insentience

from WordNet (r) 3.0 (2006)

insentience
    n 1: lacking consciousness or ability to perceive sensations
         [ant: {sentience}]

from The Collaborative International Dictionary of English v.0.48

insentience \insentience\ n.
   The state or quality of being insentient; lacking
   consciousness or ability to perceive sensations.
   [WordNet 1.5]