She now implies that she is entirely innocent. Up until this scene, judging the extent of Gertrude's complicity in the murder of King Hamlet has been difficult. Then again, you may interpret the scene as being another proof of Gertrude's innocence. On the other hand, perhaps she does see the Ghost and only pretends not to. Gertrude's black heart impedes her vision, refusing her the sight of her loving husband. She refuses to see the Ghost because of her own guilt. Of course, one can also make a case for interpreting the scene as an indictment of Gertrude. We can interpret Shakespeare's choice to blind Gertrude to the Ghost's presence and to deafen her ears to her son's insistence that the Ghost exists to mean that Shakespeare fashioned Hamlet as a madman, no longer merely acting the part. The Ghost's invisibility to Gertrude raises the question of Hamlet's sanity. There is both simple irony and dramatic irony. He has said he will silence himself, and he is indeed silenced. The irony all belongs to Polonius he is there to trap Hamlet and finds himself trapped instead. According to the post-Freudian interpretation, the need to expiate his misplaced sexual feelings has caused him to stop thinking and act for a change. In a grandly impulsive moment, Hamlet has finally acted on his bloodlust, a bloodlust he has sublimated until this moment. Still impassioned by his encounter with Gertrude, still inflamed with his sexual tension, Hamlet stabs Polonius. In a passionate outburst, Hamlet threatens his mother, holding up a mirror and saying, "You go not till I set you up a glass / Where you may see the inmost part of you." Gertrude, terrified, assumes that her son intends to murder her and calls for help, to which the hidden Polonius reacts without revealing himself. Polonius, obscured by the tapestry, has prophetically and ironically placed himself to "silence me e'en here" and quietly observes what transpires between Gertrude and her son.