life after death
You already live forever. This is how we know:
If there are ideas in your head then you are conscious.
So applying Occam's razor, YOU are those ideas.
Ideas are naturally shared.
The page on identity shows how you switch bodies.
You are only aware of one idea at a time (or at most, 6 or 7 in short term memory). So your consciousness is very simple.
Many of your ideas came from before you were born. So you are older than your current body. If you have friends, children, or ideas worth sharing, then you (your ideas) will live forever.
Evolution confirms this: we evolve to pass on whatever traits helps us survive. So only those passed on traits matter. The part of you that matters is the ideas that live after the body dies.
Our ancestors knew this. Bodily death is part of life. "Spirit" is ideas. It is consciousness. It lives after death, and must be shared if we are to be happy.