I've spent a lot of time trying to write drafts for a theory, and while I love Lost I'm not expert with the Wiki stuff, and pretty soon it won't matter what I think so I figured I'd lay out some thoughts I have about everything that is going on.
I believe that the MIB is a genie, or I suppose more correctly a djinn, and Jacob was his master. I first read the idea here on there on the site, and ever since then have thought about it when watching Lost. The master/slave relationship is explained by this, as is much of the strange yet strangely limited power that floats around. Similarly, a set of "rules" would govern a master/djinn relationship, though obviously the "rules" aren't particularly clear at this point. Much of what we know about Jacob and MIB's conflict can be explained through this relationship, however there are still a lot of holes when it comes to the Losties, the Others, and certain aspects of the island. Here's my best attempt at putting my thoughts together.
So far I think most people are assuming that the MIB's name has not been revealed because his name has some sort of significance that the viewer would understand. I posit that the MIB actually has no name. In his realm of existence as a djinn, names have no meaning. As a completely separate being from that of a human, he has no name, he has no use for a name, he is simply what he is. MIB refers to Jacob by name, but Jacob never does the same. This could still be a deliberate hiding of MIB's identity but it does seem likely that this djinn has no name. Since Jacob is in fact a human, albeit a powerful one but still a human, he describes the MIB as just that; a man wearing black clothes. This would mean that Jacob is the master. Through his "wishes" he has gained some sort of limited immortality, though we have seen that he is nothing more than ageless flesh and blood. I'm willing to bet that him and Richard share the same type of "immortality." It is possible that the djinn's powers are limited to some degree, which is why Jacob can in fact (and does) die. So, Jacob gets this ability from MIB, and either because of the powers bestowed by MIB, or because of his master status with MIB, he is able to pass this ability on to others.
If MIB is a djinn and Jacob is his master, then obviously there's some backstory between them. Of course anything of that nature is of of the utmost speculation, I've thought up a plausible explanation based on what little we know about Jacob and our narrow view of some sort of philosophy he has. We've all seen the ruins on the island, so presumably something was happening in this spot long before the Black Rock ever came. We also know that this "game" has been going on long before 1867 as well. Now there's a couple of possibilities at this point; it really depends on what the island actually is. There may be enough clues out there to point to one being more plausible than the other, but I don't care to dig that deep at the moment.
- Jacob was part of an ancient civilation, the same civilization that built the statue and what we later see scattered on the island as ruins. He was a normal human for the time period and somehow stumbled across a "lamp" where he found the djinn. Perhaps some personal event in Jacob's life (much like we saw with Richard) caused him to become disillusioned with reality. Maybe there was a lot of war, or anything big or small really, that made him want to really explore human nature. Jacob wants to be able to create a world where people are inherently good because it's the right thing to do, and he uses the MIB's power to carry out this experiment again, and again, and again always failing. This "game" has continued right up until and beyond Jacob's death with our current group. This explanation ties together the ruins with everything, but my next possibility actually seems to make more sense to me.
- The island itself is the lamp. This theory is more in line with the island's strange properties; the EM pockets, the time descrepancies, etc. could all be a result of how this mystical "lamp" exists in the natural world via somewhat scientific means. Of course there's also the possibility that Jacob used MIB's powers to construct this strange world so that the outside world couldn't interfere without his assistance; there's really no way to know at this point and nothing about any of the "weirdness" would neatly explain the ruins of what was probably some sort of established civilization at one point in time. But the island being the lamp itself would very nicely wrap up the whole cork-in-the-bottle thing and MIB's desparation to leave the confines of his lamp and exercise his malevolent freedom in the "real world." The wine bottle analogy coupled with MIB being his most violent and menacing in his smoke form quite beautifully illustrates the whole whispy, smokey, genie-in-a-bottle kind of thing. Then of course this all means that all of the events of the island are actually taking place inside the djinn's "lamp" which really doesn't make much sense if Jacob is the MIB's master. So there's a lot of ways it could go, each possibility explaining some aspects quite well but making little to no sense in other areas. There's then the possibility that the island is some sort of combination of the two, but a combination of the djinn's container and a construct of Jacob's doesn't make any sense at all. What does seem clear is that even though Jacob is the master, and even if the island is essentially the djinn's domain, both of them weild a great deal of power over the island and there are "rules" to keep them at an uneasy peace with each other.
But we all see that the peace does not last, so then we get to why is there a conflict between djinn and master. Being the evil thing that the MIB is, he wants nothing more than to be free from his confines. Through Jacob's cleverness with his "wishes," the MIB has been in his service for a very long time directly or indirectly facilitating Jacob's ability to "bring people" to the island. Since the MIB is evil and likely considers himself superior to humans, he grows bored with watching Jacob's "test of human goodness" (for lack of better term) fail time and time again. He wants to stop serving Jacob, but because of the master/djinn relationship he must find his loophole. All the MIB needs to do is simply convince someone to kill Jacob, but over time it likely becomes clear to the MIB that it is quite difficult to convince a human to kill another human, and thus reinforcing Jacob's notion of inherent goodness despite whatever carnage has continually taken place on the island. Of course the MIB finally succeeded.
