The idea that Shakespeare presents in the play is that the order of things will fall into anarchy in the play.
Explanation:
This is the first scene of the tragedy of Macbeth and serves as one of the best introductions to a play as it is simultaneously revealing an important plot element and making a case for a major theme of the play.
The phrase 'fair is foul, foul is fair' shows this.
It is a paradoxical argument that shows the anarchy that the system is going to fall into when the characters of the play decide to think that foul is indeed fair for their own means.
In that sense, the idea of losing morality and a sense of paradox is what is primal in the play.
