Does-the-self-interest-theory-depend-on-a-notion-of-undivided-identity-

Does the self-interest theory depend on a notion of undivided identity? How or how not? What are the arguments for and against a divided identity?

answer it from the book and you can use a little from the website

this is the link of the book (reason and persons) http://www.chadpearce.com/Home/BOOKS/161777473-Der…