"she sat down on a kitchen stool with the mysterious letter in her hand.
Who are you?
She had no idea. She was Sophie Amundsen, of course, but who was that? She had not really figured that out - yet.
What if she had been given a different name? Ann Knutsen, for instance? Would she then have been someone else?"

(Shophie's World, Jostein Gaarder, p. 3)