I have really been getting into all of the Bible symbolism... and after the last episode, I thought of this....
In the Bible, Jacob had a TWIN brother named Esau, right??? Jacob & Esau were rivals.
So, isn't it possible that Fake Locke isn't fake at all, but John Locke's actual twin brother? If he grew up in foster homes his whole life, wouldn't it make sense? Because how would he know if he had a twin?
I don't know how or why... but I have this sneaking suspicion that the real Jacob may end up being dead John Locke. Just because the "they aren't who they seem" theme seems to be running rampant right now.... also Frank L. says something to the effect of 'good usually turns out to be bad'.
FLocke = smoke monster or spirit of evil (whoever that may be) Dead Locke = good spirit dead (bad spirits rival).
but then who was the Jacob WE saw in the Temple?
its probably completely wrong. I always have some crazy theory... but I was right about the finale ending "mid-bomb"... so who knows.