This was an awesome episode! It explained so much! But I think I need to watch this episode again to get all the details and take everything in!
I can’t believe we still don’t have MIB’s name, hopefully we’ll get it soon!

The flashbacks made him an even bigger jerk in my mind. We now know that almost everything he told Richard was an outright lie. And regardless of what the MiB did, Jacob drew first blood. He's the one who resorted to violence during each conflict with the MiB and he murdered his own brother. He and the Psycho!Fake!Mommy (as QKate dubbed her) pretty much insured the MiB would go bad. All of this on top of the fact that he freely admitted that he's been bringing people to the Island for thousands of years to fight and suffer and die, all so he could prove a philosophical point to his brother.

They might as well call him that, the whole man with no name thing is getting annoying. Anyway, after they had him bring about the deaths of Sun, Jin, Sayid, and Lapidus just to finally convince people he was evil, they sure did a poor job of showing us why. Honestly, I felt sorrier for him than I did Jacob. Jacob was a whiny little mommy's boy, the MiB was the interesting twin. Even when he stabbed the Psycho!Fake!Mommy, I didn't feel like he'd done anything particularly awful. The woman bashed a woman's head in with a rock and murdered an entire village; someone needed to take her out.

Honestly, if they had sprung this asinine bit of writing on us in the first season, I would have quit watching right there. I love the fantasy genre, but this just took the cheese factor way too high. Also, if that thing is the source of life or whatever, why'd the Island sinking not obliterate humanity?

So now we know the Island's reason for existence has nothing to do with imprisoning the EVUL MiB. It's just ... there. Oh, and God is apparently a cave on the Island. That's random.

Considering she has no name, I figure that title is as good as anything else. So I'm guessing she's apart of some type of long chain of people who guarded the Island. Okay, that's kinda interesting, but why does she have superpowers? Who started these people? Why'd she slaughter everyone in sight? How did she kill those villagers if she isn't a smoky? Will we get answers to any of this? Probably not.

Okay, this actually makes sense. Latin was Jacob's first language, he set up the Others, thus they view Latin as some kind of sacred language since their god gave it to them. See, Lost writers, this is what a good answer looks like.

This episode basically took all of the elaborate theories people had built up and knocked them down in favor of two kids squabbling on the playground. There's no greater meaning to anything. Jacob just brings people to the Island because he's a sick twisted freak and the MiB kills them because he hates his brother, hatred that's just a bit deserved.

The time period is several thousand years ago.
A woman wearing an ancient red dress surfaces in the ocean, amidst the wreckage of a ship. It seems she was on a ship but then a storm hit. The woman washes onto the shore of the Island. We discover she's heavily pregnant. Her arrival on the Island draws parallels to both Rousseau's and Claire's arrivals (there are many more mirrorings to these two women throughout the episode). The wounded woman meets another woman inland and they talk in Latin. The wild woman is something of a hermit; she live alone on the Island. She nurses her back to health. We discover that the woman in the red dress is named Claudia (she may be of Roman descent). The wild woman helps to deliver her baby. Claudia names the baby Jacob. She expects only one baby but another arrives. Both are boys, twins. The unknown baby doesn't receive a name. Jacob is a large, healthy looking baby, wrapped in white cloth, while No-Name is a smaller baby, who struggles in black cloth. Subtle. The fact that Jacob is given a name and No-Name doesn't, is significant. Names have power, so Jacob has the advantage over his brother simply because he has a name. No-Name on the other-hand, has no name to identify him; he's a lost soul.
The wild woman kills Claudia and raises the babies as her own. My thoughts are that she has been in the jungle for so long, that it's made her very lonely and jealous of Claudia. She probably kills the boys' mother because she wants to mould the boy into ways she sees fit.

Some years pass and No-Name grows up to become a teenager (from now on we'll call him BIB - Boy In Black). BIB finds a game in the sand. The counters are black and white stones. Very familiar-looking. The game is an ancient Egyptian game called Senet. Jacob plays the game with the BIB. The BIB doesn't want Mother to know about the game, Jacob promises he won't tell her. Back home, Mother weaves a tapestry not unlike Jacob's in The Incident (but with a more simple design). Jacobs seems naive and can't lie, so Mother eventually finds out about the game and goes off to talke to the BIB. We notice that Mother appears to favour the BIB over Jacob, perhaps because he shares similar traits to her. She calls him 'special' and announces that she left the game for him to discover, but is she telling the truth? The BIB wishes to know what's 'across the sea'. He hopes for a mysterious, unknown homeland. Mother convinces him that the Island is all that exists. She reassures him that he will never have to worry about death. Wow.

