No discussion of evil in Shakespeares play Macbeth would be satisfactory without considering its most famous symbols of evil: the coven of witches whose interactions with Macbeth play such a vital role in his thinking about his own life. Banquo and Macbeth recognize them as something supernatural, part of the landscape but not fully human inhabitants of it. They have malicious intentions and prophetic powers. And yet they are not active agents in the sense that they do nothing other than talk and offer visions and potions. The witches have no power to compel.
If we are to explore the significance of these witches we must do so by treating them as vital poetic symbols in the play, essential manifestations of the moral atmosphere of Macbeth’s world. The most obvious interpretation of the witches is to see them as manifestations of evil in the world. They exist to tempt and torment people, to challenge their faith in themselves and their society. They work on Macbeth by equivocation, that is, by ambiguous promises of some future state. These promises come true, but not in the way that the victim originally believed.
The witches thus make their appeal to Macbeth’s and Banquo’s desire to control their own future, to direct it towards some desirable ends. They have no power to compel belief, but they can obviously appeal strongly to an already existing inclination to force one’s will onto events in order to shape the future to fit one deepest desires. Banquo’s importance in the play stems, in large part, from his different response to these witches. Like Macbeth, he is strongly tempted, but he does not let his desires outweigh his moral caution:
But ’tis strange, And oftentimes to win us to our harm The instruments of darkness tell us truths, Win us with honest trifles to betray’s In deepest consequence. (1. 3. 120-124) Macbeth cannot act on this awareness because his desires (kept alive by his active imagination and his wife’s urging) constantly intrude upon his moral sensibilities. Hence, he seizes upon the news that he has just been made Thane of Cawdor, using that information to tell him what he most wants to believe, that the witches tell the truth. 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. (1. 3. 129-132) But Macbeth’s inner question here has already been answered by Banquo a moment before (in the quotation immediately above). Macbeth’s framing the question in this way is an indication, not that he has not heard what Banquo has just said, but that he doesn’t want to believe it. The witches, in other words, appeal to what Macbeth wants to believe. They don’t make him believe it.
And they do not tell him what to do in order to achieve what they prophesy. They say nothing about killing Duncan (or anyone else). In that sense, they cannot be the origin of the idea of the murder. They may be appealing to that idea, but they do not create it. The same is true of their later prophecies about Birnam Wood and about no one of woman born being able to harm Macbeth. These confirm for Macbeth the fact that acting on his desires will keep him secure, that he can take charge of his future with nothing to fear.
But these prophecies do not offer any specific instructions about immediate actions. We must, thus, resist any temptation to see Macbeth’s actions as determined or controlled by the witches. He is always free to choose how he is going to act. Hence, these witches exist as constant reminders of the potential for evil in the human imagination. They are ineluctably part of the natural world, there to seduce anyone who, like Macbeth, lets his imagination flirt with evil possibilities.
They have no particular abode and might pop up anywhere, momentarily, ready to incite an eternal desire for evil in the human imagination, the evil which arises from a desire to violate our fellow human beings in order to shape the world to our own deep emotional needs. It’s important to note that the witches are not dealt with in this play. By the end, Macbeth has been defeated and killed, but the witches are still around, somewhere. It’s as if such a conclusion is saying something like, “Yes, you have dealt with one evil man, but if you think you have therefore dealt with evil, you are indulging in illusory hopes.
The cyclical nature of the recurrent visions of evil may be underscored by a predominant contrast throughout the play between light and darkness. Macbeth is an intensely dark play, metaphorically and literally. After Duncan’s conversation about the natural pleasantness of Macbeth’s castle, such references to nature as benevolent disappear, and we are plunged into a world of twilight and darkness, a constant sense that Macbeth’s prayers to the evil in the world are bringing out the gradual extinction of any life-sustaining light and growth.
The forces of Malcolm are described in terms of regeneration and a newer and healthier vitality (the miraculous power of the English king to heal illness is an important image of that point). But there may be no firm sense that the final triumph of the forces of goodness over this manifestation of evil have done anything to alter the recurring cycle. For the play has not banished the darkness; it has simply brought back a circle of light.