I’ve been trying to piece together some stuff from the show, and figure out just exactly why the light in the cave was of such importance. I don’t know if this has been brought up already or not, so if it has i apologise. I’m not even sure if this is obvious or a really stupid idea, but after that finale, we don’t have too much to go on.
I think the reason that light in the cave was so important was because it was what kept the afterlife in existence. Maybe when it was stated several times that if MIB got his way ‘everyone you love would be gone’, it didn’t mean they would physically die. As we heard Christian say, some people died before Jack, some long after, but they were all there. In this afterlife there is no now, so it could mean you’re able to spend eternity with everyone you ever loved, even people that aren’t dead yet, everyone you want to be with is there, thats a beautiful concept.
this makes me think of some of the promises that Jacob made to people, such as telling Dogen he could be with his son again, i guess he wasn’t lying. Now think if that light is what i think it is, and by it being put out this afterlife ceases to exist, everyone you love will be gone. Those are pretty high stakes, and to me adds deeper meaning to the light, why it needs to be protected and why they showed us the afterlife scenario. Thinking this way, i actually feel a bit happier about the way it ended, and the final ten minutes don’t seem so random. I know this is a little outlandish, but there really isn’t any logical way to explain the importance of a light in a cave.