alt Hacker NewsOk, but then I fear you're either contradicting yourself, or addressing a point I didn't make.
Let me restate:
1. energy123 says that, if we completely annihilate the body of X and then we re-assemble it one planck time later, X is still the exact same self after the annihilation as they were before.
2. I reply: a monist must hold the position that X died with the annihilation and the recomposed being is a different self, Y, which just so happens to have the same memories as X. If you insist that the new being is still the same self X, you must assume that something that was not in the body survived the complete annihilation of the body and was put back in the body during the re-assembly.
3. You attempted to say that that something was the information needed to recompose the body. But now you're saying that actually we have produced two entirely different beings, A and B, both of whom believe to be X.
I 100% agree with you that this is what happened. But you cannot tell me in the same breath that X is still alive. That is a contradiction.
The ultimate challenge is always the same: assuming the technology to perfectly copy and simulate a brain exists, would you upload your mind and do you expect that it is you that awake inside the machine? If you answer "yes" you must concede you are a dualist. A monist can only answer "no". And, as I gather from this discussion, a functionalist would (i) answer "yes" after redefining what "you" means, (ii) mean "no" because as you just admitted we created two new beings, (iii) upload themselves and then die happy knowing that something else with their memories will live on.
(I realize you actually have not explicitly objected to this specific challenge yet, so maybe we fully agree and that's that)
[We are very much in speculative territory here of course, it is not a given that duplication or upload is possible at all for a human mind]
I would say that both A and B would claim to be X and have the "continuous"[1] experience to be X while agreeing that they are distinct persons. I think that the question of whether A or B, both, or neither is the true X, is not a scientific question, and as a philosophical question, a fairly empty one.
Regarding the challenge, I would expect that the consciousness would be forked: there is a "me" that would awake inside the machine and would be very glad to be alive, while the "me" outside would experience dying. This seems to go against the exclusiveness of the experience of being themselves, but assuming the existence of the magically perfect duplication, both would be valid experiences and again neither could make a claim about being the real me. I don't find this to be a contradiction.
An interesting question would be whether consciousness can be reunited after being forked.
But all of these scenarios have been explored extensively. Are you familiar with the Egan's "Permutation City"?
edit: I was not familiar with the functionalist position, but for the little I read, it seems to me that it is just a variant of the monist position. You could say I'm a functionalist I guess. Also I believe that we are fundamentally in agreement and we might just disagree with definitions of words.
[1] what does "continuous" even mean? Do one have a "continuous" experience of being yourself after a night's sleep? After anesthesia? After a coma?