This was a wonderful book. As I recall, it catalogs a lot of convincing evidence that things come into conscious awareness basically upon a certain level of global activation in the brain -- when enough parts of the brain are "talking" about it, typically when different parts of the brain are having conflicting activation patterns. It likens this to the "workspace model" of awareness. And it's clear why the brain would need to resolve such a conflict, why it would need something like focus or attention to do so, and how this would relate to all sorts of information processing needs of organisms that behave in ways that keep them alive.

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.