Watch out, Brian!
Who is Jacob?
I haven't read this post by James McGrath 'cause it seemed a bit too spoilerish for me before the finale, but he speculates on the same question with respect to some recent casting news. We're no closer to this answer than we were at the beginning of the season. Really, we're no closer to it than we were in Season 3 when Jacob first appeared.
I do think that Locke is mistaken if he doesn't believe Jacob exists, however. Whether or not Ben has really ever seen or heard Jacob is up for grabs. Whether Ben believes he exists isn't. There's no other explanation for the scene where he turns the FDW and exclaims "I hope you're happy now, Jacob."
So, let's assume there really is a Jacob, and Ben and Richard really do believe in him. Who might it be? The fact that Claire and Christian congregate around him would seem to point toward Jack, or at least someone related to Jack, but I think it's more likely Jack will end up with Kate at the caves (see two days from now on Adam and Eve). Well, maybe it's not more likely, it would just make me happier. Other than Jack, I don't think there's a good candidate on the show right now. Possibly Locke: sending himself on a mission to kill himself would be very Lockian. He's already done it once!
I don't know how I feel about Jacob being someone we've never seen before. From one perspective, it makes perfect sense: the 815ers can't have been involved in absolutely everything we've seen so far. But from another perspective...of course they can! The show is demonstrating in Season 5 that they are the cause for many of the effects we saw in the first two seasons.
On the other hand, speculation since Jacob first appeared has assumed that it was one of the 815ers, without the benefit of the knowledge that the show would turn out to be about time travel. So, it'd almost be disappointing to find out that the fans were perceptive enough from the very beginning to figure out that Jacob was one of our own.
Next up: "I watched them all die."
What's on my mind?
Watch out, Brian!