My problem with time travel and teleportation

[TheManicMonocle]

So, there's a few things I have trouble with in the realm of science fiction.

First let's start with teleportation. As I understand it, teleportation is the act of taking an object apart atom by atom, sending those atoms elsewhere, and reassembling them. I don't see how this could be anything but lethal to any living creature. Of course, I don't mind teleporting non living objects, but as far as I'm concerned, as far as instant travel is concerned, portals are the best way, provided you don't touch their edges.

Now to my problem with time travel. Let's assume you can figure out how to send yourself back in time. Or more specifically, you travel back in time. Wouldn't you end up with less memories, and a little younger? If you send yourself backwards, how would you do that while preserving your mental and physical status in the present? Let me explain. If you're traveling backwards in time, everything that has happened is undoing itself. The eggs are being un made, the memories are being unrecorded, the food in your stomach is being unprocessed... I think you see the problem.

So, do you think these concerns make sense? Obviously this only applies from a scientific perspective, magical teleportation has its own rules.

[Strigon]

So, there's a few things I have trouble with in the realm of science fiction.

First let's start with teleportation. As I understand it, teleportation is the act of taking an object apart atom by atom, sending those atoms elsewhere, and reassembling them. I don't see how this could be anything but lethal to any living creature. Of course, I don't mind teleporting non living objects, but as far as I'm concerned, as far as instant travel is concerned, portals are the best way, provided you don't touch their edges.

Now to my problem with time travel. Let's assume you can figure out how to send yourself back in time. Or more specifically, you travel back in time. Wouldn't you end up with less memories, and a little younger? If you send yourself backwards, how would you do that while preserving your mental and physical status in the present? Let me explain. If you're traveling backwards in time, everything that has happened is undoing itself. The eggs are being un made, the memories are being unrecorded, the food in your stomach is being unprocessed... I think you see the problem.

So, do you think these concerns make sense? Obviously this only applies from a scientific perspective, magical teleportation has its own rules.

I'm with you on the first, not on the second.
Time travel isn't generally depicted as simply time going in reverse - usually, it's more like temporal teleporting. Among other, more technical issues with that interpretation.

[Lvl 2 Expert]

Why would you become younger from traveling in time? The whole point of it is that you unlock yourself from the normal time stream.

You'd probably completely change history and with that yourself anytime you so much as farted enough centuries back, because the slightest differences in peoples day lead to slight differences in the sex they have which leads to different sperms winning which leads to a lot more slight differences in a lot of peoples days, but I don't think you'd necessarily have to become younger. Although that would probably make it even more popular.

As for the teleportation: If a machine has a way to build a complete new me either out of a bunch of molecules that have been beamed over or out of a stream of data from a human-scanner I'll gladly believe that same machine can also get the electrical signals and such copied. After all, you wouldn't expect a transported item to drop to zero Kelvin because the machine could somehow not copy heat. If it's such advanced techmagic, why not?

[TheManicMonocle]

Why would

As for the teleportation: If a machine has a way to build a complete new me either out of a bunch of molecules that have been beamed over or out of a stream of data from a human-scanner I'll gladly believe that same machine can also get the electrical signals and such copied. After all, you wouldn't expect a transported item to drop to zero Kelvin because the machine could somehow not copy heat. If it's such advanced techmagic, why not?

But if you have the new me thing you also run into the problem, "is it still really you?"

[Tyndmyr]

Meh. If one hand touches the other, I don't worry about which hand is really me.

Don't see why the time dimension should be treated any different from the other three with regards to identity.

It does present certain practical difficulties though.

[Kantaki]

But if you have the new me thing you also run into the problem, "is it still really you?"

Eh, if it looks like a duck, sounds like a duck and thinks like a duck it's most likely still Kantaki.
So, I wouldn't have a problem with that aspect of teleportation.
The being ripped apart on a molecular level part on the other hand? Not so much.

[Lvl 2 Expert]

But if you have the new me thing you also run into the problem, "is it still really you?"

Sure, but that's a philosophical question, it might not bother new me that much, he's him and he's fine with that.

What I usually wonder with teleportation technology is: If you can scan a person and make an exact replica, why is it only ever, even by bad guys, used to make a single replica for each deleted original? Why not hack someones teleporter and stream soldiers out of it? Or microbots. Or airborne viruses. Or nerve gas. It can just make anything you want right? Is that what industrial replicators are, just the back ends of teleporters, making everything anyone needs in any amount? And is there a reason star ships still need to be assembled in a dock? Can't you just build a really big teleporter and copy one ship as often as you like? Teleporters are a really underused piece of technology, probably because trying to really find its full potential would just break most worlds.

