, Escher, Bach. Chalmers’s Ph.D. thesis became his first book, The Conscious Mind.

HOW “THE HARD PROBLEM” WAS BORN

When I asked where “hard problem” came from, Chalmers replied that in the early 1990s, he started distinguishing consciousness from cognitive functions like perception or “self-monitoring,” which he called “the straightforward stuff.” At some point “it just became useful to say, ‘That’s the easy stuff and [consciousness] is the hard problem.’” After he referred to the "hard problem" in a talk at a big conference in Tucson in 1994, the phrase 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 philosopher to point out that consciousness is a special problem. Thomas Nagel made the same point in his 1974 essay “What is it like to be a bat?” 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.”

REJECTING MYSTERIANISM

Chalmers dislikes the view that consciousness is unsolvable, a position that philosopher Owen Flanagan has labeled mysterianism. Chalmers has always believed that “there’s a solution out there somewhere and we ought to be able to find it.”

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... 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.”

HOW A CONSCIOUSNESS-METER WOULD HELP

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 seemingly comatose 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.” On the other hand, the fundamental principles of physics remain mysterious. “You never see why they have to be that way.”

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?

CAN PHILOSOPHY HELP YOU LIVE?

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. On the other hand, belief in anatta might help you become less selfish and more compassionate toward others. “As a moral view, I find a certain appeal in that.”

ESCAPING INTO VIRTUAL REALITY

Chalmers is writing a book about virtual reality, which Meta and other companies are pitching to the public. [The book, Reality +: Virtual Worlds and the Problems of Philosophy, was published in 2022.] Soon, “we’re going to have the option of spending more and more of our time in a virtual reality.”

His book argues 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.’”

FREE WILL, MORALITY AND MEANING

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.”

Some people who believe in free will “look for a causal role for consciousness in the physical world. I’m somewhat agnostic on that.” But 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,” he suggested. “The more consciousness, the more value.” Consciousness, he added, seems to be the key to our sense of meaning. Consciousness “takes somehow all this activity in the brain or body and turns it into meaning, like water into wine.”

Further Reading:

See also my in-depth profile of Christof Koch in Mind-Body Problems.