Let's consider a science fiction idea: super-old age.
If science ever gave humans the capacity to live many hundreds of years, I think the biggest challenge would be maintaining the will to live. Finding a reason to get out of bed in the morning would become increasingly difficult as the decades and centuries passed.
Once someone has met a challenge, and met it several times, the challenge loses interest. It becomes boring. The things that occupy most of us through life -- raising a family, financial security, career -- would have no appeal to the super-old one who has done all that once or twice. Anyone with half a brain would be rich by the age of 150, simply through the working of compounded interest; he could be irresponsible for his first century of life and still get rich in 50 years.
The super-old would turn to intellectual and artistic challenges to keep busy, but someday these would get old. If one has spent the years 224-235 of his life mastering ancient greek, will he be able to muster interest in latin? Or will he think, “Eh. Been there, done that.”
Let’s say a 90-year old with an active mind and a love of life develops a passion for sculpture. She wants to sculpt like Michelangelo and Milo. She dedicates herself to learning the art and after 20 years is pretty good. After 40 years she is the greatest sculptor that ever lived. She creates masterpiece after masterpiece -- 10, 50, 100… 200? At some point she will either get bored or find her artistic limit and begin repeating her early success, back when she was creating first rate art. Someday it will be time to move on, probably to mentoring young sculptors. The day will come when teaching loses interest.
Boredom is a minor nuisance to us now, but to the super-old, it would be a matter of life and death. Finding values, nurturing them and keeping them alive would become an industry in such a culture. People with active minds and a passionate love of life would do the best in super-old age, but even they would find their limits.
If humans could live to say, 400, I believe the greatest cause of death for those over 300 would be suicide. If everything has lost its value, what is the point of continuing existence? Sitting around all day bored out of one’s mind is no way to live. Those who lost the desire to move and eat would die; cause of death: terminal ennui.
The threat of bad philosophical premises would grow with age. To someone who believed this world is an illusion and the world after death is reality, super-long life would be sheer torment. Those who believe that man is by nature corrupt and doomed to fail would have a hard time finding and maintaining values to live for. It might be that only the exceptionally rational make it past a certain age.
Perhaps the greatest gift the super-old could have would be the capacity to forget. If one had a 40-year old body at the age of 340, and had forgotten the family he raised three centuries back, then getting married and raising children might appeal to him. People might even develop techniques to forget the past in order to keep values fresh.
These musings are science fiction now, but someday they might be very real concerns.