Macbeth is a critical play which works at various levels. Here Shakespeare gives us timeless symbols of crucial yet unnoticed forces at work in any society. In the play, together they utter the gist of all happenings when they say, “Fair is foul, and foul is fair.”
The witches are a symbol of inconceivable forces lying in the depth of individuals which affect the larger processes, they are “posters of the sea and land.”
In the very first act of the play they tell us that they know when the battle will be lost and won, they’re at the uppermost layer of the dynamics of this plot.
As destabilising sources, they provoke new orders. Much more than any other characters of the play, the witches are the symbol of much wider significance.
They live away from the civilised society, it shows us their neglected position. Banquo says, “they look not like th’inhabitants o’th’ earth.” They live in the damp earth, forest and the desolate surrounding. Away from the affairs of state, they are the symbol of neglect which keeps entering into the established order.
In the play, Macbeth questions the traditional norms. Unlike Banquo, he makes a conscious choice from the suggestions of the witches. Hence the witches may symbolise this world itself where choices are numerous for the onlooker and the final choice determines the real values of a character.
They stand for the metaphysical aid at the service of dark motives sanctioned from some mysterious source. Lady Macbeth tells us of this character of the witches when she reads the letter from Macbeth for the first time.
The witches stand for the suggestions of our dark fantasies. In the play, Macbeth and Lady Macbeth yield to such suggestions. They provide foreknowledge and the evil in it attracts us.
They have a language of paradox and ambivalence. Under the presiding force of Hecate, the deity of sorcery, their motive seems to be “double, double, toil and trouble.”
The witches are the symbol of unrecognised forces which stand larger than our will. Their evil hints are irresistible so the characters in the play fall prey to them. The second witch talks of their “charm of powerful trouble.” (Act 4:1)
They reveal the self-deception of society. They live in shadows; they are exiled from the violence of civilised orders. Banquo sees them as the bubble of this earth. Like water bubbles, they form and then vanish away.
The influential suggestions made by them have a radical side to it. They symbolise transgression. The witches utter sentences are full of deceptive meanings. They wrongly assure Macbeth of his invincibility with double-edged proclamations which are true in context but false in outcomes.
They say “none of woman born shall harm Macbeth.” He is not to be vanquished until Great Birnam Wood comes to Dunsinane Hill. All these are naturally impossible yet Macbeth falls before the cheat codes of nature. Hence the Witches are, as Macbeth says, “unknown power” who do “deed without a name.”