[Tvtyrant]

Sure, but that's a philosophical question, it might not bother new me that much, he's him and he's fine with that.

What I usually wonder with teleportation technology is: If you can scan a person and make an exact replica, why is it only ever, even by bad guys, used to make a single replica for each deleted original? Why not hack someones teleporter and stream soldiers out of it? Or microbots. Or airborne viruses. Or nerve gas. It can just make anything you want right? Is that what industrial replicators are, just the back ends of teleporters, making everything anyone needs in any amount? And is there a reason star ships still need to be assembled in a dock? Can't you just build a really big teleporter and copy one ship as often as you like? Teleporters are a really underused piece of technology, probably because trying to really find its full potential would just break most worlds.

In Star Trek they are capable of teleporting people's brains out of their heads and making sentient holograms, but these don't provide much military function because they are so easy to jam. The "civilization so advanced we can't jam their signals" is an accurate and common trope, because once you can destroy each other via teleporting bombs the game is really about constructing and deconstructing firewalls. Q doesn't actually do anything the enterprise can't, but he can effect them and they can't effect him.

As for cloning people, I believe the response humans and other species had to immortality was to decide to remain mortal. 1,000 like minded soldiers will show no intellectual flexibility, while ten with different ideas may be less powerful in the short run but will have a larger pool of ideas to draw from. Immortality is a dead end, so most species instead focus on individualism and flexibility of thought.

[The Eye]

First let's start with teleportation. As I understand it, teleportation is the act of taking an object apart atom by atom, sending those atoms elsewhere, and reassembling them. I don't see how this could be anything but lethal to any living creature. Of course, I don't mind teleporting non living objects, but as far as I'm concerned, as far as instant travel is concerned, portals are the best way, provided you don't touch their edges.

You can also teleport by bending space.

[Tyndmyr]

Eh, if it looks like a duck, sounds like a duck and thinks like a duck it's most likely still Kantaki.
So, I wouldn't have a problem with that aspect of teleportation.
The being ripped apart on a molecular level part on the other hand? Not so much.

Precisely.

Oddly enough, viewing time as just another dimension also precisely resolves the supposed ambiguity over identity with being disassembled and reassembled.

Consider the instance where a human sees his arm detatched from him, across the room. It's still his arm, and he recognizes it as part of his body, but the discontinuity of it's detatchment is cause for concern.

So too it is with being disassembled to be reassembled elsewhere. It's not so much the "being elsewhere" as it is the being taken apart that is alarming. Travel there via bus would elicit a great deal less concern.

Humans like all of their bits to remain connected. So long as that remains true, other things like speed of travel are not a big deal.

[factotum]

Eh, if it looks like a duck, sounds like a duck and thinks like a duck it's most likely still Kantaki.
So, I wouldn't have a problem with that aspect of teleportation.
The being ripped apart on a molecular level part on the other hand? Not so much.

OK, let's posit a teleportation system: it scans you to determine all the matter making up your body and transmits that data to the other end, where the duplicate is created; the original you is then vaporised to prevent there being two of you floating around. One day, this process goes wrong and there are now two people, both of whom believe they are Kantaki and who are physically and mentally identical to each other. Which one is the "real" you?

[NichG]

OK, let's posit a teleportation system: it scans you to determine all the matter making up your body and transmits that data to the other end, where the duplicate is created; the original you is then vaporised to prevent there being two of you floating around. One day, this process goes wrong and there are now two people, both of whom believe they are Kantaki and who are physically and mentally identical to each other. Which one is the "real" you?

Both would be. "The real you" isn't a-priori a conserved quantity, its just one that is effectively conserved in our own experiences.

It's like asking, when you make a copy of a file on your harddrive, which one is the real file and which one is the copy. You could come up with some sort of canonical way to order them, but in practice it has no consequence. Or, if you have your corpus callosum severed, is the right hemisphere or the left hemisphere 'the real you'?

[Errata]

These being fictional technologies, they work in many, many different ways, depending on the fictional universe they appear in. There's no one form of time travel or one form of teleportation. We don't know of any way to do either, nor is either really on the horizon as something to reasonably expect. If some unexpected breakthrough did allow either, we have no basis for speculating which form would become practical with new understanding.

