What is the purpose of Macbeth's listing of disasters in Macbeth? Explain.
Your question regarding Macbeth's listing of disasters apparently is referring to his address to the three witches when he enters in Act 4, Scene 1.
I conjure you by that which you profess
(Howe'er you come to know it), answer me.
Though you untie the winds and let them fight
Against the churches, though the yeasty waves
Confound and swallow navigation up,
Though bladed corn be lodged and trees blown down,
Though castles topple on their warders' heads,
Though palaces and pyramids do slope
Their heads to their foundations, though the treasure
Of nature's germens tumble all together
Even till destruction sicken, answer me
To what I ask you.
Macbeth is becoming unnerved and desperate. He last appeared in his harrowing encounter with Banquo's ghost and was reminded of the witches' prophecy that Banquo's descendants, not Macbeth's, would be the kings of Scotland. In that same scene (Act 3, Scene 4) he first mentions the apparent disloyalty of Macduff, which further troubles him because he feels it could be the beginning of a wholesale rebellion by the thanes. He asks his wife:
How say'st thou that Macduff denies his person
At our great bidding?
She asks if he sent for him, and Macbeth replies:
I will tomorrow
(And betimes I will) to the Weird Sisters.
More shall they speak, for now I am bent to know
By the worst means the worst.
His opening speech to the Weird Sisters shows his desperation. Apparently he believes that there is a great risk involved in prying into the future. It may be a dreadful sin. It may be inviting cataclysmic disasters by trying to break into secrets known only to God and His angels. Macbeth knows that these witches are agents of the Devil and derive their knowledge from evil sources that are enemies of mankind. He doesn't know what kinds of perils he is inviting, but he doesn't care anymore. He has already sold his soul to the Devil.
For Banquo's issue have I filed my mind;
For them the gracious Duncan have I murdered,
Put rancors in the vessel of my peace
Only for them, and mine eternal jewel
Given to the common enemy of man
To make them kings, the seeds of Banquo kings. (3.1)
Two things trouble him the most. One is whether he is secure in his position as king of Scotland. The other is whether it is true that Banquo's heirs are destined to be kings and whether there is any possible way of preventing it. These are the questions he wants answered by the witches.
No doubt a motion piicture adaptation would contain all sorts of special effects during this scene. There would be thunder and lightning, wind and rain, and supernatural effects as well, such as ghostly wailing. Shakespeare had to create these illusions of demonic communion with words. The speech inviting apocalyptic disasters prepares the audience to perceive the three Apparitions as messengers from the Devil himself.
Shakespeare allows Macbeth to list all of the disasters he has encountered to really show how weak and trusting he was in superstitions. Shakespeare and the people of his time period heavily believed in superstitions, even so much that the play Macbeth itself was banned for a while and referred to as "The Scottish play". Macbeth relies heavily upon the witches and their prophesies so Shakespeare allows Macbeth to review teh disasters to show what happens when one fully depends upon superstitious beliefs. Also, since this listing occurs so early in the play, it sets up our exposition information and lays out the plot line for the remainder of the play.