Figure 8 by dctruby

This is copied from one of my comments, so I thought I'd try it out as a theory. As always, my apologies if it's been said before:

I think Lost iss all one time line that has become caught in a figure 8 loop, with the incident at the center.

Jughead will detonate and prevent 815 from crashing. The passengers of 815 will somehow decide to go back in time and prevent Jughead from detonating. This will, of course, lead to 815 crashing, and the figure 8 starts all over again.

815 crashes-> passengers go back in time-> jughead detonates-> 815 lands safely-> passengers go back in time-> jughead does not detonate-> 815 crashes.

If I draw a line on a piece of paper, I can end the line with a figure 8, without ever picking up my pen, and it would look somewhat like this: -----8. This is why I think that what we are seeing is one time line, not multiple time lines or universes.

I think at the end of the show the 815ers will break the loop, and this is the "progress" Jacob refers to. MIB thinks that 815ers will not break the loop on their own-"it always ends the same,"and takes matters into his own(?) hands, but Jacob has faith--"it only ends once"--when the 815ers break the loop.