our concepts change and evolve with the growth of scientific knowledge; what is concievable now may become unconcievable later and vice-versa. Concepts are just tools for describing the world, and we can change them and reform them if we need to. This picture of science, familiar since Quine, is pressupposed by Dennett, but implicitly rejected by Chalmers.
I'm pretty confident Chalmers would disagree with this characterization. Chalmers accepts that our concepts can change, and he accepts that if zombies fall short of ideal conceivability — conceivability for a mind that perfectly understands the phenomena in question — then dualism will be refuted. That's why the Mary's Room thought experiment is about an ideally extrapolated reasoner. The weakness of such a thought experiment is, of course, that we may fail to accurately simulate an ideally extrapolated reasoner; but the strength is that this idealization has metaphysical significance in a way that mere failure of contemporary imagination doesn't.
It may provide a fundamental theory or a list of them but not a list of fundamental entities the world is made of with a list of contingent laws of nature holding between them. What an entity such like the electromagnetic field is, is defined by what laws of nature it obeys and therefore by its relations with other entities.
If contemporary science's best theory posits fundamental entities, then contemporary science posits fundamental entities. Science is not across-the-board ontologically agnostic or deflationary.
Unless I'm misunderstanding you, your claim that a physical theory is equivalent to its Ramsey sentence is a rather different topic. I think Chalmers would respond that although this may be true for physical theories at the moment, it's a contingent, empirical truth — we happen to have discovered that we don't need to perform any ostensive acts, for instance, in fixing the meanings of our physical terms. If science discovered an exception to this generalization, science would not perish; it would just slightly complicate the set of linguistic rituals it currently uses to clarify what it's taking about.
But this shows that all the zombie arguments are question-begging, because to carry any force they must assume that there is something very special about consciousness that distinguishes it from other subjects for science in the first place.
This isn't an assumption. It's an inference from the empirical character of introspection. That is, it has a defeasible (quasi-)perceptual basis. Many eliminativists want it to be the case that dualists are question-begging when they treat introspective evidence as evidence, but introspective evidence is evidence. Chalmers does not take it as axiomatic, prior to examining the way his stream of consciousness actually looks, that there is a special class of phenomenal concepts.
I'm not a dualist, but I don't think any of Chalmers' arguments are question-begging. They just aren't strong enough to refute physicalism; physicalism has too many good supporting arguments.
Thanks for your comments!
In the second paragraph you quote, I was not trying to make a strong statement about scientific theories being equivalent to Ramsey sentences, though I see how that is a natural interpretation of it. I meant to support my previous paragraph about the lack of a strong distinction between conceptual implications and definitions, and contingent/nomological laws. For each "fundamental law of physics", there can be one axiomatization of physical theory where it is a contingent relation between fundamental entities, and another...
Let's say Bob's terminal value is to travel back in time and ride a dinosaur.
It is instrumentally rational for Bob to study physics so he can learn how to build a time machine. As he learns more physics, Bob realizes that his terminal value is not only utterly impossible but meaningless. By definition, someone in Bob's past riding a dinosaur is not a future evolution of the present Bob.
There are a number of ways to create the subjective experience of having gone into the past and ridden a dinosaur. But to Bob, it's not the same because he wanted both the subjective experience and the knowledge that it corresponded to objective fact. Without the latter, he might as well have just watched a movie or played a video game.
So if we took the original, innocent-of-physics Bob and somehow calculated his coherent extrapolated volition, we would end up with a Bob who has given up on time travel. The original Bob would not want to be this Bob.
But, how do we know that _anything_ we value won't similarly dissolve under sufficiently thorough deconstruction? Let's suppose for a minute that all "human values" are dangling units; that everything we want is as possible and makes as much sense as wanting to hear the sound of blue or taste the flavor of a prime number. What is the rational course of action in such a situation?
PS: If your response resembles "keep attempting to XXX anyway", please explain what privileges XXX over any number of other alternatives other than your current preference. Are you using some kind of pre-commitment strategy to a subset of your current goals? Do you now wish you had used the same strategy to precommit to goals you had when you were a toddler?