The creative responsibility of an actor is obliged to carefully study the text, scene by scene, elucidating the general and immediate concern of the character, along with the objectives they have as well as the tactics that the character employs to achieve them.
             In Act I, Scene 5, Hamlet's overarching motivation is to find out the identity and the nature of the ghost. Is it his father? Why the ghost is haunting the castle? At the beginning of the scene, Hamlet has been lured, against Horatio's better judgment, away from his friends to a remote place. Hamlet said in the scene before that he did not value his life, but he clearly has some reservations as he begins the scene by saying "Where wilt thou lead me? speak; I'll go no further." He is essentially bargaining with the mysterious ghost, hoping that the ghost will reveal his mission rather than force him to perhaps risk his life by going to the edge of the castle wall. After all, the ghost might be a devil.
             The ghost of Hamlet's father, if one accepts that the ghost really is Hamlet's father and is telling the truth, is trying to persuade his son to avenge his murder. The ghost of the old king wants his son Hamlet, who he knows is an intellectual, indecisive, but loving boy, to act in a murderous way. So the ghost uses every persuasive technique at his disposal. He uses logic, showing Hamlet that only the victim could know how he was killed in such a strange way. He uses ethical appeals to Hamlet as a Dane: "Let not the royal bed of Denmark be/A couch for luxury and damned incest." And he also uses emotional appeals to Hamlet: "If thou didst ever thy dear father love-"
             The ghost is angry, because only he, at this point in the play, knows that he was the victim of a "foul and most unnatural murder." Even his former wife and queen does not know what Claudius is capable of, and this desire to reveal the truth is one reason that the ghost is so determined to explain how: "the wh...