One could read Hamlet simply, simplistically even, as a revenge tragedy. Hamlets father, the king of Denmark, is killed by his brother, Claudius, who, overriding the rights of succession, appropriates both the crown and the wife of Hamlets father. The ghost of the father reveals everything to his son, and all the elements of the revenge tragedy are in place: Hamlet has an obligation to avenge the murder, the usurpation, and the adultery. This he does by killing Claudius at the end of the play.
However it is clear that the theme of vengeance is merely a vehicle used by Shakespeare in order to articulate a whole series of themes central to humanity:
Dilemma and Indecision
For Hamlet nothing is simple, everything raises questions. His dilemma is not about what decisions he should take but rather whether he will be able to make any decisions at all.
It is possible, even probable, that in his particular fashion Shakespeare wanted to disrupt the conventions of classical tragedy, which he may have seen as too heavily laden with stereotypes.
Hamlet and Metaphysical Doubt
Hamlets tragedy appears as the quintessence of a moral and metaphysical instability which some associate with the experience of modernity. Hamlets decline and bitterness indeed match his extraordinary lucidity. The tragedy of Hamlet, nevertheless, clearly exceeds the boundaries of the tormented consciousness of its protagonist.
Hamlet and Madness
Most of the characters observing Hamlets behaviour cant agree whether it is fake and calculating or whether the prince really is suffering from a mental illness threatening the noble, sovereign reason which separates men from beasts (Claudius). Claudius himself is conscious of the fact that the conduct and words of his nephew are at one and the same time completely irrational and absolutely coherent. Basing his judgement on the theories of ancient medicine, he attributes the ambiguities of the deranged speeches to the workings of a harmful temperament provoking a state of deep melancholia.
Each character tries to decipher the madness of Ophelia and Hamlet because the ambiguities of their deranged discourses seem to reveal a terrible sickness capable not only of threatening the psychological equilibrium of the individual but of infecting the kingdom as well as the world beyond
However, Hamlets madness has not only the effect of disturbing those around him, it also allows him the freedom to transgress the courts rules of etiquette and obedience without incurring immediate punishment. Hamlet, under cover of madness, takes on the role of a critical and sardonic commentator on the schemes of other characters,
Amongst Hamlets principal targets are his mothers infidelity, Rosencrantzs servitude and the devouring ambition of his uncle whom he reminds, by means of a riddle, that all are equal before death.
So, what is the answer to the central question: is Hamlet mad? Is he mad partly because his pain and metaphysical doubt are beyond him? Is his madness a strategy for better observing and manipulating others, and furthermore to protect himself? Or does he take cover under an artificial madness which absolves him from all responsibility and allows him to find comfort in inaction, to split himself in some way, to be at once an actor in and a spectator of the staging of life, of his life? Or is he, all things considered, just insane?
Hamlet and Ghosts
Three other Shakespeare plays have ghosts as characters: Julius Caesar (Brutus is visited by the ghost of Caesar), Macbeth (Banquos ghost interrupts Macbeths banquet) and Richard III (the king is haunted by the ghosts of his victims).
In Hamlet, the role of the ghost, who appears as early as the first scene, is to trigger the action by revealing Claudius crime and by demanding vengeance. It is one of Shakespeares glories, he continues, that he took the conventional puppet, humanised it, christianised it, and made it a figure that the spectators would recognise as real, as something which might be encountered in any lonely graveyard at midnight
Hamlet gives us seven soliloquies, all centred on the most important existential themes: the emptiness of existence, suicide, death, suffering, action, a fear of death which puts off the most momentous decisions, the fear of the beyond, the degradation of the flesh, the triumph of vice over virtue, the pride and hypocrisy of human beings, and the difficulty of acting under the weight of a thought which makes cowards of us all.
The language is extremely beautiful. Shakespeare was in love with words. His soliloquies are pieces of pure poetry, written in blank verse, sustained by a rhythm now smooth, now rugged, by a fast or a slow pace, offering us surprises in every line.
The soliloquies are in effect the hidden plot of the play because, if one puts them side by side, one notices that the character of Hamlet goes through a development which, in substance, is nothing other than the history of human thinking from the Renaissance to the existentialism of the twentieth century.
Hamlet and Theatre
Structurally Hamlet offers all the characteristics of classical tragedy. The first act gives us nearly all the elements necessary to drive the plot. The second act accelerates the action until the formidable explosions of the third act, which can only lead to the tragic denouement of the fifth act.