Hamlet was indeed a very sane man. He was only feigning madness to further his own plans for revenge. His words were so cleverly constructed that others will perceive him as mad. It is this consistent cleverness that is the ultimate evidence of his complete sanity. Can a mad person be so clever? No, a mad person cannot. Hamlet is sane and brilliant.
After Hamlet, Horatio, and Marcellus see the ghost, Hamlet tells Horatio that he is going to "feign madness". If Horatio is to notice Hamlet acting strange it is because he is putting on an act. "How strange or odd some'er I bear myself/(As I perchance hereafter shall think meet/To put an antic disposition on)/That you, at such times seeing, never shall,/With arms encumbered thus, or this headshake ,/Or by pronouncing of some doutful phrase,/As "Well,well,we know," or "We could an if we/would,"/Or "If we list to speak," or "There be an if they/might,"/Or such ambiguous giving-out, to note/That you know of me-this do swear,/(I,v,190-201).Hamlet states that from this point forward I may act weird but to ignore my acts of madness for they are just that, acts, and are in no way a sign of true madness. Only a sane and rational person could devise such a plan as to act insane to convince others that he is insane when he actually has complete control over his psyche.
Hamlet only acts mad when he is in the presence of certain characters. When he is around Polonius, Claudius, Gertrude, Ophelia, Rosencrantz, and Guildenstern he acts completely irrational. When Hamlet is around Horatio, Bernardo, Fransico, the players, and the gravediggers Hamlet acts completely sane.
When Hamlet and Polonius meet in II,ii Hamlet calls Polonius a fishmonger and makes strange conversation with him. In IV,iii Hamlet refuses to tell Claudius were he has hidden the body of Polonius and goes on about how Polonius is at supper. When Hamlet encounters Gertrude in her closet, an unusual place, in III,iv. He yells at his own mother. In II,i Hamlet enters Ophelia's closet, a highly unusual act, he is dressed badly, and acts very strange towards her. Claudius and Polonius set up a clandestine meeting between Hamlet and Ophelia in III,i. Ophelia then tries to return some gifts that Hamlet gave to her and Hamlet claims that he did not give her any gifts and that he never loved her at all. During the play in III,ii Hamlet sexually harasses Ophelia in front of the entire audience of the play. In IV,ii Hamlet refuses to tell Rosencratz and Guildenstern where he has hidden the body of Polonius. Hamlet has Rosencratz and Guildenstern, two people that used to be his friends, put to death in England.
On all occasions when Hamlet is in contact with Horatio, Bernardo, Fransico, the players and the grave diggers Hamlet acts like a completely normal person under complete control of his psyche. Only a person that was truly sane and had a definite purpose behind a feigned madness could pull off such believable acts of feigned madness.
Even Claudius and Polonius believe that Hamlet is not insane.
"Love? His affections do not that way tend/Nor what he spake, though it lacked form a little,/Was not like madness. There's something in his soul/O'er which his melancholy sits on brood /And I do doubt the hatch and the disclose" (III,i,176-180).
Claudius states Hamlet's emotions are not from love. What he does is not like madness, but it has a higher purpose. Hamlet knows something is amuck and that he is going to set things right. His madness is part of a plan that he has which is about to be hatched.
"Though this be madness, yet there is/method in't" (II,ii,223-224).
This occurs when Polonius and Hamlet are talking and Hamlet is acting unusual and Polonius clearly states that he believes that there appears to be a reason behind Hamlet's actions and that they are logical in nature.
Shakespear gives a definite example of someone who has definitely gone mad in the play Hamlet. Ophelia is definitely crazy. After being rejected by Hamlet and the Death of her father she just could not handle it anymore. She went around dancing, singing about death, erratic behavior, and ultimately her "death". She just could not handle everything that had happened to her and gave up. On the other hand Hamlet is not crazy, he has complete control over his psyche.
Hamlet tells his mother that he is not mad. "That I essentially am not in madness/ But mad in craft" (III,iv,209-210). Hamlet states, that he is not crazy in a sense that he has lost it completely and gone totally insane, but crazy like a fox. He has a plan to avenge his father's murder.
Hamlet is not mad. Everything he does has a purpose to it. He is out to avenge his father's murder. The facts that support this argument are Hamlet tells Horatio that he is going to feign madness, Hamlet only acts mad in front of certain characters. Claudius and Polonius believe that Hamlet is not mad but that there is a purpose behind his madness, Shakespear gives an example of a truly mad person, and that Hamlet tells his mother that he is not crazy. These facts prove beyond a doubt that Hamlet had complete control of psyche at all times throughout the play.