I read "Virtually Human: The Promise--And the Peril--of Digital Immortality" Martine A. Rothblatt recently and it's changed my perspective on how we understand another person as well as "who I am" and what the boundaries of that is person-ness is. I honestly don't think we ever really know another person completely. We have our perception of someone but we're not able to knw what goes on inside someone else's mind, the totality of their thoughts and experiences. From that perspective, I think it's possible to recreate a person that will satisfy our emotional needs and seem to us very much like the original. There's a Buddhist quote that I like which relates to this: I am not what you think I am, you are what you think I am."