It should be said that Dennett’s overall stance on consciousness is not always entirely clear. His “user-illusion” story comes at the end of the book, and offers a not entirely implausible explanation of why we make the mistake of thinking our conscious thoughts have a reality beyond the material realm. Still, you might well wonder where that leaves consciousness itself, as opposed to our mistaken ideas about it. What about animals, who certainly don’t monitor their own thoughts, and so are surely free of the “user-illusion”, but which one might have supposed could still be conscious for all that? As it happens, Dennett raises the question of animal consciousness at various points in the book, and says he will sort it out in due course, but as far I could see he never does.
Even more puzzling is a claim Dennett makes in the course of the “user-illusion” story: “We won’t have a complete science of consciousness until we can align our manifest-image identifications of mental states . . . with scientific-image identifications of the subpersonal informational structures and events that are causally responsible for generating the details of the user illusion . . .”. This brought me up short. It is exactly what Dennett’s mainstream philosophical opponents would say. Conscious states are internal brain states that we currently refer to in other ways, but that will in time be identified by science. In the end, I was rather left wondering what the “user-illusion” fuss was all about.
more here.