Looper: 20 Mistakes Rian Johnson Should Have Avoided

3. Causality #3

Old Joe is hell-bent on terminating the rainmaker when he may in fact be terminating himself. If he did succeed in doing so according to the movie's logic he would save his wife he would be stuck in this time, time-travel is a one way street according to Abe. So, essentially he could wait around for his wife for another thirty years, in which case he would be pushing 90 years or commit suicide in the hopes he helped his younger self, that now hates everything old Joe was for killing Sara's kid. Bitter and depressed he wouldn't be the same man old-Joe's wife fell for.