Parfit argues that we are really nothing more than the sum total of all of our memories and experiences. Therefore, if duplicating all of those memories and experiences and injecting them into a new body is not enough to make the new person “us,” then there is no logical basis for believing that whoever we are today is the same “us” as the person we were 10 years ago because we may share none of the same cells (except the corneas of our eyes, since, from what I have read before, only our corneal cells are actually the same cells throughout our entire lives).
Comment on whether or not you find Parfits position convincing and why.
On a philosophical level, I do find Parfits position convincing; however, on a philosophical level, I do not find it as convincing. His examples of teleportation and of surgically replacing (or duplicating) all of our cells one at a time illustrate that the concept of self is not as simple or clear-cut as we may believe. I have thought about this in other ways: for example, I know that I have 50% of my mothers genes and 50% of my fathers genes.
If my parents had married and had children with different partners, which of those children would be “me”? Am “I” the egg carried by my mother or the sperm from my father? In my opinion, that is a very similar question to Parfits question about the split halves of one brain implanted into two bodies. If my parents had married other partners, “I” would never have existed; there would be two entirely different selves born to my parents separately and neither would be “me.” I am merely the bundle of all of the life experiences of the self that was created by my parents. The question that cannot answer is how it is that I am (in my opinion) the same person that I was 10 years ago whose entire body and mind was gradually replaced by new cells but if the same process happened in one day through duplication I would (in my opinion) be a different person, just like.