Looper (IMDB) is a dark and violent crime thriller that is also an ingenious science fiction story.

If time travel is outlawed only outlaws will have time travel. In the year 2074 time travel has been discovered and made illegal, but criminals are still making use of it. Improvements in forensic technology have made it impossible to get away with murder, so when organized crime gangs want to rub someone out they kidnap him, tie him up and send him back 30 years to 2044 where they have arranged for a hit-man to be waiting to kill him and dispose of the body.

Joe (Joseph Gordon-Levitt) is one of these hired killers or “loopers” as they are called. One day he gets a nasty surprise: the criminals in 2074 send back his older self (Bruce Willis) to be killed. Joe thinks he is pretty badass but his older self is 10 times as bad.

Old Joe overpowers Young Joe, escapes and sets out on his own mission of vengeance. It seems that in 2074 a mysterious crime boss called “The Rainmaker” has seized control of all the criminal syndicates and is killing off all the old loopers. This led indirectly to the killing of Old Joe’s wife. Old Joe intends to find the child who will grow up to be the Rainmaker and kill him before he can get started.

For Young Joe this is a disaster. Very bad things happen to loopers who don’t carry out their contracts. Young Joe needs to track Old Joe down and kill him before his bosses track either of them down.

This is all surprisingly clever and well-acted. Most time-travel movies get themselves tangled up in logical contradictions. This one sets up some basic rules and sticks to them. Within the framework of these rules the story pretty much makes sense. The rules seem to be:

1. Time travel machines exist in 2074 but not in 2044 since they haven’t been invented yet.
2. The only thing the technology can do is send you exactly 30 years back into the past.
3. This is a one-way trip. The only way to get back to your starting point is to wait 30 years.
4. It is possible to change the past. However if you send someone back to change the past and he messes up there is obviously no way to send someone back even earlier to fix it.
5. If you go back and change your own past you will see the effect immediately. However your action will only affect the future (forward from the time of the action.) Regardless of a any preexisting time loops your actions do not reflect back and change anything that happened before you took the action.

The last rule creates obvious paradoxes but it avoids the ultimate paradox that any change to the past should cancel itself out by eliminating your reason for making the trip.

I’ve been poking at this ever since I got out of the movie and, subject to these rules, I don’t see any clear logical contradictions. I do have some issues with the story but they aren’t so much about logical fallacies as questions about the characters’ judgement.
Show ▼

Assuming that you don’t mind the violence I can recommend this as a clever and well-told story with a reasonably satisfying (though perhaps somewhat ambiguous) ending.