SPOILERS for the May 11th episode of LOST follow...
I disliked the LOST episode "Across the Sea" on first viewing. From the American-accented Latin to the abrupt switch to English to the stiltedly "mythic" dialog, it bugged me. But when I ran with the mythic feel and tried to understand it in that context, I started to appreciate this glimpse into the legend as a worthy pen-penultimate episode of my favorite network television show.
If you believe Jacob and his followers, the Island is a stopper that prevents the evil of the Other (what I call Jacob's nameless twin, sometimes referred to as the Man In Black or Esau) from being unleashed on the rest of the world. The Island, in this view, is a sort of Pandora's Box, and Jacob (and eventually Jacob's successor), are charged with sitting on the lid. We lapped up this information like cream, eager to have some revelation of the Island's nature. But we didn't question it. "Across the Sea" gave us some reason to do so. At the heart of this is Mother, a Roman priestess or witch who, from the get-go, seems a shady individual. She's a staunch isolationist -- murderously so -- who charges her stolen "sons" to protect the mysterious glowing cave (presumably the future site of the Temple and its pool). She waves away the whys and wherefores by saying the explanation would just lead to further questions -- and the answers die with her. Jacob has been bringing people to the Island, putting them through trials and suffering, all in the hopes of naming a successor, eventually to do the same all over again. And he doesn't even know why.
In his origins, we see the Other's motivations for the first time from his point of view, and rather than the Bad Guy, he comes off as sympathetic. Clever and curious compared to his dully dutiful, morally infantile twin, the Other pushes at boundaries and explores his world. He uncovers Mother's great deception, and (with the nudge of his ghostly biological mother) justly rebels, seeking knowledge of his true origins and people. He resembles another mythological character -- Eve in the Garden of Eden -- who also disobeyed and partook of the fruit of knowledge. And was punished for it. The Other's only real crime to that point was a desire for knowledge over ignorance. In LOST themes, the Other is the Man of Science to Jacob's Man of Faith.
If his real mother's ghost played the role of Eden's serpent, it's interesting that in "death", the Other became a serpentine entity of black smoke, and (at least in the view of the Jacobins) "evil". I don't think the morality of this Island conflict is
completely relative: Ben and Sayid were similarly "baptized" and came out colder and more ruthless -- "corrupted" in a way that certainly brought out the worse part of their natures. But this mythic interlude showed us that the conflict between Mother and the Other began with carnage on both sides. It's significant that first blood, from the murder of the twins' biological mother, to the Other's head slammed against a mine wall, to the massacre of the castaways, went to Mother. We still don't know why it was important for the Other to be kept on the island even before his "corruption", so the entire struggle could be seen as Mother's unjustified attempts to confine her son, and the Other's struggle for freedom. The people Jacob draws to the Island are pieces in the game, and the Jacobins have been responsible for a massacre or two of their own (witness the Dharma Initiative, among other strikes). If the Other doesn't seem particularly sympathetic to the protagonists, its because, in this battle of immortal demigods, they
are no more than pieces on a board.
In the myth of Cain and Abel, Cain killed Abel because God rejected his offering but accepted Abel's. Jacob notes that Mother always loved the Other more than Jacob, calling him "special". As warring Titans, it's probable that both Jacob and the Other are separate from human morality, though they are not above human pettiness. Daddy Issues are pandemic among the characters of LOST; it seems the root of the story lies in serious Mommy Issues. Mankind is probably better off without both of these tragic demigods. It may be that the "sideways" timeline, where the Island sank and the Jacob-Other feud is presumably ended, is the best possible outcome for the Losties.