Primer explained

"If you have it, you've gotta use it."

Primer (2004) is a complex and challenging film. This article is intended to help you get the most enjoyment out of watching it.

Update: I've recorded a commentary track for the film. It covers most of what's explained below, but has some new stuff too!

What should I know before watching Primer?

(If you want to go in totally blind, that's fine - skip the rest of this section.)

  1. Primer has nothing that could be termed exposition. Nothing will be explained to you directly; you are essentially eavesdropping on other people's conversations as you follow them around. It's up to you to keep up.
  2. Consider turning on the subtitles. Some of the dialogue is muffled or occurs in the background where it's harder to catch.
  3. Even if you're firing on all cylinders, there's a point about 3/4 of the way through the film where everybody - everybody - loses it on the first watch. This is not your fault; this part of the film is very confusing and not explained very clearly. I will explain it later.

Now go watch the film and then come back.

Here is a summary of what literally takes place in the film.

Aaron, Abe, Philip and Robert are four men who work at a semiconductor firm by day and sell home-made electronic products in their spare time. But while they've had some interesting patents, they haven't made major money from the side projects. They came close once, but a man named Joseph Platts stole their idea, leaving them with no recourse.

It's been agreed that they each take turns to put an idea forward. Robert's idea is to build a strange piece of hardware which can theoretically reduce the mass of an object inside it. It does this by "blocking information", cutting the object in the box off from the effects of gravity. This is just after Christmas time (hence Aaron's new refrigerator).

The box requires superconductivity. They can't generate the low temperatures they need, so in the brainstorm session they throw out an idea or two for doing it at room temperature. They cannibalise some home appliances for equipment and a catalytic converter for palladium, and build the thing in Aaron's garage. The box also has to be hermetically sealed and flooded with argon to work correctly. Aaron also makes some unconventional modifications to the box - "It looks like a dog digested it."

While experimenting, Aaron and Abe discover that the machine works. They put a blue weeble inside the box and register that it has decreased in mass. (While fiddling with the device, Aaron pokes his hand right the way into the field and Abe puts his hands over it to drop punched holes into the field. This becomes significant later.) Aaron and Abe instantly recognise the limitless applications and value of the device they have built. They immediately cut Robert and Philip out of the loop, saying that Aaron's garage has to be fumigated.

But at the same time, Aaron and Abe also realise that if they go public with their new invention too quickly, someone like Platts will take advantage of them again. They need to fully understand it first - which they don't.

Several months pass. The four men get funding from a Thomas Granger, while Abe establishes a relationship with his daughter, Rachel. (Aaron is of course happily married to his wife Kara, with a daughter, Lauren.) Abe tries to figure out how, exactly, the device does what it does - and he fails.

This is now March.

Monday (video time code: 18:36)

The first bench scene: Abe approaches Aaron one morning. Aaron is listening to March Madness on an earphone (and continues to do so for the rest of the day). Abe persuades Aaron to take the day off work, then he leads Aaron through a series of discoveries that he has made.

After repeated experiments on the weeble, Abe realised that a weird fungus was growing on it. He took it for analysis and was told that the fungus was perfectly ordinary, but that the amount of growth he had seen was consistent with years of time passing, not days. Suspicious, he put his wristwatch in the box. He discovered that what they had built was a time machine, which works like this.

The two of them immediately reason that if an intelligent agent was put inside the box, it could deliberately exit the box before it entered, travelling backwards in time. Abe then reveals to Aaron that he has already done this:

  • Abe built a coffin-sized time machine, which we shall call Box A, and placed it in a unit at a self-storage facility.
  • At 08:30 Monday, Abe primed Box A to activate itself in fifteen minutes.
  • He drove away from the self-storage facility and isolated himself at a hotel in Russelfield.
  • The box activated at 08:45 and was completely powered up at 08:49.
  • At 15:15, Abe returned to Box A and switched it off. It took another four minutes to power down completely. As it powered down, he climbed inside.
  • Abe waited six and a half hours (in the film the figure is repeatedly stated as "six hours"). At the correct time, he climbed out of the box just after it was activated - at 08:45 Monday.
  • Abe then approached Aaron for the first bench scene.

Now it's 15:15 Monday again, and Aaron and Abe-2 are able to watch Abe-1 return to Box A, climb in, switch it off and disappear into the past.

Tuesday (31:22)

Abe shows Aaron that he cunningly made a single excellent stock trade during Monday too.

On Tuesday, Abe goes through the same routine but this time Aaron insists on following along. By now, Aaron already has his own box built: Box B.

They switch on the boxes at 08:30 Tuesday, hide at the hotel all day and then return to the boxes at 15:15. Abe departs Box A at 08:45 Tuesday as expected, but Aaron gets jumpy towards the end of the ride, and exits Box B a minute or two early (or, from Abe's perspective, a minute or two late), suffering a severe physical reaction. The time is 08:50 Tuesday morning.

The dialogue during these scenes reveals a few more noteworthy facts.

  • Abe and Aaron are trying to modify history as little as possible. They isolate themselves at the hotel in order to minimise the effect. In particular, if they were to accidentally prevent their doubles from departing the timeline as scheduled, this would present a major problem, since there would now be multiple Aarons/Abes.

  • The other important line is "the boxes are one-time use only". What Aaron means by this is that after you have climbed out of a box, you CANNOT go back to it later, switch it off and climb in a second time - because that's what your past self did. You cannot use the same box to continuously loop through the same day.

    This is not actually true. For the purposes of this plot summary, however, all we need to know is that Aaron and Abe both believe this is true and operate under this assumption.

They make some more money on the stock market. That evening, they have a slightly drunken conversation with Aaron's wife Kara about the prospect of having unlimited wealth. Aaron raises the hypothetical of punching Joseph Platts in the face, then going back in time and tell himself not to, making it so that it never happens. Abe says they "can't do that", not because it's morally wrong to punch Joseph Platts in the face, or because Aaron can't tell Kara about the time machine, but because this would result in there being two Aarons. Which is bad.

"But the idea had been spoken. And the words wouldn't go back once they had been uttered aloud."

Kara also mentions a mysterious noise in their attic. Birds? Rats?

Wednesday (42:00)

The same routine again.

Aaron and Abe argue at the supermarket and the gas station that morning about paradoxes, free will, paranoia and predestination. One particular point that Aaron raises is the problem of living in a universe which has been engineered by somebody else. At the hotel, and then later on Wednesday afternoon at the library, Abe and Aaron discuss the problem that Aaron is keeping the time machines secret from Kara. They also discuss the problem of Robert and Philip. They agree to give them a certain amount of patent rights and/or equipment and/or cash in order to salve their consciences instead.

They loop back in time as normal. At 08:15 Wednesday, shortly after getting out the machine, Aaron is bleeding from his ear.

That day, make their successful trades. In the afternoon, they finally admit that the garage has been "sprayed", and work at the garage with Robert and Philip resumes. Robert and Philip have now received their gifts from Aaron and Abe.

Robert reports an interesting story. It seems that Monday night was Robert's birthday party. Abe wasn't there, but his girlfriend Rachel was there. So was Rachel's ex-boyfriend, who walked into the party brandishing a shotgun. So was Aaron, who by all accounts risked his life to defuse the situation safely.

On Wednesday evening, while Aaron and Abe are outside looking for Aaron's missing cat, Abe is angry that Aaron, a family man, risked his life in such a way. Abe is genuinely confused that Aaron acted so uncharacteristically irresponsibly. Aaron makes excuses and claims that since the discovery of the time machines he is seeing the world differently, referencing their conversations of earlier in the day. However, this does not fully explain his actions.

Thursday (48:45)

The same routine again.

During the day spent at the hotel, Aaron's cell phone rings. It is Kara, asking about dinner. This is a mistake, since Aaron is supposed to be sequestered. Abe tells Aaron not to bring the cell phone back in time with him - this is a perfectly sensible way to avert the possibility of a paradox.

They loop back in time as usual. On the second time through Thursday, Aaron watches a sports match (whose outcome they already know) while Abe eats a muffin. Then, on the way to a restaurant, Aaron's cell phone (which he has foolishly brought back in time with him) rings again.

This is a problem, and a critical turning point in the film. There are two Aarons at this point (one at the hotel), and, due to Aaron's clumsiness, two of his cell phones (one at the hotel). If the phone in Aaron's hand is ringing then, so Aaron and Abe reason, the phone in the hotel cannot be ringing. Symmetry is broken and history has changed. History can be changed.

Friday (52:10)

At about 02:00 on Friday morning some kids set off car alarms outside Abe's home. Abe goes to Aaron's house and gets him out of bed. Abe reveals that he has been routinely turning the boxes on at 17:00 and turning them off the following morning.

Abe then puts forward a confusing and potentially dangerous plan to visit Joseph Platts at his home, punch him in the face, then, around 03:00 Friday, to use these boxes to go back in time to 17:00 Thursday and make sure that neither the car alarms nor the punching happen. In theory, as a result, both Aaron and Abe's doubles would stay in bed all night, get into their boxes at 15:15 Friday as normal, and leave this timeline permanently, leaving just one of each of Aaron and Abe behind.

As they climb into the car, however, they realise they are being followed by Thomas Granger, Abe's girlfriend's dad and the project's main source of funding. Granger has several days' growth of beard on his face - but Aaron last saw him at 18:00 Thursday, when he was clean-shaven. Abe phones Thomas Granger's number and the guy who answers is indeed Thomas Granger... but he's not the guy who is following them. Something really weird is going on. This man is a different Thomas Granger who has come back in time using one of the boxes, probably exiting the box at 17:00 Thursday when Abe switched them on.

Aaron runs after Granger and when they get close to one another, Aaron trips and falls while Granger falls completely unconscious. They put Granger to bed at Abe's house; Aaron cannot approach him with actually somehow knocking him unconscious. They check that the boxes are indeed turned on. Aaron proposes shutting them off to see if Granger is inside, an act whose consequences would be exceedingly difficult to guess at. They do not do this.

Why has Granger come back in time? Obviously at some point in the future, Aaron or Abe told Granger about the boxes. Then, something happened to prompt Granger to head backwards in time to this point (the earliest he can go) and start observing them. They conclude that the situation would have to have been a real emergency but they have no clue what it could possibly be. "The permutations were endless." History has definitely changed now that Granger has come back, but they have no way of guessing whether the emergency in question has been fully averted by his brief interactions with them and the rest of the universe - he has only been out of the box for about eight and a half hours.

And so Abe loses his nerve.

It is now revealed that there is a failsafe box, built by Abe, in a second storage unit. This box has been running for 3 days 22 hours - in other words, since early on Monday morning. Abe started the box at about 05:00 Monday, then went back to bed until 08:30 when he returned to start Box A. At roughly 03:00 Friday, Abe returns to the failsafe box, with four days' oxygen and water and a small tank of medical-grade nitrous oxide, enters it and travels all the way back to 05:00 Monday.

Monday again (59:06)

Abe (now Abe Two) exits the failsafe box at 05:00. He travels to his home and gasses his double in bed with the nitrous oxide. He stashes his double in his bathroom.

Now we come to the second bench scene. As in the first bench scene, Aaron is listening to what is supposedly basketball on his earpiece. Abe Two is ill, after four days of very little food, and in shock, after violently gassing his double. Aaron, however, repeats most of the same lines as last time.

In fact, when Abe faints, it is revealed that Aaron is not listening to basketball. He is listening to a recording of that very conversation. How can this be? The recording must have been made in some previous timeline. This is not the original Aaron. This is not the original timeline. It never was. This Aaron has come back in time from the future.

"At this point there would have been some... discussion."

Aaron and Abe confront one another and explain everything that has happened. This is the most difficult sequence in the film to follow, partly because of the complexity of the plot but mainly because, due to the lack of CGI, it was impossible to put more than one Aaron on the screen at the same time. The two major discussion points are:

  1. How?

    Aaron's line, "They are not one-time-use only. They are recyclable," means that although you cannot re-enter a box you climbed out of, you can bring another box with you, activate it once you climb out, and later use it instead, travelling back to the same moment in time again - or a few minutes later, at any rate.

    In some previous timeline, Aaron discovered Abe's failsafe box, anchored 05:00 Monday. He then got inside the failsafe and used it to go back in time, taking with him a second, folded-up time machine. This is the Aaron with the hood.

    On arriving home at 05:00 Monday, Hooded Aaron set up his second time machine as Failsafe Box B, let's say at 05:15 Monday. Hooded Aaron then went to his home and drugged his double's breakfast cereal milk, then stashed his comatose double in the attic. This is the noise that Kara mentioned on Wednesday night. This means that there are now two Aarons in this timeline, permanently. Hooded Aaron assumed his double's identity and recorded all of the week's conversations.

    Then, he used Failsafe Box B (remember: he cannot re-use Failsafe Box A since he already climbed out of it once) to go back in time to 05:15 Monday yet again. He took yet another time machine with him, which he set up as Failsafe Box C (05:30 Monday). He becomes Aaron Three, with the white jumper, no hood. Aaron Three arrives at his house just as Hooded Aaron has finished drugging and stashing Aaron Prime. Aaron Three tries to subdue Hooded Aaron in turn, but this time he is too exhausted, and Hooded Aaron wins. After a conversation, however, Aaron Three persuades Hooded Aaron to leave. There are now three permanent versions of Aaron: Aaron Prime, who is drugged in the attic; Hooded Aaron, who has left town; and the Aaron we have been looking at since the beginning of the first bench scene, with the headphone in his ear feeding him lines, is Aaron Three and always has been.

    Aaron Three has had a LOT of exposure to the boxes. This is why he began bleeding from his ear on Wednesday, and it also why his contact with Thomas Granger nearly killed them both.

    It is Hooded Aaron who is the narrator of the story. The "primer" of the title is Hooded Aaron's phone call to Aaron Prime.

    So which box did Abe use to come back in time? Logically, Abe must have used Failsafe Box C, since Failsafe Box A contained Hooded Aaron and Failsafe Box B contained Aaron Three. How did that happen? Aaron must have SWAPPED Failsafe Box A and Failsafe Box C. The box that Abe believed was Failsafe Box A (anchored 05:00 Monday) was actually Failsafe Box C (anchored 05:30 Monday). This is not seen or even alluded to in the film, but it is necessary to resolve this plot hole.

  2. Why?

    Problems of logistics aside, the last remaining question is why Aaron chose to come back in time so far, sacrificing so much, permanently duplicating himself twice. What is he trying to set right, exactly?

    The key to all of this is the party. It is obvious, though left largely unsaid, that when Rachel's ex-boyfriend walked into the room with a shotgun, things could have gone considerably worse. Aaron Three, we remember, risked his life to successfully defuse the situation. We now understand why he would take this risk. There are two other Aarons in this timeline, one of them being Aaron Prime. Aaron Three does not matter - he is a non-person, a walking dead man, and he has no right to Aaron Prime's family. He has no life to risk.

    If I may jump ahead in the film slightly, the basketball scene (which takes place sometime in the middle of Monday) is also important. This scene further establishes that it was Aaron who originally invited Will, Rachel's ex-boyfriend's cousin, to the party - and that it was Aaron who suggested that Will should bring Rachel's ex-boyfriend with him. In other words, whatever originally happened at the party was indirectly Aaron's fault.

Aaron Three thought the problem permanently settled. But the fact that Thomas Granger came back in time to 17:00 Thursday indicates that it was not, and something bad was still looming in Aaron and Abe's future. However, it is Monday morning again, and both Aaron Three and Abe Two are prescient now. They decide to engineer the situation to end better this time, with Rachel's ex-boyfriend actually arrested and jailed.

