You think so? I've enjoyed being able to see the changes in science and technology over time. My counterpart enjoys the cultural shifts, but to each their own.

[She's chattering, but it's not mindless. She'd noticed the slight frown, the sudden edge in his gaze. It's subtle, but oh, it's there. And just as his expression has changed just slightly, so too has her own: her eyes gleam in eager delight, because she and Robert had spent so long doing something so dull, and oh, she misses him terribly, but this is fun.]

But as to what keeps me immortal . . .

[Not rendered her as such. Hm.]

--I suppose, if you were poetic, you might call it the principle of what if. I am . . . a possibility, you could say. Alive and dead all at once, constantly caught in a state of both and neither-- and thus, unable to die.

[That explains almost nothing while being absolutely accurate.]