Blind as a Bat: A Case of Mind vs. Body

Almost 40 years before the publication of “Mind and Cosmos,” the philosopher Thomas Nagel laid out the difficulties scientists face in trying to explain how the human brain gives rise to consciousness. His essay, as influential as any in the philosophy of mind, is called “What Is It Like to Be a Bat?”

By emitting “rapid, subtly modulated, high-frequency shrieks” and comparing them with the echoes, Dr. Nagel wrote, bats create a finely detailed, three-dimensional mental map of their world. But we humans are fundamentally incapable of imagining — and understanding — the animal’s inner life. Subjective experience, he concluded, is irreducible to physical terms. And so even the most precise theory of the brain can never fully account for the existence of mental phenomenon.

Plenty of philosophers, like Patricia Smith Churchland and Daniel C. Dennett, believe Dr. Nagel is wrong. The mind, they say, is simply what the brain does — a different way of describing the same underlying phenomenon. The entire field of neuroscience, including the $100 million brain initiative announced last year by the government, is tacitly built on that assumption. Someday, when scientists have mapped and fully analyzed the neural circuitry, lurking somewhere in the details will be an explanation for consciousness.

To believe otherwise, as Dr. Nagel does, implies that the mental is fundamentally different from the physical. The mind-body problem, as philosophers call it, goes back at least to the days of Plato and Aristotle. A century from now, the debate will probably be with us still. Whichever side is correct, the human brain may simply not be capable of understanding itself, no matter how hard and how long it tries.

Related Coverage

  1. Raw Data: Beyond Energy, Matter, Time and Space Jul 21, 2014