I agree eternal_student about the emergence thing, i think that consciousness could 'emerge' from the integration of individual neurons in a similar way as the economy emerges from the interaction of individual people, but leaving at that is, as you say, kind of unsatisfactory. At the very least, it can't explain the very core of human consciousness, which is the creation of the sense of self, and 'qualia'.
I have to wonder though, what makes you say you're a dualist? By saying that consciousness supervenes on neurons, isn't that the very definition of physicalism? Can you explain how 'the magic of emergence' achieves this physical - nonphysical interaction in a dualistic theory? Or even if that's not clear, why do you still hold that dualism is necessary?
Thank you for an interesting question question. I fully accept the notion that consciousness "supervenes" upon the very-large-scale interaction of neurons and the living beings that host those neurons, and the environment that hosts those living being (especially upon the social interactions between those living beings in that environment). I.e., I accept that consciousness is an 'emergence'. And yet I identify my view of mind as dualistic. So, you seem to be asking: 1.) how a view of mind that accepts emergence can at the same time be dualistic (and not be hopelessly inconsistent or otherwise unworthy of further consideration by rational people); and 2.) why would that dualistic element be necessary given the full acceptance of what we now know about physics in general, neurophysics, and the dynamics of large and complex systems.
To fully answer these questions would take a lot of writing and further discussion. I am not adverse to that, but for immediate purposes, let me point out that I have presented my views regarding mind in detail on my personal web site at:
Consciousness, A Short Course
Now let me say a few things. As to what I am calling "question 1": Many people seem to think that when someone calls themselves a "dualist", they are fully embracing the classic Descartes view. I'm not sure if this includes yourself or not, but for the audience, please allow me to point out that dualism did not permanently fix its format in the 17th Century. It has undergone development and has responded to modern knowledge regarding the brain and its dynamics. This is not your grandfather's dualism, in other words. Modern science seems to increasingly admit that in its quest to more deeply understand the nature of reality, it must admit just how limited its currently accepted paradigms are. Physics is becoming aware that Einstein's relativity laws and quantum laws are incomplete, that more comprehensive and probably more complex theories will ultimately be needed involving further abstractions such as "curled dimensions" and spin networks and non-local phase entanglements. And then there's chaos theory and complexity and emergence, and the struggle to capture some new form of "laws" for large-scale behavior. Not to mention the "information layer" and the digital universe interpretations, the "it from bit" interpretations of fundamental reality. And what if David Bohm was right, that quantum phenomenon are not "just random" as in the Copenhagen interpretation, but that there are some subtle but substantial patterns to quantum behavior reflecting deeper reality layers. It seems to me that physics has not closed the door to a future extension of physics that would deal with the experience of consciousness, the system effect of "qualia" (qualia perhaps being in some abstract way comparable to the quantum particle in modern day physics, or the super-string in the proposed M theory). It seems to me that the more physics attempts to lock doors, the more open doors it discovers.
Interestingly, I believe that the current focus on "qualia" and the demonstrations of what PDP computing paradigms can explain about the cognitive workings of the brain indicate to the modern dualist that Descartes got it backwards. Our rational powers, our ability to think, however marvelous and unique compared to the rest of the animal kingdom, probably can (or eventually will) be explained by PDP. BUT, as to our ability to feel emotions, which Descarte seemed to dismiss as base and animal-like; well, that is actually where the "miracle" (for lack of a better term) occurs. That is qualia, that is what I conclude that physics does not currently explain. That is where the dualism is needed.
As to "question 2", just why would we possibly need an extension of physics to explain consciousness, any more than we need a special physics to explain unicorns or Santa Claus? Again, I could write all night about that, and already have wrote a lot on my web site about it. But let me just summarize the bare-bones of my own reflections on the subject.
a.) I feel that Frank Jackson's rationale about Mary The Colorblind Brain Scientist is right, i.e. that in being conscious and having experiences and emotions reflecting phenomenal experiences (or mixed phenomenal experience/memory and cognitive activity), there is "information" that is not captured by the physics of the brain and body, nor the current state of physics regarding the body's immediate environment and the universe at large.
