Sc. 1, lines 50–61: what does this speech suggest about macbeth? how does the speech support a theme?

In Act II, Scene 1, Macbeth delivers a soliloquy before the murder of Duncan.

Right before these lines, he hallucinates a knife in the air before him. In these lines, he says that half the world is "dead," and "wicked dreams abuse The curtained sleep." He is saying that half the world is sleeping, abused by wicked nightmares.

In truth, Macbeth is the one being abused by wicked nightmares. He knows better than to trust the witches prophecy, based on his own words during this speech, since he discusses witches making sacrifices to Hecate. However, rather than recognize he is being abused by nightmares, he moves ahead with this plan.

These lines suggest that Macbeth lacks self-awareness. Furthermore, these lines suggest that he is so eager for power that he ignores the signs that indicate he is about to commit a grave error.