After reading cos's theory on 2 energies I had my own idea. If Jacob is a manifestation of the energy found under the swan station, why does he seemingly live at the statue now?
My theory is that the statue is also a spot where this energy emanates, and that is why the statue was built there. Perhaps as the energy is "good", as in it heals, people of old built the statue there and worshipped its supposed powers.
Then it was destroyed at some point, perhaps this fits in with the fertility problems at the island.
The second part of my theory is that what lies beneath the shadow of the statue? Well its that positive electromagnetic energy isnt it. And if it can heal then maybe it will be the one who saves us all.
Ilana and her group ask this question to people who have been on the island before, (eg miles, frank, richard) because if they know about the energy then by extension they have been knowingly touched/healed by Jacob, then they would know the answer to that question. Richard knew it, maybe the energy caused his immortal life? Why they are doing this I don't know, maybe to keep track of how many people Jacob is touching/healing?
Well thats about it, kinda makes sense to me :) god i love this show haha