Most of the time the creators of the film Looper want us to believe that future history remains unchanged until the moment of its occurrence arrives in the present timeline. We see this with Joe’s memories. He says his memories of what is now future but was his past are “cloudy because the future is in flux.” He does not know what Young Joe is going to do, nor what Young Joe is thinking or planning, but as soon as Young Joe does anything, Old Joe remembers it.
Old Joe’s ability to remember his wife is justified by the suggestion that this part of his history has become not impossible, just increasingly improbable. The fact that when Old Joe was young he had all his silver and gold and the blessings of the syndicates on his retirement, while this Young Joe is bankrupt, fleeing for his life, and trying to fix everything by killing his older self, does not absolutely prevent all futures in which he meets and marries the girl.
It is more difficult with Seth. At the moment Young Seth loses his leg, Old Seth loses his, and remembers having lost it thirty years before. We observed the problems with this, in that once he has lost the leg he has lost the ability to be where he is; yet he is where he is, finding himself now crippled but in the place he got before he was crippled in the condition that would make it impossible for him to have gotten there. That is to some degree consistent with the memory idea; Seth changes, and his memories change, but he remains where he was.
At some point, Sara asks Young Joe what will happen if Old Joe kills Cid. Young Joe says that he thinks that Old Joe believes that as soon as that happens he will be back in the future with his wife, never having been sent to the past by the Rainmaker who now will never have existed. Were that true, it would also mean having killed Cid Joe never comes to the past and so never kills Cid–we have a grandfather paradox, in which an event prevents itself, happening only if it does not happen, not happening if it happens. The same act of killing Cid that restores Joe to the future saves Cid and removes Joe from the future, and we have an infinity loop.
Yet at the critical moment, time does not work that way or the other way. That is, in the climactic moment, Young Joe, having had a “flashforward” in which he understands all the events on the path ahead in Cid’s life, solves the problem by killing himself. The moment he does, Old Joe vanishes.
That is entirely inconsistent. We saw what happened to Seth, and if the film is to be consistent, when Young Joe pulls the trigger, Old Joe should remember the pain in his chest and should die and perhaps decay thirty years’ worth, but should be there, still, a corpse in the field.
The fact that he vanishes suggests he was never there; but that in turn creates too many more problems. Why is the truck there? Why is the silver there? He brought these to the farm; they could not be there without him. What happened to his gun–the gun he brought from Abe’s enclave? And why is Young Joe’s body here, if not because he knew Old Joe was coming to kill Cid?
If he was never there, of course, it is because Young Joe did not survive to become Old Joe; if Young Joe did not become Old Joe, then Old Joe was not sent to the past, did not run getting Young Joe in trouble, did not kill Abe’s people, did not threaten Sara, and did not inspire Young Joe to shoot himself. If none of that happened, then it will all happen. We once again have fallen into an infinity loop.
It is an exciting film and a challenging film, but ultimately it is one that does not work temporally, which time and again runs headlong into the kinds of problems that are fatal to time travel stories.