Non-existence

[Jon Paul]

Consciousness is a product of the brain and does not exist without the brain.

"Consciousness", in philosophical zombies view of reality, means consciousness of brain states, so to speak of consciousness of brain states without a brain is obviously nonsense. But as I've already said, there is no proof that brain states causally depend upon nor causally necessitate consciousness of those brain states, either. I've already given a refutation of those claims.

So consciousness of the brains states depends upon the brains states. I am clearly aware of that. That in no way, proves out of either general principles or observational knowledge, that the existence of a brain causally necessitates the existence of conscious experience. The only reason to think that it does is that I am myself conscious of my brains states, and then I am appealing to my own knowledge of my own conscious experience of my brains states, a knowledge I emphatically do not have of other brains. It is both a) externally unverifiable, and b) unnecessary to explain the brain states and behaviour of the human being, and c) unwarranted by general principles or specific observational knowledge, and d) unwarranted due to the lack of knowledge about the internal conscious experience or lack thereof of another brain, the very standard for the knowledge I have of my own conscious experience which I use to justify the idea that I have consciousness, to postulate that there is a necessary causative link between brain states and consciousness and that followingly other brains have conscious experience like I do, just because I do. From a scientific point of view, it is certainly not a valid claim.

There can be no consciousness and therefore no mind outside of the brain.

While philosophical zombies acknowledges the existence of the brain, and therefore acknowledges that there can be no consciousness of brain states without brain states to be conscious of, solipsism does not, and since you derive all your knowledge of the brain from your conscious experience of sense-data, there is no way to demonstrate solipsism to be false based on information that derives from your own conscious experience of sense-data without begging the question of realism, that reality exists independently of my conscious experience of sense-data.

In either case, both in the case of realist naturalism which denies other minds (philosophical zombies), and realist noetism which acknowledges other minds, or internal idealism/noetism (solipsism), your conclusions boil down to certain foundational beliefs and presuppositions, if you analyse it properly.