I thought the story of Jacob and his brother was as 'facilitators' - they had transcended their humanity and become the forces that cause introspection and change in the environment they were in. The way I saw it was that Jacob and his brother (who was unnamed because he was his shadow) were symbols for the job of those who help people in the Bardo (or place in between states) deal with their 'stuff'. At some point the facilitators (angel/demons) transcend their jobs and some will take it on- like Locke and Ben, who were in 'training' to be the next Jacob/Bocaj. (I just named him, lol). At some point the facilitators themselves moved on, before the survivors themselves, which was symbolized by the drinking of the river water (or lake water).

What the island itself symbolizes I think has to do with being a fluid environment- the 'heart' of the island could have been a symbol for energy- that shapes itself depending on what you're there for, and the fact that it can move through time and space (but not easily) I think has to do with the 'fact' that it's a collective environment, so it has some permanence.

@Yama, what I thought about the Dharma Initiative is that since most of the people that believe in this sort of 'place' or 'afterlife belief' is of eastern religious culture, the island itself had been initially 'shaped' with the types of beliefs the people created about it, hence the name 'Dharma', (wheel of life). I think it became the 'Dharma Initiative' when these concepts of the afterlife became more popular and universal after the 60s, and that's why most of the 'others' had that hippie 'flavor', yet their 'leader' was Dr. Chang. I wonder if Chang is Han or Tibetan- but that to me was a tipoff for the whole Bardo idea.

I think the scientific orientation had to do with how us westerners are putting our scientific interest in such formerly religious landscapes and ideas, so that the 'time/space' nexus becomes a scientific research project. And since everything is energy....

Just my interpretation, obviously.