I make no fundamental distinction between an Original and a copy, maybe that nomenclature is misleading. I use “original“ for the entity to be copied; that entity could be the tenth copy of a copy of a copy. It makes no difference. There is nothing special about the zeroth member of that line, except that that person accrued the memories that are then copied and experienced in other entities as their own. And why wouldn’t they, they’re copies.
So in your thought experiment, why (and how?) would your “self” be transported after copying? Why would you assume that? And what happens to the “original self“? You describe the experience of stepping into the teleporter and then stepping out, but this experience would require some magic to transfer the self. The much more plausible solution is that you step into a teleporter, you die, a copy of you continues your life happily on Mars but you have nothing to do with it. What would happen if you created several copies? Your model has no explanation for that. The only solution for your model is then the hive mind; the much more consistent answer is that each copy has their own mind, and does indeed think they’re original.
Your two paragraphs are confusing me. If you make no fundamental disctinction between Earth nautilus and Mars nautilus, doesn't that make them "the same person"? How can you say both "nautilus died" and "nautilus goes on living, but nautilus has nothing to do with it"? If one is alive and one is dead, that seems like a fundamental distinction, doesn't it? If the person on Mars is nautilus, then you have everything to do with that life, don't you?
I agree with your first paragraph: I don't think there is a "self" separate from the arrangement of matter and energy, no magic is needed, there is no hive mind, body on Earth cannot see through Martian's eyes. I agree with the end of your second paragraph, a consistent answer is that each copy has their own mind and thinks they are the original, but moreso - each copy is the original. Then, I must disagree with the middle bit - you step out on Mars and you have everything to do with that life. A copy of nautilus and nautilus himself step out on Mars, no fundamental distinction between them. Not in a hive-mind way, just as a necessary conclusion of your position.
No they're not the same person, all entities are individuals, all have their own mind and self. The hardware is the same, though (at least at t=t0). But the hardware is genetically identical between twins as well, without making them the same person.
Your second paragraph makes no sense: if each copy has their own mind, how can they simultaneously have your mind? And then you just wave away the necessary implications of that (hive mind). How else could it be in your model?
They're either separate entities, or they're not. If they are, the copy is a different person, and the Mars nautilius self is different from Earth nautilius self, running on the identically copied hardware. This position resolves all possible contradictions.
How would you step out on Mars without magic to replace the self of both Earth-you and Mars-you? How do you resolve just making several copies?
> "No they're not the same person, all entities are individuals"
So which one owes the bank the next mortgage payment? If they're not the same legal person then one of them doesn't. Twins have different names, different birth records, different memories, different legal and social identities. If the twins are honest people then they won't pretend to be each other and will self-separate to clear this up. Both Nautilus's, if they are honest people, will be adamant that they are Nautilus and try to use their genetic and biometric and memory records to prove it, neither will want to be the discarded one who must change their name - and neither will have any priority. At t=t0 they are, from the outside, two separate bodies who are the same person.
> "if each copy has their own mind, how can they simultaneously have your mind?"
If they are hardware identical, memories identical, who else's mind could they possibly have (at t=t0)? You copy OpenOffice onto two computers, they both simultaneously have OpenOffice. One doesn't have a different software just because future changes on one will not magically happen on the other. If brain and hardware and memories is not "what it means to be Nautilus", the what does? What else is there? The copy's internal experience will not be the experience of being a copy, it will be the experience of being nautilus with the same continuity of life experience that you have right now.
> "They're either separate entities, or they're not. If they are, the copy is a different person, and the Mars nautilius self is different from Earth nautilius self, running on the identically copied hardware. This position resolves all possible contradictions."
If they are identical in all ways at (t=t0), what specific difference are you pointing to when you say "different person"? And before you say "location", if I move location I don't become a different person. If they are identical then it shouldn't matter if you switch that sentence around and say the Martian is the real one and the Earth one is the "different person". Since you earlier said "you die, someone else goes on living on Mars and you have no knowledge of it" I think you wouldn't be as happy with that phrasing. The weirdness is that the viewpoint "I stay on Earth, a stranger appears on Mars" and "I arrive on Mars, who cares what happens on Earth" are both valid, both people experience actually being nautilus as validly as each other and neither has any better claim to the one true continuity of experience.
So in your thought experiment, why (and how?) would your “self” be transported after copying? Why would you assume that? And what happens to the “original self“? You describe the experience of stepping into the teleporter and then stepping out, but this experience would require some magic to transfer the self. The much more plausible solution is that you step into a teleporter, you die, a copy of you continues your life happily on Mars but you have nothing to do with it. What would happen if you created several copies? Your model has no explanation for that. The only solution for your model is then the hive mind; the much more consistent answer is that each copy has their own mind, and does indeed think they’re original.