> Certainly Zombie-Chalmers is inconsistent with physicalism.
Ok, good, we agree on that.
> his denial of any form of privileged access
Not of any form, no. Dennett was fine with the notion that we have privileged access to what it is like to be us (to use Thomas Nagel's phrase--Dennett's often-used term was "heterophenomenological world"). We have a direct experience of what it is like to be us, and that experience is real. Dennett just insisted that that, in itself, tells us nothing about how accurate our "what it is like to be us" is as a representation of the underlying processes going on in our brains. There are indeed images, sensations, raw feels, phenomenal properties in our "what it is like to be us"--in Dennett's terms, those are indeed intentional objects in our heterophenomenological worlds. But that, in itself, does not mean that, for example, if we say we have a mental image, there must actually be an image somewhere in our brains. There are real underlying processes going on, but we can't infer from our direct experience of having a mental image that any of those underlying processes involve images.
> I think it's important to have a certain amount of empathy here
It's not a matter of empathy; it's a matter of being consistent about the implications of one's views. I'm a physicalist, just as Dennett was. You agree that, for example, Zombie-Chalmers is inconsistent with physicalism. No amount of "empathy" can overcome that contradiction. I have to pick one or the other. I pick physicalism, not because of any lack of "empathy" for Chalmers or anyone else, but because, all things considered, that's what I pick. And having picked physicalism, I have to deny that Zombie-Chalmers is a valid concept, in order to be consistent. Just as Chalmers, to be consistent with his belief that Zombie-Chalmers is a valid concept, has to deny physicalism.
Pretty much everyone agrees that the existence of a distinction between zombie and non-zombie Chalmers is inconsistent with strong physicalism. That is the whole point. Regarding empathy, I'm saying that you appear not to understand why physicalism might not be the non-negotiable ur-assumption for someone else that it is for you. Chalmers is arguing against physicalism, so to point out that his position is inconsistent with it is not a very interesting response. You're certainly free to make your own judgment about the centrality of physicalism to your belief system; it just doesn't work as a rejoinder to Chalmers' arguments.
We could have an extended discussion of exactly which aspects of privileged access Dennett denies, but the broader point here is that he himself acknowledges the counterintuitive nature of his position on it.
> [Physicalism] is everybody's default assumption when dealing with anything that matters in practical terms.
No, it isn't. People assume that things which they take to be physical objects (such as cars) will obey physical laws. They can perfectly well do this without the additional assumption that the contents of the universe are exhausted by physical entities. Indeed, when dealing with people (who surely matter in practical terms!) it is probably a minority of the world's population who assume them to be wholly physical. The idea that non-physicalists must be worried about their cars exhibiting ghostly non-physical behavior is just silly. It is like saying that someone who does not believe that everything in the universe is made of wood must be worried that their wooden table might actually be made of chocolate. Believing in the existence of non-wooden things doesn't preclude treating wooden things as instances thereof. Almost everyone believes that there exist wholly physical objects governed wholly by physical laws, even if they don't think that all objects fall under this category.
> you appear not to understand why physicalism might not be the non-negotiable ur-assumption for someone else that it is for you
Oh, I understand that just fine. I just don't agree with non-physicalists.
I could equally well say that non-physicalists who claim that Dennett denied the reality of consciousness do not understand why their implicit assumption that consciousness must be something non-physical is not the non-negotiable ur-assumption for Dennett (and me) that it is for them. They simply fail to understand that physicalists like Dennett and me are not saying that consciousness doesn't exist. We're just saying that it's a physical process. Real consciousness--real feelings of pain, suffering, joy, and everything else that phenomenalists wax poetic about--is a physical process. It is no answer at all to say that, gee, I can't imagine how that could possibly be true, so I'm going to assume you actually mean that all those things don't exist. But that's basically what Dennett's critics have said for decades. You talk about empathy: I think that line of criticism shows an astounding lack of empathy.
> People assume that things which they take to be physical objects (such as cars) will obey physical laws.
No, they don't. Most people have no idea what the actual applicable physical laws are. People assume that things they are familiar with will show the regularities they are familiar with them having. Those regularities, to a physicalist, are all grounded ultimately in underlying physical laws, but the connection is very complex, even for objects much simpler than cars. Scientists still don't completely understand how molecules work in terms of the underlying laws of physics of atoms and elementary particles. That doesn't stop them from being able to build accurate models of molecules using higher-level regularities. The physicalist program for consciousness is simply applying to it the same methods we already apply successfully to all sorts of complex systems.
