John Horgan talks to Christof Koch about his latest book, Consciousness: Confessions of a Romantic Reductionist.

Horgan: You seem to have written your latest book in an attempt to achieve catharsis. Did it work?

Koch: Yes, it did help me resolve a long-brewing conflict between my Catholic upbringing and faith on the one hand and my scientific view of the world on the other. And writing the book also helped me deal with a more personal crisis.

Horgan: Your late friend and colleague Francis Crick once told me that free will was an illusion. Do you share this pessimistic view?

Koch: Well, Francis was right in that the standard conception of free will, that has the soul hovering above the brain and making it “freely” decide this way or that, is an illusion. It simply does not work at the conceptual or empirical level However, more subtle readings of free will remain, as I discuss in my book. Yet we are all less free than we like to believe. What remains, though, is that I am the principal actor in my life, so I better take responsibility for my actions.

Horgan: Do you think consciousness will ever be really, totally, explained? Could the “mysterians” [who propose that consciousness is not scientifically solvable] turn out to be right?

Koch: There is no law that states that all phenomena will have an explanation that humans can apprehend or understand. But my gut feelings—based on the past several centuries of progressively ever more successful explanations of the natural world—is that there will be better and better answers to the puzzle of our existence. We are not condemned to wander forever in some sort of epistemological fog. We will know. We will understand consciousness.

Horgan: Can you tell my readers, briefly, what Integrated Information Theory is and why you think it may be the key to consciousness?

Koch: The Integrated Information Theory of consciousness of Giulio Tononi is a general and quantitative way to approach the problem of consciousness. Ultimately, science needs to explain why some systems—a healthy and awake human brain, for example—give rise to conscious sensations, to experience, while other biological networks—the immune system, for example—do not. We also need to answer questions about consciousness in severely injured brain patients, in new-born babies, in a fetus, in dogs and cats, frogs, bees and flies and in artificial creatures, in iPhones and the internet. And only an information-theoretical account of consciousness is rich and powerful enough to be able to answer those sorts of questions in a meaningful and empirically accessible manner.

This is a clip from an interview — the whole interview is worth watching.