Hmmmm, what an interesting conversation! I like to cleave to the definition of tragedy that it must end on a positive note, or at least a note of home (as the feud nears its end in the final scene of Romeo and Juliet, despite the lovers' deaths). In my opinion, Macbeth is no exception. Macbeth's "vaulting ambition" has been stymied by his death and Macduff presents Macbeth's head to Malcolm as he becomes King of Scotland. Malcolm and Macduff, to put it very simply, are the hope of this play. The villain (Macbeth) is dead. There is hope for Scotland yet again. We can see this positive spin in Malcolm's final speech:
We shall not spend a large expense of time / Before we reckon with your several loves, / And make us even with you. My thanes and kinsmen. / ... As calling home our exiled friends abroad / That fled the snares of watchful tyranny, / ... By the grace of Grace / We will perform in measure, time, and place: So thanks to all at once and to each one, / Whom we invite to see us crowned at Scone.
The good subjects of Scotland will, therefore, be rewarded for their devotion just as Macbeth and Lady Macbeth were punished for their lack of that same devotion. Further, Malcolm will waste no time rewarding those very faithful subjects. Malcolm does nothing less than call this a "new age" of justice for Scotland, ... and he will be its rightful king.
I don't agree with the first post. I think that justice is done and I don't think that the witches or Malcolm deserve to be punished.
The witches did not cause Macbeth to do what he did. They were just predicting the future. They did not say he had to become king by killing Duncan, for example. Blaming them is like blaming the weatherman if he predicts it's going to be cold and I go and kill someone to take their warm clothes and house. It's not his fault and it's not the witches' fault.
Saying that Malcolm has "the potential to be another Macbeth" and therefore justice has not been done is overreaching, in my opinion. I can't imagine that we could be justified in going around punishing people for what they might do.
So, I think that justice has been done by the end of the play. It's rough justice -- no courts, no laws. But in the end, the truly guilty pay for their sins.
When we think about the full implications of this question, I think the answer can become quite disturbing. My first question in response to your question would be who is justice served against at the end of the play? Obviously, we could say that Lady Macbeth and Macbeth have justice served against them. Clearly Lady Macbeth's descent into madness and the way that she potentially kills herself seems to be an appropriate ending for a woman that has abandoned herself to the forces of evil so completely. Likewise, Macbeth's death at the hand of Macduff, whose family he so cruelly slaughtered, seems to be appropriate given Macduff's cause for personal vengeance. So, to this extent, we can say that justice has been served.
However, let us just for one moment consider the other characters in the play. How are the witches punished for their acts? They receive no form of justice. In fact, they appear to be left out their unmolested, ready to tempt their next victim and having interfered in the life of Macbeth without any consequences. Likewise, I would also want to ask some serious questions about Malcolm, who in Act IV scene 3 seems to show a worrying ability in the same kind of lying and manipulation that Macbeth has demonstrated. Note how in this scene he deliberately lies to Macduff to test his loyalty, exaggerating his faults:
Nay, had I power, I should
Pour the sweet milk of concord into Hell,
Uproar the universal peace, confound
All unity on earth.
Even though he later goes on to disavow such grandiose claims, he strikes the audience in his language as having the potential to be another Macbeth. In one film version of the play, it ends with Malcolm going to see the witches in the same way that Macbeth saw them at the beginning of the play. The message is obvious. Has Scotland, by disposing of one tyrant, only served to replace him with another?
Such issues raise questions about the extent to which justice is served in the play. We can conclude that the obvious villains receive justice, but we are left with the rather nagging possibility that the other villains and potential villains in the play are left unpunished.