Written 25th February
Based on the last couple episodes, from what I have read, I am thinking that many people are viewing the names and numbers too narrowly (or maybe my understanding of what other people have thought has been too narrow). By narrow, I mean some believe that the names on the lighhouse and cave are for the same purpose (which is what I believed as well until I thought about this in more depth).
We have names and numbers in the lighthouse (light) and names and numbers in the cave (dark). I wondered if MIB and Jacob have spent all this time identifying the final pieces of their game and now have it narrowed down to the most important. I also wonder if Jacob is searching for a successor to protect the island, perhaps MIB is also searching for a successor to fulfill his role (Jacob gets to die, MIB gets to leave). Or he is simply keeping tabs on Jacob’s candidates in order to influence them away from Jacob? Of course, this begs the question — why would Jacob start looking for candidates to protect the island (and therefore, succeed him) and narrow down his list unless he knows he will die at some specific point in time? However, MIB is aware of his list. So that does have my mind going in circles.
Kate’s name is present in the lighthouse, but from what we know, not in the cave. That leads me to conclude that she may be a candidate to replace Jacob, but not MIB or is not of interest to MIB. Moreover, her number is not one of the numbers we have grown to know oh so well, so perhaps Kate has a special purpose for Jacob as No. 51, even if not a candidate.