HAMLET On him, on him! Look you how pale he glares,
His form and cause conjoined preaching to stones
Would make them capable. [to Ghost] Do not look upon me
Lest with this piteous action you convert
My stern effects! Then what I have to do
Will want true colour, tears perchance for blood.
GERTRUDE To whom do you speak this?
HAMLET Do you see nothing there?
GERTRUDE Nothing at all, yet all that is I see.
HAMLET Nor did you nothing hear?
GERTRUDE No, nothing but ourselves. (3.4.121-131)
But what, who are you looking at? Gertrude has asked. On him, on him! Right there, HIM! Look you how pale he glares—and while glares might suggest anger, it’s more generally intensity, a fixed stare—his form and cause conjoined preaching to stones would make them capable. If he were to look like that at even the most inanimate of objects, they’d come to life at his command—and pity him, so beseeching is his look. The Ghost’s countenance, it seems, is still showing more sorrow than anger. Hamlet can’t take it anymore, this reproach, this reminder of his own inadequacy, at the very moment when he’s been venting his fury on his beloved mother rather than converting it into action. Do not look on me lest with this piteous action you convert my stern effects! I’ll just lose it completely, I’m barely keeping it together (as you can see), I’ve got to remain focused on revenge, yes, and the way you’re looking at me now—it just makes me so, so sad. Dad. Then what I have to do will want true colour, tears perchance for blood. I’ve only just said that I was capable of drinking hot blood, and now that’s all fading away with my resolve, dissolving in tears, in grief.
Gertrude’s baffled, concerned, appalled, by the situation and by Hamlet’s anguish: to whom do you speak this? Hamlet’s equally baffled: do you see nothing there? Nothing at all, yet all that is I see. I can’t see anything there, no, but I’m in full possession of my faculties, I can see everything else. I can see you, your distress. Nor did you nothing hear? No, nothing but ourselves. (And as I’ve suggested before, occasionally in performance Gertrude does see the Ghost, which is a bold choice, and hard to pull off in light of this bit of the exchange in particular.) Nothing but ourselves is defiant, a bit, but also sad: it’s just the two of us here now.