Almost universally, religion makes some claim about what happens to a person after death. Whether it be reincarnation or heaven or becoming one with Xenu, some non-material part of the person manages to persist and transcend death. But what is the nature of the "soul" and does it exist?

What is the soul? How does it change over the course of our life? What do different religions have to say about the soul? What does science have to say? Does the concept of the soul make sense or is it part of our human longing to make sense of the universe and find purpose?