I think that the duality of humanity is revealed in the drama through characterization. Shakespeare shows Macbeth and Lady Macbeth, husband and wife, to possess the capacity for great brutality as well as great weakness. There is an intricacy to their characterizations and this comes out of Shakespeare's desire to illuminate the duality of human beings. Both characters lack singularity in their dimensions. They are complex and distinct, reflecting the true character of humanity. Lady Macbeth is presented at the start of the drama as a firestorm insistent on acquiring power by any means necessary. She is shown to be one who insists on wrangling Macbeth's will to her own subjectivity. Yet, as the drama progresses, her character is shown to be one that devolves into a sense of suffering and guilt for her actions. In contrast, Macbeth is shown to be one who is loyal at the start of the drama, incapable of murder and betraying one who showed much in way of honor to him. Yet, these noble traits are supplanted by a lust for power and a lack of coherence in surmise as he becomes someone who embraces murder and slaughter for his own purpose. In this, Shakespeare presents human beings are being a totalizing vision that consists of contradiction and a lack of clarity. This dualistic character ends up defining what it means to be a human being.