Yin and Yang by kether

I believe that MIB and Jacob were once brothers that were polarized by their parents. Jacob sided with the mother, embodying all the classic aspects of feminine energy; emotional, each person should make their own choices, gentle suggestions as opposed to "the rule of Law" , etc. In doing this, Jacob demonized the father and turned against him (possibly even killing him). MIB sided with the father, imposing intense punishment for bad or wrong choices, and characterizing the emotional mother as "crazy". (possibly even killing her). As punishment they were banished to the island, with only each other as company, sentenced to remain until they could resolve their differences, using the people that were brought to the island to live and act out their process. They have been through over one hundred candidates so far without success. The ultimate goal is to heal the gap between masculine and feminine, yin and yang, po! sitive and negative.

What we are seeing in season six is each of our characters embodying a single aspect of identity, some more obvious than others. Clearly Sawyers issue was TRUTH, and Ben's was POWER. They couldn't have hit it over the head more times in each of those episodes. Sayid's had to do with LOVE/SACRIFICE, Jacks with REDEMPTION/FORGIVENESS (no longer needing to prove himself to his father, or to have his son prove himself to him), Kate's with PERSEVERANCE/COMMITMENT (as opposed to always running away). Perhaps Hurleys will have to do with LUCK (destiny), and the Kwons with FORGIVENESS (they do have some stuff to forgive each other for, right?) Each of the characters we have seen so far in the sideways has viewed themselves in the mirror, seeing these dueling aspects of themselves and making making a choice. I believe that they each made the healing choice in their sideways experience. When each of these issues becomes resolved, then Jacob and MIB can join forces to defeat the real e! nemy... who is somehow aligned with Widmore.

A few more notes. MIB sees the process as futile and unresolvable and just wants out. Jacob believes it can be done and wants to bring it all the way to conclusion with the final 6 candidates. MIB's physical body was destroyed some time ago when Jacob locked him in the cabin. Now that he has a body again he can try to get out. I believe that Jacob is looking for a body (or 6) to complete the task and do battle with the enemy that split them in two in the first place.