History Repeating by Boo

For this theory let's go back to Season 5 when the LOSTies determined to return to the island. When Jack and Co. consulted with Eloise Hawking they were told that they had to recreate as much of the circumstances of the initial crash of Oceanic 815 as possible. This included a newly deceased Locke substituting for Jack's Dad, Christian. He was even made to wear Christian's old shoes.

Now let's fast forward to Season Six. Early on we saw a dying Sayid drown in a pool, and later charged with dispatching The Man in Black with a dagger. At the time there was nothing out of the ordinary about these events. That all changed with last night's blockbuster, Ab Aeterno, in which not only did we see Richard ceremonially baptized in almost the exact manner as Sayid, but we also saw him charged with killing Jacob by the Man in Black with the exact same words as were once used to coerce Richard.

That's not the only case of history repeating. Let's look at the Claire/Rousseau dynamic. In the Season 4 finale when Kate and Co. left the island to return to the mainland they took Aaron with them and left his mother Claire behind. The last we saw of her she was hanging out in Jacob's cabin with her father Christian looking as if she were in some kind of trance. When we finally catch up with her in Season 6 she no longer resembles the sweet naive Claire we once knew. She's feral. She's crazy. For three years she's been led by the Man in Black to believe that her son is being held by the Others.

This is not the first time this has happened. People immediately drew comparisons to another mother whose child was taken from her as a baby and raised by another, Danielle Rousseau. Her child Alex was stolen by the others and kept under the reasoning that she was better off with Ben and the Others than with her birth mother. While this may have been true it doesn't explain why the Others left Danielle to live on her own constantly wondering where her child was. Flash forward to Season Six and a particularly revealing conversation between Kate and the Man in Black in which he states that he was once a man with a crazy mother and now Aaron has a crazy mother.

These can't be coincidences. They aren't merely literary parallels. They are purposeful ritual.

Someone is trying to repeat a pattern of circumstances in much the same way that the Oceanic Six had to in order to return to the island. The goal of which, I believe, is to open a door to wherever Man in Black's "home" is.

Why did the Others steal the children? It wasn't to vaccinate them. It was an order they received from who they thought was Jacob but was in fact the Man in Black. An order to create circumstances like his again (crazy mother etc.). One might even guess that if the goal is to go "home" perhaps the Man in Black is looking for someone to replace him. To become his substitute so he may leave. If the following episodes continue to repeat events, keep this theory in mind.