Even if you maintain that the brain is the “sole” source of cognition, the brain is still an organ and is heavily affected by the operation of other organs.
Sure but if all of the cognition is within the brain, the rest can be conceivably simulated as inputs to the brain, we might also have to simulate an environment for it.
Yours is ultimately a thesis about embodied cognition, as I understand it. If cognition is strongly embodied, then a functional human brain will need to have a very accurately simulated/emulated human body. If cognition is weakly embodied, and the brain’s digitalised neuroplasticity is flexible enough, we can get away with not simulating an actual human body.
I don’t think the debate is settled.
The cognitive system embedded within the body that is writing now (‘me’) sometimes registers certain things (‘feelings’) and sometimes doesn’t, I call the first “being conscious” and the second “not being conscious”. Then I notice that not all of the things that my body’s sensory systems register are registered as ‘conscious feelings’ all of the time (even while conscious), and that some people even report not being aware of their own sensorial perception of things like vision.
Whatever thing causes that difference in which things get recorded is what I call ‘consciousness’. Now I ask how that works.
Presumably, that it has the type of cognitive structures that allow an entity to feel (and maybe report) consistently feelings about the same sensory inputs in similar contexts.
I don’t know how well our intuition about ‘consciousness’ tracks any natural phenomenon, but the consistent shifting of attention (conscious VS subconscious) is a fact as empirically-proven as any can be.