I know of at least one case or condition that shows the body can operate completely on its own without consciousness, and that is the condition of sleepwalking or parasomnia.
Source: HowStuffWorksSleepwalkers are capable of performing a variety of activities, from simply getting up and walking around the room to driving a car or playing an instrument.
Sleepwalking isn't the only parasomnia. There's also sleepsex, sometimes called sexsomnia or SBS (somnambulistic sexual behavior). It's pretty much what it sounds like — sexual behavior during sleep. People with this condition might touch themselves sexually or initiate sex while asleep. They only know it happened when their roommate or partner mentions the incident. One man was actually acquitted of rape after using the defense that he was asleep at the time of the assault
On another thread, DrNoGods tried to counter by saying that sleepwalkers are conscious.
It seems that he or she is forgetting that sensory information can be processed unconsciously, e.g. 'subliminal perception'. The body can also move on its own or without conscious will, and we have plenty of examples when it comes to reflexes and other types of involuntary movements. This convinces me that the body is capable of being an automaton or in zombie-like mode. Again, if the brain/body has no need or function for consciousness, then we can't say that consciousness is tied to the brain. Also, the experts define sleepwalking as "unconscious" behavior.I'd argue that the sleepwalker is still conscious in that the brain is working and some sensory input is working, but while still in a state of sleep. Such people can apparently navigate a room, make it to the fridge and eat a snack, etc. which would not be possible without some of the usual sensory inputs and processing by the brain.
For debate:
1. IF there is no functional role for consciousness, then does that mean it is not tied to the brain? If not tied to brain, then can it exist separately?
2. Is sleepwalking a valid example of the brain/body being able to function without consciousness? And by that I mean being able to perform virtually all possible bodily actions that we tend to describe as being "conscious" or alert behavior, such as eatting, talking, driving?