The rare movie that can claim a kinship with Mandelbrot and Heisenberg, Shane Carruth’s Primer won Sundance’s Grand Jury prize as well as its Alfred P. Sloan prize for science-themed movies. (Carruth took part last week in AMMI’s inaugural Sloan Science on Film Dialogue.) With questions about the film’s brain-spraining narrative multiplying as rapidly as its self-cloning, time-traveling protagonists Abe and Aaron, the Voice asked the 31-year-old Carruth to help separate science from fiction and untangle some of the movie’s knottier mysteries. (Spoilers below.)
How did you come up with the film’s principles of time travel? Richard Feynman has some interesting ideas about time. When you look at Feynman diagrams [which map the interaction of elementary particles], there’s really no difference between watching an interaction happen forward and backward in time. That’s something I got interested in early on. I always knew what the story was thematically before it turned into science fiction. It would be about trust and how that’s linked to what’s at risk. I was reading about innovation and that’s where I got the setting. Now what is this device? At that point, I’m where a lot of sci-fi writers are—just going through the list of what this thing could be. When I got to the ability to affect time, there was a lot of material to mine that I hadn’t seen before—it’s usually warpspace or wormholes. In almost any time travel story, people pick themselves up at one point in time and then immediately exist at another—they move from the present day to the 1950s or prehistoric times, and I never liked that because if I were to jump back a day, I’d find myself in a different space because of the orbit of the earth. Whenever you’re addressing moving in time you need to talk about space. When you walk to the door you have to walk every moment between here and there, so it seems that, if you’re moving through time backwards, you should have to pass through each moment back to get there. That would be the price you pay.
How much real science is there in the movie? There’s almost no time travel–related science. What they’re trying to do at the beginning, degrading gravity using superconductors—that was technically researched. The point where it goes from saying we’re doing such an efficient job degrading gravity that we’re also blocking time—that’s the leap. But there are plenty of stories in the history of innovation where you’re heading towards one thing and there’s a side effect that turns out to be the valuable thing, like John Bardeen’s accidental invention of the transistor. For a while I believed that asking to travel in time was too much, but I could almost believe that you could send information. It took a year to write the film and by the end of it—I probably shouldn’t say this out loud—I have a sort of proof that it can’t exist. If you buy that it exists, it means something more profound about where we live. It means we don’t live where we think we live.
How comprehensible is the film supposed to be after a single viewing? I’m always worried Q&As are going to turn into 30 minutes just talking about plot points. But people don’t necessarily want to know the answer to everything, they want to know that there is an answer. I know that you could watch it and think it’s some kind of random assemblage, like it’s a tone poem to time travel. But to know that there’s a method to it is half the battle. Two viewings seem to do it, but I can’t say you have to see it twice; that’s so pretentious.
Does everything add up, or did you deliberately leave a few loose ends? It’s never tidily summed up, but I’ve made sure the information is there. Almost every detail, from who the narrator is to how many Aarons there are in the end. But there’s one piece of information that isn’t, and that has to do with [potential funder] Granger coming back and how he was able to. That’s purposely vague. Abe and Aaron each have a point in the film where they find themselves in someone else’s past, and they both react a little differently to it. This is Abe’s moment. This man has found out about the machine and he’s used it to come back, but they don’t know from what point in the future or who told him about it. That’s what spurs Abe to reboot the whole thing, that’s how he reacts—let’s redo everything and then I’m the one in control. It was important that the audience be in the same place that they are—there isn’t any way to know. That’s the one big question that comes up, and I’m satisfied by that—that’s supposed to be the big question. I stuck with the rule that we were going to be with Abe, that we were going to see his experience. Although the narration is coming from Aaron, we only know about Aaron’s experience from voiceover and flashback material, mainly because there was no way to tell a story from multiple points of view dealing with multiple histories.
How many clones of each character are there by the end? The narrator is the second Aaron, so he doesn’t have direct information about what happens after he leaves. There’s a struggle between the second and third Aaron, and after that point [the narrator] is talking in very subjective terms: “How many times did it take before he got it right? Two? Three? 20?” He doesn’t actually know. We’re seeing information, but he doesn’t have direct knowledge of it, so there’s no way to know how many there are. There’s at least three Aaron that he knows about, and at least two Abes. But it could be lots.
Can you elaborate on the concept of recursion in terms of time-travel paradoxes? I have a degree in math and my favorite subject was non-linear dynamics. You have an equation y = x, and you take that answer and feed it right back in for x, and you chart this and sometimes you get fractals and sometimes you get orderly systems. The idea of recursion and whatever it leads to—that informed a lot of the story, the idea of creating a feedback loop. This isn’t really addressed in the film, but the reason Granger is unconcious is because he’s suffering from recursion. What I think happened is that Abe told Granger about the machine. This man who’s been told by Abe about the machine uses the machine to come back and somehow has an interaction with Abe so that now Abe probably won’t tell him about the machine and yet he still finds himself there. Without coming out and saying it, the film is built on the idea that these paradoxes are a way to understand things. The universe is not going to explode or break down if you create a paradox. Whatever’s going to break is probably going to be you.
What’s your next film? I’ve been working for a long time on this romance that has nothing to do with science. An 18-year-old oceanography prodigy falls for the daughter of a commodities trader; it’s set at sea off eastern Africa and southern Asia, and it’s about trade routes and smalltime transport. But now I’m sort of leaning towards this other story, which is science fiction, and would be a much bigger budget. Basically there are robots, but they’re not manmade; they appear to be at first. The story starts in the past, and there’s information given to people, symbols and glyphs and things they think they’re seeing. It’s not scientists, it’s random people that it’s happening to, and . . . the end result is we’re talking about devices that the universe is inspiring people to make without them actually knowing it. The universe is 50 billion years old and we’re on a planet that’s 4 billion and it only took a fraction of that for us to get here. It seems like if you look into the night sky, you should see evidence of civilizations that are not 100 years more advanced but millions if not billions of years more advanced, and yet when we look, we don’t see anything. This is the story to explain why that is.