Another approach to the ones given earlier is to examine the characters who, though in similar situations, contrast with Macbeth and therefore show a more or less moral or just way of acting. In other words, both Banquo and Macbeth hear prophecies, but only one is willing to commit a foul deed to make the witches' prophecies come true. Both Lady Macbeth and Macbeth plan the murder of Duncan, but only Macbeth feels guilty. Both Lady Macbeth and Macbeth know the prophecy that Banquo's sons will be kings, but only Macbeth acts on the prophecy. Macbeth acts to protect his family line, but Macduff sacrifices his family for his country. There ae more of these types of contrasts. But you might, as you examine these contrasts, consider how just and moral Macbeth seems when he is compared to other characters in the same or comparable situations.
I think that there are many ways to approach an essay of this magnitude. One way that I see is to examine how the play addresses the question, "What is justice?" Is justice a sense of fairness? Is justice something that must adhere to a structure or moral order? Is justice something related to power, the notion of might makes right? These are particular issues that the play links to its discussion of justice and being able to examine these ideas can be explored through Macbeth's and Lady Macbeth's actions. The notion of justice and morality being something that exists in the world or something that is created by individuals remains one of the most compelling aspects of the work, worthy of exploration through questioning, analysis, and character responses to situations.
Concerning essay ideas for Shakespeare's Macbeth, most moral and justice issues are talked about often, and center on Macbeth and Lady Macbeth. One that isn't often discussed, and is ambiguous (which makes for a good essay) is the question of Macduff's duty, or the shirking of it, when he leaves his family alone and exposed in Scotland.
Macduff goes to England to join forces with Malcolm against Macbeth. This is probably something his sense of justice requires him to do, and it certainly is necessary for the good of Scotland.
But when he does so, he leaves his family alone and unprotected.
Research questions might be:
- Is Macduff's leaving his family alone and exposed in Scotland immoral?
- Is Lady Macduff's condemnation of her husband as a traitor figuratively true (a traitor to his family)?
- Is Lady Macduff's reaction understandable, but misguided? Or does her reaction demonstrate accurate judgment?
Any way, that's one idea for you.