From PhilPapers forum Philosophy of Mind:

2012-01-23
What it is like to have been a zombie
Reply to Bill Meacham
I cannot make headway with the idea that consciousness is not necessary for certain responses. Even if we note that there is a circularity hanging on "consciousness" and "response" and replace "response" with "movement" then we must be reminded that under the principles of science consciousness is neither necessary nor not (contingently) necessary for movement, but necessarily cannot affect matter at all.

As I pointed out earlier, in the 60's experiments run by Stan Grof at the Esalen Institute people could recall their experiences from operations when they were in deep anaesthesia, and not merely while they were semi-aware. Of course, it would not be productive to ask what their experiences were while under.

There is a danger of claiming too much for the brain sciences. Their anthropomorphism and animism (as arises in, for example, speaking of response rather than movement, and the idea of a consciousness function) veil the epistemological vacuum that emerges from their reductionist enterprise. Philosophers beware.