By Monday afternoon, Aaron and Abe are both suffering from the effects of a great deal of time travel - they are unable to write correctly. Remember when they put their hands into the machine?

At this point, the narrator, Hooded Aaron, reminds us that HE, of course, does NOT come from a timeline where everything worked out perfectly. In fact, he was never originally at the party. He has no idea how long it will take for Aaron Three to "reverse-engineer a perfect moment". From what we see in the film, though, for Abe Two and Aaron Three, it appears to work first time. The jealous ex is arrested and jailed. The End.

On Monday night Aaron Three crashes at Abe's house. Abe Two cannot sleep. And with that problem resolved, everybody lives happily ever after.

With the following exceptions.

Tuesday again (1:09:28)

Aaron Prime wakes up in his own attic after being drugged for 24 hours by his double.

Abe Prime wakes up in his bathroom after being gassed for 24 hours by his double.

There are three running failsafe boxes which evidently nobody has thought to shut down, in addition to Abe Prime's original Box A, which hasn't been activated yet but is nevertheless operational. "They'll be building their own boxes in another day. And [Abe Prime] already knows what they built."

Aaron Three and Abe Two wind up at the airport. Aaron is going to steal his double's passport and leave the country, because he can never go home. He has lost Kara and Lauren to Aaron Prime. Abe, meanwhile, is going to stay behind so he can sabotage their doubles' attempts to build the time machines. And, more sinisterly, stay close to Kara and Lauren. And protect them from Aaron Three. What?

And finally, on the other side of the world, Hooded Aaron makes his phone call to Aaron Prime. Maybe Aaron Prime records it and believes it, maybe he doesn't. Hooded Aaron explains the entire story, including why he drugged Aaron Prime, and thus "[repays] any debt I may have owed you".

"You will not be contacted by me again. And if you look, you will not find me." Hooded Aaron hangs up, and begins construction on a time machine the size of a warehouse. The End.

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Discussion (170)

2009-11-10 22:36:25 by Ben:

Bravo. Really, this is fantastic.

2009-11-11 00:11:28 by Thrack:

Heh, you actually wrote another article about Primer. Cool. I haven't read it yet though because I haven't seen the movie. I plan to though. Eventually. (And if I remember, I'll turn on subtitles.)

2009-11-11 16:31:55 by Cory:

There were a couple things I could never resolve... This helps a lot.

2009-11-11 21:28:26 by John:

Nice article! Your first article on Primer was what prompted me to see it. Great movie!

2009-11-12 08:24:06 by scotherns:

How many viewings did it take you to get all this? Superb work figuring it all out!

2009-11-13 22:44:29 by MrX:

There are no flaws in how Primer deals with time travel. I think you misunderstand how it works. Instead of there being a global timeline, it instead works on the basis that every human has its own timeline at every instance. Normally, ALL instances of time will have the same timeline for any person, only that it is shifted in time. But Primer says that there are infinite YOU's, all in sequence. But that each of those YOU's are independent beings. Since normally there is nothing to make them act differently, they only appear to be the same person.

So you can indeed use the same box if you want. Suppose you enter the box at 2 PM and exit it at 1 PM. You then wait around for an hour and stop your double from entering the box. You can then enter said box no problem for a second time.

But let's suppose you DON'T enter the box. No one is entering the box. Truth is that a few minutes into your own personal timeline's future, there IS someone in the box (he is going back in time from everyone else's POV). However, from your personal timeline's point where you stopped your double from entering the box, there won't be anyone there. So if you DO enter the box, there will be a double in the box with you, but a few minutes into the future from your POV (your future is actually back in time for everyone else) and this is perfectly fine as there is never more than one person in the box at any given time. You will never meet this double because he is in your immediate personal future (unless he goes back in time to meet you).

Back to the situation where you DON'T go into the box. What then? If you don't go into the box, who will stop the double on the next iteration? Well, no one. You stopped him from getting into the box. So if you wait around for two hours, then if you could look two hours into Earth's past, you would see that no one is there to stop the "double". So he gets into the box, goes back into the past, waits an hour and stops his double. This scenario will flip back and forth.

And this is actually what the story of Primer is all about. If you get into a ping pong situation, you only fixed the situation for a segment of your personal timeline (if you fixed anything at all). The other side of the ping pong timeline is still screwed. And this ping pong effect is what happened when they use the failsafe (and knocked the guy out and put him in the attic). This is why Thomas Granger came back. Because half of the timeline is screwed and in that messed up half, Granger used the box to try and come back and fix things. Only problem is that he calculated the amount of time to go back wrong. He ended up on the wrong side of the ping pong timeline. The side he ended up, the timeline was already "fixed". His presence there will have unforeseen effects because he's just created his own ping pong timeline without realizing it. In the timeline that isn't screwed, Granger has no need to get in the box because everything is fine (these two scenarios will happen one after the other continuously). So you have the failsafe of Aaron ping ponging with the ping pong timeline of Granger. What effect this will have overall will be unpredictable.

2009-11-14 16:08:17 by Mick:

Sam, I guess you're just that good of a writer, but I enjoyed reading this more than actually watching Primer.

2009-11-15 07:51:36 by Ian:

You ask why Abe Two suggests that he's staying to protect Kara and Lauren from Aaron Three. In that same conversation, Aaron suggests that they kidnap Kara and Lauren, make doubles of them, and then go travel somewhere with copies of each in separate hemispheres. Abe Two wants to make sure this never happens -- that Kara and Lauren's lives are never disrupted by their doings.

2009-11-17 11:22:47 by M:

after reading this, i though you might have a giggle at this:

bottom right is a character interaction line flow for Primer (the rest of the image is pretty fun too!)

2009-11-17 11:25:45 by Sam:

Randall Munroe is a quitter. His main error was to treat time as a one-dimensional axis.

2009-11-28 07:52:35 by Ryan:

Are you entirely sure the phone call is placed to Aaron prime and not Abe prime?

2009-12-02 03:09:48 by Ian:

I don't think it really matters who the phone call is directed to.

2010-01-12 16:15:27 by nogenius:

There's the graph of primer that xkcd did (although I expect it's wildly inaccurate)

2010-01-31 22:17:19 by Katrina:

If Aaron 3 steals his own (Aaron Prime's) passport, how did Aaron 2 (Hooded Aaron) get to France?

2010-02-28 12:57:00 by Wepol:

OK, but why did <u>Abe</u> failsafe (for four days) all the way back to Monday when he didn't need to?

2010-02-28 18:33:50 by Sam:

Because he felt he'd lost control of the situation and he'd lost his nerve. This is pretty clear from the movie.

2010-03-03 04:08:58 by Sammy:

Not really sure what this is. I'll try to read this when I am not so tired and write some feedback. I really loved the Primer Universe book. Is any of this based on the book or just personal speculation? The whole hidden clue thing makes me wonder if any other films are similar to this effort by the film maker. Too bad he only made one film. Leaps and bounds better than the Prestige.

2010-05-29 11:46:36 by Fixer:

It just popped into my head this evening: How did Aaron bring the failsafe machine back with him? I can see bringing the "coffin" back, but how do you take the machine into itself? Do you take a new box and the machine in with you?

Oh, my head.

2010-06-06 07:54:06 by Astyanax:

The answer to this question is that you can make doubles of the machine just like you can people. All you have to do is fold one up and take it with you, and make sure your double on the other end doesn't take it back inside at the end of the day. Since Aaron was keeping two of his doubles from going inside again (drugging and persuasion), it's safe to say the extra machines also stayed outside.

It's like wishing for more wishes; you can use a time machine to make more time machines. :-) Rule of thumb: always take a time machine with you when you go inside one. :-)

2010-08-13 09:42:38 by Bobz:

This is great! But..... the explanation says - "They put Granger to bed at Abe's house; Aaron cannot approach him with(out) actually somehow knocking him unconscious." - However, in the film, both Narrator Aaron and Aaron Three suggest that it is Abe's proximity that causes Granger's unconsiousness. Why would being close to Abe cause Granger's unconsiousness?

2010-10-03 02:14:14 by Carnate:

Very nice explanation of everything but at the beginning of the article you mention "While fiddling with the device, Aaron pokes his hand right the way into the field and Abe puts his hands over it to drop punched holes into the field. This becomes significant later." I don't see where you explain where this is significant.

2010-10-30 18:19:11 by Chuckles:

The first time we see Aaron on the bench it is Aaron "recording the conversations of the day'. He is wearing the earpiece only for cosmetic effect because he knows he will be wearing the earpiece when comes back. If he doesn't wear the earpiece while recording he will not be able to record people's reactions to the earpiece when the same conversation comes up again.

Imagine if Aaron recorded the conversations and the next time around he wore red, floppy, clown shows. By introducing a new visual variable the recorded conversations would become much less helpful.

Aaron is so smart that he knows he needs to keep as close to the same appearance as possible to try to keep the conversations the same. Since Aaron knows he will need the earpiece later in order to listen to the conversations he knows that he needs to wear it while recording in order to keep the conversations the same as the recording.

2010-12-08 13:02:22 by Mika:


According to a theory on

"The idea — such as it is — is that is Granger talks to Abe, he'll tell him something that'll motivate Abe to use his failsafe box to go back and reset everything, thus preventing Granger from ever traveling in time, resulting in a paradox. It's this looming paradox that causes Granger to black out whenever Abe is near."

2011-03-12 06:42:58 by Seething:

Reading this has made me very angry! And my head hurts! Pay for my brain transplant!

2011-03-20 05:19:17 by TomC:

I would also like to know more about the punched holes - how are they significant later in the film?

Useful explanation thanks, but my head is still resisting the knowledge.

2011-04-24 16:51:06 by urza:

Thanks a lot for excellent explanation. I finally get it.

Last time I felt like this was while studying the formal definition of halting problem :)

2011-04-29 20:45:24 by Indigo:

"Abe then puts forward a confusing and potentially dangerous plan to visit Joseph Platts at his home, punch him in the face, then, around 03:00 Friday, to use these boxes to go back in time to 17:00 Thursday and make sure that neither the car alarms nor the punching happen. In theory, as a result, both Aaron and Abe's doubles would stay in bed all night, get into their boxes at 15:15 Friday as normal, and leave this timeline permanently, leaving just one of each of Aaron and Abe behind."

You see, Abe should have thought this one over.
Their daily trips go from 08:45 to 15:15 (or 15:15 to 08:45 rather) on the same day. If they had managed to sleep through the night, they would've woken up Friday morning, restart the machines at 08:30, set the 15 min timer, and jump in at 15:15. Meanwhile, the leftover duo would have witnessed another set of doubles re-emerging from the storage facility shortly after 08:45 Friday morning. The problem of duplicates remains.
In theory, it might have possibly worked if they somehow convinced their doubles to leave the machines on and not restart them so that when they went back, they would be able to go as far back as 17:00 Thursday afternoon (the same emergence time of the duo that prevented the kids setting off the car alarms). Of course, they can always just kill them too! Abe's stock plan was much more sound.
Indeed, we find out near the end of the film that any time symmetry is broken in a manner that significantly affects your double (ie. not entering the box when he/she should have), we get the duplicates dilemma. Think of how many Aarons there would have been if he didn't nail that party plan on his third run. He would've had to keep going back and convincing the previous to take a hike.

It helps to remind oneself that the premise for time travel in reality is not understood at all. So we go on what is presented by the storyteller. In this case, history can change and branching timelines exist. The story unfolds from a particular perspective - Abe's perspective - starting from a particular timeline (a timeline where Abe did not go back to gas himself, but a timeline already altered by Aaron). If the story followed Aaron in a certain timeline, we could have seen him going to the party to witness the incident, going back to drug himself, recording the week's conversations, going back again to fight himself, and convincing the previous to leave, and so on. It might have been a longer movie, and probably not as intriguing. Stranger still, it might have been a very different movie altogether if it were told from either Aaron or Abe who got drugged. From their perspective, they just built a machine they didn't even understand yet, and suddenly they wake up in the dark not knowing how they got there. This subject does tend to get confusing. I kept asking myself, how could symmetry really be broken? Wouldn't I always see the end result? In other words, if I wanted to go back a few hours to make a change.. to say hello to myself for instance; wouldn't I have seen myself greet me a few hours ago in the first place? And so, you can get trapped in this circular logic if you don't accept certain rules like the possibility of multiple timelines.

2011-06-02 00:23:59 by dan:

I don't see why the hole punch bits from the beginning are relevant, does anyone know why?

2011-06-02 00:26:06 by Sam:

The hole punch bits aren't relevant. What's relevant is that Abe and Aaron both stick their hands into the machine.

2011-06-02 10:23:32 by Dan:

*is stupid* I still don't understand why their hands going into the machine is relevant :\

Concerning Aaron swapping the Failsafe boxes: wouldn't Abe know his failsafe, f0, has been swapped for Aarons f1 or f2, as the timer would differ by the time it takes Aaron to exit f0 and set up f1/2? Assume it's not that bit a time difference and doesn't really matter.

2011-06-22 16:41:27 by clarissa:

I disagree that he builds at warehouse sized Time machine at the end. Because that makes little sense what is he gonna take back that needs that Much space? And he can only use it ONCE. Instead there is the last line of the movie. " Good morning, every have meter.... everywhere.... everywhere." What is he asking them to build every half meter.... everywhere? Time Machines... a LOT of them.

He is filling the warehouse up with a LOT of time machines, that way he can turn them ALL on at once. This way he will always be able to go back to the moment they were ALL turned on... and be able to always have a fail safe, until his health gives out.

2011-07-03 05:32:59 by Peter:

I have a few questions, if anyone could help :)

1) At the point where Abe and Aaron are testing their device at their garage and they think they blew it. Then they decide to remove the case so they can pick up Aaron's camcorder. Now all this is long before the fateful Monday in March when the whole main plot begins. After they both say '1-2-3' and remove the case, the scene blacks out and changes, showing Abe unconscious on the floor and the sound of static can be heard. It's really strange; what on earth happened here? Notice how Aaron calls him on the phone and Abe wakes up; then the scene REPEATS and Abe is still on the floor while Aaron's voice continues talking (asking him if he's hungry) and Abe is shown to pick up the phone again. It looks like there's TWO Abes here... For example, we see that one Abe gets up and Aaron is heard saying 'Abe, it's 7'. Then we see Abe getting up AGAIN and Aaron now says 'Abe, it's 7 at night'. This repetition of movements, and the way the scenes are presented, show (at least to me) that we have here TWO Abes. My initial theory was that this was a result of Abe Prime's proximity to the time machine which he had brought in his house (???) to test it, after they took Aaron's camera out of it and removed the case, and somehow he'd fallen unconscious as a result of so many 'leaks' (no cover). But I really am not sure. So what's up with this scene here?

2) After the last scene at the fungus lab, right after Aaron asks "Wait digital or old mechanical?", and Abe replies "Exactly. I did both." Then Aaron: "And?" and Abe: "I want you to do it". At that point... Well, first, I want to make sure: this is on Monday late morning, right?

3) Anyway, the NEXT scene shows another Aaron playing with some garden clips while next to him we hear Abe and Aaron talking (about to discover what their device really is; it is heard in the background "We thought we were degrading gravity" etc.) Now, it is obvious this Aaron is impatient as they are already in the storage facility as well. He keeps looking at the clock on the wall, which however shows 14:08. So which Aaron is this and where and when did he come from and why is he there and when does he intend to leave and where to?

