Advertisement I know the evidence is strong-it is just hard as humans I spose to grasp the notion of no pain. I'm just looking at it this way-if you chuck a T onto a hot plate it is going to try and get off. Why? Surely something must be registering that something is wrong, and isn't that the true evolutionary function of pain? What is the difference between pain and "negative stimulus" as some people have made reference to? I am sure that the whole concept of pain, if they had one, would be deprived of the psychological input of human pain, but does pain necessarily have to be registered consciously?