Does Shakespeare attempt to use the Gravedigger as a means of carrying on a character of antic disposition after Hamlet becomes transformed?
In Act 5 scene 1, we see Hamlet transformed ("This is I, / Hamlet, the Dane." V.i.271), showing the true nobility of his character. Can it be said that the gravedigger serves to continue the character of maddness within the play?
That being said, is the gravedigger is used as a foil to further eluminate the traits of the new Hamlet with Hamlet's disposition prior to the transformation?
Shakespeare's tragedies tend to include comic relief in them at some point and to some degree. These instances of comic relief often occur right before a major plot twist or development. In "Romeo and Juliet", for example, the scene where Mercutio makes fun of the nurse in the square shortly before he is accidentally killed by Tybalt, is a funny scene. It precedes Romeo's killing of Tybalt that gets him exiled. Another example is "Macbeth" and the scene with the drunken gate keeper that precedes the discovery of the dead King Duncan. This scene in Act 5 of "Hamlet" with the gravedigger is another instance of comic relief. It also serves as an opportunity for us to hear more of Hamlet's contemplations. The contemplation of what happens to a man once he's dead (ll.210-219) is something of a repeat of an idea that Hamlet expressed in Act 4, sc. 2 (ll.19-25). In that Act 4 scene, Hamlet is supposedly spouting gibberish as he carries on his "antic disposition". That he repeats this idea in serious dialogue with Horatio gives some evidence to the idea that Hamlet is not mad. The gravedigger is not a mad character at all, but one who has become desensitized to what he does, as Horatio said in l. 69, "Custom hath made it in him a property of easiness." The gravedigger jokes and sings because he's done his job for many years and the sadness or horror of gravedigging is no longer with him.
We can always try to contextualize Shakespeare nowadays with lit. theory of all sorts, but the likely answer is much simpler--audiences love scenes where low class individuals trade in paradoxes for comic effect. For ex: one of the most famous scenes from Monty Python and the Holy Grail is the "gravedigger" type scene where teh two field hands are basically piling up mud and making a fool of the knights that question them, utlizing similar paradoxes.
This scene was, perhaps, the "highlight" of the play. When David Garrick (the famous Shakespearean actor responsible, in large part, for 18th C. bardolatry) redrafted Hamlet for his 1772 performance, he cut out the scene altogether because he felt that audiences responded more to the gravediggers than they did to the entire plot.
I think that sometimes the simplest answer is the correct one in Shakespeare. The gravediggers are amusing, and their "maddening" discussion--garbed in paradox--is also paradoxically candid and straightforward. This provides a contrast to the "grave" aspects of Hamlet's ruse--where the King's motivations, Gertrude's motivations, and Hamlet's motivations, involving Polonius, R & G, in turn---do not have the same candid nature. They put an entire kingdom in peril, and their lies/misrepresentations don't have quick answers, wheras the gravediggers' ruses do.
By definition, it's satire. That's probably why audiences loved the scene, and why it's still a treasure to see the full scene on stage. Nearly every movie version of Hamlet cuts out everything but the Yorick speech.
The tenor of their speech is light, yet sophisticated. But their theme is fitted to the scene--it's gallows humor, quite literally.
In a play that has so much death in it, where suicide, murder, and Hamlet's intention to murder the King darken all humors, death provides a release, if only for a moment, from death.Strange how it all works out.