How does Brutus respond to the appearance of Caesar's ghost and why?

Julius Caesar’s ghost first appears to Brutus on a night when he cannot sleep. It seems as though Brutus’s guilt and worry keep him awake. He has no idea what the apparition is and only knows that he is terrified: “Art thou some god, some angel, or some devil, / That makest my blood cold and my hair to stare?” Interestingly, the ghost replies that he is “Thy evil spirit, Brutus.” The ghost could represent both Caesar’s revenge and Brutus’s conscience, which partially spoke against killing his friend Caesar.

The spirit simply says that he will see Brutus at Philippi. This is a portent of doom signifying that Brutus’s military campaign will not go well and that he will lose his life. Brutus then wakes his servants in a fright and asks if they have cried out, but they all deny it. Caesar’s ghost does appear to him again “in Philippi fields,” which discourages Brutus so much that he decides to commit suicide: “I know my hour is come.” Brutus does not seem particularly enthusiastic about the way his coup has gone, and the ghost symbolizes how the death of his friend weighs too heavily upon him to live.