The tone of the play is fatalistic, creating the sense that the natural world has been thrown out of order by Macbeth’s unnatural ascension to the throne. Violence or the possibility of violence exists throughout, and there are very few light or playful moments. The play opens in the aftermath of a bloody battle, and even though the rebels have been defeated, this opening creates an unstable and threatening atmosphere and a tone of justified fear. The appearance of the witches suggests that the world of the play is one where supernatural elements can torment humans and unleash dark forces against them. The first time the witches appear, their references to “fair is foul and foul is fair,” and “fog and filthy air” convey the sense of an impending storm, and the elements in conflict with each other. The setting, the references to battle, and the natural phenomena all serve to quickly create a tone suggesting that the world is a hostile place.
After Macbeth murders Duncan, the tone becomes even more foreboding, as Macbeth’s guilt causes him to become paranoid. Rather than appearing triumphant when he returns to his wife in Act 2, Scene 2, Macbeth is horrified. He worries that he was unable to say the word “Amen”, indicating that he has possibly damned his soul, and he also reveals that “methought I heard a voice cry, “Sleep no more!” (2.2.38). This moment could have been triumphant for Macbeth and his wife, but instead is the turning point after which neither of them will ever be able to feel a sense of peace again. Adding to Macbeth’s own paranoia and guilt, the world itself seems to have come unhinged from reality. Immediately after Duncan’s death, an Old Man reports that a falcon was killed by an owl, and Duncan’s horses ate each other. At the banquet in Act 3, Scene 4, Macbeth is tormented by visions of Banquo’s ghost, leaving him panicking that “the time has been/That, when the brains were out, the man would die/And there an end. But now they rise again” (3.4.78-80). The rules of nature no longer apply: sleep disappears; the dead re-appear; animals become cannibals.
By the end of the play, the tone has devolved from fearful and foreboding to deeply pessimistic. Both Macbeth and Lady Macbeth disintegrate from the charismatic and keenly intelligent characters we see at the beginning of the play into shadows of their former selves. Lady Macbeth kills herself, tormented by guilt. “What’s done cannot be undone, she says,” (5.1.60-61) reflecting her despair. While Lady Macbeth began the play as a woman who believed she could change the course of her destiny, she ends it without any sense of agency, resigned to the consequences of her tragic mistake. Macbeth persists in his arrogant belief that the witches’ prophecies mean he is indestructible until he is confronted by the actual truth of their words. When a messenger reports that Birnam Wood is in fact approaching Dunsinane, Macbeth realizes all is lost, and resolves to face his death, seeming to even welcome it. “I ‘gin to be aweary of the sun/ And wish th’ estate o’ th’ world were now undone,” he says. By the time he meets Macduff in battle, he seems fatalistically curious about how a man “not of woman born” will kill him, no longer convinced he is actually invulnerable. The final scene has a fatalistic tone as Macbeth finally accepts his mortality and realizes he is not above the laws of nature.