I suppose it stems from Adam and Eva in S1 and Jack saying to Kate saying feels like we've been here a hundred years. I know some people believe the losties are reliving this journey over and over. I found the conversation when Saywer/Miles met with Jack/Kate to be an implication of this theory

"maybe this is deja vu"
"what's with you and getting off this island, you sound like a broken record"

This could obviously be natural banter but it seems to me it's a small hint ;)

(not that i'm a believer!)

I am leaning towards believing in this idea.

I have nearly finished reading Valis (the book Locke gives Ben early this season). It is not so much as reliving as it is living memory of all descendants we stem from. Given the multitude of lostie connections, it seems many of them would hail from a shared lineage, and thus embody a similar living memory.

that's a fair and knowledgable point.

considering the title of the show was originally called the circle, i am inclined to run with this idea too.