Jacob, clever fellow that he is, either knew this would happen, or perhaps realized that he would possibly tire of living and doing this work century after century and would one day actually want to die, or maybe a little bit of both. Because of this he used his powers to groom people over time to become his replacement based on their actions on the island. Though he himself doesn't want to or simply can't carry on forever, he does want this project of his to live on and he also wants to keep the djinn sealed off from the rest of the world. Therefore he has to be extremely meticulous in his replacement, and that's much of what we've been seeing in our snippet of the "game." If the MIB can circumvent the rules and prevent Jacob's replacement from somehow officially taking Jacob's seat as the master of the djinn, then he will no longer be bound by his rules of servitude and can ultimately take over the human world, which to my understanding is what the race of djinn ultimately strive to do.
Although there are some holes and inexplicables in there, I believe a lot of that framework could be much of what the Jacob/MIB/island mystery is all about. Getting down to the particulars of the candidates, the time travel, Widmore, the non-candidates, Desmond, healing, pregnancy issues, whispering ghosts, and the big ol' FST is a lot trickier.
Given that The Exit is in Tunisia, and the ruins and statue appear to be Egyptian in nature (at least to a casual viewer), and Tunisia's relative proximity to Egypt considering the size of the world, there is some link here but I can't exactly connect it with all the djinn/lamp stuff. The connection might somehow be incidental to Jacob and the MIB's centuries-long stalemate and not necessarily integral to their conflict. However, I still can't quite put it all together.
Though Widmore likely understands the nature of Jacob and the MIB, it's unclear what his motives are. Most of what we know of Widmore is via Ben who has always been a liar and while it would seem the island has always been his top priority, his diminished role as the stakes are continually raised seems to suggest he didn't know quite as much about the island as he claimed to, or as he thought he did. Then again, maybe he knows exactly what he needs to know; that the island is a vessel for a malevolent mystical being that needs to be contained at all costs. Then we have the Ben/Widmore conflict. Being that the show is as close to the end as it is, my best guess is that as some sort of self serving capitalist Widmore wants to capture and control the djinn for himself. He likely tried to assume the role of Jacob's replacement during his time on the island, but due to his selfish motives went about trying to harness the djinn in ways that led to his eventual banishment. Or something along those. Either Ben in is an idiot, or he somehow realizes how terrible the djinn actually is which is why he is willing to do any and everything no matter who gets hurt in order to keep the island from being found. The two problems are a) what effect did the pool have on Ben, and b) I am doubtful that Ben ever knew any more than Richard and we've seen that Richard didn't know that much, and I believe it's safe to assume that at this point the audience knows as much as Richard knows about the island/Jacob/MIB.
The Candidates: What makes a candidate? Why have people who aren't dead been crossed off the list? There's got to be a connection between certain character's actions leading to them being crossed off the list, and the whispers of those who "can't move on" because of "what they've done" as well as MIB's "judgment" of folks like Eko and Ben. My best guess is that Jacob has outlined a sort of right and wrong criteria for the island since it seems his purpose is for people to "be good" of their own accord. Perhaps as part of his experiment Jacob permits the MIB to kill those who have broken a certain number of these rules and are thus no longer candidates. Or, conversely, this could be some kind of arrangment that the MIB has with Jacob in exchange for the power Jacob has been granted. It's a little hard to say who's got the ultimate say-so when it comes to death, but this right-and-wrong arguably forms "the rules;" we just don't know if these are Jacob's rules, the rules of the lamp/island, or the rules that come in to play when dealing with the vast power of a djinn.
One of the hardest pieces of the story to fit into this man-with-a-moral-agenda-got-ahold-of-a-djinn theory is all the time travel stuff. It just doesn't fit with anything, and perhaps my inability to see the connection rests with my personal dislike of all the time travel; it was a strange direction to take and in my opinion nothing but a flimsy way to explore the rather boring time period of the DHARMA Initiative. There is the interesting matter that only certain people seemed to be traveling through time, presumably the candidates but why? Miles, Daniel, Charlotte, Kate, and Juliet weren't among those that were not crossed out when we saw the Lighthouse/Cave, but it's certainly possible that at the time they were all candidates as well, when we've at least seen "Burke" and "Austen" crossed out later. While that could all be explained, I doubt that's something that will be addressed in the last 3 episodes, assuming any of the time travel stuff is touched on at all which seems slim to none. Even so, it doesn't seem to serve any purpose. We also have the issue of Jin going back in time but not Sun which is strange as well. This could mean that Jin was the candidate and not Sun, though their deaths in the sub would seem to suggest the opposite. They could of course been a candidate as a pair, since throughout the show they have essentially functioned as two halves of a whole. Any way you cut it, it still doesn't all fit together.