2011-07-04 03:21:57 by Jfjdkf:

The hands are relevant because they stick them in there when testing and that part of their bodies are aging faster than all the others, just like the webel growing mold the hands age causing them to not be able to control writing. Which is why Aaron said he knows the letters he just can't get his hand to make them........ I think.

2011-07-15 04:03:31 by Anonymous:

Would it be possible to:
- Modify the small prototype box to eject any object inside at the right time
- Power it up, intending to insert a diamond a few minutes later
- A few moments after powering it up, at the window, the duplicate future diamond should be ejected
- Don't insert the diamond, effectively doubling your money. So much easier than going in yourself and doubling money by trading in the stock market (forex would've been better). I would think that'd raise some insider trading alarm bells.

2011-07-18 23:39:13 by blackacidlizzard:

You're loading ideas you have about time continuity which are not in the final cut of the movie. Unless you have inside information on the writer's intent, you are making assumptions with no backing.

There is no reason to think that observer-dependent wave collapse plays any role here. No examinations of the hand or paper placed in the already active field which is open to observation are ever carried out - how would you know if your hand aged a few thousand minutes? No mention is made of effects of observation, the characters are worried about the lack of environmental containment suitable for the field ; and the idea that a camera signal full of static equals probabilistic indeterminacy is a ridiculous leap.

The question of whether time is singular or branching is irrelevant, all that can be known is what is observed, and every observer will always only know one path, whether or not there are any other paths. This movie treats time branching the same way "Pee-Wee's Big Adventure" does: it is never mentioned or hinted at.

A confrontation with your other self "causing" two of you to exist in the same timeline is laughable. Lock yourself in a room, fly to the moon - there are still two of you in the same timeline. The only concern that is close to this is that the chain of causality flowing from any action (not just meeting yourself)may cause your other self to not get into the box - which would leave two of you permanently walking the earth.

There's alot of good stuff in this post, but when you assume you make an ass out of yourself and anyone who accepts your assumptions.

2011-07-21 01:59:01 by HelloWorld:

I think being unable to write was just a side-effect of several trips inside the machine. It seemed to affect the brain somewhat. Aaron told Abe to compare it to writing with his left hand and they looked the same.

2011-07-21 02:26:15 by HelloWorld:

Also, It didn't make sense for Abe to have affected Thomas just by proximity, if the reason was causality. Abe and Aaron doubles have gone near each other and prevented each other from going back without suffering the same effect.

I'm thinking something like this happened: In one timeline, Thomas Granger found out about the machine, and probably used the failsafe. In the same timeline, Abe used the same box and was disintegrated. This sorta explains the proximity problem between Thomas and Abe.

2011-07-26 10:53:43 by Betty:

I enjoyed the film, but I could not buy into the fact that either character's main concern was to go back in time to manipulate the stock market and basically steal money in that way. These guys created a Time Machine, they're geniuses. Both characters develpment indicated that their primary concern would be to continue research related solely to the time machine and its effects. They wouldn't be interested in punching someone in the face or stealing money, that part just didn't fit, and really didn't add anything to the film. And for a couple of geniuses, go figure, they invite an ex-boyfriend to the party for no reason whatsoever, out of the blue. Are these guys high school dropouts? Yeah, sounds like it to me. Carruth could have easily found a more realistic scenario for the emergency travel back circumstances.

2011-08-05 04:50:11 by Brad:

Awesome, awesome explanation. But to me, the lingering question is... what happens to the other Abe? One flies off at the end of the movie, one wakes up in the attic, and the other....

2011-08-14 08:12:18 by Ichneumon:

Not a time machine the size of a warehouse.

Not thousands of time machines in a warehouse all turned on at the same time.

Thousands of time machines in a warehouse turned on at *different* times.

Set them to kick on in sequence; one at noon, one at 1pm, one at 2pm, etc., day after day, week after week.
At any time in the future, you can return exactly (well, within the hour) to any date/time you choose. Just pick the machine that activated at the date/time you want to travel back in time to, and hop in.

Even better, you no longer have to do it all in one session -- you don't have to sit in a box for a full month to go back in time a month. Get into the box that started 4 hours ago, spend 4 hours in it, then get out, stretch your legs, go to the bathroom, have lunch, grab another oxygen bottle, then get into the box that started 4 hours before *that*, etc. Repeat until you've gone back however far you want.

2011-10-02 08:41:35 by raymond:

I appreciate the author's input on this film. It stimulated a lot of interesting reads.

Given the "reality" of the movie, what would happen if you put a running time machine inside of a another time machine then turn that machine on?

From what I can tell, you can only travel back in time to the point where the machine was turn on. That's like an anchor point. When you turn the machine off, you are in essence opening up a door through time. However, it seems you MUST sit in the time machine for the length of time the time machine was on. You have to experience that time (in essence, you gain that time as part of the time travel). But I was thinking if there was a way to compound the length of time you traveled through, and decrease the amount of time you spend in the box by sitting inside 2 time machines.

I know this is all fiction, but it's neat to think about.

2011-11-11 23:29:29 by tre:

So much to read, not sure if this has been touched upon, but if one of the premises is alternate time lines, you don't necessarily need 'multiple' failsafes for the scenario to play out. the only thing that need exist is the 'you' in the box you came out of. It creates what seems to be a paradox, but if the concept is changeable/multiple time lines, as soon as you step out of the box, whether you are still in it or not is irrelevant.
i.e. you can prevent the 'earlier you' from entering it if you desire, but because it's an alternate timeline, you just prevent the 'you' in that timeline from going back to create another version, etc. (yeah, splinters get nuts to follow)
Think of it this way - if you can in fact go backward in time, the moment you step out potentially creates a new timeline where anything that happens from that moment forward is irrelevant to the old timeline, including the part where you were sitting in the box going backward. It's like creating a wormhole between alternate realities - once you step out of the hole and the machine shuts down or whatever, you are in a new place/time with new causalities. So if you wanted to re-use the same failsafe, you just keep the 'other you' from getting into it, say by drugging him in your attic, then you can use the same (empty) failsafe box to go back again.

2011-11-11 23:35:15 by tre:

With that said, the last scene would, however, require one additional failsafe (which is mentioned in the movie) for both of them to have been able to go back via the long-term failsafe mechanisms to have fore-knowledge at that moment. But this only means that for that last 'loop' from Aaron's perspective, he only need 'allow' Abe to enter the first failsafe while he enters the second. He could have technically used the other failsafe many times already and come out of it again playing the long-loop again and again and the only thing he need to each time is make sure that Abe wasn't entering it at the end of the long-loop.

2011-11-11 23:42:34 by tre:

Oh, and of course the duplicate thing - any time you 'prevent' yourself from re-entering at the end of the loop is where the potential for a duplicate of yourself would occur.... until you re-enter the box again and go back to create yet another different time line (and another potential for a duplicate) - there would only end up with one duplicate of yourself in any one timeline - at least in the same-box-reuse scenario. As soon as you prevent yourself from entering the same box making it available for 'new you', you need to get 'old you' out of the way when you go back and until you loop again (or old you loops at all), there are two of you. If you don't loop in his stead, there is two of you. But as long as you continue to re-use the same machine preventing 'old you' from doing so, that time line is left with one of you and you become a duplicate back at the same point in time with a new branch.
A 'third' you wouldn't occur until you prevented 'old you' from going and did not take 'old you's place then repeated that whole process yet another time. I didn't see anything in the summary that would have suggested that.

2011-11-18 02:05:32 by booboobear:

I just have once concern regarding the bench scenes in the movie. I don't believe it's Aaron 3 the entire day. I think the very first time you see them on the bench, they are in the 1st timeline and it's the original Aaron and the original Abe that traveled back on that 1st Monday afternoon to Monday morning to tell Aaron about the boxes. Aaron is wearing an earpiece, but his reactions and demeanor seem genuine and there a few scenes that same day when he's not wearing an earpiece at all. I think that when Aaron 2(hooded Aaron) went back through the failsafe to Monday, he recorded all conversations from the week. the second time we see them on the bench on Monday, it's Abe's double and Aaron 3. The first bench scene is original Aaron and Abe from the very first time travel while his former self from the day is waiting at the hotel.

2011-12-28 12:53:44 by Maxim:

Why would Aaron built a new LARGE time machine in the end of the film??? For what purpose? To send MANY people back in time? What for?

2012-01-02 16:45:43 by John:

@Maxim: He left the country and has to now survive a lifetime in that time line. He is probably being commissioned to build it. He probably has no use for such a large time machine himself, but I'm sure that the military would love to have technology like that on such a large scale and would pay whatever it takes for it.

2012-01-02 16:45:43 by John:

@Maxim: He left the country and has to now survive a lifetime in that time line. He is probably being commissioned to build it. He probably has no use for such a large time machine himself, but I'm sure that the military would love to have technology like that on such a large scale and would pay whatever it takes for it.

2012-01-07 07:45:31 by Nina:

That would be the French military?

2012-01-09 14:04:17 by Pete:

The Primer concept was a great story, unfortunately, it got swallowed up its own ass by the random, confusing dialogue and the shocking continuity problems. Not bad for $7K, but would have been better if the director didn't take himself and the story so seriously.

2012-03-03 07:03:05 by uday:

awesomemovie and awesome explanation

2012-03-15 06:38:23 by J:

"At this point, the narrator, Hooded Aaron, reminds us that HE, of course, does NOT come from a timeline where everything worked out perfectly. Hooded Aaron has only been to the party once, and he has only seen how it originally played out."

This is wrong.... And I think the movie contradicts itself too. The first Aaron never went to the party. The third Aaron went to the party back when he was second Aaron. However, second Aaron never gets to go to the party at all because third Aaron makes him leave. Thus, when second Aaron makes the phone call and says that he can say what he did when he went, he must be wrong. Unless third Aaron or second Abe told him what third Aaron had done.

2012-03-15 19:18:20 by Thirteen:

Thanks for the explanation of Primer - really useful. I felt so stupid watching this film. I couldn't follow all of the subtle plot lines at all. Just vague ideas as to what was going on. So it's nice to have it laid out like this, assuming it's all correct of course! I don't want to know if it's not though!
Reading some of the comments here blows my mind though. This is just a made-up story someone wrote and turned into a film ..... for fun. It's extremely doubtful that they discovered time travel in the process and that their "theory" holds any water, so I just don't understand why people even try to rip it apart, find flaws in it, expand on it. What's the point? Just enjoy the movie, doin't suck all the fun out of it. And yes I know some people are just discussing what was in the film-maker's mind and that's completely separate - nowt wrong with that.

2012-03-25 06:34:56 by RobertLockard:

Amazing article! This is quite an achievement. Well done, sir. Now the only thing I need to figure out is why the movie is called Primer in the first place.

2012-03-31 05:31:17 by Noni:

I think the simplest explanation for Aaron's warehouse-sized time machine is to enclose a very large amount of air, water, and food. It could be a long-term failsafe.

I also wonder about nested running boxes. Run box A for a week. At the end of the week, enter box A with box B and turn on box B. When you emerge from box A at the start of the week, you've got box B, /which has been running for a week/. Assuming that nested boxes don't destroy the universe or something, this method could enable you to go back even before the machine was invented.

2012-04-04 22:11:15 by piton:

One confusing thing in the movie is that they call their (causally) past ones their doubles. Their existence is based on that the "double" will enter the machine later, so they remember everything the double experienced.
This confusion leads to that you cannot focus on the more difficult parts, and end up more confused.

2012-04-05 10:24:58 by ryan:

There is either a typo or something I'm not understanding from the explanation. In the explanation you write that His wife asks him about the rats in the attic on Tuesday nite while they're drinking a few beers but then at the bottom of the explanation you say that they had this conversation on Wednesday. Is the original Aaron (Aaron_0) the one that had the original conversation with his wife or is it the Aaron that has already went back via the failsafe?

2012-05-20 18:56:50 by Bar:

Great piece. Primer is one of my favourite movies. Such a lot to think about in there.
I'd hazard a guess that if indeed the large warehouse is to be a time machine, it could not only be used to take back large supplies of oxygen, food and supplies, it could also concievably be used to contain a dwelling, cars, helicopters, weapons, or ANY technology. If you started the machine today and left it running for ten years, then potentially you stop the machine in ten years time, and fill it up with rayguns and iPhone25's and $50 billion in used 2012 banknotes(Without getting in yourself), that stuff could magically appear in five minutes time. Or lets say you turn it on now and wait fifty years till someone invents a zero point energy machine. You could stick that in the machine and get it out in five minutes. There's no limit to what could be sent back in a warehouse of that size... I suppose it's about learning to think big!

2012-06-18 19:34:01 by lenmorvash:

greatly explained, i only understand like 50% of the movie before this, just still thinking about the difference of Primer's mechanics+heat time machine versus Stephen Hawking's timeholes time machine

2012-06-18 19:36:12 by lenmorvash:


the idea is great, but i can't imagine staying in a hotel or any way to be sequestered for 10 years to avoid a paradox,

2012-08-07 12:25:06 by VK:

You are awesome. Thanx a lot!

2012-08-16 18:56:38 by curiousgeorge:

The issue I have is something mentioned during the director's commentary but not really explained and that is that at no point in time is matter and energy static. That is to say, the entire universe is constantly expanding so if you were to move in time it would also be necessary to move through space also else you'd end up exiting into where the time machine was and not where it is.

2012-08-16 19:20:52 by Sam:

Primer is actually one of the few time travel movies which deals with this properly. When you are travelling back in time, you are also following the path backwards through space, because you are inside the box the entire time.

2012-08-17 03:29:46 by curiousgeorge:

So, let's say that once inside the box one were able to accelerate one's self to a velocity approaching the speed of light in order to benefit from the effects of time dialation. Other than seriously complicating the math, that would significantly reduce the amount of time needed to stay in the box and hence the need for large amounts of oxygen, water, food...etc.

2012-09-24 13:23:34 by Tulsa:

On Monday, the day starting when Abe and Aaron meet on the bench, why is Aaron sometimes wearing an earpiece and sometimes not? For instance he has no earpiece the when Ane shows him Abe's double the first time.

2012-10-20 20:34:33 by MindPuck:

@Tulsa: I think someone kinda answered this already. The presence of the earpiece depends on which timeline we, the viewers, are being shown. In the "original" timeline, there shouldn't be an earpiece at all.

@Peter this question is totally bugging me as well, arghhhhhh!

"2011-07-03 05:32:59 by Peter:

I have a few questions, if anyone could help :)

1) At the point where Abe and Aaron are testing their device at their garage and they think they blew it. Then they decide to remove the case so they can pick up Aaron's camcorder. Now all this is long before the fateful Monday in March when the whole main plot begins. After they both say '1-2-3' and remove the case, the scene blacks out and changes, showing Abe unconscious on the floor and the sound of static can be heard. It's really strange; what on earth happened here? Notice how Aaron calls him on the phone and Abe wakes up; then the scene REPEATS and Abe is still on the floor while Aaron's voice continues talking (asking him if he's hungry) and Abe is shown to pick up the phone again. It looks like there's TWO Abes here... For example, we see that one Abe gets up and Aaron is heard saying 'Abe, it's 7'. Then we see Abe getting up AGAIN and Aaron now says 'Abe, it's 7 at night'. This repetition of movements, and the way the scenes are presented, show (at least to me) that we have here TWO Abes. My initial theory was that this was a result of Abe Prime's proximity to the time machine which he had brought in his house (???) to test it, after they took Aaron's camera out of it and removed the case, and somehow he'd fallen unconscious as a result of so many 'leaks' (no cover). But I really am not sure. So what's up with this scene here?"

