However it is not "just made up" as might be implied by the term "fictive." It is based on the memories of actually living as that person. Nor is it just a "story" with no impact to or from the physical reality of who the person is.
Our stories have impacts, absolutely. So there can be elements of self-fulfilling prophecy in terms of attributes, but none in relation to identity.
(as an aside I think Glaucon's position is not the same as yours)
I would say that there is without a doubt a degree of coherence over time and it is extremely obvious when this coherence is lost or radically altered. For example I've always liked chocolate and in particular dark chocolate. If I suddenly stopped liking it people would notice and find that odd.
Certainly some attibutes often continue. But many change. The 7 years to the 22 year old has radical changes in these attributes and behaviors. If these are the self or evidence that it is the same person, shouldn't all the changes at least force us to speak in terms of percentages of identity?
I disagree and I think you are playing games with the term same, trying to make it mean "unchanging" when it is an innate part of life to change over time.
Not playing games. If I have a pattern of blocks and I over a period of time slowly replace all the blocks and change the pattern it this 'thing' has changed. It is fundamentally no longer the same. My wife could come home and say 'Oh, look at Simon's pattern. The pattern he keeps on the kitchen table.' And in some abstract sense, not really revelent to the blocks, since this is a metaphor, she can use the definitive 'the pattern' or the possessive Simon's pattern. While, in fact I could have built up the original pattern on another table in another room in the original shape with the blocks in the original pattern.
Our blocks are replaced. Beyond that a great deal is added. And the patterns are changed.
I still see no evidence that it is the same person - who has changed. It could just as easily be another person, which, in fact, is what I think it is.
The change was dramatic in the cases I saw.
I thought your point was that they reconstructed the same self. I misunderstood. I thought the point was the abiilty to reconstruct the same self. I was contrasting it with people who after a time are very different people - taking this literally or figuratively for now.
Actually that is a misnomer. Some cells are replaced quickly, mouth and stomach lining, some not at all such as many neurons and female reproductive cells. Also replacing parts is not a problem as long as the integrity of the pattern is not degraded.
Degraded is generally a negative term. The incredible changes in the brain in adolescence is at worst neutral. It is true that some cells do not reproduce, but interestingly enough the hippocampus, in change of memory, does make new cells and vigorously. Since much defene of continuous identity or selfhood is based on memory there are problems right there. Also the interconnections between cells change radically, pathways get strengthened, atrophy, etc. Levels of neurotransmitters, hormone levels in the body, patterns of brain use - via MRIs - can be see to change over time also. All this is reflected in the changes in behavior, tastes, attitudes, interests, and so on. If, as you said before the self if what the body does, it is doing something quite different.
At what point does change in something make it something else?
Replacing parts is not a problem as long as the integrity of the pattern is not degraded.
Ibid
You are neglecting that this particular pattern is self repairing, flexible, adaptable and capable of incorporating growth and change.
To me is not an issue of repair. I am not saying something bad is happening. I just see no evidence that it is the same self that is changed.
Functionally efficient is sufficient in this case.
It might be for others, but for the actual person in question, whether or not it is the same experiencer is an issue.
There is every reason to assume this and it is in fact the assumption. If you want to contend otherwise you need to offer more than your dissatisfaction with the status quo.
I am glad you see it as an assumption.
The two are the same and the fact that the one becomes the other and no other is sufficient. You point to what is not relevant and act like it should be.
I pointed out in my block metaphor that this 'becoming' is fragile. Perhaps technology will reach a place where one could atom by atom replace a person's parts with others AND build the original human. I don't even see that as far fetched with nanotechnology.
Which one would be the first experiencer?