In The Conscious Mind, David Chalmers writes:
Chalmers wrote: Why should there be conscious experience at all? It is central to a subjective viewpoint, but from an objective viewpoint it is utterly unexpected. Taking the objective view, we can tell a story about how fields, waves, and particles in the spatiotemporal manifold interact in subtle ways, leading to the development of complex systems such as brains. In principle, there is no deep philosophical mystery in the fact that these systems can process information in complex ways, react to stimuli with sophisticated behavior, and even exhibit such complex capacities as learning, memory, and language. All this is impressive, but it is not metaphysically baffling. In contrast, the existence of conscious experience seems to be a new feature from this viewpoint. It is not something that one would have predicted from the other features alone.
That is, consciousness is surprising. If all we knew about were the facts of physics, and even the facts about dynamics and information processing in complex systems, there would be no compelling reason to postulate the existence of conscious experience. If it were not for our direct evidence in the first-person case, the hypothesis would seem unwarranted; almost mystical, perhaps.
In Until the End of Time, Brian Greene wrote:
We know a good deal about the physical particles, structures, and processes going on in the brain. The physical can explain all the things Chalmers and Greene mention. But that's all they explain. No neuroscientist will point to Structure 1, Process A, Impulse Alpha, etc., and say, "And that is how consciousness is produced. It is those combination of elements that makes it happen."Greene wrote: And within that mathematical description, affirmed by decades of data from particle colliders and powerful telescopes, there is nothing that even hints at the inner experiences those particles somehow generate. How can a collection of mindless, thoughtless, emotionless particles come together and yield inner sensations of color or sound, of elation or wonder, of confusion or surprise? Particles can have mass, electric charge, and a handful of other similar features (nuclear charges, which are more exotic versions of electric charge), but all these qualities seem completely disconnected from anything remotely like subjective experience. How then does a whirl of particles inside a head—which is all that a brain is—create impressions, sensations, and feelings?
And no being studying all of that will conclude that we are conscious. No physical properties and processes describe or explain anything other than the physical properties and processes.
It all explains how we, for example, distinguish different frequencies of the spectrum within a certain range, beginning with photons entering our eyes. Just as we can describe how mechanical things we have made so the same thing. It doesn't explain how the clump off physical matter inside our skulls have subjective experience or awareness.