Your description of teleportation sound like the Star Trek model, but that's no more common than and possibly less common than the wormhole model in which two points of space are made to be adjacent somehow. If Star Trek teleportation could perfectly replicate the exact state of every particle, then we would expect it to result in a living being. Whether that being is "you" is a matter for philosophers. If it wasn't accurate enough for that, then it would also not be accurate enough for many types of non-living objects either. The real question that needs explaining under that model is why it's a teleporter and not a replicator, since it's incinerating the being at the origin point, possibly for no good reason. Normally this would involve some hand waving about quantum mechanics, and it being impossible to read the full quantum state of the object non-destructively. But in real life it's probably just impossible, full stop, so the explanations are a plot device working backwards from how they would like teleportation devices to work in their fictional setting.

Your time travel model is not one of the common models in fiction. If everything rolls back at the same rate, including yourself, and nothing changes, then has anything even occurred? Normally the time traveler has some form of privileged status that allows them to change or observe the past for it to be considered time travel. Your idea that it would have to work according to the pointless model is based heavily on assumptions that would need to be supported more than you've done.

[factotum]

Both would be.

It might be difficult to persuade Kantaki 1 and Kantaki 2 of that, though.

[Lord Torath]

The Getaway Special had a teleport effect that generated a field that physically moved the material to be teleported to the new location, displacing the material at the destination. Just how the matter was moved was never covered (higher dimension? magical "pop"?). Meant that teleporting into atmosphere took a lot more energy than teleporting into a vacuum. But there was no disassembly-reassembly involved.

[NichG]

It might be difficult to persuade Kantaki 1 and Kantaki 2 of that, though.

In the distant future, being able to get along with yourself will be an important survival trait...

[gomipile]

Of course, I don't mind teleporting non living objects, but as far as I'm concerned, as far as instant travel is concerned, portals are the best way, provided you don't touch their edges.

Now to my problem with time travel. Let's assume you can figure out how to send yourself back in time. Or more specifically, you travel back in time. Wouldn't you end up with less memories, and a little younger? If you send yourself backwards, how would you do that while preserving your mental and physical status in the present? Let me explain. If you're traveling backwards in time, everything that has happened is undoing itself. The eggs are being un made, the memories are being unrecorded, the food in your stomach is being unprocessed... I think you see the problem.

So, do you think these concerns make sense? Obviously this only applies from a scientific perspective, magical teleportation has its own rules.

You accept portals as cromulent science fiction. Special relativity is an observable fact. Put the two together, and you necessarily get time travel that doesn't act the way you assume in your time travel paragraph.

If you have a portal with one end stationary relative to, say, a spot on Earth, that end's reference frame is fixed there. Call that end "end A." Now send the other end on a high speed journey and then bring it back to near the same spot on Earth and set it next to the first portal. That one is "end B." Let's make the journey such that end B is now one minute younger than end A. You can now walk through the portals in either direction to quickly travel forwards and backwards in time one minute per loop. Nothing physical is changing about you, so you won't lose any memories you wouldn't have normally lost while walking a short distance.

There are a few catches here. You can't go back further than when the portal loop was created, and you can't go forward past when the portal loop lasts. If the portal breaks down, is destroyed, whatever, then that's the limit of how far into the future you can go. And if you get too close to that point and it stops working while you're there, you're stuck in the future.

Beyond that, there can be restrictions based on whether time travel a.) causes causal loops, b.) fractures reality into multiverse parallel universes when you go backwards in time, c.) other unforeseen rules of time travel that can only be discovered after inventing and testing time travel.

In case a., the loop will get clogged up with people walking through it eventually, so you'll want to make the interval longer than the one minute I said above. In case b. you've created a bridge between parallel universes, and stuff that happens in the universe on the past side of the portal won't necessarily happen in the universe on the future side.

[Strigon]

Both would be. "The real you" isn't a-priori a conserved quantity, its just one that is effectively conserved in our own experiences.

It's like asking, when you make a copy of a file on your harddrive, which one is the real file and which one is the copy. You could come up with some sort of canonical way to order them, but in practice it has no consequence. Or, if you have your corpus callosum severed, is the right hemisphere or the left hemisphere 'the real you'?

That's not true at all. One of you is conscious, and has been for several years. The other only thinks he has.
The fact is, this sort of teleportation kills. It then rebuilds, but with a different consciousness. Theoretically, at least; we can't say for certain without knowing what causes consciousness. But if you use that system to, say, visit Fiji, you will die having never visited Fiji. Fiji will simply have a visitor who is fundamentally like you in every way. Your family won't miss you, the world won't miss you, but you're consciousness will be gone.

