UPDATE: Film.com just posted an exclusive infographic explaining the timelines. Click here or scroll down to check it out.
Let's jump forward two minutes into the future when you read this article before seeing "Looper" and complain about spoilers. We've come back from the future and inserted this warning that you're gonna be mildly spoiled. You're welcome.
Now, within that spoiler warning (seriously, don't read on unless you've already seen the movie), we've also honed in on the central paradox of time travel in writer/director Rian Johnson's fantastic new sci-fi action fiesta, which is that if you go back in time as Bruce Willis does, you're changing the future, so how could you have ever gone back in time? Just like if you discovered we spoiled the movie, but then we went in and put a warning, you wouldn't be spoiled and why would we go back in the first place? Headache? Us too.
Let's slow things down a peg and take you through time travel a la "Looper": Joseph Gordon-Levitt's character, creatively named "Joe," is a Looper (hitman) in the present (our future) 2044, and, somewhere in his future (2074), the mafia has a time-machine and is sending poor saps back to be killed and done away with. Of course, the mob is paranoid as hell and makes all their Loopers kill their future selves before they collect their final payday.
The thing is, in one timeline of our story, which we'll call TIMELINE A, Young Joe kills his older self (Willis), gets his golden parachute, lives the high life, gets older, becomes a lowlife drug addict, meets a girl, cleans up his act, and Old Joe lives the quiet life of peace with his girl in China.
THEN, thugs come in, take Old Joe, kill his girl, but just before they put him in the time machine — which is a dead-ringer for the Trinity Gadget, the first atomic bomb tested in July 1944 — Old Joe takes them out and hops in the device.
He arrives in 2044, and, instead of Young Joe killing him, Old Joe knocks his younger self out and heads on his mission to change the future, thus creating TIMELINE B in which both Young and Old Joe are hunted by the mob.
We won't go in-depth on the rest, you'll have to see it for yourself, but what we can glean based on these details is that the time machine itself must be nuclear powered, thus the visual callback to the Trinity Test. We also know that two timelines can exist concurrently, but with events in TIMELINE B affecting Old Joe's memory of TIMELINE A, as well as injuries sustained by Young Joe. Hence, when Young gets his ear wounded, Old suddenly has the scars. Ditto when Young carves messages (painfully) into his own skin for Old to read later.
That's also why Old Joe doesn't just shoot Young Joe: He will cease to exist, Marty McFly-style.
It's good to bring up "Back to the Future," because not only is it Rian Johnson's favorite time travel movie, but it also seems to be the storytelling model for him, namely that you can exist in an alternate timeline until something cataclysmic happens, like your dad never hooking up with your mom.
Johnson forgoes the more fatalistic time travel of Willis' other classic sci-fi vehicle "12 Monkeys," where if you went back in time, you always went back in time. No carving stuff in your arm, no heads fading off photographs. If it happened, it happened — one timeline.
Perhaps the best way to justify this approach is to let Johnson himself do it, in his interview with I09:
"The big thing that I learned from watching all of these time travel movies and just giving it a lot of thought was, the best time travel movies are like a magician performing a trick," he said. "Especially any time you're going to send somebody back. Any time you're traveling back in time, the logic of everything is going to collapse on itself if you take too close a look at it. You're just going to get paradoxes that are not going to make sense. So you realize that your job as a storyteller is, to a certain extent, to create a set rules of rules that you stay consistent to, but also (for lack of a better word) fooling the audience that this makes sense for two hours."
Fool me once, shame on you. Fool me twice, bravo, Rian Johnson.
(Originally published on Oct. 1, 2012, at 8:21 a.m. ET)