Even for experts, the vegetative state is a very disturbing condition. It illustrates how the two main components of consciousness can become completely dissociated: wakefulness remains intact, but awareness--encompassing all thoughts and feelings--is abolished. By wakefulness, I mean that patients in a vegetative state have sleep/wake cycles. At the times when they seem to be awake, their eyes open and sometimes wander. At other times they keep their eyes shut and appear to be asleep, although they may open them and stir when touched or spoken to. These patients usually can breathe without technical assistance and can make a variety of spontaneous movements--such as grinding teeth, swallowing, crying, smiling, grasping another's hand, grunting or groaning--but these motions are always reflexive and not the result of purposeful behavior. Typically patients will not fix their eyes on anything for a sustained period, but in rare instances they may briefly follow a moving object or turn fleetingly toward a loud sound.