The deeper that investigators dig, the more hidden chambers they find. Last Wednesday, scientists in England and Belgium reported that five people with severe brain injuries who had been identified as “vegetative,” beyond reach, showed activity on brain imaging that strongly suggested conscious awareness. One of them, a 29-year-old man thought to be “vegetative” for five years, began to answer yes and no questions by alternately showing brain activity when thinking about tennis (lighting motor areas), then about walking in his house (lighting spatial areas).

A locked door on consciousness had swung open, all right; but on the other side was yet another dark corridor. After five years of being in effect buried alive in its own skull, what kind of consciousness was left for this patient? Who, exactly, lives behind those blank eyes? And, for that matter, what name do we give to this conscious state that looks totally absent, except for the ghostly blinking pixels on a brain imaging machine?