The boys go boar-hunting and chase the boar through tall grasses. This brings to mind the scene in Sundown, in which Sun is chased by the MIB and also the scene in the Pilot, where a polar bear charges Sawyer. But some hunters beat the boys to their catch. The brothers run to tell Mother. She tells the boys that the other people shouldn't be on the Island and that only they belong and are 'here for a reason'. Mother then blindfolds them and leads them through the jungle. She tells the boys that people 'come, they fight, they destroy, they corrupt, and it always ends the same.' This speech is repeated by the MIB in The Incident (but as JOpiniated points out) Jacob adds, 'it only ends once. Anything that happens before that is just progress.' It seems he's found a way to end the game. Mother tells 'her' boys that she's made it, so they can never hurt each other. Wow. So she's the one responsible for their (almost) immortality?
They arrive at a stream, leading to a cavern lit with a brilliant golden white light. Is this the 'beautiful light' Locke saw back in Season 1? Possibly. Mother tells the boys that there is light in the cave and that they are to protect it and prevent other from discovering it and trying to possess it. She tells them, 'there is some of this very same light in every man, but they always want more.' If people try to take the light, it will go out; everywhere. This is similar to what we've been told about the Island (if Smokey leaves the Island, everything will cease to exist or go to hell). The cavern of light brings to my mind Greek myths and the biblical story involving the Tree of the Knowledge of Good and Evil. Is the warm light responsible for the healing pool in the Temple and the seemingly supernatural powers of the Island? I certainly believe it's possible.

Jacob and his brother play another game of Senet on the beach. Jacob isn't happy with the rules that the BIB has created and complains. The BIB replies, 'one day you can make up your own game and everyone else will have to follow your rules.' I think Jacob took this idea to hear, and then some. The BIB sees a ghost of their real mother, Claudia, but Jacob doesn't see anything. Claudia takes the BIB to see his people (the survivors of the the ship-wreck) on the other side of the Island. These people have created their own villages and made the Island their home. Claudia tells him that he longs to go 'across the sea' because that is where he came from and Mother killed her and that she is their real mother. During the night, the BIB wakes his brother and leads him to their peoples' camp, to live with them. He explains to Jacob that Mother lied about everything. Jacob snaps and beats up his brother, but Mother arrives in time. The BIB leaves them, he just wants to go home.

Jacob and his Mother are all that remain of their twisted 'family'. She reveals to him that she killed their mother because she didn't want them to become corrupt like their people. She has a very low opinion of people, shared by her 'son' - the MIB later on. But how is she any different? She kills people in cold-blood!

Many years pass and Jacob is now a 40 year old, still living with Mother. Jacob spies on his people from afar. They are constructing a well. He meets his brother to play more games of Senet. The MIB explains to Jacob that he doesn't think much of their people and that they're just a means to getting him off the Island. He tells Jacob that he's found a way off and talks about places on the island where 'metal behaves strangely' (obviously the same pockets of electromagnetic energy referred to in previous episodes). He throws his Roman dagger to prove his point. It curves in mid-air and strikes the wall of the well. The dagger is heavily-magnetised. The dagger is not unlike the one found in the episodes, Sundown and Ab Aeterno. Jacob wishes to stay on the Island but the MIB wants to leave. Mother spies on the workers.

Below the well, the MIB stokes a live brazier. Mother talks to him and he tells her that he's been searching for 'her' light cave all his life but hasn't found it. He worked with others to locate the light in other areas on the Island. We discover the MIB created the Frozen Donkey Wheel (but at this stage it's not frozen) and others are creating the mechanism to link it too. They have constructed a wall, beyond which is the beautiful light and water. The Wheel channels the light and water, so he when he turns it, he can leave the Island (I'm not sure how this works - it seems more mysticism than science but I'm okay with that). Mother says her goodbyes and smashes the MIB's head against the wall. She clearly doesn't want anyone to possess the light. Not even 'her' favourite son.

