If it is possible for the copying to be nondestructive, then why make it destructive?
At the moment, all we get is multiple versions from the same base entity, separated by time but not space. So it’s frustrating that most of the thought experiments avoid the complement: multiple versions of the same base entity, separated by space but not time. The “Kill you to teleport a new you” scenario comes across as contrived. Let’s look at “scan you to teleport a new you, but no one dies”, and see what model of identity comes out.
Well, I’d expect that spatially-but-not-temporally-separated copies would lack the memory/body method of communication/continuity that temporally-but-not-spatially-separated instances have. They’d probably share the same sense of identity at the moment of copying, but would gradually diverge.
If it is objectively impossible to determine which is the original (for example, replication on the quantum level makes the idea of an original meaningless), that would differ from the version where a copy gets teleported to Mars, and thus the Martian copy knows it is a copy, and the original knows that it is the original. I don’t really know what to make of either scenario, only that I’d expect Martian Me to be kinda upset in the second, but still to prefer it to destructive copying.
In the case of non-destructive copying, which copy will I end up experiencing? If it is a 50⁄50 chance of experiencing either copy, then in cases where the copy would inhabit a more advantageous spatial location than the one I was currently in (such as, if I were stuck on Mars and wanted to go back to Earth), it would be in my interest to copy myself many many times via a Mars-Earth teleporter in order to give myself a good probability that I would end up back on Earth where I wanted to be.
Let’s say I valued being back home on Earth more than anything else, and I was willing to split whatever legal property I had back on Earth with 100 other copies of me. Then it would make sense for my original self on Mars to tell the scientists: “Copy me 100 times onto Earth. No more, no less, regardless of whatever I, the copy on Mars, say after this, and regardless of whatever the copies on Earth say after this.”
I would end up with a very high probability of experiencing one of those copies back on Earth. Of course, all of the copies on Earth would insist that THEY were the successful case of subjective teleportation and that no further teleportation would be required. But they would always say that, regardless of whether I was really one of those experiencing them. That is why I pre-committed to copying 100 times, even if the first copy reports, “Yay! The teleportation was a success! No need to make the other 99 copies!” Because at that point, there is still a 50% chance that I am still experiencing the copy back on Mars—too high for my tastes.
Likewise, the pre-commitment to copy myself no more than 100 times is important because you have to draw the line somewhere. If I had $100,000 in a bank account back on Earth, I’d like to start out with at least $1,000 of that. If you leave it up to the original Mars copy to decide, then the teleportation copying will go on forever. Even after the 100th copying (by which point I might have already been fortunate to get my subjective experience transferred onto maybe the 55th Earth copy or the 78th Earth copy or the 24th Earth copy or the 3rd Earth copy, who knows?), the copy on Mars will still insist, “No! no! no! The entire experiment has been a huge stroke of bad luck! 100 times I have tried to copy myself, and 100 times the coin has landed on tails, so to speak. We must make some more copies until my subjective experience gets transferred over!” At this point, the other copies would say, “That’s just what we would expect you to always say. You will never say that the experiment was a success. Very likely the original Matthew Opitz’s subjective experience got transferred over to one of us. Which one, nobody can tell from the outside by any experiment, as we will all claim to be that success. But the odds are in favor of one of us being the one that the original Matthew Opitz is subjectively experiencing right now, which is what he wanted all along when he set up this experiment. Sorry!”
But then, what if tails really had come up 100 times in a row? What if one’s subjective experience really was still attached to the Martian copy? Or what if this idea of a 50⁄50 chance is total bunk in the first place, and subjective experience simply cannot transfer to spatially-separated copies? That would suck.
What if, as the original you on Mars before any of the teleportation copying, you had a choice between using your $100,000 back on Earth to fund a physical rescue mission that would have a 10% chance of success, versus using that $100,000 back on Earth to fund a probe mission that would send a non-destructive teleportation machine to Mars that would make a copy of you back on Earth? If you believe that such an experiment would give you a 50⁄50 chance of waking up as the Earth copy, then it would make more sense to do that. However, if you believe that such an experiment would give you a 0% chance of waking up as the Earth copy, then it would make more sense just to do the physical rescue mission attempt.
These questions really do have practical significance. They are not just sophistry.
