The rift, the crystal tower, and the seat of sacrifice (Spoilers up to 6.0)

[Vyrerus]

We travel from there back to a point before the timelines split, arriving in the shared past of both our timeline and the bad timeline. Therefore we set those events in motion for both timelines, not just ours.

There has to be a prime timeline that is free from time travel in order for derivatives to come about, otherwise there's no impetus for time machines to time travel.

The time split occurs the second the time machine is finished in the 8UC timeline, before it's ever used to go back in time because its entire reason for existence is to go back in time. A time traveler cannot mute the reason that impelled them to make their time machine. The 8UC realized this, and also realized they would be helping an AU.

I don't know if this means they're the prime timeline, but it does mean that in spite of shared history, enough was different with their universe that there is no, and can never be an, Elpis conjunction in theirs.

And that's because the Elpis conjunction is ultimately only possible in our timeline. It doesn't effect any time line that cannot support its conjunction. The Elpis conjunction is dependent on the sacrifice of the 8UC, a timeline where the WoL dies.

There had to be an original sequence of events where the WoL was absent from Elpis. We cannot perceive them in our story though, because of the conjunction.

[Iscah]

There has to be a prime timeline that is free from time travel in order for derivatives to come about, otherwise there's no impetus for time machines to time travel.

That really depends on how you approach it in the first place, but okay. Let's say for the sake of argument that there is some kind of prime timeline where we were not involved in the events at Elpis, the Final Days got started some other way, and we somehow innocently overwrote that timeline by visiting Elpis and creating the loop. In that case the original timeline is already so completely overwritten that characters are aware of our past visit to Elpis before we experience it for ourselves.

(Personally I disagree that it can work this way, because we only got to Elpis because of elements influenced by our past present in Elpis, like Argos accepting us and Elidibus remembering that he saw us there. I think it's an infinite loop, and it has no clear origin; it simply is.)

The time split occurs the second the time machine is finished in the 8UC timeline, before it's ever used to go back in time because its entire reason for existence is to go back in time. A time traveler cannot mute the reason that impelled them to make their time machine. The 8UC realized this, and also realized they would be helping an AU.

"Before" and "after" become rather less stable concepts in a time travel story. The split occurs long before the time machine is created, because G'raha will travel back in time to create that split. If the timeline only split when the machine was built, that would not save the WoL hundreds of years earlier.

As for a time traveller not being able to erase the reason for their going back in time, that is only the case in a non-splitting timeline.

It is my exact argument that doing something to erase the original reason for time-travelling - amid the broader category of doing anything that alters the known future that the traveller came from - will cause a split, and that is exactly what G'raha did.

His origin and his reason for travelling to the past remain in existence, in the bad timeline. His actions create a world incompatible with the events leading to that bad timeline, so the timeline splits (does not overwrite) into a second parallel timeline from that point onwards. The bad timeline remains part of his personal past even though objectively those events never occur in this one.

I don't know if this means they're the prime timeline, but it does mean that in spite of shared history, enough was different with their universe that there is no, and can never be an, Elpis conjunction in theirs.

And that's because the Elpis conjunction is ultimately only possible in our timeline. It doesn't effect any time line that cannot support its conjunction. The Elpis conjunction is dependent on the sacrifice of the 8UC, a timeline where the WoL dies.

There is no need for the Elpis loop to be completed in the other timeline. Only one version of the WoL needs to visit Elpis, and that will flow into both halves of the split timeline, because the events happen objectively earlier than the split.

And the 8UC timeline is never "sacrificed". They thought they were going to overwrite it, but they didn't. It continues to exist. Not that it has any bearing at all on the Elpis time loop beyond paving the way for it to form.

[Iscah]

The time split occurs the second the time machine is finished in the 8UC timeline, before it's ever used to go back in time because its entire reason for existence is to go back in time.

I forgot to directly address this point earlier – there is no reason for the mere existence of the time machine to create a split without actually being used. The closest thing is that objectively the timeline may already have a second strand that will be/has been created by the time machine when it is used, but that will have existed since before the machine was complete.

Depending on the story's approach to time travel, the act of time travelling may directly cause the split, but I don't think that can be the case here or the Alexander storyline could not exist and stable time loops could not form.

So that brings us back to my theory that altering the known future is what causes the timeline to split, while also leaving the possibility that the time traveller can avoid altering anything significant (or alternately play a part in something that needs to happen, but they weren't previously aware of in detail) and safely return to their original future.

[Lyth]

The rules of time travel are always story dependent, but you certainly can have a 'Stable Time Loop' in which the effect precedes the cause. Early in-game examples of this are the Alexander storyline, in which Backrix's watchbook ends up becoming Quickthinx's futurebook, and the second loop in which Mide and Dayan end up travelling to the past to become the predecessors of the Hotgo tribe who create the Enigma Codex. Yet another example is the A12S timegate mechanic, in which you travel back in time to kill the four Generals and release your past self from temporal stasis in time to dodge Alexander's attack in the cutscene before the fight.

