"Though this be madness, yet there is method in't." (Act II, Scene II)
What does it mean? At this point of the play, Hamlet and Polonius are interacting onstage, but this quote is technically spoken by Polonius to the audience, in an aside. What Polonius is saying is that, even though Hamlet is talking crazy, it actually makes sense, or it has a "method." Polonius's assertion is ironic because he is right and wrong. Polonius believes Hamlet is acting "mad" because Hamlet's love of Ophelia has driven him to such. While Polonius is correct to think that there is reason behind Hamlet's actions, he is incorrect as to the cause. Hamlet is purposefully acting mad to disguise his true mission to avenge his father's murder.