[Bohandas]

So, there's a few things I have trouble with in the realm of science fiction.

First let's start with teleportation. As I understand it, teleportation is the act of taking an object apart atom by atom, sending those atoms elsewhere, and reassembling them. I don't see how this could be anything but lethal to any living creature. Of course, I don't mind teleporting non living objects, but as far as I'm concerned, as far as instant travel is concerned, portals are the best way, provided you don't touch their edges.

It comes with free resurrection though. In fact the thing that always bothered me about that sort of teleportation is that it's not put to good use resurrecting the dead. Just save some of these patterns. I mean granted you'd have to restore them to the last time they teleported and lose anything afterward but it's better then nothing. You could also use it to duplicate people and objects if you fed in new material but kept an old pattern.

In any case some science fiction uses very large-scale quantum teleportation in which matter is instantly transposed rather than being converted to energy and transmitted

And teleportation in D&D and most first-person shooters that have it works closer to a hyper-drive, with subjects being propelled through an alternate dimension (which in the first-person shooters generally atteacts the attention of creatures from that plane and provides the main conflict of the game [ie Doom, Quake, Half-Life, etc])

Now to my problem with time travel. Let's assume you can figure out how to send yourself back in time. Or more specifically, you travel back in time. Wouldn't you end up with less memories, and a little younger? If you send yourself backwards, how would you do that while preserving your mental and physical status in the present? Let me explain. If you're traveling backwards in time, everything that has happened is undoing itself. The eggs are being un made, the memories are being unrecorded, the food in your stomach is being unprocessed... I think you see the problem.

This really only applies to the type of time travel in movies like The Butterfly Effect and stories like Through the Gate of the Silver Key

[Bohandas]

The Getaway Special had a teleport effect that generated a field that physically moved the material to be teleported to the new location, displacing the material at the destination. Just how the matter was moved was never covered (higher dimension? magical "pop"?).

Don't diss the magical pop, that's been done with electrons

EDIT:
Or at least I think it was electrons. It was one of the sub-atomic particles.

[theNater]

OK, let's posit a teleportation system: it scans you to determine all the matter making up your body and transmits that data to the other end, where the duplicate is created; the original you is then vaporised to prevent there being two of you floating around. One day, this process goes wrong and there are now two people, both of whom believe they are Kantaki and who are physically and mentally identical to each other. Which one is the "real" you?

A related question: When a cell copies itself through mitosis, which of the resulting cells is the original and which is the copy?

That's not true at all. One of you is conscious, and has been for several years. The other only thinks he has.
The fact is, this sort of teleportation kills. It then rebuilds, but with a different consciousness. Theoretically, at least; we can't say for certain without knowing what causes consciousness. But if you use that system to, say, visit Fiji, you will die having never visited Fiji. Fiji will simply have a visitor who is fundamentally like you in every way. Your family won't miss you, the world won't miss you, but you're consciousness will be gone.

Given that we don't know what causes consciousness, how can you be sure that the consciousness in the rebuilt body is a new one, rather than the old one transmitted to the new place?

[Bohandas]

1,000 like minded soldiers will show no intellectual flexibility, while ten with different ideas may be less powerful in the short run but will have a larger pool of ideas to draw from. Immortality is a dead end, so most species instead focus on individualism and flexibility of thought.

But why don't the Borg seem to do it either?

[NichG]

That's not true at all. One of you is conscious, and has been for several years. The other only thinks he has.
The fact is, this sort of teleportation kills. It then rebuilds, but with a different consciousness. Theoretically, at least; we can't say for certain without knowing what causes consciousness. But if you use that system to, say, visit Fiji, you will die having never visited Fiji. Fiji will simply have a visitor who is fundamentally like you in every way. Your family won't miss you, the world won't miss you, but you're consciousness will be gone.

If the teleporter works, that is to say if it constructs an exact copy correctly, then both versions are have been conscious for several years, or are not conscious at all correspondingly. This is regardless of what you happen to think consciousness is, since the teleporter can just as well be specified to 'copy that too'.

[Strigon]

If the teleporter works, that is to say if it constructs an exact copy correctly, then both versions are have been conscious for several years, or are not conscious at all correspondingly. This is regardless of what you happen to think consciousness is, since the teleporter can just as well be specified to 'copy that too'.