2012-11-04 12:10:58 by Potkingthefirst:

Primer 1(Redux)(Summary)

Abe the 2nd has decided to watch over the original Abe and Aaron and stop them from discovering time travel. After his disastrous attempt of sabotaging the coffins. He has made a severe mistake in which he informs Mr. Grainger of time travel, in hope that his funding to another project would push the original Abe and Aaron to pursue other projects. Unbeknownst to Abe the 2nd, he inspired Mr. Grainger not to fund the other project, but instead to seek the newly created failsafe box, which unexpectedly resulted in Mr. Grainger going back several months which explains why everything goes black and Abe Prime is on the floor in the first movie. Also the mysterious warehouse is explained in which Aaron the second, seeks to become truly prescient.

IDK, I really wanted to expound on the original movie and fix the plot holes, I'm just a time travel nerd. How does it sound?

2012-11-12 17:37:23 by Vladimir:

Does Primer have branching timelines, or a single timeline you can "edit"? Near the end of the movie, the narrator says "the last revision is what counts, apparently". Since the narrator is Aaron, that belief makes sense, because how else do you justify abandoning your wife and kid in a different timeline, just to save some folks at a party?

But if there's a single timeline that gets "scratched" whenever someone enters a box, I don't understand how Aaron and Abe were able to use two different boxes to go back in time together. So it seems the movie has a plot hole that I can't close. Anyone?

Reply to Noni about nested boxes: sorry, you can't go back another week. When you get into box B, you'll backtrack along the path that box B took through spacetime, so you just end up where you started.

Another interesting point: what happens if you put a working box on a scale? I gave it some thought, and came to the conclusion that a box with a person inside has to weigh less than one without. (If you use it to go forward in time, it weighs more, as usual. If you go forward and back, it cancels out.) And then I realized that the original purpose of the boxes in the movie was to reduce the weight of objects. Wow!

2012-11-12 17:43:02 by Vladimir:

Reply to RobertLockard: the movie is called "Primer" because it's about who is more prime than whom.

2012-12-08 21:35:55 by Richard:

what i dont get is what the debt is and if all is resolved at the end , them why is he building a warehouse sized time machine at the end

2012-12-23 02:44:11 by Nebuler:

As I see it, Hooded Aaron (2nd Aaron) brings another box back with him (recycling he calls it) and sets it up when he gets out, goes and records all the conversations for himself. Then uses the box he brought back to go back yet again and becomes 3rd Aaron.

As 3rd Aaron he interacts with his past self (2nd Aaron) and convinces him to leave. It is at this point 3rd Aaron has stopped 2nd Aaron from ever using the second box and becoming the 3rd.

Also 2nd Aaron had subdued Aaron prime which altered the events that had Aaron prime entering the failsafe in the first place to become 2nd Aaron. This frees up the failsafe to be used by Abe and as 3rd Arron is the current Aaron at this point and he used the second box they would have never been in the failsafe at the same time.

I'm going on the idea here that time does not retroactively correct itself (otherwise 3rd Aaron would never exist as 2nd Aaron never went back to become him.) So with this you could go back in time and kill yourself or your parents but remain there in a timeline where "other" you does not exist.

The questions I don't understand are: When Abe prime and Aaron prime awake, what are there lives like, how will they react to what there counterparts did while they slept? Does 2nd Abe prevent them from ever going back again? What happened in the off screen timeline that causes Granger to go back? Which Aaron is it at the end in france 2md or 3rd?

2012-12-24 21:04:47 by Aditya:

But if Abe(2) stays back to sabotage the making of the time machine by their doubles..dont all subsequent timelines get affected as well by either the late making of the machines and boxes or them never getting made at all?

2012-12-28 18:07:28 by Jim:

I applaud this very thorough explanation of the plotline in Primer, (probably the most thorough there is on the net), however there is only one tiny aspect that I disagree with. At the end of the film, when Abe travels back a week and tries to undo his mistakes, that is indeed Aaron 3 he is speaking to but was not at the beginning of the film. In the beginning, he is speaking to Aaron 2, who successfully plays out the timeline as he intended to originally. When Abe travels back to alter the timeline, he is met by Aaron 3 BECAUSE he fail-safed and Aaron has supremacy over the timelines since he stole the original fail-safe machine. Abe can never go back farther than Aaron, but each time he does he will displace and be met by additional "layers" of Aarons who has traveled back along with him to negate whatever Abe attempts to change. Basically, whoever can go back the farthest in time has the most control over the universe but at the cost of having the most duplicates at any given time.

To answer some other questions and pose new ones on here, Aaron 2 is talking to Abe 2 over the phone and explaining why he was knocked unconscious by one of his own doubles. The "debt" he is repaying Abe is stealing the fail-safe machine and thus robbing Abe of having ultimate say over the fate of his invention, not to mention forever distorting Abe 2's timeline.

There are also a lot of questions here about what effect any particular action has on other people's timelines and what not. Understand, what Primer demonstrates is that when it comes to time travel, subjective experience is all that matters. You can do whatever you want and alter timelines however you see fit, but only YOU will experience any altered timeline you have created. Everyone else that doesn't make the trip you made will be oblivious to any changes you have made as their timeline will stream with those events always having occurred. That is why Abe 1 is oblivious he is talking to Aaron 2 in the beginning because that particular Abe never traveled that far back yet. Therefore, he will always remember the timeline that way with never having interacted with Aaron 1 on the bench. Aaron 2 (and ostensibly Aaron 3) must remember what originally happened with the original Abe in his own particular timeline.

As to who is building the warehouse sized box at the end of the film, it seems obvious to me that is in fact Aaron 3. I say obvious because his facial hair growth is slightly less than Aaron 2's in the kitchen scene, indicating he hasn't gone as long without shaving.

Finally, I have always wondered, what would happen if you put a box on an airplane and turned it on right before take off? Would you immediately exit the box before even making the trip you were about to take?

2013-01-02 09:49:18 by Josh:

So I decided to revisit one of my all time favorite movies, Primer. This was my 3rd time seeing it again. I agree and disagree on various parts, but I have another question more importantly, one I had not put much thought into previously. It's not mentioned in this wrie-up and I didn't see anything about it in the comments either. Is it safe to assume that Rachel does indeed get kiled at the party? My guess is that she does get killed at the party, and perhaps Aaron feels responsible for inviting the ex-boyfriend. I can't think of any other reason that Aaron would be so determined to correct the events of that night. I think that Aaron goes back and stops the armed gunmen, but all he does is prolong her death until a later date, as evidenced by the future Granger, they both agree he should only know about the machine in the case of an extreme emergency. After this realization he concludes it wasn't enough, and resolves to go back a second time, this time getting the shooter arrested. Perhaps it doesn't add up but it makes some sense to me.

The other thing I don't understand is the logic behind the fail safe device. The fail safe device doesn't actually accomplish anything for them in the movie. The original boxes are set in a loop so that they will not meet their past selves, and they will always stay one day ahead of their copies on the timeline. Even once they are finished making their fortune and stop using the boxes, they will still maintain their own time line. The point of this is that even though they travel back in time, they keep their original lives by making their past selves travel back also, in a constant loop. Abe and Aaron take over their copies lives, while the copies take over their copies lives, and the copies of the copies take over their copies lives in an endless loop. The fail safe can go back the entire length of time it was active, but all this does is leave them in the past, essentially ereasing their future. Unless they go about the grisly task of killing their copies in the past, and taking over their lives, they can't actually change anything. By going back they can only alter the lives of their copies, their future selves are simply left stranded and alone. The fail safe device is the only way for these time travel twists and turns to be possible, but from a logical plot standpoint, its existence does not make sense.

I also thought of what I think might be an inconsistency, what happens to Aaron 1 when he uses the fail safe device and then relives that week, this time recording all the conversations as Aaron 2. At this time there should only be Abe 1, but Aaron 2 has now replaced Aaron 1. Aaron 2 now goes about the week pretending to be Aaron 1 with Abe 1. We know that Aaron 2 drugs Aaron 1 and puts him in the attic, we see this when Aaron 3 comes back on Monday. Are we to believe that Aaron 2 keeps Aaron 1 in the attic for 4 days? What about the fact that when Aaron 3 arrives we see Aaron 1 escape from the attic that same day (Monday). The only logical conclusion is that Aaron 2 actually killed Aaron 1, but this can't be true because Aarons wife talks about hearing noises in the attic on Tuesday or Wednesday. We know that the last scene on the bench is Aaron 3 talking to Abe 2 on Monday, meaning that for the majority of the movie we are seeing Aaron 2. We know that Aaron 1's first 4 days are never shown, I believe it must have something to do with the Party. There must have been a good reason for Aaron to go all the way back, seeing as they were making a killing in the stock market.

Thanks for listening to my ramblings, haha

2013-01-03 13:42:02 by Monkeytoe:

The problem with these explanations is that it is impossible for Aaron 2 or Aaron Prime or Aaron 3 to live at the same time for more than a short period. In this explanation, Aaron 3 convinces Aaron 2 to leave town and not go back in the box. In that case, no Aaron 3 could exist. Aaron prime only exists until he climbs into the box, at which point he becomes Aaron 2. there is a brief period (6 hours) when both Aaron 2 and Aaron prime exist at the same time, until Aaron prime climbs into the box, leaving only Aaron 2 in existence.

If Aaron 2 climbs in the box, then there is a brief period (less than 6 hours) when Aaron prime, Aaron 2 and Aaron 3 all exist, until Aaron prime and then Aaron 2 each climb into a box, leaving only Aaron 3 in existence.

If Aaron 2 never climbs into the box, there is no Aaron 3. If Aaron Prime never climbs into the box, there is no Aaron 2. Once past the 6 hours, only one Aaron remains - who is the original Aaron, just with all of the experience of going back and forth in the box and spending time as Aaron Prime, then Aaron 2 and finally Aaron 3.

It is therefore impossible for Aaron 2 to go to France and build a warehouse sized box - unless Aaron 2 is a manifestation from so far in the future that he and Aaron Prime can exist at the same time. At some point, Aaron Prime has to disappear by going into the box in order to create Aaron 2, leaving only one Aaron. It is possible to have a finite period of infinite Aarons as he keeps looping back by climbing into the box, but ultimately, the line reverts back to a single Aaron.

If any Aaron were killed at teh party, it would kill all Aarons. Example. Aaron Prime gets into box at Midnight Friday and gets out at noon Friday creating Aaron 2. Both Aaron Prime and Aaron 2 exist between noon and midnight friday. After midnight, only Aaron 2 exists. thus, if Aaron 2 gets killed at 11 p.m. on Friday, Aaron is dead. If, instead, Aaron 2 goes into a box at Midnight Friday and goes back to 12:05 p.m. Friday, there are now three Aarons in existence between 12:05 friday and Midnight Friday. After midnight on Friday, only Aaron 3 remains. Thus, if Aaron 3 gets killed at 11 p.m. at the party, no Aaron exists after midnight. If one of the other Aarons finds out and then does not get into the box, then the subsequent Aaron was never created. If Aaron 2 does not get into the box at midnight, Aaron 3 never existed.

2013-01-03 13:54:23 by Monkeytoe:

Think of it another way, Aaron is a single line that loops back on itself each time Aaron (in whatever iteration) climbs into a box and the aaron line cross its own path when Aaron (now Aaron 2) climbs out of the box at an earlier time. It just continues looping back on itself, but it is still a single line. If you break that line at any point, it is the end of Aaron. Otherwise, the "box" is not a time-travel device but a cloning device creating new, entirely independent, Aarons.

2013-01-10 17:35:38 by Jim:

As far as the Thomas Granger incident, a lot of people are forgetting some key details. Granted, the most reasonable explanation is that Granger is sent back because at some later date Rachel is in fact murdered by her ex boyfriend. For whatever reason, (probably because they were arrested for punching Joseph Plaats in the face), neither Abe nor Aaron could be sent back to prevent it. So one of them must have told their version of Thomas Granger to use one of the boxes (presumably Abe's) to go back and stop them from punching Plaats so that they don't get arrested and therefore can use the boxes to ensure nothing ever happens to Rachel. Him falling unconscious in Abe's presence could be because if two people use the same box they become saturated in a magnetic charge. (Positive repels positive, negative repels negative). But I have a much simpler and simultaneously much more complex alternative explanation for Thomas Granger's presence:

Let's break down exactly what happens solely within the Granger event itself: Abe and Aaron get in their car on their way to punch Plaats in the face. On their way they notice Granger sitting in the car. Who do they call to verify it is his double? Thomas Granger. In the middle of the night. Granger likely has called i.d. and probably recognizes Abe's voice. It stands to reason that perhaps the phone call Abe made somehow leads to Granger discovering the time machines and using one to go back in time. The reason he is knocked unconscious by Abe's presence is because he is suffering from recursion. Abe is the source of Granger's paradox, he called him, he came back in time, and around and around we go.

2013-01-13 22:01:41 by Matthieu:

2012-11-12 17:37:23 by Vladimir:

>Reply to Noni about nested boxes: sorry, you can't go back another week. When you get into box B, you'll backtrack along the path that box B took >through spacetime, so you just end up where you started.

Why should we take the same path ? We are in a new timeline with a one-week "loaded" box so when the box is turn off the time encounter a cul-de-sac and go back the other way, and we end-up one another week earlier. We don't know how it works, if the machine load with "negative time", set a spacetime path or just define an interval where the time flip-flop, we can only make guess.

About the end, it could be Aaron 2 planning to life inside a machine so "you will not find me". With 1300*one month he has more than a century to spend, and he can even invite babes inside (ok its not very realistic...)

2013-01-17 15:09:33 by Maw:

I still don't understand why Aaron had to go back to Monday twice thus creating Aaron 2 and 3 permanently. What was he trying to accomplish?

2013-01-17 16:40:56 by Jim:

@ Maw : Aaron traveled back because in the original timeline, he was not at the party. As the audience, we are left to only speculate as to what occurred and will never truly know what actually transpired in the original timeline, especially since the level of deception in which Aaron is willing to go is finally revealed to us at the end. Now, in order for him to alter the past from what originally happened, he had to take his past double's place. In order to do that, he had to render his double unconscious to occupy his role so that the world is not encountering two Aarons simultaneously. (This would obviously raise some concerns). We learn, however, that a third Aaron returns from the future and attempts to render Aaron 2 unconscious but is unsuccessful. Clearly, while this indicates something still went wrong when he tried to correct the past, it also is due to the fact that Abe failsafed and had no intention of telling Aaron about the boxes, thus resulting in a third "layer" of Aaron in the timeline Abe 2 has arrived at.

This is problematic for Aaron because if he is never told about the boxes then his doubles will not vacate timelines that he intends on occupying by entering the box at the intervals in which he did. He would be condemned to either having to kill his own doubles to remove them permanently if he wanted to keep traveling or stop traveling altogether, neither of which sound like very attractive options to Aaron. Thus he failsafed to return to an earlier point than Abe so that he will forever have supremacy over the timelines. (The film depicts Aaron as the kind of person that probably didn't like when he first learned of the machines and realized he was existing in a universe altered by Abe. He is the kind of person that would rather have that power over others). So to answer your question, what he is trying to accomplish is to produce an outcome of perfect results for himself, an obsession that has consumed him since he became intoxicated with the power to travel through time and set things howeveri he sees fit.

