Throughout the play, the themes of revenge and madness often appear.
Not only in the main character Young Hamlet, but also the other characters.
From the beginning of the play Hamlet is depressed. When asked about his depressed appearance and demeanour by Gertrude, Hamlet replies, "Seems, madam? Nay, it is. I know not seems".
Here he is saying 'I am what I appear to be' he is, looks and acts depressed. Also at this point in the play his sanity is clear. Clearly, Hamlet makes a statement about his mental health when he commits himself to avenge his father's murder. This quote allows the reader to follow Hamlet's train of thought in his role as student, mourning son, and Prince of Denmark:
"I'll wipe away all trivial fond records, All saws of books, all forms, all pressures past That youth and observation copied there, And thy commandment all alone shall live Within the book and volume of my brain".
In the time in which this play is set, avenging the murder of a father was part of one's honour, and had to be done. In the above quote Hamlet is stating his commitment to avenge the death of his father and maintain his own honour. At this point in the play, there is little doubt about Hamlet's state of mind, or his intentions.
In act two, Hamlet spends most of his time reading and talking with Polonius, Guildenstern, Rosencrantz, and the players. At the very end of this second act, Hamlet refers to his filial duty to avenge his fathers' death. Hamlet then admits he is merely feigning insanity when he says, "I am but mad north-north-west. When the wind is southerly I know a hawk from a handsaw". Admitting he is only acting 'mad' implies he is secure with his plot. Hamlet also seems to portray a willingness to accept this plight with, "...for there is nothing either good or bad but thinking makes it so..." In this quote, Hamlet is stating that behaviour shapes reality (peoples views).
Again, Hamlet is stating his commitment to avenge the death of his father:
"I should ha' fatted all the region kites With this slave's offal. Bloody, bawdy villain! O, vengeance! What an ass am I! This is most brave, That I, the son of a dear father murdered, Prompted to my revenge by heaven and hell..."
Although Hamlet is certain it was Claudius who murdered his father, he wants others to be definite about it, he needs proof. He devises a plan in which he will catch Claudius by his guilt via a play, and then everyone will see what is rotten in the state of Denmark: "The play's the thing wherein I'll catch the conscience of the King".
He wants the proof from someone he admires and trusts. Hamlet says to Horatio "Observe mine uncle. If his occulted guilt Do not itself unkernnel on one speech, It is a damned ghost we have seen".
Perhaps he wants proof from someone who he trusts because he suspects that he himself is mad and unable to read body language clearly?
In this scene, while Hamlet is describing to the players how his lines should be read, he says "Suit the action to the word, the word to the action". If only Hamlet would follow his own advice, his problems would be resolved sooner. This shows the inconsistency within Hamlet, since he maintains distance between words and actions, while debating that others should not.
It becomes interesting that Hamlet's uncle is to be judged upon how he acts during the play. If Claudius' character is supposed to be a superb actor and does not reveal his guilt, his life will be spared and Hamlet will have none of the proof of which he seeks. Yet, Claudius is a poor actor, and when he rises during the play Hamlet reacts with "What, frighted with false fire?". It is as if Hamlet is saying 'it's only a play, it is not real'. Hamlet does mention something similar to this in his previous lines "Your majesty, and we that have free souls, it touches us not".
This evidence drives Hamlet to saying more words, this time referring to killing, "Now I could drink hot blood". Hamlet referrers these actions to a role, in this instance, the role of Nero, "The soul of Nero enter this firm bosom". Again later, Hamlet talks himself out of character and does not kill Claudius. He 'puts it off' until a later date and he states:
"When he is drunk asleep, or in his rage, Or in th' incestuous pleasure of his bed, At game a-swearing, or about some act That has no relish of salvation in 't-Then trip him, that his heels may kick at heaven, And that his soul may be damned and black".
Hamlet is waiting for Claudius to fit the part of the villain, and then catch him out. His actions are paused whenever something or someone does not fit the part. After Hamlet backs out of killing Claudius, he says to his mother "O shame, where is thy blush?" Here, he is saying how he is disappointed for his mother not only for marrying his uncle, but for not being true to herself. Again, Hamlet is contradicting himself. Throughout the first two thirds of the play, Hamlet, to himself, has been untrue.
At this point in the play, Hamlet is still uncertain as how to proceed. Hamlet is caught in his inner turmoil of acting out his role, as feigning to be mad, and objectivity. Finally, Hamlet's thoughts and actions are placed in order, and he makes the decision to uphold the destiny his father had proclaimed. Hamlet makes this important decision while watching the soldiers going off to battle:
"The imminent death of twenty thousand men That for fantasy and a trick of fame, Go to their graves like beds, fight for a plot Whereon the numbers cannot try the cause, Which is not tomb enough and continent To hide the slain? O, from this time forth My thoughts be bloody or be nothing worth!"
Hamlet reasons that these soldiers fight and die simply because that is there fate, regardless if the plot of land they are fighting for is significant or not. He realises what his role is. And so, he does not hesitate in his position when he returns from England, and fully takes up his role. Upon his confrontation with Laertes, he says "This is I, Hamlet the Dane" meaning the true King of Denmark. This action by Hamlet is appropriate for someone as wronged as he was. In his reaction to Ophelia's death, Hamlet again displays behaviour that backs up his role as being mad. She was his true love interest, and perhaps loved her more than her brother. This is shown by Hamlet's statement "I loved Ophelia. Forty thousand brothers Could not with all their quantity of love Make up my sum".
Hamlet reluctantly acknowledged that he should have loved her, but did not. If Hamlet truly loved Ophelia, he would not have treated her so harshly. Hamlet is now committed to role playing, and portraying love for her at this time, fits the role.
In the remaining scenes of this play, Hamlet is fixed in his role. He has a bit of time to tell Horatio his tale of escape before he is challenged by Laertes. Hamlet has no choice but to accept the challenge, he must defend his honour. Hamlet enters this match, but more importantly, accepts the role of his destiny to kill Claudius, and avenge the death of his father. Hamlet kills Claudius and does the done thing at that time - avenge the death of his own father.
It seems apparent in the play, that to have survived, one needed to be able to play their role properly and act and/or hide accordingly.
If ones role was not fulfilled in its entirety, people died;
Polonius attempted to convince Claudius that Hamlet was in deep love with his daughter. This led Polonius to spy on Hamlet, and since he was not successful in that venture, it cost him his life. Ophelia obviously was unable to bear the burden of her father's death, and that her true love was the one who had killed him. This resulted in her going into insanity, which resulted in her death. Claudius was unable to successfully conceal his guilt, thus Hamlet had the proof he needed to confront him.
Yet, the irony of the play Hamlet Prince of Denmark lies within the main character. If Hamlet had acted as the ghost of his father had initially instructed, no one except Claudius would have died. Therefore, Hamlet merely verged on the brink of madness and this was due to having to do his quest for the truth, which lies within us all.