The Macbeth's descend into madness. Lady Macbeth sleepwalks, delivers her "Out damn spot" speech, and commits suicide. Macbeth depends wholly on the witches' prophecies. Learning of Lady Macbeth's death, he gives the "out brief candle" speech on the shortness and futility of life.
"It is a tale
Told by an idiot, full of sound and fury,
Signifying nothing."
Macbeth is now the epitome of nihilism.
