Asked if they know the answers to all the questions they raise on the show right away or sometimes figure it out as they go along, the duo said it was a combination of the two. Lindelof recalled how the entire pilot was put together – including writing, casting and production – in 12 weeks, which didn't allow much time to come up with any long-term mythology. However, once the series was given a full season order, beyond the initial 12 episode order it received, Cuse said he and Lindelof sat down and discussed, "What the overall mythological underpinnings of the show would be. We quickly landed on the ending, and then constructed this broader road map of other mythological points we'd hit on this story."
While each season of Lost is mapped out, the duo said you have to, "let the show organically tell us what it's going to be," bringing up the character of Ben Linus as an example. Ben was originally only intended for a three episode arc, and Lindelof and Cuse were playing a bit of wait and see as to whether or not he would turn out to be the leader of the Others, based on how things went with the actor playing the part. But once Michael Emerson was cast, "he was so good, we ended up writing eight episodes for that guy," in Season 2, and then made him a regular. The decision to extend the original Ben storyline, in which he was held captive within the hatch, then had an influence on other storylines – Lindelof said they'd already decided that Michael, forced to help the Others to get Walt back, would kill Ana Lucia and Libby. But by extending Emerson's time on the show, Michael's specific task now became to free Ben.
Lindelof said they also knew from the start that Kate had killed someone and that it was probably her father – but, "the question became 'when do we pull the trigger on [telling that story]?" and that the key was to, "bring it to an emotional point where it's relevant to what's happening on the island. "
However, Lindelof and Cuse said that things had changed considerably now that they know the end of the show, with Lindelof explaining, "Certainly since we got an end date, that sort of fly by the seat of your pants story is gone now. Showing scenes [set] three years from now, you can't change it."
Cuse said that while they know the fans love to dissect the mythology, "We probably spend 80% on character, and 20% on mythology," stressing that he thinks the focus on the characters, is "Why the show crossed over to not being a small genre show." That being said, he acknowledged, "This year will probably be a little bit more science fictiony."
Lindelof laughed that, "We sort of suckered people into this show but not presenting it as a science fiction show right out of the gate," noting that there were elements early on that were, "like a Rorschach test", saying that when Flight 815's pilot is killed, someone who didn't like sci-fi would think, "there has to be a rational explanation." Even the reveal that Locke could walk on the island was tempered by the fact that they still hadn't revealed why he was in the chair in the first place, leaving the opportunity that, "it could be psychosomatic." Lindelof said Raiders of the Lost Ark was a great example of a story that has blatantly science fiction elements, noting, "Nazis melt and ghost fly out of this ark," but that it waits a long time before presenting these elements, allowing the audience to fall in love with Indiana Jones first. Lindelof said he felt shows like Invasion probably had a harder time finding a wide audience because, "They said 'Alien!', right out of the gate.'"
Lindelof said that when it came to slowly building into more science fiction, "Lost has really been about the long con, because by the time we get to season 6, it's going to be f**king crazy!"