Macbeth examines the nature of evil and the corruption of the human soul. In Macbeth evil is the opposite of humanity, the deviation from that which is natural for humankind, yet evil originates in the human heart. Supernatural and unnatural forces are the agents of human beings, not their instigators. The witches’ words do not seduce Macbeth. He is compelled by his own ambition and his wife’s ruthlessness. Similarly, spirits do not solicit Lady Macbeth, rather she invokes their aid for her purposes.
The character Macbeth, like the play itself, is a collection of contradictions. His wife believes that his “nature / . . . is too full o’th’ milk of human kindness / To catch the nearest way” (1.5.15 17, all references are to Stanley Wells and Gary Taylor, eds., William Shakespeare: The Complete Works [Oxford: Oxford University Press, 1988]). At the beginning of the play, he seems the epitome of a loyal subject, valiantly fighting the rebel forces to protect the king and preserve his power. Described as an almost superhuman warrior on the field of battle, brave Macbeth “carv’d out his passage” (1.2.20) through the enemy till he reached the traitor Macdonald, “unseamed him from the nave to th’ chops, / And fix’d his head upon ... [the] battlements” (1.2.22 23).
When we actually meet Macbeth and Banquo, however, we see interesting contrasts that belie the great hero. His first words, “So fair and foul a day I have not seen” (1.3.36) echo the “Fair is foul, and foul is fair” (1.1.10) of three witches in scene one and immediately link him to them. Upon his bidding, the witches speak, greeting him with three titles: Thane of Glamis, Thane of Cawdor, and king hereafter (1.3.46 48). Macbeth hears their words not with the detached skepticism of Banquo but with a kind of fear. For him, this is not a revelation of the future but an invasion of his private, hidden thoughts. His first reaction is like one who has been discovered. Banquo asks him, “Good sir, why do you start and seem to fear / Things that do sound so fair?” (1.3.49 50).
After Ross and Angus inform him that Duncan has bestowed upon him the title of the thane of Cawdor, validating the witches’ second title, Macbeth analyzes their words: “This supernatural soliciting / Cannot be ill, cannot be good. If ill, / Why hath it given me earnest of success / Commencing in a truth? I am thane of Cawdor. / If good, why do I yield to that suggestion / Whose horrid image doth unfix my hair / And make my seated heart knock at my ribs / Against the use of nature? (1.3.129 36). The witches’ words were neutral. It is Macbeth that puts a moral value to them, concluding that he must perform an unnatural act to acquire the title of king.
But the clear knowledge that killing a king, a kinsman, and a guest in his house is against all social propriety, natural order, and human or humane behavior puts Macbeth at war with himself. As he says, he dares to “do all that may become a man; / Who dares do more is none” (1.7.46 47). It is impossible to murder Duncan, a man of great virtue and sound leadership, and remain human. His desire for the crown and his revulsion at the means he must use to obtain it cause him to vacillate. At Lady Macbeth’s urging, he agrees, “I am settled, and bend up / Each corporal agent to this terrible feat” (1.7.79 80), putting aside his earlier refusal, “We will proceed no further in this business” (1.7.31).
Having performed the act, he is immediately filled with remorse. His bloody hands are a “sorry sight” (2.2.19). He cannot voice an amen to an overheard prayer, “I had most need of blessing, and ‘Amen’ / Stuck in my throat” (2.2.30 31), having made himself no longer a man, no longer worthy of blessing. He imagines a voice crying, “‘Sleep no more, / Macbeth does murder sleep’” (2.2.33 34). He is incapable of returning to Duncan’s chamber to put the bloody daggers with the grooms. Hearing the knocking at the gate, he says, “Wake Duncan with thy knocking. I would thou couldst” (2.2.72).
Despite his profound remorse, he does nothing to right the wrong. His fear of earthly justice compels him to make more inhuman choices. He proceeds with the plan to place the blame upon the grooms and kills them before they can establish their innocence. He believes Banquo suspects him and attempts to have Banquo and Fleance killed, succeeding only with Banquo’s death and Fleance’s escape. Murder becomes his primary tool of leadership. Having missed the opportunity to kill Macduff, he resolves to kill Lady Macduff, her children, “and all unfortunate souls / That trace him in his line” (4.1.168 69). By the end of the play, Macbeth is a bloody tyrant, disappointed in all aspects of his life-—his reign, his marriage, a family for a potential dynasty-—and damned for eternity in his death.
Lady Macbeth’s decline mirrors her husband’s. Denying her humanity, she too turns against human nature. To contemplate such horror and steel Macbeth to kill Duncan she calls upon spirits “that tend on mortal thoughts [to] unsex . . . [her] / And fill . . . [her] from the crown to the toe top-full / Of direst cruelty” (1.5.40 42), turning her into an unnatural creature like the witches, who are neither male nor female. Her denial of her essential nature is unsuccessful. She cannot bring herself to murder Duncan for the human reason that he resembled her father as he slept. Despite her assurance that “A little water clears us of this deed” (2.2.65), she cannot forget her actions. The innocent dead haunt her dreams as she walks through the castle in her sleep, washing her hands, trying to remove the stain of her inhuman acts. But no water can clear the blood from her hands; no power can free her from her guilt. “What’s done cannot be undone” (5.1.65).
The evil of Macbeth and Lady Macbeth is so great that ultimately it destroys both of them. The human soul cannot endure such evil. One way or another evil destroys the soul. Knowing he is doomed to lose, Macbeth still battles against Macduff, the representative of virtue and the redresser of the play. Lady Macbeth is defeated by madness and death. Evil is incompatible with humanity.