That doesn't follow. There was definitely only one you, now there are two. Your consciousness doesn't extend to both bodies simultaneously, that would require FTL communication. There is a new consciousness. Which means there is an old consciousness. The two may be interchangeable from an outside perspective, but they aren't from an internal perspective.
Even worse, it's impossible to tell if you solve that problem. If you step in it, you won't know if you're killing yourself.

[Tvtyrant]

But why don't the Borg seem to do it either?

Supposedly because they gain new insights via absorption. Really it's because the borg got more idiotic with each episode featuring them, starting out as a cosmological horror and ending as a group of robotic bug people with a queen and everything.

Star Trek was always meant to be a sounding board for bourgeoise values from the 1960s, which puts limits on its effectiveness as a cohesive world. Like how the world is supposed to be both meritocratic and yet provides equivalent socialistic access to resources.

[Lvl 2 Expert]

That doesn't follow. There was definitely only one you, now there are two. Your consciousness doesn't extend to both bodies simultaneously, that would require FTL communication. There is a new consciousness. Which means there is an old consciousness. The two may be interchangeable from an outside perspective, but they aren't from an internal perspective.
Even worse, it's impossible to tell if you solve that problem. If you step in it, you won't know if you're killing yourself.

Or there are two new consciousnesses. The old one lived in a brain that has been taken apart after all. But it was reconstructed with exactly the same types of molecules, the same electrical currents, the same salt concentrations and fluid pressures, and that was done twice.

That's the problem with immortality through cloning. It's fine from the perspective of the clone, who remembers having been alive and gets to be alive for a while longer. It's also fine from the perspective of everyone who knew the original, to them it's still there. But from the standpoint of the original the exercise was pointless, they're still dead. Since they're dead though, we don't have to worry about what they would think of it.

[NichG]

That doesn't follow. There was definitely only one you, now there are two. Your consciousness doesn't extend to both bodies simultaneously, that would require FTL communication. There is a new consciousness. Which means there is an old consciousness. The two may be interchangeable from an outside perspective, but they aren't from an internal perspective.
Even worse, it's impossible to tell if you solve that problem. If you step in it, you won't know if you're killing yourself.

It only requires communication to remain one consciousness. There was one you, now there are two yous, each of which is an equal continuation of past you, but each of which is wholly independent of the present other.

Write it out with time explicitly, and it's a tree with an equal branching point. Both branches are equally part of the same tree, but are separate from eachother.

[Darth Ultron]

One day, this process goes wrong and there are now two people, both of whom believe they are Kantaki and who are physically and mentally identical to each other. Which one is the "real" you?

Star Trek the Next Generation did this in Second Chances with two Rikers :)


1.Teleportation by ''taking atoms apart'' is only one way of doing ''science based teleportation.'' And it is the Star Trek way, but it is not the only way.

Want some wacky real world science: https://en.wikipedia.org/wiki/Quantum_entanglement

and

https://en.wikipedia.org/wiki/Quantum_teleportation

So sure it's a lot of wacky stuff...and it is not teleporting....yet. But it sure seems like it might be possible some day.


Fictional time travel has the traveler in a ''static time reality bubble'' so they are not effected by time travel itself.

[veti]

That doesn't follow. There was definitely only one you, now there are two. Your consciousness doesn't extend to both bodies simultaneously, that would require FTL communication. There is a new consciousness. Which means there is an old consciousness. The two may be interchangeable from an outside perspective, but they aren't from an internal perspective.

Nothing "follows", because as mentioned above, we're talking about figments of our own and others' imaginations. It can work any way we can imagine.

Complaining that someone else's version "doesn't follow" makes about as much sense as complaining because "it's not yellow".

Imagine for a moment we have Star Trek-style transporters, which really do break you down into some kind of pure information and reassemble you at a distant point. Now, you may say that it "kills" the old you and creates a new one (indeed, as I recall Dr McCoy sees the process very much in those terms, and refuses to step into them). But if people willingly subject themselves to this process on a daily basis, suffering no ill effects - what's wrong with that? Who cares that it's not "the old you"? What does "old", or "you" for that matter, even mean in this context?

TL;DR: What is this "internal perspective" you speak of, and why should we care?

[Bohandas]

That doesn't follow. There was definitely only one you, now there are two. Your consciousness doesn't extend to both bodies simultaneously, that would require FTL communication. There is a new consciousness. Which means there is an old consciousness. The two may be interchangeable from an outside perspective, but they aren't from an internal perspective.
Even worse, it's impossible to tell if you solve that problem. If you step in it, you won't know if you're killing yourself.

When a paramecium divides, which is the original?