Quote Originally Posted by Vyrerus View Post
It's entirely relevant, since all we'd need to avoid time travel is to, IDK, have Hydaelyn tell us the truth about stuff. But you know...

Since the setting does allow for timelines to change, then the idea of, "This is how it always was." falls completely apart. That is supposition no stronger than any other. Remember the Shadowbringers trailer? Let what was written be unwritten and all that jazz?

We're not writing how it's always been. We're rewritinghow it will be. The 8UC timeline is actually the prime timeline in FFXIV's universe, where there is no WoL involvement in Elpis at all, because in the 8UC timeline there was never a Crystal Exarch preventing the 8th Umbral Calamity. And the WoL there dies and can't go back in time, or even to The First, to cause recursive paradoxes.
The nature of the timeline (at least as I work it out) has only a single version of events up to the extraordinary events of Shadowbringers causing it to split in two from that point onwards.

Because it is a single timeline at the time of Elpis, when we travel back from our branch of the later timeline, we end up in the shared past of both branches, and the events we experience happen and carry on into both futures. There is no timeline where the WoL from timeline branch B did not visit Elpis.

Meanwhile, Hydaelyn can't tell us anything that we didn't know when we came to Elpis, or it will alter the situation and break the time loop. As soon as we tell her we've been there, she immediately gives us all the additional information she can provide to us.

And no, the idea of stable time loops does not have to fall apart just because it is possible to change things. As I see it, a time-traveller's actions do not automatically change the timeline, or events such as Alexander's time loops would not be possible. Most tellingly, the "save your past self" moment would not be possible if a traveller's actions always split the timeline, and would not be necessary if there was some "preceding version" of events where somebody else saved us.

Making sense of the two types of time travel in a single set of rules requires (IMO) a universe that "prefers" a single timeline and stable time loops when time travel occurs, but armed with the right fore-knowledge of events at the destination, it is possible to disrupt things so the original outcome is not possible – for example, ensuring that the First was not primed for Rejoining on the known date of the Eighth Calamity. The outcome is irreconcilable with the time traveller's original future, and a new timeline has to be created for this new and incompatible version of events.