There's an episode of the old-time radio series Lights Out Everybody, from the pen of creative luminary Arch Oboler. The plot of The Immortal Gentleman rather startled me when, as a kid, I first listened to it, alone upstairs in my darkened bedroom.
It is the future. Or, at least, we think it is. A man from the present day falls asleep in an auditorium during a boring lecture, and "wakes up" to find himself in the remnants of the very same auditorium. He is soon tagging-along with a band of people who are on a mission. In the future --- in their time --- people live forever. And they're seeking to end that, by any means necessary.
The moral of Immortal Gentleman --- that humanity should live and then die, making way for newer, younger people --- has always stuck with me. When we're young, we rarely seem to think about death. If we do, it's typically something we don't look favorably upon. The idea of living forever is an inviting one. But at what cost? Is an infinite lifespan really all it's cracked up to be? Let's think about it for a moment.
If humanity were to find a way to exponentially increase its lifespan, then presumably we'd have conquered aging. That would seem to be the only way to avoid death. So then what happens? Do we continue to procreate? If so, where would everyone fit? Would the Earth's resources be stretched to the breaking point? Would the reality of economic sustainability require folks to work all their lives? If there is no death, there would be no retirement, surely? And people would have to work all their lives in order to maintain a prosperous and productive financial environment.
What would happen to hierarchy? What opportunities would there be for the "young" to supplant the "older?" What endeavors would people undertake? Would we become bored with life? Would progress in various fields slow down? Humans have improved upon the theories and practices of those who came before them. If no one dies, would the once-creative begin to develop narrow minds as they grew older, and older, and older? Would the "younger" generations have a chance to bring fresh ideas to the table?
Of course, most everyone is afraid of death. Even many religious folk, who believe in some sort of wonderful afterlife, aren't too crazy about the notion of dying. But isn't the point of Heaven (or whatever it is that the various religions throughout history have termed their positive afterlife) that people's fears of non-existence are assuaged by the promise of immortality, provided you repent your sins? It can be argued, however, that immortality is a curse, not a blessing. Would everlasting life be something we'd really want? I can't even comprehend.