In King Lear there are no ghosts, as there are in Richard III, Julius Caesar, or Hamlet; no witches, as in Macbeth; no mysterious music of departing daemons, as in Antony and Cleopatra. King Lear is haunted by a sense of rituals and beliefs that are no longer efficacious, that have been emptied out. The characters appeal again and again to the pagan gods, but the gods remain utterly silent. Nothing answers to human questions but human voices; nothings breeds about the heart but human desires; nothing inspires awe or terror but human suffering and human depravity. For all the invocation of the gods in King Lear, it is clear that there are no devils.
— Stephen Greenblatt, from Shakespeare and the Exorcists (via radagast)