There is a Ship of Theseus about a ship being replaced piece by piece over time until the whole ship is built from the replacement parts. Is it still the same ship or not?
The same goes for people. Our cells are being replaced constantly and approximately every 15 years (if I remember correctly) you are completely new person from the point of view of what are you made of.
Yesterday I have listened to an interesting conversation about failure of individuality and about how we are each part of a web of relationship, and a thought occurred to me.
Maybe, like in the case of the ship or our body, we live even after we die. Not in some spiritual way like a ghost or soul but as a part of other people lives. Our friends, family, coworkers, even strangers we have affected in some way.
In this web view of life, even when we are no longer here, the web is still here. People live after we die, affected by our lives. So we are replaced by our children and other people, but the continuity goes on. Just like with the ship and our bodies.
The ship is not the same after we replace everything, we are not the same after 15 years, but we still consider us to be us. This is just an extension of this. If we consider others to be an extension of us, we live on forever.