Granted, this doesn't strictly seem to imply predestination, because you can still fail the dps check during Timegates and let your 'past self' be killed, causing a raid wipe in the present.

I don't think there's much point in trying to decipher the exact layout of the current expansion's time loop just yet, because it's still currently unfolding and the writers always love slipping in surprise reveals in the final raid tier. I also find that it helps to revisit some of these raid stories after you've had a bit of additional perspective from elsewhere, as Alexander is much more interesting post-Twinning and Eden is likewise better enjoyed with the insights gained from Cylva's story.

[Necrotica]

Having the effect precede the cause is the whole problem. It does not work. In a fictional setting you can do whatever you want, but it is not good writing.

[Iscah]

Having the effect precede the cause is the whole problem. It does not work. In a fictional setting you can do whatever you want, but it is not good writing.

Yes, but this is a fictional setting we're talking about, and maybe it is bad writing, but that doesn't change the fact that they wrote it in a way that relies on a stable loop where the effect preceded the cause.

You can wish that they didn't make that choice, but for the sake of interpreting the storyline as it exists, you just have to accept that those are the rules it is following and it makes sense within those rules.

[Cleretic]

I don't understand people who don't understand Endwalker's time travel. But maybe that's because I grew up with Doctor Who, which is a perfect teacher of the golden rule of time travel stories:

Time travel works however the story needs time travel to work this week.

Once you learn that, all time travel stories work just fine. It works how it's put forward to work,the rules are as internally consistent as they need to be, and there is no prize for 'outsmarting' the story by claiming it's not. Hell, the time travel story that most people here apparently hold up as the gold standard of time travel stories in games is even less consistent than Endwalker; Chrono Trigger gives an explanation of time travel early on that's completely sound, except for the part where after that first little story arc, its time travel never works that way again. Chrono Trigger works so loosely with time travel that I'm not even sure I can quantify how many times it contradicts itself or how many time travel rulesets it sticks to, because it so thoroughly embraces the approach of having time travel work in the exact way that would be most effective at this very moment.

And nobody complains about Chrono Trigger's time travel being inconsistent, because consistency was never actually important. I think people complaining that Endwalker's time travel 'doesn't make sense' (which it actually does as long as you remember that it it only has to stand up to its own rules) actually just want an opportunity to try to tear down Endwalker, and have decided that 'proving it wrong' will be some kind of victory.

[Necrotica]

I don't understand people who don't understand Endwalker's time travel. But maybe that's because I grew up with Doctor Who, which is a perfect teacher of the golden rule of time travel stories:

Time travel works however the story needs time travel to work this week.

Once you learn that, all time travel stories work just fine. It works how it's put forward to work,the rules are as internally consistent as they need to be, and there is no prize for 'outsmarting' the story by claiming it's not. Hell, the time travel story that most people here apparently hold up as the gold standard of time travel stories in games is even less consistent than Endwalker; Chrono Trigger gives an explanation of time travel early on that's completely sound, except for the part where after that first little story arc, its time travel never works that way again. Chrono Trigger works so loosely with time travel that I'm not even sure I can quantify how many times it contradicts itself or how many time travel rulesets it sticks to, because it so thoroughly embraces the approach of having time travel work in the exact way that would be most effective at this very moment.

And nobody complains about Chrono Trigger's time travel being inconsistent, because consistency was never actually important. I think people complaining that Endwalker's time travel 'doesn't make sense' (which it actually does as long as you remember that it it only has to stand up to its own rules) actually just want an opportunity to try to tear down Endwalker, and have decided that 'proving it wrong' will be some kind of victory.

I have to admit I have not seen many topics on the final fantasy 14 forums talking about the problems with chrono triggers time travel.

And I was complaining about this games time travel the first time I played Alexander content. The lack of initial time line to then cause the time loop. Cause and effect is a must for me to enjoy something.

[TheMightyMollusk]

The way it seems to me, time travel within the same Shard doesn't work, because you can't change the past. This includes going back to the pre-Sundering era, because it's still technically the past of the same Shard. But jumping to another Shard changes the variables enough to break the time stream, or at least create an alternate one.

To use a (probably bad) metaphor; traveling back in your own past, like Alexander, is just riding the train back along the tracks. It can only go one way. Jumping across the Rift and traveling through time is diverting the train onto a new set of tracks.

[KageTokage]

Somehow it never really occurred to me until now, but it's going to feel awful when after eliminating this supposed grave threat to the star in the Pandemonium raids, we're forced to just let Themis/Elidibus be dealt the same hand he was originally; to be left oblivious to the tragedy that would later befall his world.

I suppose there is some slim chance things might manage to end on a brighter note, but I'm not counting on it.