After Hamlet has had the players perform The Murder of Gonzago, a re-enactment of what Hamlet believes has been the murder of his father, Hamlet is convinced of the guilt of Claudius, but he does not act because he observes Claudius at prayer. Fearing that if he kills Claudius while he is praying, the king will become a martyr and his soul will be saved, Hamlet hesitates again because of his rationalizing.
However, in Scene 4 of Act III, Hamlet fails to reason and, acting rashly, he kills Polonius.
- Polonius urges Gertrude to talk to her son and chastise him for his behavior
- When Hamlet enters, Gertrude tells him he has offended his father, meaning Claudius, but Hamlet retorts that she has offended his father, meaning King Hamlet
- They exchange more double entendres, but Hamlet contends that he will present her with a figurative mirror in which she can perceive the "inmost part" of herself. This remark frightens Gertrude and she cries out.
- Polonius calls out, too, and Hamlet impetuously stabs at the curtain behind which Polonius hides, stabbing him.
- Hamlet and his mother ironically have a conversation that should have occurred earlier:
As kill a king, and marry with his brother.
- Hamlet further confronts his mother with the death of his father, but the ghost of King Hamlet intercedes and Hamlet relents.
- He realizes that his mother has played no part in the death of King Hamlet and he urges her to stay away from Claudius
- Hamlet tells his mother that he must go with Guildenstern and Rosencrantz
Act III scene 4 is very important as it represents a moment of key truth telling between Hamlet and his mother, Gertrude. Up until this point, Hamlet has assumed that his mother is completely on the side of Claudius, and in this scene, which comes straight after the performance of his special play in which he confronts both Claudius and Gertrude with the reality of what they have done, he decides to confront her with her faults and also attempt to win her over to his side. This is a pivotal scene therefore, as after this scene it is clear that Gertrude begins to suspect her new husband of being the author of the death of her former husband.
What happens in this scene is that Gertrude decides to challenge Hamlet about his conduct and actions in staging the play that has been presented in Act III scene 2. Polonius decides to eavesdrop behind a tapestry. Hamlet enters and when he threatens his mother, Polonius cries out, and Hamlet kills him, thinking he is Claudius. He is disappointed and saddened to see that it is only Polonius. He then confronts his mother with what she has done and how she so quickly forgot her first husband in order to marry her second. The Ghost appears as well, though this visitation cannot be seen by Gertrude, and causes her to question Hamlet's sanity. However, it is clear that Gertrude is deeply upset by her son's words, as she says:
Thou turn'st mine eyes into my very soul,
And there I see such black and grained spots
As will not leave their tinct.
Later on she says that Hamlet "hast cleft my heart in twain," indicating how this scene has challenged her. Key questions to think about in this scene is the nature of the relationship between Hamlet and his mother, and how in particular it changes from the beginning to the end of this scene. It is clear that this conversation has caused Gertrude to examine herself and to be shocked by what she finds within her. This represents a change in the relationship between Gertrude and her son on the one hand, and Gertrude and Claudius on the other hand, as following this scene it is possible to see how Gertrude becomes suspicious and distrustful of Claudius and favours Hamlet more, trusting his words.
Also it is important to think about the role of the Ghost in this scene and what it adds: what is the impact of the Ghost on Hamlet and how does it affect him in later scenes? It is clear that following this scene Gertrude is slightly more distant from her husband, and some productions choose to make this overt.