2013-01-27 06:02:37 by headache:

so after all of this my head hurts.....

2013-02-20 20:48:42 by VuffiRaa:

Thank you!

This explanation is awesome! How often did you have to watch the film in order to write it? :P

2013-03-08 21:30:39 by cool:


2013-03-20 12:09:47 by Teddy:

How does the watch run forward when going backward through time?

2013-03-20 16:02:26 by Bobber:

here is a thought, if you started a smaller box in the future, then got into a larger box with the smaller box running and you outside the smaller box and went back in time, then emerged from the larger box with the smaller box and got into the smaller box, could you go back into what would be the future...

2013-03-20 17:52:02 by Sam:

Bobber: or you could just wait a while

2013-04-10 16:12:44 by Jim:

@ Teddy : The watch runs forward because it is still subjectively experiencing time progressing forward. What was odd that they noticed was the AMOUNT of time that the watch had subjectively experienced and the actual time that had passed from outside the box. This indicated that the watch was experiencing twice the amount of time because its arrow of time was no longer linear but parabolically shaped. Therefore it was making forward and backward trips which resulted in a doubling of the minutes it had experienced subjectively. The only flaw the film has from this standpoint then is that Aaron and Abe would have had to subjectively experience 12 hours in the box to travel back 6.

@ Bobber : No. What you just described is essentially what Aaron did to travel back farther than Abe. He folded up the failsafe box and took it back with him into his box. He then opened the failsafe that had been running the entire time within the first box and traveled back in it to an earlier point. What would happen in the scenario you presented is that you would wind up deeper in the past, not farther in the future.

2013-04-17 10:16:55 by BishopAP:

I don't understand Abe's and Rachel's relationship. She's supposed to be his girlfriend, right? Why do they seem increasingly distant as the movie progresses? At the party scene near the end, they don't even speak to each other and it looks like she's there with a date. Even on the phone, Abe doesn't seem to be very passionate or show any kind of romantic emotional attachment to her. Also, I don't understand how she could be at the party originally. Abe has to be told at one point that Aaron stopped her shotgun-wielding ex-boyfriend, which means that she was there and Abe wasn't. But later, it's established that the only way to get her to attend the party is to have Abe invite her, that she only goes because he's going to be there. In a movie as complex as this, it's easy to miss that one minute detail that pulls it all together, but having just watched it twice in a row, I can't figure this one out.

2013-04-17 16:25:06 by Jim:

@Bishop. From how I understood it, Abe and Rachel's relationship is one in which Rachel is more interested in Abe than he is in her. They don't seem to me to be officially boyfriend and girlfriend, but they are in the early stages of developing a relationship. (This is commonly referred to simply as "talking" in the modern dating lexicon). Maybe I am looking too deep into it but it seems that Abe is reluctant to have a full fledged relationship with Rachel because the film seems to depict her as a bit of a floozie. (She just broke up with her ex, she is "seeing" Abe and at the party flirting with some random guy which seems to be the catalyst for her ex walking in with the shotgun, I don't think they went to the party together). As far as the inconsistency you pointed out, good point, but I think a simple resolution for continuity here would be that Abe may very well have invited her to the party in the original timeline and just simply didn't go. After all, it is clear to us that whichever timeline we're talking about, he and Aaron have been working around the clock on a time machine. In a more grim possibility, perhaps in the original timeline neither Abe NOR Aaron went to the party in the original timeline and Rachel was killed at the party. We will never truly know what originally happened because Aaron has permanently altered events, which is the entire point Carruth is making with his cautionary tale about time travel.

2013-04-21 09:20:21 by Lance:

Thank you for this explanation! It cleared up exactly what I had missed.

After watching it again, here are my 2 cents, I believe there has to be minimally 4 Aarons. Aaron Two, who is narrating, mentions that he had thought it would be a good idea to record the conversations of the day, but he never actually did it. He just says it's an idea he had. That means that in order to even have a recording, Aaron Three (or higher) would have had to make a recording for the Aaron we are watching when he stops the ex boyfriend. So, we would have Aaron Prime, Aaron the Narrator, Aaron the Recorder and Aaron the ExStopper at a minimum.

2013-04-28 18:38:16 by Lance:

Forgive me if this has already been mentioned but I watched Primer twice yesterday, the second time after reading the brilliant analysis/explanation above, and I could swear that at the very end, there are TWO Aarons in France (starting to build the warehouse-sized device). If you watch closely (and this happens throughout the film) there are varying amounts of facial growth on Aaron. Sometimes he's clean-shaven and then in the next scene he has 2-days' growth. However, and this is the biggie: if you watch carefully at the end, the first dialog spoken by (an) Aaron in France is "Morning" by an Aaron with not too much facial hair and no one standing near him, his back is to the camera and he's facing to his left (looking towards left of TV screen). Then the camera swings left and there's an Aaron with almost a beard (much more facial hair than the one who said "morning") and people all around him, with him facing the camera and looking to his left (to the right of tv screen) who then says "every half meter... everywhere". Then the camera swings right again to the Aaron with no one around him, still back to camera & facing 'left' who repeats "everywhere". The french guy seems to even look back & forth between the two Aarons as they each speak. I've run it back dozens of times and I'd swear there are two of them. Presumably Aaron Prime (Hoodie Aaron) and then the one who left at the 'end" (last scene in the USA). Can anyone confirm this for me? I'm 99% convinced that there are either two of them in the scene or that they are suggesting that there are two Aarons in separate locations and both are building enormous boxes. After watching it yet again just now, I'm even more confused, 'cause although in the first part of the scene they even pan around the 'room' to show they're indoors, yet (my) second Aaron is near a forklift and it appears to be outside. Can anyone check the ending & see if you can figure out if I'm right that there's "something there" and, if so, what the heck it is? Thanks!

2013-05-14 02:35:05 by Rob:

I saw this too and you are right... there are two at the end. However, this could be Aaron 2, who was convinced to leave, or he could have just created more versions of himself to assist with whatever project he was working on. I like the theory that someone mentioned above: he is trying to ultimately control his universe. I would love to see a sequel that follows his project though!

2013-05-17 18:29:43 by RedHaven:

Great article. This movie is among my favorites of all time. It is amazing what you can do with $7000 budget.

I have read many of the comments here. Someone above mentioned an early scene where Aaron is picking Abe up at his apartment and the camera keeps cutting to Abe asleep on the floor. Aaron says "it is 7pm" or whatever. I have been wondering if that was done just to disorient the viewer because it doesn't seem possible that either of them had gone back that far at that point. It does seem odd though because if one or both of them had come back that far, a reminder of what time it is might be needed.

I have often wondered about Aaron's new refrigerator. It is new (he tells his wife that they have to throw out the first couple of batches or ice). I was thinking that it was somehow related to when he is getting ready to take the copper tubing from Abe's fridge. Again, it doesn't seem like the time travel would have started at the point but it seems odd that the script makes such a big deal about the ice. Of course, the script was written to keep the viewer off guard so there is a fair amount of dialog that is not related to the plot.

Finally, I always assumed that the reason Grainger had come back was related to his daughter getting shot and/or killed at the party the first time through and that Abe told him about the box and he used it to stop the shooting. They say that they may have told him if it was an emergency.

2013-06-04 20:12:05 by steady:

Interesting film, but surely time only speeds up inside the box, everything outside the box remains the same therefore no time travel

2013-06-08 19:57:46 by Jim:

@Steady. That's not entirely accurate. Time does not "speed up" or slow down within the box Abe and Aaron have built. Rather, think of the interior of the box as a state in which an arrow of time does not exist. A zero time state so to speak. Since time is nonexistent within the box, the way it works is that if one from outside the box were to plan on entering the box in the next 8 hours and spend a subjective 8 hours in the box, then presumably they should emerge from the box at the onset of those 8 hours. The individual that emerges will be that individual from 8 hours in the outside world's future, and thus successfully completed a time travel trip. What confuses many people about the concept of Carruth's time machine is that they are accustomed to thinking of a time machine as a device that somehow propels backward through the fabric of spacetime. Carruth's machine doesn't do this, it instead keeps the traveler temporally immobile as the world around them is still subjected to the linear flow of time.

2013-06-18 23:10:30 by Romain:

I'm adding to all this because I found this discussion great, and it helped me understand the movie (on which I think I have a good grasp now).
I think there are mistakes here and there in the interpretation of each person (personal opinion of course), and I found this chart that sumerizes the story very well :

A few things are not noted on the graph. The most important thing they haven't noted is the dispute Abe and Aaron have at the Airport at the end (the version of them that came back last (called Abe5 and Aaron6 in the chart)). I think that part is very important. Abe5 wants to stay back to avoid the first versions of Aaron and Abe to ever making the machines and also keep an eye out on the other other version of Aaron that exists in this timeline (called Aaron2 in the chart, the one who discovered Abe did a failsafe and uses it to take control over Abe. He does that by bringing the two machines in the fail safe one (the machines can fold as said in the movie). He then has two extra machines (that's what he means when he says they are recyclable. By bringing them with him, he dupplicates them). He uses one as a new failsafe machine for himself which he starts just after arriving. He uses the other to put where Abe put his failsafe and starts it a bit later so Abe still thinks he has his failsafe, but it comes back later than Aaron's new failsafe. But that's all explained in the chart anyways).

So anyways, Abe5 says that's the reason he's staying behind, but Aaron6 knows that Abe has always envied the situation Aaron had with his family. He secretely loves Aaron's wife and probably wants to build a machine and bring her and her daughter in it with him to create a double for his own. It's pretty far fetched and there is no way of knowing if he will do it, but that's what Aaron is getting at at the end when they fight at the airport, and Abe doesn't refute his theory, he only says "stay away from them. All of them".

What Jim said about the way the machine works seemed very interesting, and I loved the idea at first. It makes a lot of sense. But I didn't understand why the fungus would develop way faster than usual in the machine (around 1330 times faster). So after seeing the movie for the second time, I think I got how the machine works.

Let's call the moment when you start the machine A. And the moment whe you stop it B. If you put an object in the box, start the machine and stop it a minute later, the object will have spent approximately 1*1331 minutes in the box. What happens is that the object goes back and forth between A and B approximately 1331 times. It has to be an odd number of cycles for it to exit out of B (the moment the machine is stopped).
And of course they can do it the other way round (that's the interesting part, the part that allows you to travel through time but never earlier than A, the moment the machine got started). They turn the machine on (moment A), then one minute after turn it off and put the object inside (moment B). The object oscilates between B and A approximately 1330 times. This time it's an even number of cycles so the object comes out at the B moment, it can't come out at the A moment because it is inanimate and it comes out when we decide to open the box, so pretty much just after putting it in.

So that's when the idea of putting a human in becomes interesting. He can decide to come out. Lets say he starts a box at 12:00, turns it off at 12:01 and gets in. If he stays for the whole cycle, he will stay in the box for approximately 1330 minutes. But if he gets out when his timer indicates one minute (so just the time to go from B to A for the timezone inside the box), then he comes out of A at 12:00. And he sees of course his double turning on the machine.

ANyways that's what I gathered from this very interesting movie, hope it helps.

2013-06-19 20:55:03 by Jim:

@Romain: Your breakdown of how the machine works in the film is accurate. You or I, (or any other physical object), will continue to subjectively experience time passing because we have no choice, our atoms are structured this way. The subjective experience of time while in the box is described as parabolic, meaning one is oscillating backward and forward, backward and forward instead of just forward in time. Like a loop. The overall effect is a multiplying effect of the time experienced while inside the box.

What I mean by a zero time state is that the environment within the box is one in which the actual field being produced inside is dislocated from the constraint of the standard arrow of time. It is unbound, or as Abe put it, untethered to what you or I would consider the standard progression of time moving from past to present. Instead, the field inside the box swirls from past to present back to past and back to present again. The trick is to exit once it has flipped back to past again. Carruth's idea of the box's operation was based on the Meissner effect, in which magnetic fields are expelled and the result is a current that doesn't weaken with time. It remains the same. This effect was extrapolated upon by Carruth to give the machine it's anomalous effect.

2013-06-22 13:05:13 by koniczynek:

It's actually said at the end of the movie, that boxes aren't one time use only

2013-07-08 15:18:48 by teresa:

Am I the only person worried that we now have two Grangers in this timeline? Because current-timeline-Granger is not going to get in the box since his daughter doesn't die in this timeline. (Or did I see a body bag and that was from-the-future-Granger?)

2013-07-08 22:25:08 by Jim:

@Teresa. It is indeed concerning there are two Grangers now, but bear in mind the final timeline we see being set is from the perspective of Abe 2, who has returned to Monday of that week, before the Granger incident occurs. Whether or not there will be another visiting Granger in the timeline he currently occupies remains to be seen, the prevailing theory seems to be that there will be.

The reasoning behind this theory largely being that the party, Aaron's numerous trips back, the Granger incident and Abe 2's extended journey to the beginning of the week are all somehow connected. What the characters in the story have found themselves trapped in is what can most accurately be described as a feedback loop. Like when a microphone is placed in front of a speaker.

Given that the method of the machine's operation is contingent upon a fundamental premise,(which is one of "what has happened is going to happen," because events, although still linked, are now in an un-sequenced format), every event that occurs impacted by a trip backward in time is an event that has occurred prior to its cause. For example, if you turn on the box and you immediately emerge from that box, what that means is that it has been determined you are going to make that trip backward.

This also then means that whatever motivated you to make said trip will likely still occur as well, from a probabilistic standpoint. Otherwise, it is unlikely you would have any presence there at all. What Abe understood and Aarond did not was that in order to avoid becoming trapped within a feedback loop one must travel backward without being motivated by any one specific event, but to instead generally profit from the trip so that personal events are not pre-set. (This is why he insisted on maintaining strict symmetry, no tv, no phones, etc.).

This does not necessarily mean a timeline cannot be altered, but what it does mean is that whatever alteration you made to the timeline is now merely the result of a future action set to occur you are already experiencing the effects from, whether you are aware of it now or eventually will be later. Feedback loops are Carruth's primary warning against the use of time travel.

2013-07-08 22:29:26 by Sam:

I don't know what you mean by "prevailing theory", but it's pretty clear to me that by the end of the film, the shotgun/Lauren/Granger situation is totally resolved... leaving Abe and Aaron with a different and much bigger set of problems, which cannot be resolved using time travel.

2013-07-08 22:58:57 by Jim:

@Sam. Well, I say prevailing theory because I felt it was seemingly obvious to most people that by the end of the film it becomes clear that the entire string of events are related in a non-linear causal format.

The very new yet still somehow mysteriously broken refrigerator in Aaron's kitchen at the beginning of the film, (likely the result of a previous temporal generation of either Abe or Aaron using the copper tubing), Abe's initial introduction of the machine's function to a very impatient Aaron from an unknown and apparently relatively distant future, (he is impatient because this is his umpteenth time experiencing it), the "leaks" in the boxes, (likely the result of a future Abe tinkering with the boxes), Granger's inexplicable appearance, (likely the result of a desperate future Abe sending him back to alert his past self to the degree in which things have spiraled out of control), and finally the appearance of Rachel's boyfriend at the party, who as we all now know was and always had been invited by an Aaron from the future.

Nothing is resolved, everything has simply been reset to its starting position.

Feedback loop.

2013-07-08 23:04:38 by Sam:

I agree with nothing that you just said, particularly the likelihood of the things you claim to be likely.

