Hamlet's state of mind is very debatable thoughout the play. His sanity has been questioned for hundreds of years, and my belief is that Hamlet was sane. The play begins with Hamlet grieving over his dead father. He is also troubled by his mother's quick and incestuous remarriage to his uncle, and the appearance of a ghost that looks like his deceased father.
In ACT I, Scene V, Hamlet returns from talking to the ghost. Horatio and Marcellus question him hysterically about the ghost, but Hamlet refuses to talk. Instead he makes them "swear by his sword" not to mention anything about the ghost. He then tells them that he may start acting strange or crazy, but that he really isn't either of the two. This act alone indicates that he realizes some of his actions may appear to be bizarre, but he is aware of what he is doing.
Hamlet's first act of "madness" occus in ACT II, Scene I. Ophelia is in her room sewing, and Hamlet burst in grabbing her by her wrist. He did not say anything but shook her slightly and then left without breaking eye contact. Hamlet did this becuase he knew Ophelia would tell Polonius, who would then tell the king and queen. He planned this action to insinuate his madness. Hamlet wanted people to think that he was crazy becaue crazy people can get away with more strange and rash comments or actions than sane people can.
In ACT III, Scene II, Hamlet lectured the players on how to act out the parts he wrote for them. The fact that Hamlet thought to add this trap into the play to see if his uncle was guilty or not guilty provides evidence of Hamlet's sanity. If he were insane, he...