Well, I wasn't trying to make a moral argument, although I guess the way I phrased things might suggest otherwise. Heck, I just have this strong intuition that

Well, I wasn't trying to make a moral argument, although I guess the way I phrased things might suggest otherwise. Heck, I just have this strong intuition that there's a countdown timer inside us, which will lead us inexorably to death. Maybe I can't argue convincingly for it, but I feel there have to be evolutionary reasons for why such a timer must exist, and the idea of making room for young organisms seemed like a fruitful way towards an explanation. So here's a last and final argument for such a countdown timer: there are no immortal species in nature. That's more of an "existence proof" than a "constructive proof", but it does strongly argue that there is a reason why death is necessary (without providing the reason, for I can't think of one that will persuade you).