It's all about Interconnectivity.

Rating: 10/10 (3 October 2008)

A well done movie. Most people say the ending is confusing, but how easily they forget that the whole movie is confusing, and if the meaning of the movie is a good one, that's the only way such an end could stick out in their heads. So, I thought the whole movie might be underrated, since I felt like the theme was never cleared up. I never thought it was as simple as being about madness, memory, or doomsday. I figured it was about interconnectivity. All of those other themes are just intertwined and reoccurring elements because of the time travel element in the story. The whole movie is a look at Cole's life through this era of time travel, and how he is not big enough to save the world, but plays a vital part in making it better, and suffers along the way, just like us all.
In the beginning of the movie, when Cole keeps repeating, "You can't change the past," he is already too much of a pessimist for the demands of such a task. But whether he is defeated because he is just that way, or he is just that way because his memory is scarred from childhood first, is something of irrelevance; It's not important which caused which, only that strong interconnection from time travel caused his memory and negativity to intertwine. (His memory of the bad guy who rudely pushes him takes the form of Brad Pitt's character, either because he mixes his personal feelings with the mission (defeatist), or because his memory finds something reminiscent of the enemy to Brad Pitt's character, who is involved with solving the plot (memory). He mentions that he "had always known you like this" to Madaline Stowe's character either because he strongly related to the woman at the airport from her distress and yet ability to smile at him, and carried out his own personal motivations based on that (defeatist), or because he actually remembers in some small way, that it is a loophole of the same, exact person, since his childhood connection with his own demise is strong enough to allow him to recall that about her, leading her to smile as she is aware of this (memory).)
The final scene is only meant to further reinstate the subject of interconnectivity: As Cole was not strong enough for the magnitude of the task, we see even one of the lead scientists having an encounter with the event under scrutiny, proving that we all eventually are interconnected at an astonishingly close range, and that we are bound to encounter any highlighted event in one manner or another. The film, having already examined Cole's life and demise for all it's worth, now passes the massive task through the scientist's existence, as we can already see certain personality traits in her that will lead her to struggle in her own quest for the truth: she is insecure (working in insurance), rigid, overly-thoughtful, and a little naive to trusting. The only difference is, that as time travel interconnects her own personality with her memory, this experience on the plane will be the moment that replays over and over in her own mind, showing the greater the task is in the world, the more we are all victims to our own insufficiencies of it.