You seem to be responding to a Michael Crichton type doomsday situation, when that quote comes out of the mouth of a religious fundamentalist character, who doesn't even say it in a doomsaying way so much as chastising in a memento mori sort of way.
Then perhaps I should clarify: the Alpha Centauri character Sister Miriam Godwinson is no fiction writer, at least not in this world, her spiel just reminds me of one.
