I judge a Lost episode's greatness based on how much I enjoyed the mythology in the episode. This week, there wasn't much... at least not until the end. I don't have a whole lot to talk about this week because I don't care much about Kate's story and that's about all we got this week. That being said, I did like the episode. Kate's story was well acted and edited. It didn't drag on too long and we now know why she was so torn up when she ended up at Jack's before the Ajira flight. We got to see Cassidy again this episode and the twist to that storyline was that Kate left Aaron with Claire's mom... not a huge shocker and it won't have a big impact on the overall plot.
It wasn't a BAD episode per se, but there wasn't much too interesting as far as the mythology of the show goes. We got some speculation on the rules of time travel from Miles and Hurley. Miles seemed to be the surrogate for the writers while Hurley was speculating on behalf of the viewers. The conversation let us know that the Losties can't change anything in the past because everything that they are going to do in 1977 has already happened, though they haven't experienced it themselves. That is to say they can't kill Ben because he grows up to be the Ben from season two. Ben doesn't know this of course because 1977 is Ben's past... he'll remember (theoretically) Sayid shooting him, Kate and Sawyer taking him to the Others and so on. But he can't die... the universe would course correct that, because Ben needs to be around in 2004.
We see Kate and Sawyer deliver Ben to Alpert at the end of the episode and it's here that Alpert indicates that Ben can be saved by the island, but if Richard helps Ben he'll never be the same again. Ben won't even remember "any of this" ...which was a vague way of telling us that Ben probably won't remember any of the Losties in 2004. It's possible Ben experiences amnesia and forgets the Losties all together, forgets he was shot and everything. It seems like a convenient way of making Ben forget the Losties, by just wiping his memories of 1974-1977... but this could be part of the whole course correcting thing Ms. Hawking talked about back in season three. We know Ben remembers the events of 1973 when he came to the island, met Annie and Richard... because he was still hanging on to that carved doll he got for his birthday. It's unclear if Richard or the island is going to actually wipe his memories or if he'll just forget that Sawyer and Kate helped him... It's intriguing either way.
At the end of the episode we get to see Ben and Locke back in, what we can assume, is the present. Ben wakes up and Locke welcomes him back to the land of the living. I think the next episode or two will focus on the events of 2007 and what Ben and Locke need to do to prevent or perpetuate the war coming to the island. I think we won't see any more of young Ben for a few episodes while Richard and the island wipe his memory. Perhaps we don't see young Ben again until he's actually old Ben... meaning that Ben is fixed up in 1977 and recuperates for a while but doesn't return to Dharma. It's during this time that he tricks Widmore and Ms. Hawking into leaving the island and he steals Alex from Rousseau in 1988. It's only after all of this takes place that he goes back to Dharma, claiming to remember nothing of being shot, only that the Others helped him and have let him return. It's unlikely that Dharma just lets him back into their ranks, so there must be something more to it...