Time-Travel Paradoxes in Cinema

Just in time for TERMINATOR: GENISYS, our resident scientist weighs in.

Viral pandemics; zombie apocalypses; nuclear armageddon; alien invasions; machine uprisings. That such tropes surface again and again in science fiction and fantasy cinema shouldn’t really surprise us - they are lenses through which we can wrestle with some of our more existential fears, examining our place in an overwhelmingly large universe and trying to shake loose some solace in the attempt. And is there anything crueler, more central to the human narrative than the relentless march of time? Is there anything more tantalizing than the possibility that we, creatures who analyze, learn, and adapt, could reach back across time to our younger selves, nudging our more naive counterparts around obstacles, whispering of upcoming tragedies, and slyly pointing the right way at the forks in life’s roads?

Again and again, we find our science fiction films going back to the well of time travel. But, despite this brief glimmer of hope, there’s always an undercurrent of resignation. Even if we were allowed to move freely in time the way we do in space, the overwhelming complexity of causality seems to guarantee that we’d birth all manner of unintended consequences or that, despite our best efforts, we'd find that the broad strokes of our future were immutable no matter how we changed the smaller details. Either way, the future to which we'd like to return is no longer in the cards, due to our meddling, giving us that classic corollary of time-travel yarns: the temporal paradox.

Time-travel paradoxes in film tend to fall in two main camps. The first is the grandfather paradox, whereby a time traveler, in the course of fiddling with the past, accidentally alters events central to her present -- say, preventing her grandfather from ever meeting her grandmother and erasing herself from their future in the process. Only by existing in the first place was she able to travel into the past, but while there she screws things up so badly that there’s no longer a future with her in it. The Back to the Future series tackles this trope literally, with accidental time traveler Marty McFly so badly mucking up the beginning of his parents’ romance that he literally starts fading out of existence. Not learning to leave well enough alone, Marty then tries to fiddle with his future self's life, only to trigger another grandfather paradox whose consequences are far worse than a simple McFly-less timeline. The Hugo award-winning episode of the original Star Trek series, “The City on the Edge of Forever,” provides another great, poignant, example. Dr. McCoy of the starship Enterprise is accidentally thrown back in time to the New York slums of the Great Depression, where he saves the life of social worker Edith Keeler, fated to die young in a traffic accident. Keeler's example of tolerance so influences the subsequent national conversation that the United States never enters the second World War until it’s too late, and fascism spreads unchecked for the next 300-plus years. The utopian Federation of McCoy’s time is never formed, and it’s only when the Enterprise’s Captain Kirk follows McCoy back and allows Keeler’s death, despite having fallen in love with her in the meantime, that the proper future is restored.

The other main time-travel conundrum we tend to find in cinema is the predestination paradox. Here, a time traveler is motivated by some earlier event to take a trip into the past, only to find that he ends up causing the event that prompted the trip in the first place. No matter how he'd like to change events in the past to tweak his future, he's fated to make the same, circular journey. The film Interstellar provides a recent example of this paradox. Amid a severe climate crisis, ghostly messages begin appearing to Astronaut-turned-farmer Joseph Cooper and his young daughter, pointing the two of them to a secret NASA installation where Cooper is recruited to travel through a wormhole to a supermassive black hole in a distant galaxy. In the course of his mission to find a better home for the remainder of humanity, Cooper falls into the black hole, only to encounter an advanced intelligence that protects him from the black hole's singularity. Encased inside a tesseract built by the hyper-dimensional beings, Cooper is moved through both space and time back to Earth, where he realizes that he is now the ghostly presence who was communicating with his younger self. Cooper finds that he can pass the solution to humanity's crisis, learned during his painful journey, along to his future adult daughter, but he also realizes that he must close the loop of the paradox and send younger Cooper the messages that propel him toward the answers his daughter is seeking.

Perhaps the best known example of the predestination paradox in film is found in The Terminator -- a film by director James Cameron which shares enough similarities with a short story by "The City on the Edge of Forever" scribe Harlan Ellison that it prompted an out-of-court settlement with the notoriously litigious author. The Terminator opens in an apocalyptic future where machine intelligence Skynet, tasked with protecting humanity, has decided that the most efficient solution involves eradicating the biggest threat to the species -- humanity itself. The nuclear strike launched by Skynet was largely successful, and it is now in the process of mopping up the few surviving humans using killer robots called Terminators. Resistance leader John Connor and his fighters are proving particularly troublesome, and Skynet, which has been tinkering with time travel in its spare time, decides to send a Terminator in the past to kill Connor's mother Sarah before he's ever born. Connor catches wind of this and sends soldier Kyle Reese into the past to stop the Terminator. Reese succeeds, falling in love with Sarah in the process and fathering the young John Connor, catching Skynet in a classic predestination paradox: in trying to rub out Connor before his birth, Skynet actually incites the conception of its greatest enemy.

This month at the Alamo Drafthouse, we'll see the next chapter of the Terminator saga, which promises an alternate take on Skynet's time-travel hijinks. Will the machines manage to squash the human resistance before it starts this time, or will the future, through its sneaky paradoxes, still manage to find a way for the survivors to hold together? Will the humans be able to stop the apocalypse now, or are they just as fated to take the journey to a future war with Skynet? Given the abundance of evidence in the cinematic canon, it seems unwise to bet against the future...

This was originally published in the July issue of Birth.Movies.Death. magazine. Terminator: Genisys arrives in theaters today. Check drafthouse.com for listings.