In Macbeth, what role do Macbeth's visions and hallucinations play in the develpoment of his character?

In Macbeth, Macbeth's visions and
hallucinations serve as symbols of Macbeth's inner conflict throughout the play.  Macbeth has his
first hallucination when he envisions the dagger at the beginning of Act 2.  At this point in the
play, he is still considering whether or not he should follow the plan that he has made with Lady
Macbeth to murder King Duncan.  Macbeth acknowledges that Duncan is a good king and that he is
loved by all in Scotland; however, his desire for power challenges his sense of loyalty to Duncan
and Scotland.  Macbeth thinks that the dagger calls him towards committing the murder, so he
decides to go through with the plan.  Later, Macbeth has Banquo murdered to protect his place on
the throne, but Macbeth also realizes that Banquo is a good man.  He hallucinates Banquo's ghost
after he falsely honors Banquo in front of the guests at the banquet.  So, Macbeth's
hallucinations show that Macbeth is grappling with the decisions that he has made while trying to
go after his ambition.