MiB as a candidate who rebelled... or, Jacob is the new Kelvin by Chris C

I think it's fair to say these are questions we should be asking after seeing "The Substitute": is MiB right? Is the Island actually important? Does it really need protecting? Jacob thought it did. What situation from previous LOST seasons does this resemble? The hatch. These are questions we were asking ourselves in season 2: is the hatch actually important? Do they really need to push the button?

"I needed a sucker to save the world after I'm gone."
--Kelvin

Jacob has been stuck on the Island "pushing the button," as it were, and he has been waiting for his replacement. I think Jacob brought MiB to the Island, just as he brought everyone else. MiB was a candidate, and was chosen to become the next Jacob. Their relationship at that point may have resembled Kelvin and Desmond: Jacob was teaching MiB what, as "Jacob," he needed to do... whatever it involves, the gist was that protecting the Island is his duty. I think MiB was not a believer, and therefore refused the job. Maybe Jacob wants to "go home" (whatever that means) the same way MiB does, just as Kelvin did... but he needed a sucker to save the world after he was gone. Jacob has kept MiB on the Island ever since. Maybe it was a punishment, maybe an attempt to break him, or maybe he needed him to stay there until there's another candidate... another believer... another sucker to save the world when he's gone.

And that's the great irony of season 6. John Locke, the ultimate believer in the hatch, is now the great skeptic. All we need now is Jack Shephard to become the new candidate, the new Jacob, the new great believer, and we'll be looking at the hatch in a mirror.

"Nothing. That's the joke. There's nothing to protect it from, it's just a damn Island!"
--Flocke, to Sawyer