My daughter wrote letters to her future self when she was about 8 years old. She had noticed that perfectly nice kids sometimes turn into grumpy teenagers, and she wanted to tell herself not to do that. Now that she's 15, she refuses to read these letters. She thinks her 8-year-self has nothing to teach her. Possibly cute, but something of a dolt -- I think that's about how she sees her past self. I personally think her 8-year-old self was a genius, and want her to get a hearing.
Her ... wait a second! The standard metaphysics says a person is a single entity about whom different things are true in the past and the future. My daughter is an entity such that once she wanted to avoid teenage grumpiness. Now the very same entity doesn't want to avoid teenage grumpiness. A subtly different view sees persons as collections of temporal stages. One stage of my daughter wanted to avoid teenage grumpiness. The stage that exists right now doesn't want to.
So this is my question: does the temporal stage story have a different upshot with respect to my daughter's problem than the standard story? If people exist in stages, do we have past selves in an especially robust sense? Can we wrong our past selves by not listening to them (that's stage talk) more than we can do wrong by not caring about what we used to want (that's standard metaphysics talk)? Does picking one of these theories or the other make a difference to how I ought to counsel my daughter?
Don't know yet -- I'm just thinking aloud. Truth is, I don't want to figure this out so I can counsel my daughter (I already have: READ THOSE LETTERS!) I just want to know if different theories about the self are really different enough to generate different life decisions. Or they all just rival "ways of thinking" about the world, with no palpable consequences?
Next on my personal identity reading list--Eric Olson's What Are We? and David DeGrazia, Creation Ethics.