Just to pick the lowest-hanging fruit: the new refrigerator isn't missing any copper tubing, and that scene takes fully three months before the first time machine is constructed.

2013-07-09 15:10:04 by Jim:

@Sam That's quite alright Sam, we don't have to agree. That's what makes the film so great, it's open to endless interpretation. However, the refrigerator issue is difficult to ignore.

You don't find it at all odd that Aaron's brand new refrigerator, (we know it's new because it has a bow on it), is malfunctioning, malfunctioning by creating dirty ice, that Aaron and Abe later remove the copper tubing from Abe's (not Aaron's broken) refrigerator later in the movie, and dirty ice is sometimes caused by faulty or missing copper tubing that connects the water supply line to refrigerators?

I understand that it initially seems far-fetched, seeing as the opening scene takes place 3 months before the "first" machine is built. But what we are ignoring is that at the very end of the film, Aaron is building a much larger box, one the size of an entire room. So we now have a giant box being created in March, (perhaps even one that an individual could conceivably exit from long before the internal structure has been fully built so long as all of its doors have been closed the entire time leading up to someone going in and using it to build the internal structure), a broken refrigerator and an unknown number of Aarons and Abes roaming the Earth. None of this is temporally connected?

2013-07-10 07:54:59 by Billy:

My question is why does Aaron find it necessary to record the conversations when he has lived through them? Also, if Aaron2 went back with the idea that he would record the conversations, why does Aaron3 attack him (as Aaron2 would know that he would have to travel back [again] to listen to those conversations while they were happening in real-time)? Aaron3 would be like, "Ok, dude. Here I am. Things are going as planned. Give me the recording and do whatever it was we planned to do at the outset."

To the above: the premise of the movie is that in order to travel back in time, you have to switch the machine on at the point you want to travel back to. That is why Abe turns on the failsafe machine Monday morning. You can't travel back further in time to a point when the machine hasn't been invented.

2013-07-10 11:01:28 by Billy:

Just to expand on my response to above ... this is filmmaker Shane Carruth in an interview when Primer came out:
What’s the strangest interpretation you’ve heard?
The strangest interpretation involves somebody who has decided that from the first scene they are already using the device to travel back. And that gets really odd. In the story, in the beginning we’re seeing Christmas trees and red bows and even Christmas lights in the backyard. Then there’s a moment where it fades out and when it fades back in, we’re talking about March Madness. And so it was always my intention that it be understood that there’s a gap of time here. The way the boxes are set up you could never go back any further than the first moment the box is set up.

I’ll get a question about whether the refrigerator was bought from one of the double’s stock money. It’s really awful because I kind of have to say, “Well, that was actually three months before.” To try to explain the plot in that kind of weird detail it means that it didn’t work. I didn’t communicate properly with that person. And so they’ve thought something else entirely.

2013-07-10 12:19:57 by Sam:

Haha, that is awesome. Do you have a URL for that interview?

The remark about crushed ice at the start of the film is more about establishing scenery. We see some of the actually rather dull details of Aaron's family life, his daughter ("She needs a bath"). Later on we see the cereal he eats for breakfast (always), and supermarket shopping, and filling up at the gas station. The whole movie is set against this incredibly low-key, pedestrian suburban backdrop. The most interesting thing in Aaron's life is a crushed ice machine! You can see why the time machines would drop a bombshell on that.

2013-07-10 12:22:56 by Sam:

Something which is interesting, though, is the scene where they're filling up their cars and Aaron talks about "How did it get like this?" This raises the interesting notion that there might be other people in the world who've independently discovered this method for time travel, and managed to keep it secret. What have they done with their machines? How have they modified or controlled the world, to what advantage?

It's clearly established that their boxes can't go back further than Monday. But it might be that their entire world is the product of much earlier time travel by completely unseen people. This edges in to fan fiction but it's still a pretty neat thought.

2013-07-11 05:40:16 by cole:

i've tried to read every comment and there is just one thing that doesn't make sense. Be it one time line or several time lines... If one person stopped their previous self from getting in, all non primes of that person and timelines would cease to exist. If that prime person never entered the boxes, there would be no event of new timelines being created. or am i missing something?

2013-07-11 14:05:21 by Jim:

@Billy: I suppose if Carruth said that, then you are indeed right and my proposed theory (one of many) is totally wrong and off base. I guess I tossed it out there based on two things, 1: a total lack of trust in anything the character of Aaron said or did in the movie, and 2: the fact that what a lot of people overlook is that it was actually he, Aaron, that first stabilized the machine and got it to work 3 months prior to Abe's first use of the box. The feedback loop potentially being initiated by him tampering with a makeshift design and to his shock being confronted by an Aaron from the future, setting the events in motion. But like I said, this must not be at all possible.

@Sam: That is an interesting point, I have had the same thought myself. Particularly when he said the line "What's worse, being paranoid or knowing you should be?" As if saying, if we were able to do this, someone else must have already at some point in which case we are living in a universe already altered and designed by them. (This could have fueled his rationale to begin altering the universe himself, since from his perspective it's likely other people have already been doing it). It would also be the only way in which what I proposed would be possible, if Aaron had hooked up with one of those individuals and was able to travel farther back.

@Cole: The reason the primes and timelines don't cease to exist is because once you've made a change akin to the one you're describing, preventing yourself from traveling, all that means is that you are now occupying a revised timeline. It's easier to think of it in terms of a set of train tracks, and you are the train. When the train wants to go in a certain direction, the tracks are forked and the train diverts from the original path. Those tracks still exist, but you are simply traveling down a diverted set of tracks.

2013-07-12 22:33:19 by TheRizz:

My thought on the handwriting is that entering/exiting the field is always exposing them to at least a lesser version of what you see Aaron experience in his first travel (the one where he exits too early/late) - some kind of shock to the system caused by the time field.

Note: This also leads to another question - did Aaron actually exit the box at the wrong time, or did another Aaron/Abe come back in the box that was supposed to be, then replace it with another box brought back with him (causing the time to be off by a few minutes)?

2013-07-21 05:18:13 by Lanter:

Interesting question: Could Abe have created a more effective failsafe option by doing the following:

1. Prior to informing Aaron of the discovery and prior to building any additional boxes, Abe Prime builds an original failsafe box (which as I understand it, is basically what he does in the movie).

2. Instead of activating the timer and immediately leaving (as is the generally accepted practice so as to avoid a future encounter with a double), Abe turns the box on and waits in the storage unit with a handgun.

3. If some other version of himself exits the box, he kills that version of himself (or really anyone else who exits the failsafe box).

4. Dispose of the body (which should be doable since nobody would be looking for the victim - is it even a crime to kill your doppleganger from the future?). Logistically, this would be difficult, but logically it could be done.

5. Never tell anyone of the discovery and never create another box.

Had he (or anyone) used the failsafe box at any point, he would know that building the time machines had created some sort of problem in the future. By killing that person, he would effectively close the loop at the source w/out needing to engage in some sort of battle of wits with any future doubles.

If nobody exits the box, it means that it is never used at any point in the future, and it can be assumed that by building the additional time machines, he does not create some sort of terrible dystopian future.

Granted, whomever travels back in the failsafe box could be armed. However, if it were someone else who travels back, they won't be expecting Abe Prime to ambush them. And if its some future version of himself who wants to kill Abe Prime so as to assume his identity, they can have a shoot-out in the storage unit to see who gets to be the sole Abe.

Again, the logistics would be a pain, but I believe the logic holds. Thoughts?

2013-07-21 09:00:10 by Pat:

Just a few quick things about Aaron's new refrigerator. The dirty ice is caused by breaking in the new water filter. Just like using a brita, you get dust in the first few batches that you run through it. It has nothing to do with being tampered with due to their experiments. The copper tubing holds the freeon and is in no way attached to the water line.

Also, up until the most recent invention, these guys are working 9-5's and have only been mildly successful in their garage company. They had to find outside funding for their major project. So maybe it's in there to signify that buying a new refrigerator was a big deal and all that Aaron could have afforded. Until march, that is.

2013-07-21 21:43:17 by Ken:

That Caruth interview is at

2013-07-25 16:29:37 by Romain:

One thing to try and explain the changing timelines and if things that can happen or not.

I see it this way. A new timeline is created everytime someone (or several people) exit a box. It is a new timeline because there is a new version of that or those people. Every time line is independent. You don't change the past or the future, you just create a new timeline in which you can either make sure everything happen like the previous timeline you've experienced or change things.

It's like Einstein's theory on relativity. There is no absolute time. Time is a subjective notion, you don't have one omnipotent person that observes the general timeline. Each person lives their own timeline from their point of view.

2013-07-29 14:29:54 by Jack:

Thank you! I had read several versions but this makes the most sense. I’m also grateful to those above offering their theories, too!

2013-07-30 16:27:30 by theotheralan:

Much of this discussion reminds me of one of the only the other time-traveling stories that tries to deal with potential paradoxes in an intelligent way - The End Of Eternity by Isaac Asimov (MAJOR SPOILERS AHEAD!!). There, all time-jumps occur in the same continuum - whatever changes the time-traveler makes in the past have already occurred. Its simply impossible to change the timeline, since whatever changes you make have already been made. Events will unfold in such a way as to prevent the time-traveler from causing a paradox (e.g., he gets nauseous when he approaches his double).
The one MONSTER exception to this occurs at the end is similar to the movie's 'failsafe' - after discovering the ill-effects time travel has on humanity, the travelers jump to the distant past and prevent time-travel from being invented in the first place. They should have winked out of existence at that point, but (sadly?) they do not. (END SPOILERS)
In any event, highly recommended for an original and intelligent time-travel story.

2013-08-09 17:03:38 by Jason:

I'm fascinated to see that this movie is still being discussed in such detail.

While I like this explanation more than others online, I think it overlooks a fundamental problem with the theory of time travel Caruth is advancing. It also overlooks Caruth's own explanation of the Granger incident. Here's what he said (from the Village Voice in 2004:

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."

So Granger is struck into a comatose state because his interaction with Abe "breaks" his personal timeline. He can't be there if he prevents the event that sends him back; he is a paradox. Rather than getting "erased from existence" as in a movie like Back to the Future or Jumper, he gets struck into a coma.

The problem is that this explanation -- from the horse's mouth -- is disregarded by the final scenes. Aaron2 has created a recursive paradox by drugging Aaron1 and stuffing him in the attic for 4 days (*note that he probably had to drug him repeatedly, hence the scuffling sounds from the attic during the week, and why Aaron1 is able to get out of the attic on the final Monday observed - his dose hasn't been renewed). Aaron1 cannot have found and used the first failsafe box if he was drugged in the attic. Aaron2 should have fallen into a coma as soon as he got near Aaron1. Also, Aaron3 has created a paradox SIMPLY BY COMING BACK. His interaction with Aaron2 ensures that Aaron2 (hoodie Aaron) will NEVER get into the failsafe on Friday, since Aaron2 left town. Aaron3 should have been struck comatose at that moment.

Caruth intended to use the Granger incident to show the effect of paradoxes using his operable theory of time travel; and as a catalyst for the films final scenes and big reveal. Instead, it actually broke the coherence of his narrative.

2013-08-16 19:01:06 by Jim:

Although some of my theories have been enthusiastically demonstrated by others as being in conflict with Carruth's intended meanings in the film, his comments stated above regarding the Granger incident seem to be in line with what I have proposed in earlier comments.

Also, if what he says is indeed true, (and considering that the entire world of Primer spawned from his mind I think it's pretty safe to say it is), it would also strongly suggest that something did in fact happen to Rachel in an alternate timeline. The reason I say this is because the only purpose Granger originally served Aaron and Abe was to finance the development of their project. Seeing as how they now possessed time machines and were instant billionaires, financing was no longer an issue. So why would Abe have any need to tell Granger about the machines? We know from the ensuing conversation between he and Aaron that it would have to be a serious emergency for him to do so, like if his daughter was murdered. Carruth's explanation for Granger's presence essentially confirms that something tragic happened to Rachel in some iteration of reality, the same iteration that the farthest traveled Aaron originates from as well.

2013-08-28 16:37:31 by RBM:

If it were me, I would turn the box on one hour before a huge Powerball drawing. Then I'd wait around until the drawing, find out the winning numbers, then turn the box off and climb inside, then buy a ticket as soon as I get out. The whole process would only take a couple of hours (at most), and you'd be hundreds of millions of $ richer.

2013-08-29 14:55:43 by Jim:

@RBM That would be a good idea, I've had similar thoughts myself. But in reality, if one had a machine such as that, money would no longer be of any consequence. All methods of making money rely upon the fundamental principle of time moving forward, once you could go backward there would be endless ways to make an instant fortune. The power one would possess in having the ability to travel through time, (and being the ONLY ones having this ability), would extend far beyond any level of power achievable through money. Indeed, they would ultimately have control over all things.

2013-09-02 02:47:41 by JG:

I made the mistake of watching the film pissed at 2am. I'll have to watch it again when I'm in a better state of mind.

2013-09-16 23:14:29 by emcee:

First, GREAT article.

A couple comments. As some others have mentioned, the reason Abe Two alludes to protecting Kara and Lauren from Aaron Three is because Aaron Three suggested the possibility of making doubles of Kara and Lauren, and Abe Two doesn't want him to do this.

I'm in agreement with some other commenters that the new time machine being built at the very end is not the size of a warehouse. Aaron is clearly heard telling the workers, "Every half meter". As other commenters have suggested, this implies that he plans to build a warehouse full of time machines, rather than a warehouse-sized machine.

But my real question is this - WHICH Aaron is it building the new warehouse time machine(s) at the end - Hooded Aaron or Aaron Three? You state that it's Hooded Aaron, but is it really? At the airport, Aaron Three states his intention to steal Aaron Prime's passport and leave the country. Does the fact that the warehouse workers are speaking French indicate that it's Aaron Three building the new machine(s), rather than Hooded Aaron?

Personally i think the jury's out on that question, and i don't think it can be definitively stated which Aaron it is.

2013-09-17 16:16:40 by Jim:

@emcee: You are correct. It cannot be truly determined which Aaron is building the machine/s in France. Mainly because of the nature of what we're trying to determine, I mean all three Aarons are the same person. It stands to reason that if not in contact with one another, they would all do the same things independently.

2013-10-01 08:19:45 by Trent:

So what happens if you bring a time machine that has been running for a week back in time with you through another time machine that had been running for a week?

You turn machines A and B on at 6 am Monday morning. On Friday morning at 6 am you travel back through machine A, bringing machine B with you.

Now you're back at Monday morning, 6 am with a second time machine that has been running for a week.

What happens if you get inside machine B on Monday morning at 6 am?

2013-10-01 21:59:48 by Jim:

@Trent : Essentially what you're describing is how Aaron used the failsafe machine to travel farther back than Abe. He took a machine that had been turned on at the earliest point and took it back with him in his machine, opened it and traveled back to that point. What would happen in your scenario is that you would simply arrive back at 6 a.m. Monday, because that's when you first turned it on. Regardless of how long your machine has been running, (machine B would have been running for 2 weeks btw), it will not take you farther back than the moment it first became operational, because there would be nothing to exit out of prior to that.

Also bear in mind, the minute the machine starts is the moment your double will exit it. So as soon as you started machines A and B at 6 a.m. on Monday, two of your future selves will exit both boxes, with the double exiting box B having expected to arrive sooner than that.

2013-10-03 20:24:23 by Michael:

How is it possible to relive the same day more than once without creating endless doubles?

How can Aaron redo the party 20 times?! There would be 20 Aaron's.

