Hamlet was not insane. Learn about Hamlets destructive madness, and what he did.

Hamlet appears to be insane, after Polonius's death, in act IV scene II. There are indications, though, that persuade me to think other wise. Certainly, Hamlet has plenty of reasons to be insane at this point. His day has been hectic--he finally determined Claudius had killed his father, the chance to kill Claudius confronted him, he comes very close to convincing Gertrude that Claudius killed his father, he accidentally kills Polonius, and finally the ghost of his father visits him. These situations are enough to bring Hamlet to insanity, but he remains sharp and credible. Hamlet is able to make smart remarks to Rosencrantz and Guildenstern, comparing then to sponges, When he (Claudius) needs what you have gleaned, it is but squeezing you and, sponge, you shall be dry again, (pg 98, 20). This is random and unexpected, as many of his actions, but the comparison makes sense; Rosencrantz and Guildenstern soak up all the kings favors, only to become dry again after they mop up the King's mess (spying on Hamlet, and getting Polonius's body).

David Garrick in Hamlet, I, 4

Book signing and Hamlet Au's interview with Julian...

Hamlet

Later, with Claudius, Hamlet tells how lowly a king can be by saying, A man (beggar) may fish with the worm that hath eat of a king, and eat of the fish that hath fed of that worm, (pg 99, 29). This also makes sense, and is not quite as random; when Hamlet confronts Claudius, and the king asks where Polonius is, Hamlet immediatly begins the comparison by telling Claudius that Polonuis is at supper (the worms are eating him for supper, and so on). This proves that Hamlet had some kind of planning for this degrading comment, and that his thoughts are not scattered and he is able to stay focused. There is a question of what being insane...