To break the walls down on this thread, interested folks probably want to look at the question of qualia and the knowledge argument before they start wondering about free will in particular.
Not relevant. You need not know what someone else’s subjective experience is to know that it would violate all understanding of the physical universe for them to have free will.
“The wall” doesn’t come from any dispute around the subjective experience or the objective physical nature of the universe. It comes from the (understandable) discomfort with the conclusion and the necessary corollaries of that conclusion.
Totally relevant. You claim that someone having free will would violate all understanding of the physical universe. This is absurd, and therefore we should reject it.
If, however, information which is non-physical information exists, like TKP suggests, then we have evidence of an ontological jailbreak. If one such jailbreak exists, it suddenly seems much more absurd to claim others can't for some reason.
TKP doesn’t suggest “non-physical information” exists. It suggests that some information cannot be relayed through means other than direct personal experience. When the actual blue light hits Mary’s retina, that is net new information, and information that could not have been conveyed by numbers on a monochrome screen. It is very obviously physical: the text “blue light has a wavelength of 450nm” conveyed in light at 700nm is a totally different piece of information that will be processed by the retina and the brain totally differently from an actual beam of 450nm light.
Critically: in either case the brain will process those photons hitting the eye with a combination of random and deterministic processes. This is a physical fact, not a thought experiment, and so I think warrants a stronger rebuttal than simply asserting, “this is absurd, and therefore we should reject it.” If it’s not a physical fact, explain what other non-random and non-deterministic process is happening.
What specifically is absurd? That your subjective experience disagrees? We can reliably and trivially produce all sorts of illusions in which your subjective experience loses touch with objective reality.
“The wall” doesn’t come from any dispute around the subjective experience or the objective physical nature of the universe. It comes from the (understandable) discomfort with the conclusion and the necessary corollaries of that conclusion.