"Hie thee hither, that I may pour my spirits in thine ear."
on reading his letter, she wishes to fill him with her ideas, ambitions and boldness. After only a few scenes it becomes apparent that it is Lady Macbeth who makes the decisions for them both. She is a very determined person; she also seems very unfeminine and sometimes even evil. She is also highly ambitious. However, although at first she appears completely heartless, saying she would have "dashed the brains out" of a child of hers in order to become queen, she rarely actually commits an important crime. Her first sign of weakness is that she would not actually kill Duncan herself, saying that,
"Had he not resembled
My father as he slept, I had done´t"
In the first few scenes she seems to be as evil as she proclaims she is, but as the play develops, so her conscience catches up with her and she becomes mentally ill. She shares the symptoms of sleeplessness and hallucinations with Macbeth that hark back to when he heard the voice call "Sleep no more!" immediately after Duncan’s murder. This seems to be a curse, as does the vision of bloody hands. If indeed it were an actual curse then this would mean some greater force is involved in the story, but it could alternatively be nothing but their consciences and feelings of guilt and remorse.
Lady Macbeth had many reasons for wanting her husband to kill the king; mostly she was driven by ambition. She lusted after a royal title and power. "The golden round" is the euphemism she uses for the crown, to her this symbolises both wealth and power. The power was perhaps the most important thing to her; control seems to be a major factor in the marriage and her main reason for the murder. Alternatively she could be driven by the pride she felt in her husband’s success when he won the first titles. Or she could be driven by greed. She could long for a higher social status, or there could be other, larger factors in the murder…
When she pleas that fate should remove her womanliness and talks of killing babies it is becoming clear that she is becoming obsessed with the idea of power and titles. She does not seem merely preoccupied by power she is completely obsessed with control and dominance…at whatever cost. Even if it means losing that part of her which is human, her soul perhaps, she wants to be queen. This does not seem to me like the result of greed, she appears to be either truly evil, or mentally unstable, or both. I think it is very likely that her controlling nature was played upon by fate, a recurring theme in the play. Maybe the witches control her mind. The witches are the personification of a twisted and evil force. Maybe the devil speaks through them, or maybe they themselves can manipulate fate by building on the vices of people around them. I think it is more likely that they have control over Lady Macbeth, either through her mind, or external factors, than that they left detail concerning the execution of the murder to chance.
The witches may not be real at all; they too could be a hallucination, just figments of Macbeth imagination. They reflect what his thoughts are, and make him realise what is likely to happen, or what he wants to happen when they appear. The only flaw in this argument is that Banquo too can see the witches so they are definitely manifesting themselves as a physical presence. At first the witches seem to be on Macbeth´s side, they want to help him gain power, but when he does as they say and becomes so far entangled that he has no way out they turn against him and predict not success, but his downfall.
Maybe the murder was not due to any plan or force, other than a combination of chance and circumstance "fate and metaphysical aid". Many stories and plays rely upon good or bad fortune to help the plot unfold. Usually, however Shakespeare’s plays are more sophisticated and there can usually be found a reason for an event.
I conclude that Lady Macbeth was a tool of fate. I believe the witches manipulated her, or their controller did so, to in turn exercise her influence over Macbeth and play out a series predetermined events. I do not think there is meant to be a reason in this play, but there is a moral, a mystery, and a great underlying evil. I do not know what Shakespeare wanted this evil to represent, perhaps he did not know himself; or perhaps it represents the vulnerability of all humans to fate, or chance; perhaps it pessimistically represents a basic evil in humans; or perhaps he wrote it to enthral his audiences and leave them wondering…
