Final answer:
The lines 'Fair is foul, and foul is fair: Hover through the fog and filthy air' from Shakespeare's play Macbeth are a paradox that highlights the theme of deception and ambiguity.
Step-by-step explanation:
The lines 'Fair is foul, and foul is fair: Hover through the fog and filthy air' are from Shakespeare's play Macbeth. These lines are an example of a paradox, which is a statement that seems contradictory but may actually be true.
Here, the paradox emphasizes the theme of deception and ambiguity in the play, as what may seem fair can actually be foul, and vice versa.