Imagine the "destroy the original" part of the teleportation fails. Is your consciousness still in your original body or on Mars? Certainly, still in your original body.

Now the doc is replacing parts of your brain with silicon. It's posited that it makes no difference to your mind. Because of that, is your consciousness still in your body? Very probably.

So I'm not following their logic.

> Imagine the "destroy the original" part of the teleportation fails. Is your consciousness still in your original body or on Mars? Certainly, still in your original body.

How do you reach this conclusion? The only conclusion I can reach is that an identical consciousness is certainly in both bodies. (And as soon as both bodies are making new memories, you have a "fork", where the two persons stop being identical)

How would that work? Would you control both bodies, see through both set of eyes, think with both brains? How would the ineffable quality that makes you feel like you are you get transported to Mars? I don't think that's a tenable possibility.

There is no single "you" in this scenario, there are two distinct persons. One experiences being transported to Mars, the other experiences the transporter failing and them being stuck on Earth.

I think we're talking at cross purposes. Me, the body I inhabit, is still on Earth. The person on Mars, who likely also has a consciousness, and is for the whole world exactly the same as me, is still not me, but someone else, because I am on Earth, and I can't be in both bodies.

So I will not take the teleporter any more than I will shoot myself.

This conflict only exists if you believe in a single, inviolable self.

Which cell is the “real” one when it divides? Which branch of a tree is the true tree?

Both versions of you have equal claim to the past, as long as the copy is truly identical.

> and is for the whole world exactly the same as me, is still not me

If both are identical I don't see why both aren't equally me.

> because I am on Earth, and I can't be in both bodies.

Why must there be a single continuation of "me"? I wouldn't necessarily consider this true even under current medical technology - we can split the brain in two and have two parts that do not directly communicate.

What if the process is symmetrical (one body in, some kind of mitosis occurs, two bodies out at equal distance)? Does one get assigned "the real me" at random? If both have the same memories/personality/train-of-thought and experience the process as continuous, why not both?

But we are not talking about mitosis, so we don't need to go there. We are taking about a machine that assembles atoms on a remote planet. None of the atoms come from your current body. What magic would transfer your consciousness into this clone?

> But we are not talking about mitosis, so we don't need to go there

I'm probing to get a better understanding of your belief system. How does it hold up under symmetrical cloning?

> What magic would transfer your consciousness into this clone?

I'll label:

* IM: Immaterial "me" - a "soul", impacted by the physical. May impact the physical or just be an observer depending on variant of dualism

* PM: Physiological "me" - personality, memories, train of thought, currently physically instantiated as a brain

From what I understand, you believe there's an IM controlling a PM, and the IM is a different kind of stuff that would not be cloned. On cloning of PM you think this happens (at the instant of cloning):

    IM    New soul
    |     |
    PM    PM

You ask "Would you control both bodies, see through both set of eyes" because you thought sunaurus is proposing this happens:

       IM 
      /  \
    PM    PM

Whereas I (and I think sunaurus) don't believe in an IM. We think two physically identical persons really are identical, including whatever we'd call consciousness, so it's more like:

    PM    PM

Others may believe that all is not necessarily physical but does at least supervene on the physical (so identical PM has identical IM arising from it):

    IM    IM
    |     |
    PM    PM

I can't seem to be able to reply to your comment below, but thanks for the clear illustration. I don't disagree with PM PM; I don't believe in souls. What I do believe in is that there is a quality of consciousness that is linked to the PM - what makes you see through your own eyes and not others. That quality does not seem transferable, in that bodily possession is not a thing.

If you posit that teleportation is equivalent to spaceship, and that a single consciousness cannot inhabit two bodies, then what is your hypothesis about the more-or-less instant transfer of that quality to a remote planet's newly created clone?

> I don't believe in souls

Consider IM to be any immaterial "self" that you believe wouldn't be included in the clone - doesn't have to be a soul as various religions may conceptualize.

> and that a single consciousness cannot inhabit two bodies

I believe there could be two bodies with identical personalities/memories/train-of-thought/etc. (whatever we label as consciousness) at some instant, but they would diverge due to different environments and not have any kind of special link between them.

> what is your hypothesis about the more-or-less instant transfer of that quality to a remote planet's newly created clone?

In my view it's just included in the clone - there's nothing extra that hasn't been cloned that needs to be transferred afterwards. If you totally clone an ocean, it has the same waves.

That brings me back to my original question:

> What is the difference between slowly replacing your cells a few at a time through biological processes, and instantly replacing all of your cells through the teleporter?

If you believe that you die when your cells are replaced (because you are in the old cells and thus can't be in the replacement), then I understand your point of view. But if you're saying that slowly replacing you is different than quickly replacing you, then I would be super curious to hear the logic for this! (This is a sincere comment, I am not seeing the logic myself and would really like to understand it)

So, the slow replacement preserves consciousness. Why, who knows, but it happens to us already every day, so we can take it as granted. If it didn't, we'd be someone different every day, with false memories, and while it's not impossible there's not really many places reason can take us from there.

