Reading Macbeth with Homeschoolers

I lead a homeschooling group in discussing Macbeth yesterday. The group invites me annually to lead them in discussing one of Shakespeare's plays. I guess the word has got out that I love Shakespeare. Two of my kids are participants in this group. I was surprised how they were able to read, engage, and discuss the text. It proved to me that young people are more capable of reading and discussing great texts than we think. We can coach young people to develop the arts of learning: grammar, rhetoric, and dialectic. These are the skills of reading, speaking, listening, and conversation.

One thing that stood out in our discussion was an early line: "Fair is foul, and foul is fair." What does this mean? One of the things that makes a text great is that it call for multiple interpretations. One thing I think this is saying is the distortion of standards in the world. What is considered good is actually evil. What is considered evil is actually good. Another interpretation is that the witches are stirring the pot. They are corrupting lives. They are tempting Macbeth to evil. Macbeth seems similar to the Garden of Eden where the serpent tempted Adam and Eve that they will be gods. Macbeth is tempted to become king. He uses horrible means to become king. Our society, however, thinks that the ends justify the means. Machiavelli would be an honorable statesmen in our society.

Another important scene is when Lady Macbeth calls on evil:

"Come, you spirits/That tend on mortal thoughts, unsex me here,/ And fill me from the crown to the toe top-full/of direst cruelty. Make thick my blood;/Stop up th' access and passage to remorse...

Come to my woman's breasts/and take my milk for gall, you murd'ring ministers,/Whatever in your sightless substances/You wait on nature's mischief. Come thick night,/And pall thee in the dunnest smoke of hell,/ That my keen knife see not the wound it makes,/Nor heaven peep through the blanket of the dark/To cry "Hold, hold!"

What does this passage mean? Macbeth after planning on killing the king has second thoughts. Lady Macbeth calls on evil to help her play the man's role and do the killing herself. Later on we find Lady Macbeth washing her hands continuously, but she can never wash the blood off. She is tortured by her venomous deed.

Macbeth when faced with the consequences of his evil actions cries out:

"To-morrow, and to-morrow, and tomorrow/Creeps in this petty pace from day to day/To the last syllable of recorded time,/And all our yesterdays have lighted fools/The way to dusty death. Out, out, brief candle! Life's but a walking shadow, a poor player/That struts and frets his hour upon the stage/And then is heard no more. It is a tale/Told by an idiot, full of sound and fury,/Signifying nothing."

This is my favorite passage in the whole play. What is life? Does it have meaning? Is there an author? or is life meaningless with no ultimate purpose?