DOC JENSEN: Another popular theory making the rounds is that we're dealing with alternate realities. For example, there are people who think the flash-forwards are merely possible future scenarios, not written in stone.
CARLTON CUSE: We want people to believe in the stakes of the show. The problem with alternative realities is that you never know when the rug is going to be pulled out from under you. We want the audience to believe that the jeopardy is real. Postulating alternative realities would be an escape valve that would be damaging that as a narrative value.
DAMON LINDELOF: You can get away with it in Heroes, where there is an apocalyptic future you want to avoid. But we're doing the opposite. We want to work toward a future where Jack is absolutely miserable and wants to go back to the Island. Everything we present to the audience has to be factual.
CUSE: We want the audience to believe that is THE future. We don't want people thinking, ''Well, since there are five iterations of this, I'm not going to invest in what's happening to the characters.''
LINDELOF: We're not going to tell you that we're against bending the time-space continuum. We are very for it. Carlton and I are PRO time-space continuum bending! But we're ANTI-paradox. Paradox creates issues. In Heroes, Masi Oka's character travels back from the future to say, ''You must prevent New York from being destroyed.'' But if they prevent New York from being destroyed, Masi Oka can never travel back from the future to warn you, because Future Hiro no longer exists. Right? So when we start having those conversations at Lost, we go, ''This show is already confusing enough as it is.'' To actually have characters traveling through time has to be handled very deftly.
CUSE: For example, the fifth episode of the season [airing next week] deals with time travel and operates in different time periods. It was a tough story to break. But we adhere to our rule: no paradox.
LINDELOF: It's been weird, though. When we got back from the strike, we had to put up a master timeline of the future, from the point where the Oceanic 6 will end up leaving the Island all the way up to where the flash-forwards will end.
CUSE: And the hard thing was charting a timeline when there's a bend in space-time: How do you illustrate that kind of timeline when time isn't entirely linear? That took us an entire morning
LINDELOF: just to debate the quantum physics of it all.
CUSE: We needed to bring in a professional illustrator. [They smirk.]
I have a sneaking suspicion you're pulling my leg on some of this stuff.
CUSE: But we do feel this is a place where we can challenge the audience to create a chronology where Sayid's story happens in relationship with Jack's story, etc. We'll be adding pieces of that mosaic over the course of these five hours that should hopefully leave you with some fairly clear understanding of what happened between the time the Oceanic 6 were rescued or returned to the real world and Jack and Kate's final scene in the season finale.
NEXT PAGE: ''We could be winky about the coffin all the way through season 5. But that was one of the first things we talked about when we got back to work on the new episodes: We definitely have to show who was in the coffin.''