The Problems of 'Primer'

If you haven’t seen Primer, stop reading now! Go watch it, then watch it two more times, then discuss it with your friends, then watch it again. Okay, done? Then now you’re ready to play along! You might think there’s no real “solution” to the events in Primer, but there is. It’s been worked out by careful viewing that Aaron hijacks Abe’s failsafe device so that he can go back farther in time and override anything Abe might do. He uses this capability to interfere with his past self, and then later to interfere with that past self. At that critical point in the plot there are 3 concurrent Aarons. And as he recounts the story in voiceover, there are 2 concurrent Abes. If you can figure out that much, you’re doing pretty well. The scene where Aaron goes back stop himself –twice– runs by so quickly it’s easy to miss. So let’s talk about these time machines. According to Primer, you actually must co-exist with your former self in order to time travel. This is actually against the laws of physics, as we know them. Either your atoms exist in two places at once, or you have actually increased the net energy of the universe. Primer hints that your atoms exist in two places at once, sort of like a mirror projection, but since only your older time-traveling self is affected, this is an incomplete explanation. With a Primer box you always return to the timeline you left. Thus if you travel from 8pm to 8am on the same day, you will return to the morning you remember. So the first time we see Aaron and Abe emerge from the boxes, it is 15 minutes after they left the U-Haul bound for the hotel. The original two of them in the hotel room must follow through and enter the boxes in the evening, or their duplicates will never have emerged in the morning. That’s an essential point, which looks like it eliminates the possibility of extra Aarons and Abes from persisting. Intuition says that the person exiting the box should not be able to prevent his past self from entering the box, and that if you tries you would inevitably fail. But in Primer, if you want to you actually can prevent yourself from entering the box, and you won’t disappear. You can do this because in the timeline you exited, you did actually enter the box. That can’t be changed. You may interfere with yourself now, in this new timeline, but it’s not the earlier you. If you knock your younger self on the head in the new timeline, you won’t get a lump on your head in this one. It’s the same actors, different play. Things you don’t affect in the chain of causality go on just as they had, more or less deterministically. Since time travel happens in “real time” the amount of time a person can actually travel backwards is severely limited. They can only go back as far as the amount of time they could survive in the machine. A person could live comfortably for a year in a warehouse-sized box, but you would never want to get into a coffin-sized failsafe box you started 30 days ago, because you would have to be in there for 30 days. Another curious point in the movie that others seem to miss is that Abe and Aaron can never travel back to any point in time before they had the knowledge and intention of traveling. They cannot ever prevent themselves from building the boxes. Aaron folds up a time machine and brings it back with him in Abe’s failsafe. Presuming it takes a couple of minutes to set up and start a box, Aaron’s recycling method is good, it allows a limited number of do-overs, as time is lost each time you have to set up the new box you brought through. Plus you have to keep renting more and more storage units. One thing that isn’t addressed at all is, what happens in the original timeline? Do Abe and Aaron enter the boxes and disappear forever? Well, no. By the time they do that, there are already duplicates ready to take their places. That seems to neatly clean up the original timeline, but again it seems to preclude the existence of duplicates. One thing never addressed, because it would destroy the movie, is how exactly a person can be exiting the box into a room where time is moving forward, while you are also still in the box moving backward in time. There would be a period of overlap where you would be simultaneously exiting and staying in the box, which is impossible, as two objects cannot occupy the same place at the same time, nor can one object occupy two places at the same time.