HAMLET The spirit that I have seen
May be a devil, and the devil hath power
T’assume a pleasing shape. Yea, and perhaps
Out of my weakness and my melancholy,
As he is very potent with such spirits,
Abuses me to damn me! I’ll have grounds
More relative than this. The play’s the thing
Wherein I’ll catch the conscience of the King. (Exit.) (2.2.533-540)
A brief faltering, in the scene’s very last moment: the spirit that I have seen may be a devil—this is apparently the first time that Hamlet’s considered this possibility—because after all, the devil hath power t’assume a pleasing shape. I could be being tricked! It might not be my father’s ghost at all, it might be SATAN. Yea, and perhaps out of my weakness and my melancholy, because I’m not in a good way, physically or mentally, as he (the DEVIL) is very potent with such spirits, at exploiting any sign of weakness. (There’s pathos in that admission: I’m really not well, it’s not all an act, I’m so tired, so low, so out of sorts.) So perhaps he (the DEVIL) abuses me to damn me, deceives me in order to lead me into temptation (to kill my uncle), and so to hell!
No matter, apparently. I’ll have grounds more relative than this, far better, stronger proof than anything I’ve been told already by the Ghost. I’m going to find out exactly what’s been going on, independently and incontrovertibly. And I have a plan! The play’s the thing wherein I’ll catch the conscience of the King! It’ll force him to reveal himself, more or less own up to what he’s done. At last, a PLAN, something to do…
And with that rhyming couplet, this enormous scene, and the play’s second act, are done.