Galen Strawson has a good line about the "pizza theory of consciousness". Pizza theorists accept that consciousness is real but believe that it is pizza. Technically, this is not an eliminativist theory: pizza exists. But it is so manifestly obvious that pizza has none of the properties that we typically associate with consciousness that the theory is merely eliminativism in disguise. Perhaps those of us who reject the pizza theory simply lack the imagination to understand it. Or maybe the pizza theory is just obviously wrong.
>No, they don't.
I could have written that sentence more clearly, but I just meant to say that people will assume such objects to obey the typical regularities and constraints exhibited by physical objects (and not expect them to have weird ghostly properties). Which you seem to agree with.
> it is so manifestly obvious that pizza has none of the properties that we typically associate with consciousness that the theory is merely eliminativism in disguise
The problem with this, other than the obvious point that "extremely complicated physical processes inside the brains and bodies of humans, which we are only beginning to work out the details of" is very different from "pizza", is that no physical process can possibly have "the properties that we typically associate with consciousness", at least if "we" means Strawson and those who take his side in the debate. The only way for something to exist that has all of the properties that Strawson et al insist on is for that something to be non-physical, to violate physical laws.
Is this non-physicalism logically impossible? Of course not. That's why, as I said, nobody is going to resolve this debate with arguments. But lots of things are logically possible: Russell's teapot, Sagan's undetectable dragon in the garage, etc. That doesn't mean everything that is logically possible should be taken seriously.
The non-physicalist argument for taking them seriously with regard to consciousness boils down to a simple assertion without argument: it is just obvious to them that no amount of physical processes could ever produce the conscious experiences we all have. But this isn't science. It's just throwing up your hands and refusing to look any further. That is what Dennett and those on his side of the debate refuse to accept. There is a lot of science to be done in this area, and only a small part of it has yet been done. Let's do it and see where we end up. Is it logically possible that we will end up just where Strawson et al are now? Yes. But is that the way to bet? Dennett didn't think so, nor do many others, and nor do I. As I've already said, we'll see.
No-one would disagree with this. But you have to actually obtain scientific results before you can use them as the basis of your world view. Dennett has a tendency to gloss over the paucity of scientific results pertaining to consciousness by slipping into "pro science" vs. "anti science" rhetoric – as if to suggest that the science of consciousness would be complete by now if only it wasn't for the evil machinations of the superstitious anti-scientists. Strip away the rhetoric and all you are left with is optimism: Dennett thinks that science will explain consciousness eventually. That's a perfectly fine opinion, but being optimistic about future science is not fundamentally any more scientific or rational than being pessimistic about it.
Has had plenty of exchanges in the literature with Dennett. I have read most of them. I don't buy his counterarguments, although I admit has does have some good turns of phrase.
Ok, good, we agree on that.
> his denial of any form of privileged access
Not of any form, no. Dennett was fine with the notion that we have privileged access to what it is like to be us (to use Thomas Nagel's phrase--Dennett's often-used term was "heterophenomenological world"). We have a direct experience of what it is like to be us, and that experience is real. Dennett just insisted that that, in itself, tells us nothing about how accurate our "what it is like to be us" is as a representation of the underlying processes going on in our brains. There are indeed images, sensations, raw feels, phenomenal properties in our "what it is like to be us"--in Dennett's terms, those are indeed intentional objects in our heterophenomenological worlds. But that, in itself, does not mean that, for example, if we say we have a mental image, there must actually be an image somewhere in our brains. There are real underlying processes going on, but we can't infer from our direct experience of having a mental image that any of those underlying processes involve images.
> I think it's important to have a certain amount of empathy here
It's not a matter of empathy; it's a matter of being consistent about the implications of one's views. I'm a physicalist, just as Dennett was. You agree that, for example, Zombie-Chalmers is inconsistent with physicalism. No amount of "empathy" can overcome that contradiction. I have to pick one or the other. I pick physicalism, not because of any lack of "empathy" for Chalmers or anyone else, but because, all things considered, that's what I pick. And having picked physicalism, I have to deny that Zombie-Chalmers is a valid concept, in order to be consistent. Just as Chalmers, to be consistent with his belief that Zombie-Chalmers is a valid concept, has to deny physicalism.