Why does Hamlet pretend he is mad? And is it really essential for his schemes?
After seeing the ghost of his father in Act I, scene v, Hamlet plans to revenge his father’s murder by Claudius. Hamlet asks Horatio not to let on he knows anything when, “As I perchance hereafter shall think meet/ To put an antic disposition on” (191-2). So regardless of any interpretation by the actor, Hamlet tells us he plans on acting crazy.
“Is it really essential for his schemes?” This is subjective, of course. There is arguable evidence that Hamlet truly descends into madness. Most point to his behavior during the staged play, “The Mousetrap,” and afterward in the closet scene where Hamlet confronts Gertrude. Any argument that Hamlet is truly mad can never be thoroughly proven, however, as Hamlet had already given the disclaimer for his “antics” in Act I.
I am of the opinion that Hamlet’s antics were not really “essential” as, in the end, though he revealed Claudius’s guilt to everyone, he lost his mother and his own life. It was a Pyrrhic victory. Hamlet had the opportunity, for example, to take Claudius’s life while he was seemingly praying in the chapel, but he hesitated and dragged his revenge through another two acts, resulting in the deaths of most of the cast.
In the original Amleth legend by Saxo Grammaticus, Amleth feigns imbecility to remove the perception that Amleth would pose a threat to his uncle the new king. In Hamlet the lead character says he may adopt an antic disposition that appears to be madness to others especially Polonius. In a way Hamlet's antics are counterproductive because they actually raise Claudius's suspicions.
Madness provides a dramatic dimension to Hamlet, it also helps drive the plot and it supports one of the prime themes in the play. As for why exactly Hamlet appears mad, there is no explanation in the text. There are many theories. In a book by J. Dover Wilson, "What Happens In Hamlet", Wilson thinks Hamlet is simply trying to cover for true madness. He cites six instances where Hamlet suffers from temporary madness. Of course this is wild speculation. Hamlet's fictional life is confined to the pages of the play and it does not provide an answer to Hamlet's madness. Whether Hamlet is mad or only faking it really depends on how the actor wants to play it.