This makes no sense, unless Aaron only did the party 3 times?

But it is eluded that Abe and Aaron can easily retry days. How? Unless they kill there old selves and re get in the box themselves?!

2013-10-04 19:47:08 by Jim:

@Michael : Aaron didn't exactly say he relived the part 20 times, he wondered out loud if that's how many times it would have taken to get it right. The film indicates that it took Aaron a total of 3 attempts to get the outcome of the party just right, (according to his liking), with the original version of events at the party not having Aaron been there at all.

To answer your broader question, how can one relive the same day without endless doubles, that is at the heart of the dilemma with Carruth's time travel. The way it is SUPPOSED to work is that the traveler turns on the machine, leaves for the duration of time they wish to travel back, return to enter the box, wait in it for an equal amount of time and exit the box. If the traveler does not interfere with the course of these events, then presumably his past double will do just as he did and vacate the timeline by entering their box, thereby leaving the earliest version of someone to remain.

Now, the way one winds up with doubles is by NOT sticking to this procedure and somehow interfering with their past double entering the box as they did, thus resulting in their displacement in the timeline. The reason there are several Aarons is because he kept rendering his doubles unconscious so he could deliberately alter events, thereby preventing them from entering their boxes and resulting in a multitude of Aarons. Abe only has one double because he only interfered with one of his doubles.

2013-10-04 20:35:31 by Michael:

Good stuff, thanks for the speedy response.

Basically, if you want to attempt to alter events, you're going to wind up with a double you have to replace, as we have with Aaron x3 and Abe x2.

So if we wanted to live the same day again and again and again, we'd have to keep stopping our past selves getting in the box and get in ourselves. Creating a double each time. Each double being slightly older than the previous.

2013-10-09 04:56:04 by bc:

Maybe the only logical and useful application for a time-machine would be to give it to lesser minds who would not be able to resist using it, for money, patents, and to be left to do without them weighing you down. Abe and Aaron are not the geniuses, they did contribute, but it was not their idea and not even a project they wished to be a part of to begin with, apparently these two had cost the other two in the past and their was a clear division in the company from the kitchen table discussion.
(my two cents)

2013-10-10 00:22:59 by bc:

the Aaron that invites the ex that Abe observes is not the one that was recorded doing it, the first inviter made the basket, this one didn't hence an altered conversation playing in Abes ear.
Also two different fridges- one at the beginning with the bow is black and has sides doors doesn't it? The second is white and has upper and bottom, I assumed it was someone elses fridge not Aaron's.
(comment two having only seen the movie once and having finally read the entirety of this discussion thus far, spanning a few years)

2013-10-11 13:32:21 by BenMcClure:

Enjoyable article. I don't agree on every point, but it did open up a bunch of ideas to me. It never occurred to me to think about the connection of the "noises in the attic." If not for that, I wouldn't buy the idea that it's Aaron2 or Aaron3 in the original bench scene. But that for me is a weakness of the film - I find it hard to buy that AaronPrime could be locked in an attic for four days.

I have a question on a point I haven't heard anyone else mention - when the Granger incident takes place, I think it's pretty clear there are two people who get out of Granger's car. They are both out of focus so it's hard to see them, but one of them looks like it could easily be another Aaron. This other person never seems to get mentioned or referred to by anyone. Anyone have any ideas?

2013-10-16 02:43:50 by AnonymousC:

Hey all,

wonderful movie which I just discovered a few hours ago and amazing threads and graphs explaining Carruth's time machine.

I've got a question (in order to better understand how it's working). What would happen if Abe, before trying the machine the very first time (say on 2013-oct-15), decided to turn on the machine at 11:45am, then hide with binoculars around 12pm kinda far away and then wait for his future self to come out while strictly adhering the following rule:

"I'll always enter on 2013-oct-15 at 6pm and on 2013-oct-15 at 6pm only, unless I've seen my future-self come out"


2013-10-17 00:51:19 by Jim:

@bc : While I understand a small portion of your point, that Abe and Aaron are not ENTIRELY responsible for the creation of the invention, it would be inaccurate to suggest they did not make the largest contribution to it. Robert and Philip's work, the part Abe and Aaron were reluctant to become involved with, was centered around the creation of a rotating superconductive plate that they hoped would reduce the mass of any object that was placed on top of it. Aaron and Abe found that idea too lofty and a waste of time (ironically enough). They were more interested in working on a superconductor that could conduct at room temperature, something they felt would have been much more marketable and therefore profitable. As a compromise, they decided to integrate the two projects into one.

This is why when Aaron is demonstrating to Abe that the machine was stabilized Abe confirmed with him that he "only changed the box, the plate stays the same," because he wanted to ensure anything Aaron did to the box only pertained to their portion of the project and didn't affect Robert and Philip's. The machine they finally construct to use for time travel consists of their box and a web of Robert and Philip's tiny superconductive plates that work together to repel the magnetic fields generated by the box into its interior to create one intense field that is dislocated from the normal flow of time.

@ Anonymous : I am not sure but I think what you meant to say in your example was what would happen if Abe decided that he would enter at 6 p.m. UNLESS he saw himself exit, in which case he wouldn't enter. If he had no intention of entering the box upon seeing himself exit it, then the probabilistic threshold would not be achieved and he wouldn't ever see himself exit if it meant he would never travel. In order for the probabilistic threshold to be reached, events would have to configure in such a way that they would increase the likelihood of him entering the box in the first place. At least that's what I think.

The other possibility would be that if he decided not to enter the box upon seeing himself exit, then he would simply be watching an Abe from a parallel timeline that wound up changing his mind and traveling anyway, resulting in a doubling of himself. In any event, in terms of the actual story line of the film, had Abe decided to wait to see himself exit the storage unit on his first travel, he would have been surprised to instead see Aaron 3 exit it, as he is the one who winds up traveling the farthest back.

2013-10-20 03:53:36 by sublime:

Great movie summary! I hope I didnt miss this in the posting or subsequent comments, but I noticed that when Abe is explaining the boxes to Aaron he he casually mentions "I, my double, or or someone is coming backwards". Why would he use someone if only Aaron and Abe know about the boxes? Is he possibly referring to Granger? Why wouldn't Aaron notice the comment and ask why anyone else would be in the boxes?

2013-10-23 06:57:52 by Weebles:

This may be a dumb question, but I was really struck by the sequence within the first fifteen minutes of the movie in which Abe wakes up on the floor of his bedroom completely disoriented. The timing between the sound and the visuals is purposefully disjointed, Aaron repeats the time to him over the phone, and it seems to me that this happens somewhere in the relevant timeline (so to speak, I know there are several) of their time travels. What's going on here? It seems too intentional and too carefully crafted to be insignificant.

2013-10-31 09:08:38 by cb:

An interesting detail we just noticed. When abe shows aaron the storage unit for the first time hr checks a lock on the unit just before it. ... and is either surprised or maybe confused that it is locked. Or maybe he is just verifying it is locked. Anyways this could be a failsafe box or some other box.

2013-11-03 23:46:41 by Andre:

There's one thing I'm curious about that I haven't seen anyone address yet...
Let's say that I turn on Box A at 1 pm and Box B at 2 pm, then my friend gets in box B at 3pm to go back to 2pm, then an hour later I get in Box A at 4pm to go back to 1pm.

My friend will emerge from box B at 2pm, and I will emerge from box A at 1pm, but will we be in the same tieline or separate timelines? Since my friend went back before I got a chance to do anything, maybe she has "escaped" from anything I might do in my future, and hence she won't find me waiting for her when she goes back. And similarly, maybe if I go back further than her, I would have "overridden" the timeline when she went back by going even further back and branching off a new timeline. Or maybe we might end up together, if I don't bother her machine. Or do anything to cause my friend in this timeline who already exists to not go back at 3pm. But we've seen in the movie that you *can* interfere and make permanent doubles...

maybe it's all subjective. Maybe since I travelled further back, she will *always* see me, but I might not see her. In fact, I might prevent her machine from being turned on at all.

What if Box A was turned on at 1pm and turn off at 3pm, and my friend got in Box A, and Box B was turned on at 2pm and turned off at 4pm and I got in Box B. Who would be in the same timeline as who? Who would override who?

See, this is the problem I have in the movie when Abe and Aaron travel back in *two separate boxes* and yet emerge *together* in the same new timeline. Does this necessarily have to be the case? When Aaron uses his failsafe on Friday to travel back *further* than Abe, he still finds Abe arriving later on in his timeline. And yet, you *don't* have Aarons and Abes emerging from the boxes in *this* timeline from all the trips back to those boxes that they made before they went back in the failsafe.

2013-11-06 22:07:48 by Jim:

@Andre : Excellent question, Andre. It strikes at the heart of the complexity of Carruth's time travel. I don't know if my answer will be entirely accurate or sufficient, but I'll take a stab at it.

It's important to understand that whoever travels the farthest back will have personal supremacy over the timeline they exit. When your friend exits Box B at 2 p.m., she will always see a version of you there first because Box A was turned on at an earlier point. She will have no choice but to be at the mercy of whatever it is you are going to choose to do within the hour prior to her arrival, except preventing her trip altogether.

Now to answer the second part of your question, you hit it on the head when you said "maybe it is all subjective." Indeed, it is all subjective. The timeline your friend exits from will be her personal timeline, and the timeline you exit will be your personal timeline. Your timeline will be identical to her timeline as far as any outcomes you do not personally influence or create. The same will go for her.

If you decided to prevent her box from ever being turned on, which you could do since you will arrive an hour before it is, then all this means is that you will be occupying a personal timeline in which she never arrives. A past version of your friend from that timeline will arrive at the box at 3 p.m. and find that she cannot use it. The friend from the original timeline you vacated after she did will travel back to 2 p.m. in a timeline where you did not interfere with her trip. Nothing else could happen to her since she has already begun the trip. You will be simply existing in bifurcated timelines.

2013-11-07 07:54:12 by Bryan:


I'm going to answer your question with another question that was asked by a user about two years ago.
He said:
I have a few questions, if anyone could help :)

1) At the point where Abe and Aaron are testing their device at their garage and they think they blew it. Then they decide to remove the case so they can pick up Aaron's camcorder. Now all this is long before the fateful Monday in March when the whole main plot begins. After they both say '1-2-3' and remove the case, the scene blacks out and changes, showing Abe unconscious on the floor and the sound of static can be heard. It's really strange; what on earth happened here? Notice how Aaron calls him on the phone and Abe wakes up; then the scene REPEATS and Abe is still on the floor while Aaron's voice continues talking (asking him if he's hungry) and Abe is shown to pick up the phone again. It looks like there's TWO Abes here... For example, we see that one Abe gets up and Aaron is heard saying 'Abe, it's 7'. Then we see Abe getting up AGAIN and Aaron now says 'Abe, it's 7 at night'. This repetition of movements, and the way the scenes are presented, show (at least to me) that we have here TWO Abes. My initial theory was that this was a result of Abe Prime's proximity to the time machine which he had brought in his house (???) to test it, after they took Aaron's camera out of it and removed the case, and somehow he'd fallen unconscious as a result of so many 'leaks' (no cover). But I really am not sure. So what's up with this scene here?

2013-11-12 20:26:37 by sez:

Two things I can't figure out.

1: Monday night Abe shows Aaron the storage unit and it show them sitting in the unit with one machine (machine A). The next morning they show up and there are two machines. Did Aaron build the second machine and bring it to the storage unit between 6pm Monday and 8am Tuesday?

2: Wednesday night when Abe finds out that Aaron intervened at the party he doesn't question how he was able to. The only way for Aaron to have gone back early enough to rescue the party would be by using the failsafe machine. Or was Aaron at the party, thought the guy looked suspicious, and went to the storage unit to turn on machine A just in case?

2013-11-13 21:12:31 by Jim:

@Sez : To answer your first question, yes. Presumably Aaron built a duplicate machine between those hours because simply replicating what Abe had built was not as difficult and therefore time consuming as building the machine from scratch. All the machine is constructed out of is a metal box equipped with the the web of rotating superconductive plates hooked up to a generator to initiate it.

To answer your second question, Abe didn't ask how Aaron was able to intervene with the events of the party because he (incorrectly) assumed Aaron simply went to the party without the use of the machine at all. He was upset that Aaron would jeopardize his own life after learning of the machine because it was a historical breakthrough that would bring them untold fortune. He felt it was foolish to risk getting killed at such a time. What he was not aware of is what you said, that Aaron was in fact not originally at the party and used the failsafe device.

2013-11-21 21:44:58 by Colin:

The question of Granger's lost consciousness in the presence of Abe(does Abe lose consciousness, too?), interests me.

I think I might have an alternative explanation. Maybe.

At one point in the film Abe and Aaron are discussing shutting off the box that Granger is "in." They make it clear they don't know what would happen, and decide it isn't worth the risk.

Is it possible that Granger, distraught after his daughter's death turns off a box that Abe is "in" before entering it? This might result in an entanglement between the two. There is much quantum woo about "consciousness" so...

Of course, when Abe got into the box it hadn't been opened yet or the power would have been off, which means that Granger entered the box from his timeline from another timeline. This seems to imply that another one of their working hypotheses is broken.

Still, it's all a hypothesis till the experiment is done. Possibly Granger, not altogether intentionally, did the experiment.

2013-11-21 23:26:54 by Colin:

To "clarify."

When Granger turned off the box and got in, Abe had already turned off the still-active box later in the afternoon.

Your expectation, when that happened would be that Abe would go to get into the box to find it already deactivated. Instead, he finds it still activated and enters. The two men and two timelines find themselves entangled in the machine. When they approach each other outside of the machine after that, their entangled wave functions begin to nullify resulting in unconsciousness. Extended exposure to each other would definitely not be recommended.

On other subjects, perhaps the breakdown of the time travellers, nose bleeds, difficulty writing and the like has nothing to due with time travel as such. Perhaps exposure to some sort of... let's call it radiation... produced by the box causes the tingling sensation and other symptoms by doing damage to their bodies. Their safety procedures were pretty poor even notwithstanding the cosmic dangers of time travel. Self-experimentation and lack of control or monitoring are all on page one of the Dr. Jeckell Manual of Safety.

2013-11-28 10:16:55 by Suman:

Wow. Thanks so much for explaining it. I was completely lost. :)

2013-12-04 10:24:36 by Nike:

Great movie and thanks for all the comments. After reading all the above comments Im still left beliving the subjective theory that whenever someone enter the box a new timeline is created. Events there take their own course idenpendently and spawn new timelines. In the movie we are beeing shown events from the newer timelines as they are created. What still confuses me is this:

The Granger incident:
This seemes to go against the theory of independent timelines.

Aarons recording earphone:
As someone previosly stated, Aaron must use a earphone when he is recording to create the same visual enviroment as when he later listens to it. But in many scenes (Aaron1 in the attic, Abe1 showing Aaron3 the boxes first time) this is not visible.

Any thoughts?

2013-12-06 03:05:06 by jwac:

I would just like to reiterate that everything you need to figure out the plot is presented in the movie. The only unknowns are exactly how long it took AaronPrime to figure out about the failsafe (though it's about as long as it would take him to grow a beard going backwards) and how many times it took them to get the party right (on purpose, since beardedhoodedAaron had snatched the coveted Prime Box and passport and absconded to Polynesia or wherever...), though the word "prescient" has some implications. Of course we also don't know how many there are--Hooded Aaron "can sleep at night" if there is only one more.... addition to AaronPrime, to whom the call is made. This is to inform him of why he woke up in the attic (remember Abe built the machine after months of tinkering, AaronPrime would've had no idea what happened).

