Hamlet as a whole is primarily concerned with exploring our relationship with death; that our fear of death comes from the notion that there must be something else, and therefore from the very fact that we cant ever know for sure if there is.
This idea is explored in Hamlet’s “to be or not to be” soliloquy, where he realizes that we suffer the “the slings and arrows of outrageous fortune” rather than “by opposing, end them”, because of the “Dread of something after death”; the “undiscovered country”.
Hamlet spends the entire play struggling between the ambiguities of the numerous connotations of the word “to act”; “to do something” and “to pretend or perform as an actor”.
Hamlet’s core conflict and what he is so often criticized for, especially by himself, is his inability to act (“do something”) but his expert ability to act (that is to pretend and perform).
Coleridge argued that Hamlet is a man incapable of acting (doing); that “Shakespeare wished to impress upon us the truth, that action is the chief end of existence”.
But perhaps it is the very fact that Hamlet does not just act (do something) straightaway, as the audience would have expected the protagonist of a revenge tragedy to do, that is most important.
As well as this there is also doubling in the language used, seen in the use of puns, such as when Gertrude says “Hamlet, thou hast thy father much offended” and Hamlet replies “Mother, you have my father much offended”, and in the use of Hendiadys.
All of this doubling reflects the core of what haunts Hamlet, and that is the fear of the duality of man.
The plays and fictions of Hamlet fit inside one another until the boundaries between reality and illusion become incredibly blurred.
The major themes that therefore arise from this blurring are the conflicts between truth and illusion, honesty and pretence, reality and appearance and the boundaries between youth and age, audience and actor, and most importantly the inescapable boundary between death and life.