"Prythee, see there! behold! look! lo! how say you? Why, what care I? If thou canst nod, speak too."
This is not bravado trying to steady itself in a breeze of horror.
In order to break Macbeth down, and fully identify him with the deed of which Banquo was the horrible shadow, his temperament required that the ghost should vanish and reappear at the moment when he recovers composure. Shakspeare has marked, by Macbeth's sudden change of demeanor, that he was usually familiar with these coinages of his brain. To whatever ecstasy his feeling rose, with or without his wife's complicity, Shakspeare would have us understand that Macbeth was so fluent with these bodiless creations that he had naturalized the night-side of his mind. Therefore, Banquo must re-enter precisely when Macbeth drinks to the general joy, and to the dead man in particular. Shakspeare knew the moment when to spill Macbeth's wine and all his hardihood by putting out a disembodied hand to strike the goblet from his grasp. It was the very nick of time, but it was in the man's own temper.
Let us see how it was. The alteration of demeanor from astonishment to the abjectness of a guilty terror slips out of Macbeth's conviviality into the company, as he calls for wine and drinks "love and health to all." At the rim of his goblet he can even banter with his consciousness of murder: he is in a frame to enjoy proposing the health of
"Our dear friend, Banquo, whom we miss; Would he were here!"
Now this pretence of desiring Banquo's presence uses up what resistance Macbeth has to spare. No sooner are the words out of his mouth than he imagines how they might be answered: the imagining it is the vivid answer. When you try jauntily to job off suspicion before other persons, the cheek grows pale with dread of being contradicted. A door is thrown ajar by this wind of pretending that nothing has been committed. Come on, there! the villain cries. Has any thing happened? Is anybody outside? Let him enter and take a look around! Sure enough, 'tis there: his mind's eye sees it enter. Even when the small faults of social life are denied or disclaimed by us, a ghost is raised upon the face, a dubious semblance of your guilt in the evasive eye, or just a flicker in the corner of the mouth. Most people overestimate their strength to make a flat denial of misdeeds when their soul is reflected in the polished mirrors of watchful eyes. There is a non-committal look which collars a man, puts him in the dock, and sends him to jail before he knows that he has been apprehended.