After "This Place Is Death," I have a theory about Locke's connection to Jacob and the Monster, specifically one in which two time-lines exist concerning Locke's destiny, an original one, and a new one that was changed accidentally by Jack, and deliberately by Ben. In the original timeline, Ben never turned the wheel at all, because Locke beat him to it, turning the wheel sometime towards the end of season one or the beginning of season two (having never entered the hatch). After turning the wheel, the island sent Locke back to the 1700's, where he boarded the Black Rock under the assumed name Jacob, died upon arriving on the island, and became the spiritual Jacob we saw in "The Man Behind The Curtain" (sort of), ruling the first others, the crew of the Black Rock.
This timeline was changed when Jack saved Locke from the Monster pulling him into the ground in the finale of season one. Locke was meant to be taken over by the Monster, which would have used his body (in the same way it possessed Rousseau's crew) to lead Locke to the Orchid and turn the wheel, sending him along his destiny. Because this did not happen, Locke was forced to muddle through for months, unearthing secrets at a snail's pace, causing Ben to see an opportunity to seize power. When discrediting Locke didn't work, he tried to kill him, and when that didn't work, he decided to steal his destiny by turning the wheel. The island of course could not let that happen, so they sent him to present day Tunisia, and now he is scrambling to clean up his own mess. In the current time line, which the island is trying to fix, Jacob doesn't fully exist, as Locke did not become him when he was supposed to, and so he is in flux (where we saw him in "Man Behind the Curtain"). This i! s why the island is using Christian as a proxy, because they need Locke to go back in time and become Jacob. Theory by Ben
This timeline was changed when Jack saved Locke from the Monster pulling him into the ground in the finale of season one. Locke was meant to be taken over by the Monster, which would have used his body (in the same way it possessed Rousseau's crew) to lead Locke to the Orchid and turn the wheel, sending him along his destiny. Because this did not happen, Locke was forced to muddle through for months, unearthing secrets at a snail's pace, causing Ben to see an opportunity to seize power. When discrediting Locke didn't work, he tried to kill him, and when that didn't work, he decided to steal his destiny by turning the wheel. The island of course could not let that happen, so they sent him to present day Tunisia, and now he is scrambling to clean up his own mess. In the current time line, which the island is trying to fix, Jacob doesn't fully exist, as Locke did not become him when he was supposed to, and so he is in flux (where we saw him in "Man Behind the Curtain"). This i! s why the island is using Christian as a proxy, because they need Locke to go back in time and become Jacob. Theory by Ben
