The banquet is simultaneously the high point of Macbeth’s reign and the beginning of his downfall. Macbeth’s bizarre behavior puzzles and disturbs his subjects, confirming their impression that he is mentally troubled. Despite the tentativeness and guilt she displayed in the previous scene, Lady Macbeth here appears surefooted and stronger than her husband, but even her attempts to explain away her husband’s “hallucination” are ineffective when paired with the evidence of his behavior. The contrast between this scene and the one in which Duncan’s body was discovered is striking—whereas Macbeth was once cold-blooded and surefooted, he now allows his anxieties and visions to get the best of him.
It is unclear whether Banquo’s ghost really sits in Macbeth’s chair or whether the spirit’s presence is only a hallucination inspired by guilt. Macbeth, of course, is thick with supernatural events and characters, so there is no reason to discount the possibility that a ghost actually stalks the halls. Some of the apparitions that appear in the play, such as the floating dagger in Act 2, scene 1, and the unwashable blood that Lady Macbeth perceives on her hands in Act 4, appear to be more psychological than supernatural in origin, but even this is uncertain. These recurring apparitions or hallucinations reflect the sense of metaphysical dread that consumes the royal couple as they feel the fateful force of their deeds coming back to haunt them.
Given the role that Banquo’s character plays in Macbeth, it is appropriate that he and not Duncan should haunt Macbeth. Like Macbeth, Banquo heard the witches’ prophecies and entertained ambitions. But, unlike Macbeth, Banquo took no criminal action. His actions stand as a rebuke to Macbeth’s behavior and represent a path not taken, one in which ambition need not beget bloodshed. In Holinshed’s Chronicles, the history that served as the source for Shakespeare’s Macbeth, Banquo was Macbeth’s accomplice in Duncan’s murder. Shakespeare most likely changed Banquo’s role from villain to moral pillar because Shakespeare’s patron, King James I of England, was believed to be Banquo’s descendant.
Shakespeare also portrays the historical figure of King Edward the Confessor, to whom Malcolm and Macduff have gone to receive help combating Macbeth. Edward is presented as the complete opposite of the evil, corrupt Macbeth. By including mention of England and Scotland’s cooperation in the play, Shakespeare emphasizes that the bond between the two countries, renewed in his time by James’s kingship, is a long-standing one. At the same time, the fact that Macbeth’s opposition coalesces in England is at once a suggestion that Scotland has become too thoroughly corrupted to resist Macbeth and a self-congratulatory nod to Shakespeare’s English audience.