I guess I don't see a way to get around this fundamental disconnect right now:
As far as I am concerned, there's no sense talking about anything that doesn't contribute to a single, coherent, unified explanation of everything. 'The only thing we can be sure of is that we're conscious' is something I can agree with — but what do we do with that?
We look around, observe the universe, search out causal logic, and if we eventually arrive at
a causal model that begins with nothing and ends up explaining us, including our consciousness, we say 'this model is useful and predictive, and unlike any other, it seems to provide an account that explains everything we see. We thus consider it to be a model of the universe, of which we are a subsystem.'
You seem to say, 'we can do that, but when we're done we shrug and say, well, we might also have ghostly dualist voodoo which has no detectable effect, is unnecessary to explain anything, and is not suggested by anything except our own cultural traditions and desire to believe we're special...but we can't
disprove that consciousness is special somehow...'
Those of you who would argue that physicalism will never explain qualia must contend with the fact that
it already has. Physicalism says that we each have our own subjectivity for the same reason cameras take pictures from their own perspectives: that's what the machine does. It monitors itself, models itself and others, manipulates symbols in a workspace, applies global states like 'emotion' to modify function in response to adaptive challenges, and generally does a lot of stuff which requires it to have a 'this is me' concept. The brain needs to be able to model itself from someone else's perspective, and to integrate conflicting motor responses, and to do all kinds of **** which, it turns out, we experience as subjectivity. How else would we experience those things? Like the man inside the Chinese Room, blindly manipulating symbols? We're not the man. We're the room.
A brain is a meat machine. You build the machine, you build everything in the brain. We are in our brains. We are meat.
The devil you know
isn't better when you can compare how the two processes actually work and see that, wow, the devil I
don't know really alters a lot less in my brain! Which is me, as I know because
there is nothing in the universe except physics.
Conversely, you can get whacked on the head, black-out drunk, you can develop amnesia that rolls you back a month, and you still accept that you're you.
Would you use a machine that rolled your brain back one second, on a dare?
(Remember that me-ness is only ever
retrospective. We have absolutely no ability to look forward and say, ah, yes, that is me tomorrow. We don't know who we will be. Causality hasn't arrived yet. Me-ness is a credential that you claim looking back.)