...my conclusion is that neither the Mary nor the Zombie Argument makes a decisive case against physicalism...professional philosophers have uncovered a number of subtle and complex problems for both arguments. For anyone interested in pursuing the discussion further, I would recommend the Stanford Encyclopedia of Philosophy articles “Qualia: The Knowledge Argument” (by Martine Nida-Rümelin) and “Zombies” (by Robert Kirk).I like Metzinger's stance that consciousness is epistemologically irreducible (see his book "The Ego Tunnel"). There is one reality, one kind of fact, but two kinds of knowledge: first-person knowledge and third-person knowledge, that never can be conflated. There is a long list of ideas on why consciousness evolved, what it is good for, doing goal hierarchies and long-terms plans, enhancement of social coordination, etc. I like Metzinger's description of consciousness as a as a new kind of virtual organ - unlike the permanent hardware of the liver, kidney, or heart it is always present. Virtual organs form for a certain time when needed (like desire, courage, anger, an immune response)..."they are a new computational strategy, that makes classes of facts globally available and allows attending, flexible reacting, within context." "Reality generation" allowed animals to represent explicitly the fact that something is actually the case, the world is present. (conscious color gives information about nutritional value, red berries among green leaves, empathy gives information about the emotional state of conspecifics).
For those of you who like this sort of stuff I point out "A darwinist lynch mob goes after a philosopher" by Leon Wieseltier in the March 11 New Republic, on some outraged reactions to Nagel's new book: "Mind and Cosmos: Why the Materialist Neo-Darwinian Conception of Nature Is Almost Certainly False."
Also,"Was Wittgenstein Right? by Paul Horwich:
Wittgenstein claims that there are no realms of phenomena whose study is the special business of a philosopher, and about which he or she should devise profound a priori theories and sophisticated supporting arguments. There are no startling discoveries to be made of facts, not open to the methods of science, yet accessible “from the armchair” through some blend of intuition, pure reason and conceptual analysis. Indeed the whole idea of a subject that could yield such results is based on confusion and wishful thinking.To which Michael Lynch makes a rejoinder.
I have to end by repeating another old chestnut:
Philosophy, n. A route of many roads leading from nowhere to nothing. -AMBROSE BIERCE, The Devil's Dictionary