>We have not proven "to a level of absolutely provable certainty" that other humans are also conscious
Sure, it's not proven, it just has overwhelmingly strong empirical and intuitive reasons for being most likely true, which is the most we can say while still showing necessary humility about limits of knowledge.
You seem to treat this like it presents a crisis of uncertainty, wheras I think it's exactly the opposite, and in fact already said as much with respect to bats. Restating the case in human terms, from my perspective, is reaffirming that there's no problem here.
>we are supposed to reject behavioral and structural arguments (from 3rd person) in discussion about consciousness.
Says who? That presupposes that consciousness is already of a specific character before the investigation is even started, which is not an empirical attitude. And as I noted in a different comment, we have mountains of empirical evidence from the outside about necessary physical conditions for consciousness to the point of being able to successfully predict internal mental states. Everything from psychedelic drugs to sleep to concussions to brain to machine interfaces to hearing aides to lobotomies to face recognition research gives us evidence of the empirical world interfacing with conscious states in important ways that rely on physical mechanisms.
Similarity in structure and behavior are excellent reasons for having a provisional attitude in favor of consciousness of other creatures for all the usual reasons empirical attitudes work and are capable of being predictive that we're familiar with from their application in
"But consciousness is different" you say. Well it could be, that that's a matter for investigating, not something to be definitionally pre-supposed based on vibes.
>Not only that, but what would be an alternative to "it feels like something?"
It not feeling like something, for one. So, inert objects that aren't alive, possibly vegetative states, blackouts from concussions or drugs, p-zombies, notions of mind that attempt to define away qualia and say it's all "information processing" (with no specific commitments to that feeling like something), possibly some variations of psychedelic feeling that emphasize transcendent sense of oneness with the universe. But fundamentally, it's an affirmative assertion of it feeling like something, in contrast to noncommital positions on the question, which is a meaningful point rather than something trivially true due to a definitional necessity.
>Another issue I have with the qualia framing is that nobody talks about costs. It costs oxygen and glucose to run the brain. It costs work, time, energy, materials, opportunity and social debt to run it. It does not sit in a platonic world.
That would seem to run contrary to the point you were making above about it not being inferrable from phenomena characterized in the third person. You can't argue that third person descriptions of structures that seem necessary for consciousness are a "cop out" and then turn around and say you know it "costs" things expressed in those same third person terms. Like you said before, your position seems to be that you only know you are conscious, so you don't even know if other people are conscious at all let alone that they need such things as work, time, oxygen, or glucose. Pointing to those is a cop-out, right?