identity and descriptive names

oooh crap well i was shaving today and i realized:

i've argued before for a descriptivist theory of proper names mostly based on my particular views on personal identity. My intuition has been that you wouldn't be the same person if you decided to play basketball instead of fencing, or if you decided to become a math major instead of a philosophy one.

but, as my dissentors have pointed out, this identity of personhood isn't the same sense identity is being used when describing the person, because one is an "identity" construed in a psychological sense of what defines a person and the other is a mathematical statement based on an equivalence relationship (you are you)... or is it??

check it out: if you decide to go eat dinner with your friends instead of working out, you are inhaling the atoms around the restaurant instead of those at the gym, you're eating the particular food you ate instead of burning some calories, you're stimulating your mind with the lively conversation with your friends instead of stimulating your muscle cells to grow or your lung capacity to increase. in other words, the course of actions you take does directly effect a difference in chemical composition of your body itself, which in turn in a very literal sense make you a different person, if looked at from an atomical perspective. and if you believe that difference in sub-particles affect difference in structure, then whabam! different person.

unless i'm jumping the gun here, this would mean that the descriptions associated with your name or mine are directly connected to some difference in chemical composition associated with those descriptions, effectively being a pretty good place-marker for your identity.

i still have to work out the kinks but i think this probably has some link to a deterministic argument :)