David Chalmers, one of the foremost researchers on the nature of consciousness, writes in his book, The Conscious Mind, that:
"Consciousness is a surprising feature of our universe. Our grounds for belief in consciousness derive solely from our experience of it. Even if we know every last detail about the physics of the universe-the configuration, causation, and evolution among all the fields and particles in the spatial temporal manifold-that information would not lead us to postulate the existence of conscious experience. My knowledge of consciousness in the first instance comes from my own case, not from any external observation. It is my first-person experience of consciousness that forces the problem on me." (pp. 101,102)
What Chalmers is saying is that the materialist view that everything that exists can be reduced to matter and energy still leaves consciousness unexplained. No matter how far we reduce the processes of the brain to their constituent chemicals and reactions we can find nothing that accounts for self-awareness or sensations like greenness. Nor can we begin to explain how a feeling like guilt, or a belief, or an intention could be described in terms of chemical processes occuring in neurons.
Consciousness seems to be sui generis, unique. There's nothing else like it in the universe, and what it is and how it could have evolved are complete mysteries.
RLC
