Why does Macbeth kill Duncan?In Shakespeare's play Macbeth, the main character of the same name is not sufficiently satisfied with the high social position he occupies and the honored status he has acquired. Looking at the play simplistically, one might conclude that Duncan is murdered because of Macbeth's ambition. Ambition is a sin, of course, and so Macbeth is punished for his sins. If you don't want to delve deeper, this evaluation of the work is almost completely satisfactory, because it is very simple and clear. However, this approach converts the play from an extraordinarily complex study of evil into a simple moral drama and closes the discussion on the more interesting aspects of the play. Now, there is some evidence to support the ambition charge. Macbeth wants to be king, and refers to that desire as ambition ("I have no urge/To prick the sides of my intent, but only/Ambition that leaps itself/And falls upon the other" (1.7.25- 28).But here we must be careful not to automatically accept a character's estimate of his motivation for the truth, or at least an entirely adequate summary statement of all that we have to "undo" just what that concept contains ambition in the character to which we apply it. Fascinating aspect of Macbeth's motivation is that he is in the grip of something that he does not fully understand and that part of him certainly does not approve of. This makes him very different from Richard Gloucester, who announces his plans with joy and shows no scruples about what he must do (on the contrary: he can't wait to eliminate his next victim and invites us to share his joy). everything is clear where this desire comes from. The witches (of whom more later) work the hint into the play, but there is a strong hint from Lady Macbeth that she and her husband have already spoken about the matter well before the play begins ("What beast does not was it then? Did that make you break this enterprise to me?" (1.7.48-49). If so, the appearance of the witches may be, in part, a response to some wish in Macbeth.