The problem with the teleportation is not even that it's a quick replacement... it's that it's not a replacement at all. You're building a clone somewhere else, and destroying the original. You could build 50 clones at the same time on 50 planets if you wanted - and of course none of them would be you, there's zero chance you're preserved. So, you're dead, even if to the rest of the world it makes no difference.

Is that clearer?

What you're saying seems like a clear contradiction to me.

In your first paragraph, you say that we can take for granted that when an original is destroyed, having a replacement will preserve consciousness. Then, in your second paragraph, you say the opposite - that destroying an original would NOT preserve consciousness, even if there exists a replacement.

There must be some key assumption which lets you not see this as a contradiction. Maybe you believe that there is something extra-cellular which wouldn't get replicated in a teleporter?

I'm saying replacing a neuron or cell at a time within a quadrillion of them empirically leads to continued consciousness, and that assembling a quadrillion cells on a remote planet with no material connection whatsoever with the original body is a very different thing. You want to hide both cases behind the same word. I don't see why you think that's valid.

I think it comes down to how that replacement happens. If you keep adding new chips or whatever it is as your old cells die or get altered by the virus, that's one thing. However, if you download your conscience to silicon and have that replace your brain, that's entirely different. I'm unsure which one it was in that question.

Everyone in this comment section needs to read Greg Egan's Permutation City.

I viewed those questions as a play on the Ship of Theseus.

If the ship is completely destroyed and a perfect replica rebuilt elsewhere, is it the same ship? Almost certainly not.

If the ship is slowly replaced over time, is it the same ship? As a matter of form or psychological continuity as posited in the question, almost certainly.

Why do you think those two questions have different answers? For me, the only logical option is that both questions must have the same answer (regardless of what your answer is).

I don't follow your logic. How would constructing a new ship from new materials ever count as being the same as the original ship?

At least in the Ship of Theseus paradox, there is the case where you take the old replaced parts and construct a ship from those parts - which is an interesting question, is it the original ship? In this case, the only thing consistent about the ship is the design. Take mass manufactured goods then - are they the same article because the have the same materials?

> How would constructing a new ship from new materials ever count as being the same as the original ship?

If it's a perfect replica (as you said in your original comment) then by what parameters is it different from the original ship? Sure, cooordinates might be different, but cooridnates can change. If the exact replica switches places with the original, then even that difference would disappear.

By the way, I am strictly speaking about this topic in the context of the thread we are in. If a replica is built according to exact blueprints of a snapshot of the original (and assuming no mistakes are made), then why would the result be any different than just replacing one part on the original with an replica part made according to exact blueprints of a snapshot of the original part?

We replace the cells in our body every few months, correct? The gradual replacement is key to the continuity. I'd be ok replacing every one of my neurons one at a time but not to upload my brain to a computer and then kill myself. To an outside observer the result may be the same, but not something I'd be comfortable with. I know my consciousness is an illusion and I probably "die" every time I go into deep sleep but the key is to uphold the illusion, otherwise why go on?

But why would the feeling of continuity be broken by an instant replacement?

In both cases (gradual and instant replacement), at any given moment, there exists only one entity with your consciousness and self of sense and continuous memories leading up to that moment.

It's not a replacement, a collection of atoms is assembled on a remote planet. And it needs not be a single entity, as the thought experiment with the failure to destroy the original body shows.

I think my point is, maybe there's no such thing as continuity of experience (since we sleep every day) and consciousness itself may be an illusion. With an instant replacement, and also with a large distances, it makes it clear this is not me any longer, but if I replace my neurons gradually with digital components it's essentially equivalent to what is already happening with my brain cells, so it doesn't break the illusion. My identity and consciousness is an illusion and I just don't want to break it. I know that is contradictory and makes no sense, but that's the reason I would not use the transporter.

> What is the difference between slowly replacing [...] and instantly replacing [...]

Not to be obtuse, but... the speed.

Really this is a shortcoming of the thought experiment. Progressive replacement is subjectively more continuous than complete replacement. A better thought experiment would be to feed it out something like:

* What if we replaced every atom of you body progressively over 24 hours?

* What if we replaced every atom of your body suddenly all at once?

* What if we replaced every atom of your body, but delayed by 1s?

* What if we replaced every atom of your body, but delayed by 1 day?

* What if we replaced every atom of your body suddenly all at once, but moved about 1mm?

* *What if we replaced every atom of your body suddenly all at once, but a day later and moved by thousands of miles?"

What is the practical difference, though? From the point of view of the entity whose atoms have been replaced, I don't think that the speed of replacement has any noticeable effect. And the previous versions are all "extinct" regardless of the speed, so from the point of view of any previous versions, the situation doesn't change either.