Part of the power of Shakespeare's tragedies lies in their goofiness. Shakespeare often seems to begin with some premise straight out of an actors’ workshop, some casual improvisatory game, and then to erect some magnificent structure of rhetoric upon a foundation of sand—or no foundation at all. When I was a boy, I often attended a comedy club in Chicago called Second City, in which the actors asked the audience to call out suggestions for a skit (“Peeling an apple with a chainsaw!” “An astronaut in a spacesuit peeling an apple with a chainsaw!”). The premise of Macbeth seems devised in just this manner (“The forest marches up to the castle!” “The forest marches up to the castle and kills the king!”). For their private amusement, the witches keep calling out new roles and new situations, and Macbeth struggles as best he can to comply:

• 1. Witch. All hail, Macbeth, hail to thee, Thane of Glamis!

• 2. Witch. All hail, Macbeth, hail to thee, Thane of Cawdor!

• 3. Witch. All hail, Macbeth, that shall be King hereafter! (1.3.48–50)

In an improvised comedy, Macbeth would run around the stage, first making his own characteristic gesture, then scowling like the Thane of Cawdor, at last crowning himself with a horseshoe and holding up his riding-stick as a scepter. Of course, Macbeth is a comedy only from the witches’ point of view, and the tragic actors must maintain a certain decorum. But it is necessarily a short distance from Macbeth addressing a nonexistent dagger to Marlon Brando pretending to melt in Lee Strasberg's studio. The cast of Shakespeare's play is a gang of actors trying, with whatever technical virtuosity they can muster, to cope with the fiendish demands of a final examination in the witches’ drama school.

Because Shakespeare so completely assimilated the absurdities of the plot into a pseudo-rational structure, and because the tone of the play is so dark, it is easy to forget just how outrageous, how hilarious it all is.