If we clone A, then from A's perspective we now have A-Prime. A-Prime is unaware and believes they are A, who now presumably has been killed. If anyone didn't observe this happen, then A-Prime essentially -is- A. If they did observe it, then they know that it's technically A-Prime.
So I guess the difference is being able to observe the gradual changes. It's more tricky when discussing an inanimate object like a ship that doesn't care either way.
It's funny because we have this discussion only pertaining to humans, if we were to produce a replica computer from computer-0, we'd rename it to computer-1 and that's that. It's just because humans want to name themselves we have issues, and we can't easily ascribe a human another name (it would mean rewriting the memory of the replica to remember being called something else).
Btw, we talk about replica's but that's only because we assume the process leaves an original and a copy, but that's not necessarily so, for example a photon of high energy can split into 2 photons of lower energy. We are not talking about originals and replica's there. One can imagine that our duplication process follows similar rules.
When copying or simply making 2 out of 1, for computers, both still have computer-0 in /etc/hostname so there's that... It's just that neither of the computers will complain when we change their designation at random.
This leaves me feeling weird about the destruction of an original in any copying process. The destruction during copying feels ok, but doing it afterwards feels very bad. It's like we want consciousness to be continuous in time and not necessarily in place. But why? Again, Permutation City goes into this in a nice way...
If we clone A, then from A's perspective we now have A-Prime. A-Prime is unaware and believes they are A, who now presumably has been killed. If anyone didn't observe this happen, then A-Prime essentially -is- A. If they did observe it, then they know that it's technically A-Prime.
So I guess the difference is being able to observe the gradual changes. It's more tricky when discussing an inanimate object like a ship that doesn't care either way.