David Chalmers, author of several books on the subject of consciousness, and one of the foremost authorities on the subject, disagrees. He points out that we need to distinguish between what he calls the easy problem and the hard problem of consciousness. Posner explains Chalmers' argument this way:
Easy problems tend to be phenomena that can be explained by computational or neural mechanisms – recoiling from unpleasant odours, for example, or simply declaring “I am hungry” or some other mental state. The hard problem relates to the subjective qualities of human experience.There's more at the link. The article is a good summary of the differences between those who believe there is more to us than just our material body and those who don't.
For instance, let's say you run into your old friend Jack. You register a moment of physical recognition: “Oh, there's old Jack.” But meeting old Jack also may trigger a series of “Jack” memories, emotions and ideas, all percolating more or less simultaneously. You may perceive that Jack has aged and remember how he once looked. You may recall beautiful music that Jack enjoyed, or the brilliant shade of red of the rose in Jack's lapel. The specific presence of Jack, in short, catalyzes the non-specific emergence of a holistic range of associations, drawn from some hidden well of private experience. You and you alone know what it is like to experience this moment of reconnection. It is literally incomparable. “The hard problem is hard,” says Mr. Chalmers, “precisely because … the problem persists even when the performance of all the relevant functions is explained.”
Science can document all the processes involved in vision – electromagnetic waveforms striking the retina and proceeding electrochemically along the optic nerve to the brain's occipital lobe. But where does the felt experience of what is seen – let's say the colour red – come from? Says Mr. Chalmers: “There is an explanatory gap between the functions and experience.”