If it is possible for the copying to be nondestructive, then why make it destructive?
At the moment, all we get is multiple versions from the same base entity, separated by time but not space. So it’s frustrating that most of the thought experiments avoid the complement: multiple versions of the same base entity, separated by space but not time. The “Kill you to teleport a new you” scenario comes across as contrived. Let’s look at “scan you to teleport a new you, but no one dies”, and see what model of identity comes out.
Well, I’d expect that spatially-but-not-temporally-separated copies would lack the memory/body method of communication/continuity that temporally-but-not-spatially-separated instances have. They’d probably share the same sense of identity at the moment of copying, but would gradually diverge.
If it is objectively impossible to determine which is the original (for example, replication on the quantum level makes the idea of an original meaningless), that would differ from the version where a copy gets teleported to Mars, and thus the Martian copy knows it is a copy, and the original knows that it is the original. I don’t really know what to make of either scenario, only that I’d expect Martian Me to be kinda upset in the second, but still to prefer it to destructive copying.
In the case of non-destructive copying, which copy will I end up experiencing? If it is a 50⁄50 chance of experiencing either copy, then in cases where the copy would inhabit a more advantageous spatial location than the one I was currently in (such as, if I were stuck on Mars and wanted to go back to Earth), it would be in my interest to copy myself many many times via a Mars-Earth teleporter in order to give myself a good probability that I would end up back on Earth where I wanted to be.
Let’s say I valued being back home on Earth more than anything else, and I was willing to split whatever legal property I had back on Earth with 100 other copies of me. Then it would make sense for my original self on Mars to tell the scientists: “Copy me 100 times onto Earth. No more, no less, regardless of whatever I, the copy on Mars, say after this, and regardless of whatever the copies on Earth say after this.”
I would end up with a very high probability of experiencing one of those copies back on Earth. Of course, all of the copies on Earth would insist that THEY were the successful case of subjective teleportation and that no further teleportation would be required. But they would always say that, regardless of whether I was really one of those experiencing them. That is why I pre-committed to copying 100 times, even if the first copy reports, “Yay! The teleportation was a success! No need to make the other 99 copies!” Because at that point, there is still a 50% chance that I am still experiencing the copy back on Mars—too high for my tastes.
Likewise, the pre-commitment to copy myself no more than 100 times is important because you have to draw the line somewhere. If I had $100,000 in a bank account back on Earth, I’d like to start out with at least $1,000 of that. If you leave it up to the original Mars copy to decide, then the teleportation copying will go on forever. Even after the 100th copying (by which point I might have already been fortunate to get my subjective experience transferred onto maybe the 55th Earth copy or the 78th Earth copy or the 24th Earth copy or the 3rd Earth copy, who knows?), the copy on Mars will still insist, “No! no! no! The entire experiment has been a huge stroke of bad luck! 100 times I have tried to copy myself, and 100 times the coin has landed on tails, so to speak. We must make some more copies until my subjective experience gets transferred over!” At this point, the other copies would say, “That’s just what we would expect you to always say. You will never say that the experiment was a success. Very likely the original Matthew Opitz’s subjective experience got transferred over to one of us. Which one, nobody can tell from the outside by any experiment, as we will all claim to be that success. But the odds are in favor of one of us being the one that the original Matthew Opitz is subjectively experiencing right now, which is what he wanted all along when he set up this experiment. Sorry!”
But then, what if tails really had come up 100 times in a row? What if one’s subjective experience really was still attached to the Martian copy? Or what if this idea of a 50⁄50 chance is total bunk in the first place, and subjective experience simply cannot transfer to spatially-separated copies? That would suck.
What if, as the original you on Mars before any of the teleportation copying, you had a choice between using your $100,000 back on Earth to fund a physical rescue mission that would have a 10% chance of success, versus using that $100,000 back on Earth to fund a probe mission that would send a non-destructive teleportation machine to Mars that would make a copy of you back on Earth? If you believe that such an experiment would give you a 50⁄50 chance of waking up as the Earth copy, then it would make more sense to do that. However, if you believe that such an experiment would give you a 0% chance of waking up as the Earth copy, then it would make more sense just to do the physical rescue mission attempt.
These questions really do have practical significance. They are not just sophistry.