Even though we still don’t know his name, we now know much more about the man in black-cum-smoke monster, AKA Jacob’s brother. And, after getting some insight into Jacob and his unnamed brother’s past, the lines between good and evil—which once seemed almost too clearly drawn—have become much murkier.
The brothers come to the island still unborn, after a shipwreck causes their mother, Claudia, to wash up on the beach. We think she’s found a friend in the lone island dweller (played by Allison Janney), but it turns out island lady is violent. After delivering the twin boys, Jacob and “I didn’t pick out any other names,” she murders Claudia and raises the boys as her own.
As they get older, it’s clear that the boys are different. Jacob, always dressed in light clothing, is faithful to his mother, who says that he is unable to tell a lie. His brother, with dark hair and dark clothes, is different, “special.” And, it turns out, defiant and stubborn.
The twins’ dead mother comes to talk to the man in black and takes him to the other side of the island, where an entire world he never knew about exists. There are people living there, and Claudia explains to him where he came from and who she is, breaking his trust and fueling his desire to leave the island. Jacob can’t see her, and we don’t know why. But maybe she doesn’t want him to see her because she knows he won’t believe her or won’t leave his mother to live with these others, like his brother decides to do.
Angry with the mother who lied to him and manipulated him, the man in black moves to the other side of the island and begins his search for an escape from the island. And although Jacob stays behind, there is a sense of bitterness against his mother. They are both hurt and both doing what they feel they must, but not necessarily because they want to. It seems that neither is inherently good or evil.
Allison Janney plays the alone-on-the-island-too-long bit well, and it was difficult to tell whether she was insane or doing a truly important job. She was definitely manipulative, though, and may have passed that trait down to her sons—or maybe just Jacob. Throughout the boys’ lives, she keeps them in her grasp with a web of lies, starting with her being their mother. And when she finally takes Jacob to the source of the gold, glowing light and makes him take on the role of protector, she seals his fate somehow. After Jacob drinks the wine, his mother says, “Now you and I are the same,” which may imply that he inherited some of her less-flattering qualities.
That is the most important thing we learned from “Across the Sea:” that (hopefully) Lost won’t end with everything tied up in the neat good vs. evil bow the show’s been hinting at all season.

With just less than two weeks to go, there are still so many questions we have for this show that we love so much. "Across the Sea" gave some good answers – I thought the Adam & Eve and creation of the monster were interesting and good, but as a whole, the episodes this season have failed to tie everything together. Last night was no exception. There is so much left to explain, and so many loose ends to tie up- how are they going to give us all these answers in just 2 episodes? I’m starting to get very, very nervous- http://thesmogger.com/2010/05/11/looking-at-lost-summarizing-the-mysteries/
kristen, thought you might find this interesting... there is a lot of references to egyptian mythology in LOST (like the giant statue of taweret, the egyptian goddess of birth and rebirth) and while i am here at work being bored, i started researching the mythology of twins. after the shock of claudia being murdered by crazy island lady, diana said something that made me think.. she said in some cultures, twins are thought of as some kind of freak occurrence.. and sometimes the second born or the mother is killed (as to not produce more freaks of nature) anyway... i started thinking about how everyone that is talking about jacob and mib keep saying how they are brothers... but they are not only brothers!! TWINS! and look what i found...
"Twins can also be rivals. Egyptian mythology explores this aspect of twinship in the stories about the gods Osiris and Set, twin sons of Nut and Geb. Set was so determined to be born first that he tore his way out of his mother's womb before he was fully formed. He hated his brother Osiris and eventually killed him. In the mythology of ancient Persia, some accounts of Ahriman, the spirit of evil, say that he too was a twin who forced his way out of the womb so that he could be born first. Ahriman and his twin and enemy Ahura Mazda, the spirit of good, are symbols of opposing moral forces in a dualistic universe."
talks of rivals, the first twin killing the other, dualistic universes... sounds awfully familiar...
I am a little confused after this episode. I recently read this quote from exec producer Carlton Cuse referring to unLocke, "There is no ambiguity. He is evil and he has to be stopped."
However, I agree with you. Last night's episode did not really show a clear good (Jacob) and evil (unLocke).
Why are you assuming that the black monster is still Jacob's brother? Jacob's brother is dead.
The smoke monster _is_ evil and has taken the man in black's shape, just as it has taken Locke's shape. Don't confuse the appearance with what is behind it!
The real question is, what harm did Jacob do sending in his brother's body and releasing the smoke monster?
It is interesting that just as the smoke monster isn't really Locke, it was also never really Jacob's brother, as evidence by Jacob putting his brother and mother's bodies in the cave and it staying there until Jack finds it. It was just released and took his form. (Which is basically all we learned from this episode -- but I guess I'm still pissed they killed half of the originals left last episode, and didn't really want to go back to those left standing.)