And, whether intentionally or not, another purpose is served by Shakespeare's choice of this particular moment. It is a moment when the state of Hamlet's mind is such that we cannot suppose the Ghost to be meant for an hallucination; and it is of great importance here that the spectator or reader should not suppose any such thing. He is further guarded by the fact that the Ghost proves, so to speak, his identity by showing the same traits as were visible on his first appearance--the same insistence on the duty of remembering, and the same concern for the Queen. And the result is that we construe the Ghost's interpretation of Hamlet's delay ('almost blunted purpose') as the truth, the dramatist's own interpretation. Let me add that probably no one in Shakespeare's audience had any doubt of his meaning here. The idea of later critics and readers that the Ghost is an hallucination is due partly to failure to follow the indications just noticed, but partly also to two mistakes, the substitution of our present intellectual atmosphere for the Elizabethan, and the notion that, because the Queen does not see and hear the Ghost, it is meant to be unreal. But a ghost, in Shakespeare's day, was able for any sufficient reason to confine its manifestation to a single person in a company; and here the sufficient reason, that of sparing the Queen, is obvious.[61] At the close of this scene it appears that Hamlet has somehow learned of the King's design of sending him to England in charge of his two 'school-fellows.' He has no doubt that this design covers some villainous plot against himself, but neither does he doubt that he will succeed in defeating it; and, as we saw, he looks forward with pleasure to this conflict of wits. The idea of refusing to go appears not to occur to him. Perhaps (for here we are left to conjecture) he feels that he could not refuse unless at the same time he openly accused the King of his father's murder (a course which he seems at no time to contemplate); for by the slaughter of Polonius he has supplied his enemy with the best possible excuse for getting him out of the country. Besides, he has so effectually warned this enemy that, after the death of Polonius is discovered, he is kept under guard (IV. iii. 14). He consents, then, to go. But on his way to the shore he meets the army of Fortinbras on its march to Poland; and the sight of these men going cheerfully to risk death 'for an egg-shell,' and 'making mouths at the invisible event,' strikes him with shame as he remembers how he, with so much greater cause for action, 'lets all sleep;' and he breaks out into the soliloquy, 'How all occasions do inform against me!'