For the past few weeks, it’s puzzled me that Jack, Kate, Hurley, and Sayid “flashed” off of Ajira Flight 316, yet Sun and Ben did not. At first, I had no good answer as to why they would remain in the present while the others were flashed back to 1977 in the days of Dharma. And while I’m still not sure about this one, it’s the best I can come up with to explain why Sun and Ben are in the 2007 / 2008 timeline while the rest of the crew went back to the Me decade.
Sun and Ben couldn’t go back because they were already on the Island to begin with in the 70s.
We already know that Ben was on the Island as a teen. But what if Sun has been to the Island before as well? What if, through some sort of connection that her father had (perhaps Paik Industries was doing business with Dharma?), Sun had visited the Island sometime earlier? Suppose she was on the Island in 1977 and that’s the reason she didn’t “flash” with the rest of the Oceanic Six-ers. Maybe the Island has some sort of paradox clause, some parameters to keep you from going back in time and meeting yourself. And that’s why Sun and Ben didn’t make the leap.
Am I crazy? Probably. (According to Lostpedia, Sun wasn’t born until 1980, so my whole theory is toast if that’s true.) But there may be something here.
already & not yet 
Hmm.. that is an interesting theory. It would make sense (if in fact, Lostpedia is wrong about the year of Sun’s birth).I am very interested to see how they reconcile this. There has to be some good reason why Sun didn’t go back!
I don’t know where Lostpedia got 1980 for the year of Sun’s birth. To me, it seems like she’s older than 24 at the time of the crash.Your theory is interesting. The only thing I think we know for sure about Sun’s youth is she was in Korea when she was approx 5-8 years old (when she got the maid fired in “The Glass Ballerina.”There’s got to be some reason Ben and Sun didn’t flash back. Your theory sounds as good as anything else I’ve heard.
With LOST anything is possible!
All right, I’ve done an about face. The Island allowed Sawyer, Juliet, Locke, etc to move back in time to a period when they were already on the Island…remember when Sawyer peeked out of the jungle and saw Kate delivering Claire’s baby? He was on the Island in the “present” at the same time that he was coming “back” there. So there goes this theory.