To the actors of Macbeth
De Quincey is correct: “In order that a new world may step in, this world must for a time disappear.”
But the stage apparatus whereby Shakespeare produces this is often, it would seem, overlooked, and hence we have the legendary jinx on this play, which, when looked into properly, is seen to rest on the intractable difficulty of performance. This will be found up to the middle of Act III, after which the thing plays itself, as Hamlet does.
If the actor will bear in mind a single formula, set out by the author in his opening lines, he will navigate the difficulty and find invention where was before perplexity: “Fair is foul, and foul is fair.” It is not the significance of this line I would call attention to here, but the dual formulation. In countless passages, indeed, where any trouble arises, the player will find this the key to “hover through the fog and filthy air.”
The “dagger of the mind,” for example, tests the mettle of Shakespeare’s stagecraft by juxtaposition with the actual dagger drawn to compare with it.
I will not endeavor here an analysis of this fascinating play, or even discuss the technique of Shakespeare’s stagecraft (but note how the dagger is prepared in I, iii: 139-142), which is even now being learnt again at Wanamaker’s Globe.