http://en.wikipedia.org/wiki/Philosophical_zombie
A philosophical zombie or p-zombie is a hypothetical being that is
indistinguishable from a normal human being except that it lacks
conscious experience, qualia, or sentience. When a zombie is poked
with a sharp object, for example, it does not feel any pain. While it
behaves exactly as if it does feel pain (it may say "ouch" and recoil
from the stimulus, or tell us that it is in intense pain), it does
not actually have the experience of pain as a putative 'normal' person does.
