Alright, I've heard a few people mention that the alternate timeline began when Jacob was killed. I've been thinking about this and if that is true, then could the flash-sideways timeline be what would happen if Jacob never "pushed" anyone towards the island.
I mean, Jacob has aparently been doing this for a long time. Who's to say he didn't have an effect on poeple in the "Losties" lives before they were ever in the picture. What I'm getting at is, maybe Jacob met Lockes' father at some point in the past and set in motion him being pushed to the island. Perhaps, that is why he became a Con Man, causeing Sawyers parents to get into that argument, which caused Sawyer to need a pen to write that letter which is right where Jacob new he would be in the future.
The same with Locke. Jacob "pushed" his father, His father Coned him out of his kidney then literally pushed Locke out of a window. Where Jacob just so happens to be waiting to "push" Locke.
This can be explained with Christian as well. Jacob could have "pushed" him at some point in the past setting all of his life in motion towards the island. Christian pushed Jack to be as good as him which caused him to be a spinal surgeon at Christians hospital where Jacob was waiting on him after his first big surgery. Or even Christian having an affair which Claire was the result of giving him a reason to be in Australia where Jack had to pick his body up and they both eventually ended up on the island like Jacob planned.
In a nutshell, what if Jacob can be the cause of all the bad parental problems that the "Losties" have had. Which all results in him being able the find his chosen ones in vulnerable situations where he can easily manipulate or "push" them?
Does this make any sense? Or am I just rambling?