Mother wakes Jacob and leads him to the cavern of light. She wants him to protect it, now that his brother has gone. She explains further that the light is 'life, death, rebirth - the source, the heart of the Island.' She doesn't want Jacob to ever enter the cave because doing so would be worse than death. Mother produces a familiar looking bottle of spirits (from Ab Aeterno). She pours him a drink, chants and then hands it to him, explaining that this signifies him taking responsibility for protecting the light and the Island from others. Also, that he finds a suitable replacement when the time comes. Jacob is pained with the decision. He doesn't want anything to do with it. He also knows he isn't her favourite. But he drinks the spirits. She tells him that now, 'you and I are one and the same.' What does she mean? Protectors of the Island?

The MIB regains consciousness and finds the well and his village destroyed. His people have been murdered. Wow. One woman did all this? Maybe Mother is Smokey? The MIB destroys her tapestry loom and stabs her with his dagger. As she dies, he asks her why she didn't let him leave the Island. She replies that it was because she loves him. What? Is Mother the physical embodiment of the Island? Creepy. Jacob finds his Mother dead and his brother standing over her body. He beats up the MIB, again, then takes him to the cave with the light (I find it curious that only Jacob and Mother can locate it - maybe only the protector can find it easily?) Jacob hurls the MIB into the stream, where his body floats away, enters the cavern of light and is sucked down a waterfall. We hear a familiar tika-tika sound - Smokey! The smoke monster shoots out of the cave, swallowing the light as it comes. I presume that means the MIB became Smokey but how? My theory is that the cavern houses a huge amount of pure electromagnetic energy and that coming into contact with that energy, destroys the average person. The MIB and Jacob are essentially immortals now. So instead of destroying him entirely, the light strips the MIB to his darkened soul, which is in this case a formless pillar of smoke. I believe that in the final episodes, we may see Desmond enter that light beyond the waterfall, survive (he's resistant to large amounts of electromagnetic energy), and do something there to send the Island to the bottom of the sea.

Jacob finds his brother's body washed up on some rocks. He takes his body and Mother's and lays them to rest in a cave, with the black and white stones from the Senet game. Perhaps they're there to act as a reminder to him. We discover the bodies are Adam and Eve, the bodies found by Jack, Kate and Locke back in Season 1.

The Tawaret statue is a mother goddess figure with two ankhs (symbolising eternal life). Traditionally Tawaret had no ankhs, let alone two of them. Could the statue have been created by people who came to the Island viewing Jacob as a god etc? They possibly heard about Mother and constructed the statue. It's not a stretch then, to say that the two ankhs of eternal life represent the warring twins - Jacob and the MIB.

Think back to Ab Aeterno. Jacob sits down with Richard and explains that the Island is like a cork that plugs the bottle, preventing the wine (representing darkness etc.) from escaping into the world. Judging by what we learnt in Across the Sea, it sounds to me like he's lying to get some help. We now know a different side of the story (I don't know if it's the correct one though). Smokey is like the cork plugging the bottle. If Smokey (represented by the wine) leaves the Island, the Source (light, heart of the Island - whatever) escapes and the everything ceases to exist. So when Jacob gives the MIB the same bottle of wine to 'pass the time', he's rubbing the MIB's face in his own imprisonment on the Island. That's why the MIB smashes the bottle. Not just in anger but to symbolise his desire to go 'across the sea', to leave the Island.

Also, the parallels between Mother and Rousseau and Claire are uncanny. Raised by Another. In Mother's case it led to great problems, with Rousseau, Ben became Alex's 'father', with Claire, Aaron was raised by Kate. All were raised by people who were crazy or disturbed to some extent and all suffered for that in various ways. The MIB was considered 'special' because he was going to be the candidate to protect the heart of the Island. Walt and Aaron were considered special, maybe they were possible candidates too?

There are so many parallels/mirrorings between this episode and the many we've seen. There's so much to explore. I understand if some people didn't enjoy the episode but I think it's vital to understanding much of what we've previously seen. I think we'll see a return to some of the science aspects of the series before it ends. But I don't expect the answer will be either Free Will of Destiny or Faith or Science but instead, a balance of the two.