Why do patients with "alien hand" syndrome wake up to find themselves being strangled by their own left hand? How are some blind people able to see without being consciously aware of it? We will deal with such bizarre and unfortunate neural disorders, asking "why" -- why do certain syndromes produce these contradictory behaviors? Studies of these types of syndromes have revolutionized neuroscience. What can we learn about the human brain from these cases? Is one brain really a crowd of bickering voices?