It is possible to use language meaningfully without knowing exactly how it pans out in terms of precise configurations of matter
I have never claimed otherwise. In fact, there is literally nothing that I have exact description of, in terms of matter - neither pain nor chairs. But you have to know something. I know that "chair is what I sit on" and from that there is a natural way to derive many statements about chairs. I know that "gravity is what makes things fall down", and from that there is a fairly straightforward way to the current modern understanding of gravity. There is nothing that you know about consciousness, from which you can derive a more accurate and more material description.
Treating pain semantically as some specific brain activity buys you nothing
It buys me the ability to look at "do robots feel pain" and see that it's a stupid question.
And without committing yourself to evil dualism.
What evil dualism?
There is nothing that you know about consciousness, from which you can derive a more accurate and more material description.
How do you know? And what of things like https://en.wikipedia.org/wiki/Global_Workspace_Theory ?
It buys me the ability to look at "do robots feel pain" and see that it's a stupid question.
It doesn't seem to have given you the ability to prove that it is a stupid question.
(This post grew out of an old conversation with Wei Dai.)
Imagine a person sitting in a room, communicating with the outside world through a terminal. Further imagine that the person knows some secret fact (e.g. that the Moon landings were a hoax), but is absolutely committed to never revealing their knowledge of it in any way.
Can you, by observing the input-output behavior of the system, distinguish it from a person who doesn't know the secret, or knows some other secret instead?
Clearly the only reasonable answer is "no, not in general".
Now imagine a person in the same situation, claiming to possess some mental skill that's hard for you to verify (e.g. visualizing four-dimensional objects in their mind's eye). Can you, by observing the input-output behavior, distinguish it from someone who is lying about having the skill, but has a good grasp of four-dimensional math otherwise?
Again, clearly, the only reasonable answer is "not in general".
Now imagine a sealed box that behaves exactly like a human, dutifully saying things like "I'm conscious", "I experience red" and so on. Moreover, you know from trustworthy sources that the box was built by scanning a human brain, and then optimizing the resulting program to use less CPU and memory (preserving the same input-output behavior). Would you be willing to trust that the box is in fact conscious, and has the same internal experiences as the human brain it was created from?
A philosopher believing in computationalism would emphatically say yes. But considering the examples above, I would say I'm not sure! Not at all!