Excellent. This show has not lost one iota of inventiveness and emotional punch. Very clever how they managed to color within the lines and stick to their time-travel logic - if you can't change your own timeline, frakking around with it must create another reality - you're changing someone else's past/future, but they won't know you did it,
you won't know you did it, and you won't get any benefit from it.
Finally, a show that does time travel right!
I don't mind writers using other sorts of logic, but I do mind when the rules aren't clear or the logic is flawed. The
Lost time-travel logic is going to be tough to pull off well, because you end up with the "real" characters the audience cares about, but what about the other guys? Are they "real"? Are we supposed to care about them like the originals? Will the stories ever intersect in a literal way? I can't see how they could. But they could intersect thematically, for instance by having Jack 2 operate on Locke 2 and repair his spine (and I'm incredulous at myself that I never saw the parallelism between Jack's profession and Locke's injury!)
It's also clever that they've hit on an all-new way of doing the island/mainland story split. They've pretty much tried them all by now, haven't they? Flashback, flash-forward, split the gang between island and mainland and now, parallel realities. Is there anything else they could try if there was an S7?
So - how can the island be underwater in the same universe as non-crashing LOSTIES?
Simple: these are parallel realities, not different timelines of the same reality. It's the same logic as
Star Trek XI. You can have two Spocks in the same place because they're not the same guy.
Somehow, setting off the bomb created or altered a different reality to follow the path we're seeing. There's one reality in which 815 crashed and another reality where the island is underwater but they have no connection to each other besides the fact that they contain many of the same people, places and things.
The blast jumped realities, which might be possible if the island were a "nexus of realities" of some sort. Remember all that stuff about the importance of approaching and leaving the island on just the right heading? That could have been to keep you from blundering into the wrong reality.
Exactly how would Juliet know that it worked?
Er, um...she has a psychic connection with her doppleganger in the parallel reality who is somehow aware that her reality just changed? Or maybe we just chalk it up to artistic license. Everything in this maniac mess doesn't have to make 100% sense!
But that's not how we were told it worked in Lost. In Lost, the rule had been "whatever happened, happened". There's only one timeline. When someone tries to change history, they just end up fulfilling it. Simple, straightforward rule, that avoids the writers using time travel as a crutch.
One timeline
per reality. They're still coloring within the lines - so far.
For all we know these two timelines will somehow end up fulfilling each other...or something.
There's gotta be some connection or else the very idea is silly for a story - there's no coherence. But if the timelines intersect literally, I dunno, I think that does mean they've violated their own rules. That's why I think they might go for a thematic connection, but to do that for all the characters -yowch! That will be some amazingly tricky writing.
Unless what Kate does is shoot herself in the head because she realises what a horrible, selfish and boring human being she is, and even then it would have to happen in the JJverse and the Prime universe for me to be interested in it.
) when they set up us the bomb. 
