If you knew the ending of "Knowing," then you probably wouldn't want to watch it, because then you might know more than you needed to know. No matter how you slice it or dice it "Knowing" is an interesting concept with very poor execution, weak writing, philosophy that isn't worth thinking about, and one bizarre last half hour. But if you can say one thing about the great Nic Cage, it's that whether it's good or bad, his movies are always original. That's a my summation of the movie, if you want to go deeper, SPOILERS FOLLOW!
The part that I didn't like about the movie is that it's simply a short story stretched into two hours. How have I come to this conclusion? Because, the aliens at the end of the movie went too out of their way to get the kids. All they had to do is take the kids in the middle of the night and start over. Not like the kids would remember, it seemed as if their minds were erased when they got to their new homeworld. Of course Nic Cage would still be the messed up & doubting guy he is at the beginning, but I found his personal journey weighing down the movie anyways. So instead, the underrated I-Robot director Alex Proyas throws numbers in there, and disasters. But all of it is for naught at the end, so it kind of seems pointless. Again, the film tries to ask these deep questions about philosophy, but again, the movie's questions are worth thinking about the way they are posed here. So it's again pointless.
But don't worry, if you like prolonged and lingering shots of people and animals burning alive, you've come to the right place. If you like shots of people getting crushed by subway cars, then this is your movie. If you like shots of the end of the world overlaid by inappropriately joyful classical music, then this is the movie for you. If I wanted all that, I could have watched Final Destination, but "Knowing" thinks its way better than it is, and it disappointingly falters under its own weight. Also, you should probably be off world, or at least on the other side of the world when a solar flare strikes Earth. Those things are a b**ch!