But there's just nothing that I recall in that book that suggests or even hints at any reason for this to result in a subjective experience. And I don't believe it rules out an electron having a nano-unit of subjective experience, for example.
The book suggests that something is a subjective experience if an organism can report it as one, and goes to great detail about what's going on in the brain when an organism is able to report a subjective experience, and makes the very reasonable suggestion that something is probably a subjective experience in a brained organism that can't report it as one so long as it exhibits all the same patterns in that organism's brain (infants, other animals).
But I don't think it does any work at all to show that there is no subjective experience in plants, or rocks, or even nano-units of subjective experience in individual electrons. It can't do this, because, as far as I recall, there is simply no progress on the problem of why this global activation in the brain would produce a subjective experience.
Also, just because someone reports having a subjective experience, doesn't mean that they actually have one. I do have subjective experience, but I have no way of telling whether someone else has one, even if they claim so.
I don't believe you. ;-)
Sorry.
I know it sounds outlandish but it does point the gap in your proof.
Unfortunately all our word definitions seems shaky, if we want to describe something that is the base requirement of those very definitions.
Maybe the best we can do is to deconstruct the above using more simple or base terms, but the meaning of those terms maybe also depends on the content of experience not the mere fact of experience:
I experience thought -> experience of thoughts exists -> experience exists -> something exists
So upon experiencing thought you may conclude that "something exists", or "there IS something"...
Of course you can. You know it to be true that you posses consciousness because you experience it directly. What is impossible (empirically) is knowing that about anyone or anything else.
In a similar way, "I" can say that consciousness exists, and is taking the form I call "my perspective," but that's about all.
We know there is thinking. There is no reason to believe that subject-object duality has any basis in reality, or that any individual, including our "self", has a sufficient delineation to consider it an independent entity.
Regardless of whether there is a "you" or if it's some amalgamation of state that is loosely bounded together and "fooled" into thinking it is a unity, something is there experiencing. At least in my frame there is.
This isn't something you can prove because it comes any sort of structure capable of doing proving. It's just something that's a given and you start from there.
Descartes' "Meditations on First Philosophy" is the originator of this idea. While it is dated, the form of its principal argument hasn't changed.
With regards to conscious unity, there is at least a weak form of it in the sense that you can't experience others' experiences. While it is possible that your own experience may not be fully unified, it is (very likely) disjoint from others' experiences.
https://www.cbc.ca/cbcdocspov/features/the-hogan-twins-share...
I've never been very moved by ideas that I can't know or share other people's feelings, or other fanciful ideas like their blue is my green. It's more reasonable to assume they are like me because we share similar hardware (DNA) and software (Culture). Others hands look like mine, more or less. Others legs are like mine, more or less. And so others perception of green is like mine, more or less.
Telling me that my experience is prime, or fundamental doesn't tell me much. Similarly, saying I think therefore I am doesn't tell me much. What then am I and what is existence? I think therefore I am only as much as I think I am. And sometimes I forget myself.