I don't acknowledge an upload as "me" in any meaningful sense of the term; if I copied my brain to a computer and then my body was destroyed, I still think of that as death and would try to avoid it.
A thought struck me a few minutes ago that seems like it might get around that, though. Suppose that rather than copying my brain, I adjoined it to some external computer in a kind of reverse-Ebborian act; electrically connecting my synapses to a big block of computrons that I can consciously perform I/O to. Over the course of life and improved tech, that block expands until, as a percentage, most of my thought processes are going on in the machine-part of me. Eventually my meat brain dies -- but the silicon part of me lives on. I think I would probably still consider that "me" in a meaningful sense. Intuitively I feel like I should treat it as the equivalent of minor brain damage.
Obviously, one could shorten the period of dual-life arbitrarily and I can't point to a specific line where expanded-then-contracted-consciousness turns into copying-then-death. The line that immediately comes to mind is "whenever I start to feel like the technological expansion of my mind is no longer an external module, but the main component," but that feels like unjustified punting.
I'm curious what other people think, particularly those that share my position on destructive uploads.
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Edited to add:
Compare a destructive upload to non-destructive. Copy my mind to a machine non-destructively, and I still identify with meat-me. You could let machine-me run for a day, or a week, or a year, and only then kill off meat-me. I don't like that option and would be confused by someone who did. Destructive uploads feel like the limit of that case, where the time interval approaches zero and I am killed and copied in the same moment. As with the case outlined above, I don't see a crossed line where it stops being death and starts being transition.
An expand-contract with interval zero is effectively a destructive upload. So is a copy-kill with interval zero. So the two appear to be mirror images, with a discontinuity at the limit. Approach destructive uploads from the copy-then-kill side, and it feels clearly like death. Approach them from the expand-then-contract side, and it feels like continuous identity. Yet at the limit between them they turn into the same operation.
It's not the book, it's the story.
Moby Dick is not a single physical manuscript somewhere. If I buy Moby Dick I'm buying one of millions of copies of it that have been printed out over the years. It's still Moby Dick because Moby Dick is the words, characters, events etc. of the story and that is all preserved via copying.
A slight difference with this analogy is that Moby Dick isn't constantly changing as it ages, gaining new memories and whatnot. So imagine that Melville got half way through his epic and then ran out of space in the notebook that I want you to also imagine he was writing it in. So we have a notebook that contains the first half of Moby Dick (presumably, this is a pretty big notebook). Then he finishes it off in a second notebook.
Some time later he pulls a George Lucas and completely changes his mind about where his story was going ("Kill off Ahab? What was I thinking?") and writes a new version of the story where they go into a profitable, if ethically dubious, whaling business with rather more success than in the first version. This is then written up in a third notebook. Now we have three notebooks, the last two of which are both legitimate continuations of the first, carrying on from the exact same point at which the first notebook was ended.
There is no interesting sense in which one of these is some privileged original, as Eliezer puts it. If you can't get your head around that and want to say that, no, the published (in real life) version is the 'real' one imagine that the published version was actually the third notebook. There is no equivalent of publication for identity that could confer 'realness' onto a copy. In real life, neither or them are notebook 1 but they're both continuations of that story.
If Will Riker discovers that he was non-destructively copied by the Transporter and that there's another version of him running around, he will likely think, 'I don't acknowledge this guy as 'me' in any meaningful sense.' The other guy will think the same thing. Neither of them are the same person they were before they stepped into the Transporter. In fact, you are not the same person you were a few seconds ago, either.
Identify yourself as the book and your concept of identity has big problems with or without uploading. Start by reconciling that notion with things like quantum physics or even simple human ageing and you will find enough challenges to be getting on with without bringing future technology into it.
But you are not some collection of particles somewhere. You are the story, not the book. It's just that you are a story that is still in the process of being written. Uploading is no different that putting Moby Dick on a Kindle. If there's still a meat version of you running around then that is also a copy, also divergent from the original. The 'original' is (or was) you as you were when the copy was made.
"Moby Dick" can refer either to a specific object, or to a set. Your argument is that people are like a set, and Error's argument is that they are like an object (or a process, possibly; that's my own view). Conflating sets and objects assumes the conclusion.