b.) I feel that this can be detected, and perhaps some day even made empirical, in the human institutions of art, music and poetry. It seems to me that the "information" of experiencing emotions relative to qualia and cognitive states is reflected in that which informs the artist, the musical performer, and the poet. It never ceases to amaze me how a talented artist can capture a feeling that everyone felt that only they shared in the secure enclosure of their own subjectivity. I.e., how you can watch a movie and start feeling some emotions in response to the story as it unfolds, and then a song is presented that mimics (and thus intensifies) just that emotion that you were feeling. How did the filmmaker know? I agree that PDP does allow great flexibility in thought, such that humans can develop creative language metaphors such as "sharp cheese" (I think that's a Ramachandran example) -- perhaps the starting blocks to art. Sure, that's a PDP machine at work. But at some point, poetry and music and art seem to go beyond what a PDP machine would be capable of. (Although I remain open to rebuttal on that point; perhaps a PDP machine-poet or machine-artist or machine-piano composer exists that can make everyone cry, or is on the drawing boards tonight).
c.) I believe that there is something to the zombie rationale, i.e. that much of our behavior could exist without consciousness (thus hinting that consciousness has its own nature, despite its great entanglement with the physics of our "zombie-level" existence). I would go even farther and suggest that we have some idea of what zombiehood entails through cases of sleepwalking, absence automism, and semi-vegetative states. As such, consciousness does (to me) seem like "something different", something that came from a more complicated or more evolved set of laws and physics than that which got us to the point of "zombiehood" (zombie-ism actually covers a lot of our daily behavior, e.g. driving to work on an uneventful day). But I'm not an epiphenomenalist, so I won't go the Chalmers route and say that a zombie could do EVERYTHING we do, including talking and thinking and writing so much about consciousness. If we really were 100% zombie-equivalents, I don't think there would BE a consciousness question. Consciousness does have an effect on us, IMHO. It does affect the world of physics in which we are aware. But that's because, IMHO, it is a "trans-physics", something that encompasses but also goes beyond what we now know of physics.
d.) I wonder why natural selection and evolution, as higher mammals evolved, ignored the paths of adaptation that were so successful on the insect level, i.e. the eusocial organization models of ants and bees and termites. If the ultimate outcome of evolution and natural selection is the creation of a species that will gain the best control most of the planet's energy and resources so as to maximize its collective biomass, then you would expect humankind to be a bit more beehive like and much less individualistic. Something like the Borg on Star Trek. Evolution-wise, there should be no reason for tribal and nationalistic war, homicide and suicide (but occasional reason for quiet, unemotional self-sacrifice for the good of the overall species when threatened by the environment, as with bees and ants; but NOT for internecine threats and tribal wars, as we have long had sufficient cognitive and communicative capacities to recognize that humanity is one unified tribe). Creatures with those characteristics should have lost out to those without them, as the 'eusocial cooperatives' should have out-bred the 'warrior/individualists'. But, evolution and natural selection has to "follow the terrain" of the world in which it operates. It is constrained by carbon-based chemistry and the energy balances from the sun. I myself think that at the highest levels of organization, when biological agents have developed sophisticated sensing and information processing capability, another "set of physics" kicks in; that being the "trans-physics" behind our consciousness. This endows high-level creatures with personalities and individualities that preclude the eusocial model (for the most part) and allow the wastage of war, homicide, and suicide to take place; but simultaneously allow the joy of love, passion and music. OK, this is shaky ground, I know; natural selection is a very complicated thing that is still being argued and interpreted.
e.) Finally -- just my own subjective experience. I've read a number of recent books on the workings of the brain and how it hosts consciousness, by Ramachandran, Edelman, Damasio, Greenfield, and how such knowledge should be interpreted, e.g. by Pinker and Dennett. And every time I finish such a book I feel amazed. I feel like it all has been explained; this feeling lasts about 2 or 3 days. Then, at some odd moment, stopped at a traffic light or such, it strikes me: no, there's something more to being alive and conscious. Again, just a subjective notion.
Finally, just as a sidenote; I do consider myself to be an ultimate monist. I don't think that reality is fundamentally a blend of two different things. But, relative to what we now know and see, I think that dualism is a useful paradigm. Recall Jurgen Habermas and his "epistemic dualism / ontological monism" point of view.
Thanks again for the question. Jim G.