Metaphysics special: What is consciousness?
Francoise Hillemad/plainpicture By Anil Ananthaswamy In Cotard’s syndrome, the feeling of existence corrodes but something more fundamental does not (see “How do I know I exist“). Even though people with this rare condition feel they don’t exist, there is still an “I” experiencing that feeling. What is that “I”? One answer is that it may be a by-product of consciousness itself. René Descartes was convinced that the body and conscious mind are two different substances: the first is made of matter, the latter is immaterial. His ideas influenced neuroscience until a few decades ago, but the field has moved on. Today, it is widely accepted that our brains give rise to consciousness. But how? That is a raging debate. At its heart is what philosopher David Chalmers at New York University termed the “hard problem” of consciousness: how can physical networks of neurons produce experiences that appear to fall outside the material world? As Thomas Nagel, also at New York University, put it in the 1970s: you could know every detail of the physical workings of a bat’s brain, but still not know what it is like to be a bat. “You may know beyond a doubt that you exist, but your ‘I’ could still be an illusion“ Broadly speaking, those trying to solve the hard problem fall into two camps,