What is Jacob trying to prove? The real conflict behind the Jacob and MIB storyline by TheShadowKnows

Over the past few episodes, the MIB has seemed to be less of a villain and more of a victim. Granted, he slaughtered a bunch of people at the Temple and killed the Pilot, but overall he doesn't seem too different from Jacob, especially in the nature of the choices that they both offer. The main difference between the two seems to be a) MIB judges people and b) MIB is more open and honest while Jacob is more secretive.

What we've learned from both sides is that the MIB is a prisoner on the island. The MIB, assuming he is truthful, seems to be more of a victim however - Jacob took his body, and now he is imprisoned. Was he really evil before his body was taken? Why is he imprisoned here now... surely he hasn't been imprisoned here eternally?

Here's what I think is going on: MIB isn't being imprisoned on the island because he is "evil incarnate," but rather because he CONTAINS "evil incarnate." Or, in other words, MIB is being quarantined. I thought about this when I noticed the similarity between Jacob's words to Richard in Ab Aeterno and Dogen's earlier words to Jack about why Sayid must die. Jacob said that the island was a cork holding back evil, and that if the bottle was opened evil would "spread." Dogen said Sayid had to be killed so that his Illness would not "spread." The Illness twists people and makes them evil.

So what is Jacob trying to prove by bringing folks to the island again and again to show that humanity is "good"? Well, the problem with the MIB leaving the island would be that evil would spread throughout humanity like a disease. The MIB is arguing that he should be allowed to leave the island because man is ALREADY inherently evil, so the Illness will not change things. Jacob is trying to prove that there is still good in the world and in man - good that will "cease to exist" if the Illness escapes the island and spreads. In short, it isn't the smoke monster per se that poses a threat to the outside world - it is the Illness he bears.

The Light and Dark, then, are not Jacob and the MIB, but are the Island (a place where miracles and healing happen, i.e. a force of good and healing) and the Illness (the disease that is a force of sickness and evil). Jacob just happens to be bearing the power of the Island as its protector, while the MIB bears the power of the Illness as the Infected.

How did MIB get infected? Perhaps his mother infected him. His mother, after all, like Claire, was a crazy woman, and so he had a bad childhood - maybe he got the Illness from her.