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 one where it is a definition or conceptual relation. It is central for Chalmers' viewpoint that the relation between consciousness and functional states is irreducibly contingent, but this kind of law would be unlike any other one in physics.

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 think you are mixing two things here: whether introspective evidence is evidence, which I agree to (e.g., when I "feel like I am seeing something green", I very likely am in the state of "seeing something green"); and whether that "stuff" that when we introspect we describe with phenomenal concepts must necessarily be described with those concepts (instead of with more sophisticated and less intuitive concepts, for which the zombie/Mary's Room/etc arguments would fail).