I'm new here. Just started reading all this info and wow I am very impressed.
Anyway, I've been reading a LOT on this compendium and I've had a few thoughts on some things. Namely, issues with "time traveler's immunity" and the formation of the split dimension in Chrono Cross.
The biggest issue as the article points out about Time Traveler Immunity is that a major inescapable plot point goes entirely against it, with Marle. I've actually had a thought on this that, at least I think, would not just wrap this up but also solve a number of other issues. Namely, the thought that time traveler's immunity is not a property inherent to time travel so much as a property that time travelers have to obtain in some special circumstance.
Basically here's how I think it may have happened. At the start of the game after initial time travel, their alterations can directly affect them. This is confirmed by Marle's vanishing. I'm not sure the entity explanation is very fitting as Chrono was already well on his way to doing what needed to be done as it was and simply removing the gate would force them to go on. Also it doesn't seem like the planet would suck someone away to depressing frightening darkness. That sounds more like the darkness beyond time. As to why her disappearence wasn't retroactive maybe some very specific event "ensured" that future when Chrono actually showed up and found Marle. I don't know what detail that may have been myself though. It may be that the issue is one of probability and her disappearence occurs when the odds of her ending the family line pass a certain point. That point may be an arbitrary number but so is the "more than 3 people" limit when using gates, or a number of universal constants for that matter.
Well the big question that comes up is still the issue of why Chrono and Lucca, in the past, don't just completely forget Marle, or why they don't just go back to their own time period. Here are my thoughts. I think there's a concept even before time traveler's immunity is granted that I'll just call "timeline conservation". The idea is that the resolution of the grandfather paradox is that while one is deleted from the time line if they kill their own grandpa in the past, that deletion can't affect the mini-time line starting with their arrival in the past up to the event, or the ensuring of the event, that prevented them from being born. This prevents a paradox by mainaining that person's existance for a short while just long enough to allow them to terminate the rest of it. The idea is that while they disappear from the present era, and they vanish AFTER whatever they do in the past to ensure their deletion, the moment they arrive up until that deletion is preserved. The issue is just that from the perspective of this new time line a strange being just popped into existance from nowhere near a gate and vanished after doing something arbitrary. If a non time traveller observed this occur, they could then be sure that their reality is an altered one, not the original time line.
By extension, since Marle's presense up until her deletion are still in effect, Chrono and Lucca will still remember her since they interacted with her right up until that point. I think a time traveller interacting with one they remember up until their deletion ensures they are not altered retroactively to forget everything up until that meeting. I am not sure that's clear, but the basic idea is that so long as a second time traveller from the first's original time line would, in that time line, naturally go to that same era for whatever reason and there is some interaction between them before the first's moment of deletion, timeline conservation (in order to prevent any alteration to the initial time line such as Chrono acting differently when meeting Marle or something Chrono does altering how Marle acts and thus preventing her destroying herself, thus making a chain reaction paradox which timeline conservation exists to avoid) will not change. An "interaction" would be something as simple as someone arriving in that era since as is established ANY change could do something and timeline conservation would not be intelligent enough to know what the new arrivals could potentially do if they are altered to prevent the deletion BEFORE it happens.
I must point out that this conservation only applies BEFORE the moment of deletion. AFTER deletion the new arrivals can still do as they please to undo the effect since whatever happens after will be it's own seperate event and not cause a paradox. The only way it could occur is if the deletion altered the new time traveller's arrival (or prevented their arrival) in such a way as to prevent the deletion from occuring from a direct altering of the INITIAL events that ensured deletion. LATER events are still open to alteration by the other time travellers.
The advantage is this allows a much cleaner interpretation of the Marle incident as being exactly as the game indicates it was and it still allows the theme of the game of being able to alter the future if one exerts the needed effort to shine through. Further, the concept of time conservation preventing any event that would cause a time altering event to unmake itself through paradox, I think, negates the need to invoke "time traveller immunity". Consider time travelling to give the jerky to the Mayor's ancestor. While this event would delete the old mayor and replace it, due to timeline conservation, the original event that ensured that future could not itself be altered, so in that case Crono would still have to, at least up until he finally handed over that Jerky, maintain his memories of the present Mayor. Since Crono does not speak in the game, we can't say whether AFTER the event he lost those memories and had them replaced but the important quality of timeline alterations preserving themselves allow the event to occur without paradox. Another possibility is since Chrono didn't do something to outright delete himself but just alter himself, the new timeline's memories might wedge themselves into his head along with the old ones. A third possibility is so long as deletion does not occur, the moment he handed over the jerky, since he was still there, he'd stay the same, in a limited version of immunity.
In this idea, by the way, Lavos existing in a time bubble would not allow Lavos to end the world in spite of being killed in the past's entrance to his time bubble. It would end his effects in 1999 as well as he would not be able to emerge from that bubble in that era.
Anyway, I'd like some thoughts on this as I think it's at least worth considering as a viable alternative to the current idea of immunity.
As to the other big issue in Chrono Cross of when the split happened, I'm thinking "a little of both". To be more clear, I think that the idea of it happening 10 years before the start is right except the alternate reality that is created doesn't start at that 10 year point but rather at the other major time event, the 1006 one. The idea here is the Home World is created with a full existing time line going back a few years before the time it is actually created, so that there appears to be an issue. With this idea, since there is an alternate world at the 1006 point TO observe, Chronopolis could still be made to do it but wouldn't actually go through the event which creates it until 1010. The big issue here is it would seem on the face of it to be a predestined event, which is not how time works in this series. So, it would have to be that it gets created whether they are observing it already or not, and from what I've seen of the story, that does still seem to be the case. I may be forgetting some important detail here.
