The spring, the rules, Jacob's touch and candidates by french_guy

I will make this theory short: with the information provided in "Across the sea", I think we have enough elements to link several key concepts of Lost, namely: the spring, the rules, Jacob's touch and candidates.

- Mother shares a glass from the spring (the same water that probably healed Ben at the temple) with Jacob, and tells him after he drank it "Now, we are one and the same". Thus, in some way, Jacob and Mother are linked in a unique way and are a single entity. I assume that this is what Mother did to Jacob and BIB (boy in black): she made them share a glass of the spring, and are actually one and the same, and this is why they cannot kill each other. Indeed, they are two sides of the same person now.

- When Jacob touches someone, he shares this gift that has been given to him by drinking the spring water, and thus he becomes one and the same with these people. Consequently, they cannot kill each other. This is the meaning of Jacob's touch: by touching potential candidates to his replacement, he ensures that they won't kill each other, e.g., by fighting for the source of power that this spring represents. Furthermore, these people that have been touched will be connected in some way to the island, and will be attracted to it at some point in their lives.

- Finally, we have the rules: people that shared the water of the spring or that have been touched by someone who had are one and the same, and cannot kill each other. This is why Jacob and MIB cannot kill each other, this is why the candidates cannot kill each other.

That's it, I hope that you will find this theory interesting :-)