Witches in Macbeth

What do the witches bring to Macbeth?
Act One:

• Shakespeare uses the witches here as the introduction to Macbeth. Along with the setting, they help to set the tone for the rest of the play. 'Fair is foul, and foul is fair'. It foretells the way Macbeth gets the crown- his terrible betrayals of trust. Further on in the act, Macbeth repeats what the witches have said, 'So foul and fair a day', possibly portraying the narrow line between him and them? How similar their moralities are. The witches could even be used metaphorically to reflect the evil traits and wrongdoings in Macbeth's nature.
• There is the argument that the witches are a figment of Macbeth's imagination. Although Banquo also sees them too, even he mentions the doubt he has in himself that what he is seeing is real- 'have we eaten the insane root//That takes the reason prisoner?'. Further on in the act and the rest of the play, the idea that Macbeth could be imagining the witches seems more likely, with the apparitions he sees such as the dagger and Banquo's ghost.
• The first moment that the audience is made aware of a prophecy that Macbeth will be king, is when the witches speak of it. 'All hail, Macbeth, that shalt be king hereafter!' This could be said to have planted the initial thoughts in Macbeth's head, and could be said to be the cause of all his murderous acts.
• The witches certainly induce fear within the play, which could mean that they are there simply as entertainment value, and to keep the audience involved. At the time, with King James, the idea of witches was terrifying- many innocent women were accused of witchcraft and killed.
• Lady Macbeth appears in several points throughout the play, to bare striking similarities to the witches- in her language. In scene 5 of act one, she calls to spirits to help her. This seems much like a supernatural element, just like the witches. This point further emphasises the idea that the witches are there to show the thin line between the supernatural evil and natural evil. (Even Lady Macbeth appears as ruthless as them). 'Come, you spirits... all-hail hereafter!'

Act Two

• Despite the witches not being physically on stage in this act, their presence is still felt. In the first scene, Banquo has clearly been disturbed by the sight of the witches, 'I dreamt last night of the three Weird sisters'. It confirms to the audience that there is a reason to be fearful of them, and that they are behind all the bad things happening.
• In Macbeth's soliloquy, the goddess of witches is mentioned 'Pale Hecat's offerings'. It appears here that Hecat is one of the entities responsible for the turning point in Macbeth's speech. He decides here that murder is the way he fulfills his desire for kingship.
• The idea of nature being turned on it's head is most prominent in the fourth scene of act two. When the old man describes the natural order going wrong- when Duncan's horses eat each other. The witches being the supernatural evil could be behind the strange events.

Act Four

• In the first scene of this act, the witches are again used to start the act. They are gathered around the cauldron, using various revolting and horrible things to use for their chanting. Although they are seen here to apparently be using magic, there is no evidence to suggest that they are definately powerful in that way. It could be argued that by Macbeth's willingness to accept and believe all they do, his is in fact giving them their supernatural status. 'What is't you do?' Macbeth is keen to see and understand the acts of the Witches.
• Macbeth, like his wife, uses the language and rhythm of the witches at some points. This further provides evidence for the argument that the witches are very close to LM and Macbeth. It could even be suggested that the witches are just reflections of the natures of both of their characters.