The last, and probably most important question at this point in the game is "what the hell is the FST and what does it have to do with anything happening on the island?" Clearly the fracture point is when the bomb went off in "The Incident." Perhaps it isn't as cut and dry as it seems on the surface, but to explain the FST as something totally different AND addressing the consequences of Jughead's (probable) detonation would be an unnecessary inconvenience this late in the game. Though the island/lamp is strange and mystical, it still has a physical existence. Jacob has been acting as a guardian for centuries and while he may be quite well versed in human nature it's possible he nor the djinn understand anything about nuclear energy. When the bomb blows up, it destroys everything, including the MIB. We know that the MIB has some vunerabilities such as when it releases Locke after getting hit with some dynamite, the inability to cross ash circles and sonic fences, and MIB-as-Locke's at least somewhat apparent fear of Widmore's mortar attacks. It's not implausible to suspect that some kind of human creation might be able to seriously injure or destroy him, and what would be more fitting than a nuclear bomb? Ethan, Ben, Roger, etc. evacuated and in 1977 Jacob and MIB were both destroyed. It can be assumed that Jacob perhaps visited some of the candidates prior to 1977 (perhaps Sawyer, Kate) but his "touch," their "candidacy" doesn't mean squat since there is no island, no Jacob, or no MIB after 1977. The small changes in everyone's lives can be attributed to the butterfly effect. Even without Jacob's direct influence, he affected so many people who affected other people who affected other people that between 1977 and 2004 these small changes had led to sometimes significant soemtimes insignificate changes in the lives of our Losties, who remain pretty much the same. Except Ben. I haven't figured that one out. Now why is there an actual fracture in the timeline? Why aren't Jack, Kate, Sawyer, et al. killed by the bomb but instead hurtled through time? I have no idea. What is Desmond's power? Why does it even matter? These are things I don't at all get but if the island posesses enough power to selectively skip people through time, then this same mechanism (or the MIB's great power) may be manipulation of the "what ifs." Of course nuclear bombs don't cause time travel and timeline splits, so there's definitely something else going on here, likely to do with the strange nature of the island itself. How it all ties together is a bit beyond me at this point, because we just don't know enough about what the FST actually is.
Now, if we look at the Incident as something a little bit different, there's another explanation for the FST but like many of these theories I feel like it's probably a bit "out there" considering the time we have left. Much of this stems from other theories of read. So if I'm using your idea, thank you, I'm not trying to steal any credit! The bomb doesn't go off. Instead, via course correction, or Eloise turning the wheel, or all the EM radiation at the future swan, our Losties are simply sent back to 2007. The bomb never goes off and the DI plays out just like we all know. At the end of this current war on the island, someone emerges as the MIB's master, presumably Jack or Widmore. Widmore, likely knowing more about this situation than we do, or Jack trying to fulfill his destiny, may either wish that the bomb actually went off. Perhaps the MIB is in fact indestructible, but the nuke destroys his container, and his master (Jacob) allowing him to be free. Although I don't think an island can really "sink" the detonation of the bomb seems the most likely cause for everything being underwater. So the djinn grants this wish, thus negating everything we've seen from 1977 onward, as well as freeing the MIB. Desmond is in fact doing his little time travel thingy when switching between OT and FST. In the FST, the MIB is free and he is exercising his evil in more subtle ways. Desmond is realizing that he lived an entirely differently life before the FST, and those in love in the OT are having a memory of that love that transcends the MIB's artificial reality. Desmond is in some way trying to get everyone in the FST to "wake up" and transfer their conciousness to the 2007 OT past in order to not make this "wish." Since WHH doesn't apply to Desmond, he knows he actually has a chance at changing the future/past however you want to look at it. It's a little twisted and doesn't exactly tie it all up but eh. The FST is a really hard to thing to figure out at the moment.
There are a few questions I can't answer, such as:
Who the hell are the Others and what was the meaning and process behind their selection of people to capture?
Why did MIB choose Locke's form to be "stuck" in? He clearly didn't use this ability to fool anyone.
What happened to Claire, and why was she, presumably, not involved in the time jumps? We're pretty sure she was with the MIB, so was he the reason she didn't skip through time? If so, what is/was the extent of his involvement and control of all the time travel? And if the MIB can somehow manipulate time, does this ability extend into the FST to any degree?
The comment about Jacob taking MIB's body is very perplexing. Although it could be something as simple as Jacob wanted to look like the djinn instead of whatever he looked like at the time, that would be a totally random thing to throw in. This suggests that both MIB and Jacob have some sort of ability to take different forms, and if the MIB actually had a body at one point then much of my theory of completely nihl.
I have no idea why a woman couldn't both conceive and deliver on the island. Completely beyond me. And even though Aaron and Ji Yeong were miracles or at least seemingly important in the context of the island, they have faded into the shadows much like Libby, the Blast Door Map, and Walt's super powers.
Whew, that was a lot, and I'm sure it makes less and less sense as it goes on. The more I think about how much I actually wrote and how many gaps I poorly and simply couldn't fill in, I'm not quite as convinced as I was when I started out. But man, had to get that out before the end!