Who can know his past and present lives, not even gods, ghosts, or humans.
Gods use tools to know their future, but what about ghosts and humans? They have no way of knowing but to live cautiously.
Everyone has his or her own past life. Gods place their past lives in chaos, and ghosts place their past lives in resentment. They cannot see it but they want others to remember it deeply. And what about people? People can only be placed in other people's memories and wander around the world as time goes by.