One of the things that I am trying to get right in my brain, is all the dead people that have been seen through out the show. Basically Jacks dad and Eko seeing his dead brother. And also the times that Jacks dad has appeared to both Micheal before the boat blew and Claire in the cabin. It really points to the MIB taking these various forms and manipulating people. The only time "true people" have appeared has been to hurley. People who have seemed to be who they actually are like Charlie.

So as of right now, that's how I'm thinking. That means if someone other than Hurley is talking to a dead person, it's MIB. If Hurley see's him, it's probably the real person. Though I guess the MIB could manipulate this somehow and fake Hurley out.

But it points to both Jacob and MIB having similiar abilities. Micheal couldn't be hurt until his usefulness was over and now Jack and other candidates can't be hurt right now either. So if MIB was truly manipulating Micheal, him and Jacob have that same power. What else can they both do ? IMO it looks as though they are playing by the same set of rules.