Symbol / Motif

As the second act goes by, it seems more and more probable that Macbeth’s blind ambition is fueled by his belief in fate. Macbeth vacillates between his desire for the throne and his unwillingness to kill for it. However, on the night when he actually murders Duncan, Macbeth sees the vision of a dagger floating before him. He finally finds the courage to kill the King once he sees the blood on this illusory apparition, and that is when he pulls out his own weapon. It is at this point the dagger of Macbeth’s mind becomes powerful enough to convince him that he can no longer turn back.
In this sense, the hallucination is more powerful than the dagger he holds, because the hallucination portends his fate and keeps him from straying from his path. The dagger symbolizes Macbeth’s internal change from a noble person to a traitor, but it also shows the inevitability of his actions. Macbeth thinks that his life is now dictated by witchcraft and that he can’t turn back on his actions now that he has a sign telling him what to do. This foreshadows how he begins blindly following what fate shows him rather than abiding by his own common sense.