Time travel is a sticky subject for a plot device in that it comes with a set of built-in contradictions. Could a time traveler bring back objects or information from the future if those objects or information only exist because they were brought back from the future? (The “Bootstrap Paradox.”) Could a time traveler truly influence time if their presence in the past means they’ve already time traveled? (The “Predestination Paradox.”) Could a time traveler change something in the past that would prevent them from time traveling in the first place? (The “Temporal Paradox.”)
Some films get around this metaphysical grey area by simply ignoring these messy repercussions, but the most interesting films are those that hinge on them, exploring time travel not as a device to spur conflict but rather as the conflict itself. Here are five of cinema’s best time travel paradoxes, in all their bewildering, inscrutable glory.
5. Donnie Darko
Paradoxes: Bootstrap, Predestination
Writer-director Richard Kelly has made so many missteps in recent years (a losing streak consisting of the triple threat of Domino, Southland Tales and The Box) it’s easy to forget his debut feature was one of the most original, satisfying and atmospheric puzzles ever put to film.
Though Donnie Darko‘s circular plot revolves around time travel, there’s no time machine and the eponymous hero never goes back in time himself. Instead, Donnie (played with striking vulnerability by Jake Gyllenhaal) learns over the course of the film that he can manipulate time, altering events that have already occurred. But its a skill he realizes only because his future self has already used it, setting into motion a spiral of destruction that must be prevented – by learning to manipulate time and setting it in motion all over again.
It’s a paradox of a plot, but one more concerned with the intricate workings of a generic small town than the mechanics behind time travel. Backed by a nostalgic period setting (and a fantastic soundtrack to match) as well as a host of great actors, including Gyllenhaal’s on and off-screen sister Maggie, a young Seth Rogen and Patrick Swayze in perhaps his greatest, most ironic role, Donnie Darko is a code worth the multiple-viewings needed to decipher it. Hopefully, Kelly begins to show that initial ingenuity again.
4. 12 Monkeys
Paradoxes: Bootstrap, Predestination
Based on Chris Marker’s short La Jetée, but expanding that film’s lyrical meditation on premonition to a sci-fi saga involving bio-terrorists, a humanity destroying virus and a post-apocalyptic future spent underground, Terry Gilliam’s 12 Monkeys centers around a time traveler, played by Bruce Willis, sent to the past to prevent a catastrophe from nearly destroying the entire human race.
Things don’t go as planned, however, as things so rarely do, and Willis’ mission to save the world is hindered by the general perception that he’s a paranoid schizophrenic, an explanation so much more plausible than the reality, Willis begins to believe it himself.
In the end, even with his knowledge of future events, Willis was never truly able to keep them from happening. The paradox of a time traveler sent back to change the event leading him to become a time traveler is inherent, but the real stumbling block is memory itself, which blurs and distorts the past enough to make the same mistakes an inevitability.
3. Back to the Future
Paradoxes: Bootstrap, Temporal
Easily the lightest, most popcorn-friendly film on this list, Back to the Future is, nevertheless, serious about the implications of time travel. When he’s accidentally transported to 1955, Marty McFly (Michael J. Fox) inadvertently interferes with his own parents meeting, an event which leads to Marty’s own mother falling for him and, potentially, his ceasing to exist entirely.
Luckily, Marty and his scientist pal Doc Brown (Christopher Lloyd) devise a plan to get her to fall for the senior McFly, though their adventures in the past have interesting effects on the future. Yet unlike most other time travel films, Marty’s interferences almost universally make things better, saving his parents’ relationship, making his father more successful and putting the bully Biff (Thomas F. Wilson) in his place. In fact, the biggest paradox in Back to the Future isn’t that Marty nearly prevented his own birth, it’s that his parents seem to have forgotten that the man who introduced them looked exactly like their teenaged son.
2. Los Cronocrímenes
Paradoxes: Predestination, Temporal
Writer-director Nacho Vigalondo’s Los Cronocrímenes (Timecrimes) opens with Héctor, a seemingly average middle-age husband, peering into the forest behind his new home with binoculars and finding not birds or foxes but a young woman undressing. Naturally, he walks into the woods to investigate, only to be stabbed by a man whose face is menacingly obscured by apparently blood soaked bandages.
Describing what happens next, and how time travel becomes involved, would risk spoiling Vigalondo’s meticulously constructed script, which adds a few new mysteries for each one it solves and piles overlapping timelines upon overlapping timelines. It’s a testament to Vigalondo that he manages to keep so many plates spinning, and in such a precisely choreographed fashion, transforming a taut thriller into an expertly crafted exercise in metaphysics.
Paradoxes: Bootstrap, Predestination,Temporal
Primer is a decidedly small film – it has essentially no special effects, no big action set pieces and it isn’t interested in holding the audience’s hand through its increasingly knotty structure – yet it seems to offer the most fully realized look at the problems inherent in time travel despite of (or, more likely, because of) its impossibly low budget.
Written, directed and starring Mathematics major and engineer Shane Carruth for only $7,000, Primer isn’t a flashy film, but it uses its nuances to great effect, creating a time machine that seems real and plausible and populating its minuscule world with telling clues that hint at the consequences such a device would cause.
Carruth and co-star David Sullivan speak like real engineers, act like real people and react plausibly to an increasingly implausible scenario. Their time machine has rigidly defined rules that, rather than simplify its use, instead make its application that much more complex, leading to a hilariously impenetrable infographic that doesn’t explain the film as much as it complicates it even further.
But Primer‘s difficulty isn’t a demerit, it’s the reason the film works as well as it does. It rewards and practically demands repeat viewings, each revealing a new thread the viewer hadn’t noticed before. Ostensibly, Carruth and Sullivan are merely experimenting with their incredible discovery (and trying to make some money on the side), but the machine quickly leads to repercussions the protagonists (and the audience) don’t understand and each attempt to set things right only creates an ever more baffling mess to clean up.
It’s Primer‘s low-key (and low-budget) charm that sells the fantastic premise as a credible reality, but that credibility ultimately makes Primer‘s paradoxes even more terrifying to consider. It’s a film that eschews the larger question of “How would time travel change the world?” in favor of one even grimmer: “How would time travel change you?”