This is a defining element of their nature, a paradox that identifies them as witches: a specifically female propensity to evil–being a witch–is defined by its apparent masculinity. This also is, of course, one of the central charges leveled at Shakespeare’s theater itself, the ambiguity of its gender roles, the fact that on Shakespeare’s stage the women are really male. But the gender ambiguity relates as well to roles within the play: Lady Macbeth unsexes herself, and accuses her husband of being afraid to act like a man. What constitutes acting like a man in this play? The answer would seem to be, only killing. Lady Macbeth unsexing herself, after all, renders herself, unexpectedly, not a man but a child, and thus incapable of murder: “Had he not resembled / My father as he slept, I had done’t” (II.2.12–13). Indeed, the definitive relation between murder and manhood applies to heroes as well as villains. When Macduff is told of the murder of his wife and children and is urged to “Dispute it like a man,” he replies that he must first “feel it as a man” (IV.3.220–21). Whatever this says about his sensitivity and family feeling, it also says that murder is what makes you feel like a man.

The unsettling quality of the witches goes beyond gender. Their language is paradoxical–fair is foul and foul is fair; when the battle’s lost and won. One way of looking at this is to say that it constitutes no paradox at all: any battle that is lost has also been won, but by somebody else. The person who describes a battle as lost and won is either on both sides or on neither; what is fair for one side is bound to be foul for the other. The witches’ riddles and prophecies mislead Macbeth, but in an important sense, these double-talking creatures are also telling the truth about the world of the play–that there really are no ethical standards in it, no right and wrong sides. Duncan certainly starts out sounding like a good king: the rhetoric of his monarchy is full of claims about its sacredness, the deference that is due to it, how it is part of a natural hierarchy descending from God, how the king is divinely anointed, and so forth. But in fact none of this is borne out by the play. Duncan’s rule is utterly chaotic, and maintaining it depends on constant warfare–the battle that opens the play, after all, is not an invasion, but a rebellion. Duncan’s rule has never commanded the deference it claims for itself–deference is not natural to it. In upsetting that sense of the deference Macbeth feels he owes to Duncan, perhaps the witches are releasing into the play something the play both overtly denies and implicitly articulates: that there is no basis whatever for the values asserted on Duncan’s behalf; that the primary characteristic of his rule, perhaps of any rule in the world of the play, is not order but rebellion.

Whether or not this is correct, it must be to the point that women are the ones who prompt this dangerous realization in Macbeth. The witches live outside the social order, but they embody its contradictions: beneath the woman’s exterior is also a man, just as beneath the man’s exterior is also a woman; nature is anarchic, full of competing claims, not ordered and hierarchical. To acknowledge our divided selves and the anarchy of nature is also to acknowledge the reality and force and validity of the individual will–to acknowledge that all of us have claims that conflict with the claims about natural order, deference, and hierarchy. This is the same recognition that Edmund brings into King Lear when he invokes Nature as his goddess. It is a Nature that is not the image of divine order, but one in which the strongest and craftiest survive–and when they survive, they then go on to devise claims about Nature that justify their success, claims about hierarchies, natural law and order, the divine right of kings. Edmund is a villain, but if he were ultimately successful, he would be indistinguishable from the Duncans and Malcolms (and James I’s) of Shakespeare’s world.

The complexities and ambiguities of Shakespeare’s story are firmly based on history. The real Macbeth was, like Richard III, the victim of a gigantic and very effective publicity campaign. Historically, Duncan was the usurper–that is what the rebellion at the beginning of the play is about, though there is no way of knowing it from Shakespeare. Macbeth had a claim to the throne (Duncan at one point in the play refers to him as “cousin”[I.4.14]–they were first cousins, both grandsons of King Malcolm II). Macbeth’s murder of Duncan was a political assassination, and Macbeth was a popular hero because of it. The legitimate heir to the throne, whose rights had been displaced by the usurping Duncan, was Lady Macbeth. When Macbeth ascended the throne, he was ruling as Protector or Regent until Lady Macbeth’s son came of age (she did have children–it is Shakespeare who deprives her and Macbeth of those heirs). Macbeth’s defeat at the end of the play, by Malcolm, Macduff, and Siward, the Earl of Northumberland, constituted essentially an English invasion–the long-term fight was between native Scottish Celts and Anglo-Norman invaders, with continental allies (such as the Norwegian king) on both sides. One way of looking at the action is to say that it is about the enforced anglicization of Scotland, which Macbeth is resisting.

Shakespeare knows some of this.