Now, on to the “midi-chlorian ending for LOST.” At the heart of the island is an energy, an energy that surrounds us, and penetrates us, and binds the galaxy together. It gives life to all things, and a little bit of it is in each one of us. It is mediated to us through tiny organisms called midi-chlorians. And since midi-chlorians are so closely connected with the Force, at the heart of the island there is a high concentration not only of Force energy but of independently living midi-chlorians.
When Jacob’s brother was sent downstream into the cave of light, he landed right in the midst of those midi-chlorians. His own midi-chlorians – in essence, his soul – left his body to join with them, and having been stirred up, together they issued forth from the cave as a cloud of smoke, while Jacob’s brother’s lifeless body flowed out of the cave and down the stream, where Jacob eventually found it.
These free-standing midi-chlorians were dominated by the personality of Jacob’s brother, since none of the other midi-chlorians had ever been in a symbiotic relationship with a human host. But this “entity” found that it could find other dead individuals and draw their midi-chlorians into itself, allowing their form to be taken (although communicating with the midi-chlorians in a living person who remembered the dead individual helped fill in the picture).
Now, we can set aside other details and focus on one: why was it important for the black smoke not to leave the island? On the one hand, the symbiotic relationship between the midi-chlorians and the Force would have been disrupted if the connection between them were severed by great distance. On the other hand, the black smoke would eventually absorb everyone’s midi-chlorians, preventing their life essence, their souls, from eventually returning to the light from which they originated.
So there you have it, an “explanation” of the sort Star Wars offered for the Force. I don’t know what J. J. Abrams or Carlton Cure or Damon Lindelof would have to say about it. But I’m curious whether, if at some point they had taken the time to say these things on the show (Qui-Gon could appear as a ghost and read by blog post or something like that), would those who wanted more explanations have felt more satisfied?
Also relevant to the topic of clarifying LOST is this video explanation of LOST using post-it notes: