[Junior_G]

You see the whole "invasion" only through the eyes of Mel Gibson's character. There's no objective proof that any of the movie's plot action occurs anywhere but within his own mind.

So Gibson's character was simply an insane person seeing things? Unless Shyamalan himself said they weren't actually aliens, I have to assume they were.

[Cincinatus]

You can assume anything you want -- it's only a movie. I was offering an interpretation that, to me, makes more sense than the typical "alien invasion" that everyone assumes is happening.

As for being "insane," some might question that characterization of an intensely religious experience. Clearly, the emotional/intellectual theme of the film is Gibson's loss of faith -- it drives his entire motivation. How is that not relevant to what's happening around him?