What is the character flaw that is the cause of Macbeth's downfall?
Shakespeare's plays are usually put into one of several categories: Tragedy (such as "Macbeth"), Comedy (such as "All's Well That Ends Well"), History (Such as "Richard III'), Pastoral (such as "As You Like It"), or Romance (such as "The Tempest").
In each of these genres, Shakespeare observes and comments on the human condition. In essence, nothing much has changed about human beings AS human beings from the Elizabethan era, during which he lived and worked, to our own.
The category, "Tragedy", contains Shakespeare's "Macbeth", "King Lear", "Antony and Cleopatra", et al. In each of these, the true "tragedy" can be said to be a human flaw which sets into motion and/or keeps in motion the events which result in disaster. These character flaws have existed since time immemorial, exist in each of us today, and will likely continue to exist as long as the human race endures.
Human flaws might also be called tragic flaws, character flaws, human inadequacies, or a host of other names. By examining ourselves and those around us, we will surely observe such factors in our lives as greed, hubris, dishonesty, untrustworthiness, etc. We can also readily understand that such flaws within us contribute mightily to the state of war, the economic state, the moral state, and the state of humanity which plague us in our own time and place.
With the above as introduction and background, one can understand that Macbeth's greatest human frailty, his vaulted flaw, the tragic fiber within him which drove him to his horrible deeds, was greatly excessive ambition.
Ambition can be a desirable characteristic in any of us. Without ambition, we would remain complacent in such mundane activities as cleaning house, bathing, preparing healthful meals, etc. A lack of ambition would have an even greater effect on our going beyond the most basic requirements in our studies, or being willing to remain the person lowest in rank and most poorly paid in our careers. At the highest levels, no ambition would lead us not to have sufficient desire and drive to work for peace, or strive to cure disease, or to show compassion to our fellow man.
But ambition can also be a dangerous thing. It was ambition which caused the break in at the Watergate Hotel and brought an American president to the shame of resignation. It was religious ambition which brought about the horrifying events of "9/11". Political and military ambition has most often been the defining factor in bringing nations into war.
It was this same kind of "ambition on steroids", one might say, which caused Macbeth to hasten events which would have likely happened anyway, had he had the patience to await them. But, without patience, and with an ambition that was clearly out of control, he brought about horrendous evil, including the most dreadful crime of murder.
Shakespeare understood the human condition, in my opinion, better than any other writer of his or any other time. His studies and observations in the same have resulted in plays of great power and insight.
Certainly the traditional notion is that the cause of Macbeth's downfall is his ambition. And there is no question that much of what Macbeth does is caused by a need to better his position. As Lady Macbeth says of her husband,
Thou wouldst be great;
Art not without ambition, but without
The illness should attend it,
So yes, he has ambition, but his fatal fault is alluded to in the last line: he doesn't have the "illness" that needs to come with it. He doesn't have the burning desire, the obsession necessary to drive him to do what has to be done in order to be powerful and great. Not yet.
The witches and Lady Macbeth together push him over the edge of his own reticence, his inherent heroism and goodness, and they get him to do things that are not really in his nature. It is his weak-mindedness, his easy susceptibility to suggestion and temptation that is his tragic flaw. That's why, once he sets out on the path of murder, he can't take it; he is overcome by guilt, fear and paranoia excacly because killing for personal gain is not in his nature. Lady Macbeth, who knows her husband, is right when she says:
What thou wouldst highly,
That wouldst thou holily; wouldst not play false,
And yet wouldst wrongly win. Thou'ldst have, great Glamis,
That which cries, “Thus thou must do, if thou have it;
And that which rather thou dost fear to do
Than wishest should be undone.”
What I believe, and I grant that I may be quite alone in this view, is that Macbeth is a good man and a brave and stout warrior, who, to his ultimate, tragic downfall, is too easily manipulated, and, strong as he may be in other ways, he is very weak when faced with the trickery, prodding and chastisement of... hold on to your hats: women.
I agree with ambition, but I want to throw pride in there too. How does Lady Macbeth get him to kill Duncan? She question his manhood. She does this repeatedly. She even says she's more of a man than he is (the speech about her dashing out her baby's brains). Then, after Macbeth visits the witches again, hears what they have to say, and sees the apparitions, he foolishly believes himself invinsible. All men are born of women. How can woods march? He thinks himself safe.
In ancient Greek tragedies, hubris (too much pride) cause many a hero's downfall. I think it is true of Macbeth too.
To me, the major character flaw that brings Macbeth to his downfall is ambition. His ambition is combined with a lack of morality in his character to make him end up losing everything he was trying to gain.
To be a great hero in the days in which the play is set, a man had to be very ambitious. You did not get to be a strong leader without really wanting to. So clearly Macbeth's ambition is what has made him great.
But his ambition will also bring him down because it will cause him to go a step too far. It will cause him to kill Duncan and that is the beginning of the end for him.