The document is an essay analyzing reasons for Hamlet's strange behavior in Shakespeare's play Hamlet. It discusses several potential causes, including his father's death, his mother's remarriage, and his uncertainty over whether to avenge his father based on the instructions from a ghost that may have actually been the devil. The essay argues that the main reason for Hamlet's insanity is encountering the ghost, which makes him paranoid and indecisive about whether to believe and act on its message since ghosts were thought to possibly be devils in that time period. This leads Hamlet to question his own sanity.