The Witches’ charm is fantastic: Its ingredients, thrown into a bubbling cauldron, are all poisonous. Moreover, these ingredients are all the entrails or body parts of loathed animals or human beings, which, taken together, can be interpreted as making a complete monster: tongue, leg, liver, lips, scales, teeth, and so on. The strong implication is that Macbeth himself is no longer a complete human being; he himself has become a half-man, half-monster, a kind of chimera.

Macbeth arrives at the Witches’ lair with extraordinary boldness, knocking at the entrance in a way that ironically recalls the entry of Macduff into Macbeth’s castle in Act II, Scene 3. When he “conjures” the Witches to answer him, his language is uncompromising: He matches their power with a powerful curse of his own, demanding to have an answer even if it requires the unleashing of all the elements of air, water, and earth; even if all the universe — natural or manmade — “tumble” into ruin. His most defiant act, by far, is to desire to hear the prophecy of his future not from the Witches, who are themselves only “mediums” of the supernatural, but from their “masters,” that is, the controlling Fates.

Macbeth’s demand is answered by a sequence of apparitions. Unlike the dagger and Banquo’s ghost, these supernatural visions cannot be simply the workings of Macbeth’s “heat-oppress’d brain.” They are definitely summoned by the Witches. Once again, the audience is required to assess the extent to which Macbeth is responsible for his own actions. What is certain is Macbeth’s response to each prophetic apparition: He appears to be super-confident, even flippant, in his replies. There is little fear or respect, for example, in his reply to the First Apparition: “Whate’er thou art, for thy good caution, thanks.” And his punning reply to the Second Apparition’s “Macbeth, Macbeth, Macbeth” — “Had I three ears, I’d hear thee” — displays a comic arrogance.

Apart from the first, all the apparitions, including the fourth and final one of a procession of future kings, contain children. The juxtaposition of children (pictures of innocence) and images of death, warfare, and blood, is dramatic and terrifying, but especially so for Macbeth: For a man who has no offspring, the image of children can only fill him with hatred and loathing.

Having rejected as impossible the second two prophecies, Macbeth asks for one last favour. The result appalls him, drawing all strength from him and reducing his earlier courage. The children who appear in this procession are the children of Fleance. The reflected light of their golden crowns “does sear (cut into) mine eye-balls” and causes his eyes to jump from their sockets. The climax to Macbeth’s reaction occurs in the line “What! will the line (of inheritance) stretch out to the crack of doom?” in which he finally realises the possibility of an entirely Macbethless future.

In a scene rich with special effects — thunder, ghosts and (possibly flying) Witches — Shakespeare adds a final visual stroke: The eighth child-king carries a mirror that reflects the faces of many more such kings. The effect of infinite regression can be achieved by looking at a mirror while holding a smaller mirror in your hand in which the reflection is reflected.

The Witches confirm the inevitability of what Macbeth has seen: “Ay sir, all this is so.” There can be no equivocation, no argument, with Fate.

Emerging into the cold light of day, Macbeth seems immediately to forget the final prophecy, as he returns to the practicalities of what is increasingly a battle for his own political survival. On being informed that Macduff has fled to England, he announces his intention to wreak a terrible revenge on Macduff’s wife and children.