The comment in the interview makes no sense to me. I think it's a red herring.

2013-12-06 03:13:04 by jwac:

@Nike: Oh, and, yes, do I believe that the bench>lab>storage facility sequence jumps back and forth between the first and second time around for Aaron. The obvious way to tell is when he's wearing the earphone, but his body language and reaction time changes big time as well. AaronPrime is following every word, Aaron3 is looking at the floor and trying to get Abe to talk faster. (I think this is Carruth's way of keeping multi-time viewers entertained during this scientific process part of the movie--great for the first time around)

2013-12-07 11:24:38 by SmokeyTBear:

I have a question about the scene where Aaron3 and Abe2 are debating the party plan: Aaron says to Abe " He never fires. He didn't when I wasn't there, he didn't when I was there and rushed him, and FROM WHAT ROBERT TELLS YOU, he DOESN'T TONIGHT." (emphasis mine) .

My question is, what is he referring to when he says from what Robert tells you? Does he mean from Abe2's personal past? Or his recordings? Either of those don't seem to make much sense. If he means abe2's past, then that would imply that he has timeline supremacy, is that because he goes further back in time than Aaron3? He can't possibly be suggesting that Robert at some point travels, right?

Any thoughts?

2013-12-07 11:42:51 by SmokeyTBear:

I think I figured out the last scene/narration though:

The phone call is from Aaron 2, who feels cheated Aaron3 and feels guilty about locking up Aaron1, so he calls him Monday evening when aaron1 awakes and escapes the attic. Aaron1 at this point would otherwise have no knowledge of time travel existing, as Abe had not shown him anything. Nor would he ever, because Abe2 said he would sabotage Abe1 getting the boxes to work. Not wanting Aaron1 to be at the mercy of Abe2, he informs him of everything that occurred from his (Aaron2)'s perspective, as well as some speculation as to what he figured aaron3 would have done, based on what his own intentions were. Still not 100% though on which Aaron is in the French airport at the end. Could be 3, after he left from the airport scene. Or 1, after getting filled in and pre-emotive ly cutting Abe out, as he so quickly cut out the other 2, or even 2, I suppose- he could have grabbed the passport Monday during the day while Aaron3 thought he had left town, and that's why he was so confident Aaron1 would never find him.

2013-12-16 19:10:28 by Jim:

@ SmokeyTBear" He never fires. He didn't when I wasn't there, he didn't when I was there and rushed him, and FROM WHAT ROBERT TELLS YOU, he DOESN'T TONIGHT." (emphasis mine) ."

What Aaron means by this statement is that in the original timeline, the one un-impacted by Aaron's travels, Aaron was not at the party. (Whether or not it is true that Rachel's ex-boyfriend does not fire the gun at the party in that version is unclear, Aaron has proven to be quite deceitful and untrustworthy). The second time around, when Aaron did travel back to alter events at the party, he apparently rushed the gunman and claims he didn't fire then either. Something in that particular version of events still went wrong either at the party or later on, because Aaron felt the need to travel back yet again, presumably with Thomas Granger using Abe's box. This leads me to believe Rachel is murdered at some point in this timeline, but that is my own personal theory.

Finally, with the statement "from what Robert Tells you he doesn't tonight," he is referring to the conversation had between Robert and Abe in the garage when he tells him about the geckos, the conversation Abe first learns of Aaron's presence at the party. Aaron's point is that Rachel's ex-boyfriend never fires.

2013-12-24 00:52:10 by Chris:

One quick point; when Abe comments " looks like a dog digested it" notice he's looking at the monitor displaying the [slime covered] Weeble.

I haven't listened to the DVD commentary so not sure if this is covered there or not but this how I saw it-
Abe is in love with Kara.
We see that Abe lives a pretty solitary lifestyle. No steady girl, probably no time for a steady girl. He hides in his bedroom because some guy and his pals took over his living room. He seems pretty slow or hesitant getting things moving with Racheal [although he DID have a few other things going on at the time...]
Not only does Abe eat dinner with Aaron and his family, he'll stay longer than the rest. Help clean the dishes, sit around afterward in the living room to relax and unwind. He's comfortable there.
And Kara's there.

"What possible reason could there be to be here?" OOOhh, my wife.
"I guess that it just won't go back far enough will it." = To a time before she was mine.
"Tell ya what; put 'em in the box and make you're own set, I don't give a crap about them."

It's probably best that Abe stuck around to A] keep this timelines' Aaron and Abe from messing up the flow of events on themselves and B] protect folks from Aaron!
It's not that Abe wants to spy on Kara from the bushes or anything creepy, he just wants to protect her from the madman who stands before him. Aaron is his best friend. He knows him pretty well. He knows that the Aaron he's talking to in the airport is a changed Aaron.
People and their lives mean nothing to this guy. He ends up seeing people [including himself!!] as his own personal chess pieces. He's the one who first used the failsafe behind his friends back. Hell, it's probably Aaron who causes the Granger incident/unravelling in the first place.
And you see that he doesn't stop.

2014-01-09 21:07:36 by Steve:

Can you help me understand the part with stopping the kids from waking them up? I get that if they go into the 17:00 box at 03:00 on Friday they can travel to 17:00 Thursday and then stop the kids from waking them up etc., but wont this cause them to have permanent Doubles?

Example: Abe 2 and Aaron 2 stop Kids, Abe 1 Aaron 1 don't wake up. Abe 1 Aaron 1 go and turn on boxes at 0845. Sit in Hotel until 15:15, go into Boxes. Travel in time. Get out of Boxes at 8:45(now are Abe 1.5 and Aaron 1.5). Aren't Abe 2 and Aaron 2 still around?

2014-01-11 15:22:38 by OD:

My head is gonna explode in a few minutes.

2014-01-14 19:19:58 by Jim:

@Steve: The point of preventing the kids from waking them up was due to Abe and Aaron's interest in testing the paradox theory, while also getting to punch one of their former business associates in the face without consequence. They wanted to see if they could deliberately alter the past, and if so, what the result would be.

The way it was supposed to work was that Abe and Aaron would go punch Joseph Plaats in the face, enter the boxes, then travel back to before they performed that act to prevent the kids from sounding the car alarms and waking Abe up. That way, Abe and Aaron's past doubles would sleep through the night, enter their boxes as they always did and vacate that timeline. The Abe and Aaron that punched Plaats would be the only Abe and Aaron in that timeline now, and be able to continue their travels as usual.

2014-01-15 01:58:28 by MrLarry:

Of course, despite all these "explanations" of time travel, none of them account for violation of the conservation of mass, i.e. where does the extra mass come from that constitutes the multiple incarnations of the time travelers?

2014-01-18 01:45:47 by LucusMucus:

And here I thought having this movie explained would make my brain hurt less, lmao.

2014-01-18 01:55:48 by LucusMucus:

Mr. Larry: has it occurred to you that the laws of thermodynamics as you know them were built on the assumption of linear time? Meaning that in a world where this movie is possible, those laws would turn out to have been wrong based on lack of data.

Imagine someone insisting you use a cooking method that predates the discovery of fire...

2014-01-18 01:55:55 by LucusMucus:

Mr. Larry: has it occurred to you that the laws of thermodynamics as you know them were built on the assumption of linear time? Meaning that in a world where this movie is possible, those laws would turn out to have been wrong based on lack of data.

Imagine someone insisting you use a cooking method that predates the discovery of fire...

2014-02-02 20:17:24 by PCMan:

Hey, I wish I'd known about this site sooner. I had to watch the DVD like four times and draw time-line diagrams before I finally got it. Worth the effort though.

One thing I don't get. If you can have duplicates then you've introduced extra mass into the universe and that takes a lot of energy, not sure where this comes from. Also if you wanted to get rich, why not just duplicate gold bars, or diamonds?

2014-02-10 06:07:00 by Dee:

Oh, wait!
"The way it was supposed to work was that Abe and Aaron would go punch Joseph Plaats in the face, enter the boxes, then travel back to before they performed that act to prevent the kids from sounding the car alarms and waking Abe up."
--Thus preventing the event altogether.
"... That way, Abe and Aaron's past doubles would sleep through the night, enter their boxes as they always did and vacate that timeline." However, being that Abe and Aaron enter the machines later that day and consequently--subsequently?--emerge earlier that same day, are not their future counterparts still present on that timeline?
"... The Abe and Aaron that punched Plaats would be the only Abe and Aaron in that timeline now, and be able to continue their travels as usual."

2014-02-10 06:23:54 by Dee:

"In order for the probabilistic threshold to be reached, events would have to configure in such a way that they would increase the likelihood of him entering the box in the first place. At least that's what I think.
The other possibility would be that if he decided not to enter the box upon seeing himself exit, then he would simply be watching an Abe from a parallel timeline that wound up changing his mind and traveling anyway, resulting in a doubling of himself."

In reality, I think this is exactly the sort of predicament that results in Granger's unconsciousness. Similarly, having been confronted with the inevitable--or rather irrevocable, emergence of himself from the machine, in direct conflict with his own personal incentive, he would become unconscious, comatose in relation toward his future self, or otherwise critically cognitively impaired. This is exactly the "color" of danger that is alluded to early in the film and more thoroughly through Abe cautiousness and carefulness. Indeed, in my opinion in hindsight these two characters could be considered polar opposites in that way, from their personal choice in action and their basic opposing-yet-codependent relationship in the plot.

2014-02-10 07:09:18 by Dee:

But you know, thinking more deeply into it, perhaps that's only the sort of thing that would happen if that were to be taken a few steps further. Put simply, I see Granger's condition as internally dependent upon Abe's timeline, not on his own conflicting future, due to an infinitely occurring inconsistency.
Put another way, if Abe were to emerge into a past timeline in which for some reason Abe-prior were to witness him--the condition of Abe's conviction not to enter the machine upon seeing himself exit having already been established in his volition--it would be Abe-once-removed who would "not belong," logistically.

Therefore, if X) Abe emerges into his own past timeline, then Y) by virtue of this, Abe-prior must not have seen the event beforehand, according to his own rule. Just as you said, there is a threshold of likelihood. The event is codependent either way, both conditions being connected by a causal link.

If for some reason he already had seen himself emerge, this would mean he had changed that condition by choice, or; alternatively adhering to the rule, if X) Abe-prior sees Abe-removed emerge, then Y) Abe-prior must NOT exist in that corresponding timeline... Which is weird, to say the least. And I think it spurs a batch of fresh questions in theory for me at least.

2014-02-13 15:56:32 by Dee:

Other sorts of paradoxes are not really consequential, in light of whoever has temporal supremacy. But it really just begs the question of what exactly occurs when someone emerging in the past subsequently within a timeline in which someone has already emerged from that same machine. Such a person has decided to flip back instead and in spite of the original occupant, emerging "this time" in lieu of them. It seems like they should both experience the same timeline, but the person who returns subsequent to the original occupant must be experiencing an alternative one. This is illustrated in the film, when it appears that two oscillatory timelines occur simultaneously, both originating and terminating co-dependently. Interactions between these two timelines may cause conflicts which will engender consequences that become "permanent" outside the loop.

This way, each time an emergence occurs, alterations will appear and conflicts will ultimately influence the timeline until there are alternate possible outcomes, ad infinitum. (Only recursively conflicting events will cause paradoxes for the occupants.) However, in one way or another, there will be a point at which none of the possible occupants enter the machine, therefore belaying the subsequent emergence of an occupant and establishment of his "personal" alternative timeline.

In this event, the loop will become closed, and any subjects which had become potential occupants might now be only possibilities. Does this then mean that logistically, in such a scenario it is the occupant who emerges and prevents anyone from entering the machine at point B has the supremacy and successfully establishes a future timeline? I would think so.

As in the film, this causes an additional copy of the original occupant.

2014-03-26 16:23:45 by GOD:

Good movie. Good theories here. Has anyone here built a time machine? No. Then all this discussion is about what happens with time travel is speculation. In all likelihood, time travel is impossible. But its nice to dream. From the moment they mentioned the the ex walked into the party with a shotgun, It's obvious the whole thing was to stop it from happening, most likely a shooting.

2014-04-01 23:48:51 by Yoey:

Time travel is theoretical. Of course it will be speculation until we actual invent a way to time travel. Much like the movie details, you cannot travel deeper into the past then the point you invented it in the first place. (Or more specifically in this case, no earlier then the machine being turned on)

I love how the movie does circumvent the problem with paradoxes with the idea of alternate timelines. In essence then only timeline you can change is your own. Your personal timeline can move deeper in the past yet still retaining YOUR timeline.

Example: PersonA turn on Box A at 6am, Box B is turned on at 7am. PersonA enters box B at 8am, PersonB enters Box A at 8am. Person B stops PersonA2 from turning on BoxB. PersonB would have a timeline where PersonA2 does not travel back to the past. PersonA that did turn on the box originally has already entered the boxB and will emerge at 7am regardless of personB's actions. Thus, new timeline created. PersonA will be in a completely new timeline as the original PersonB.

The movie shows one specific timeline. The movie shows the timeline for Aaron3, his own personally created timeline.

....Just my theory

2014-04-05 05:21:09 by Ash:

My head hurts. I love this movie, but I think several people on this thread are taking their opinions WAY too seriously. We're talking about a fictional movie about time travel cloning, and people are actually arguing about the logistics of it all. Can't we all just relax, realize that it's a work of fantasy, and enjoy the entertainment aspect of it. Let's get over ourselves, shall we?

2014-04-05 06:38:29 by Joe:

Everyone seems to keep saying that Aaron was bleeding out of his ear from extended exposure to the boxes.  Evidence suggests that this is not the cause.

The evidence, aside from no one else bleeding from any other place, is that it is the ear he always has his earpiece in.  Given the use of the earpiece as the main indication of which Aaron we are seeing throughout the film, there must be more to it than it simply being an effect of exposure to the machine.

I find it more likely that it could simply be from his overuse of the earpiece.  It would be a pointless coincidence otherwise.  Am I right?

2014-04-10 03:20:17 by Jim:

@Joe : You are not alone. That is probably the second most prevalent theory about Aaron's bleeding ear, that it is the result of his overuse of the earpiece. It's possible I suppose, it just never seemed to jive with me since I've never heard of that symptom from the overuse of an earpiece before. Then again, who knows what would happen if someone had one in for the better half of a 36 hour period of time.

I've entertained a third possibility that is seldom (if ever) put forth, that Aaron's bleeding ear could be the result of a gunshot going off right next to it. Like that of a shotgun fired at a party.

@Ash : You are right, many of us have become captivated by the convoluted plot of the film, (perhaps too much so).

But the only thing I can say to that is this: for one, this IS a blog specifically about the film. If there is ANY forum  that is appropriate to vent our thoughts, theories and feelings about it, it would be this one. Second, I feel (and this is merely my opinion) that the reason the film provokes this sort of response in many of us is because it is by far the most realistic depiction of a fantastical idea like time travel that any of us have ever seen before. Indeed, if time travel ever were achieved, its process would undoubtedly be identical if not very close to the way Shane Carruth depicted it in Primer. That is what excites us. That we feel we have each been given a glimpse into what this remarkable technology would actually look like through the imagination of a highly creative mind.

2014-04-10 06:47:26 by Joe:

@Jim:  I think what I was trying to say but didn't, is that as it would be a seemingly pointless coincidence otherwise, the earpiece must be part of the cause.  I don't necessarily think it is caused by the earpiece just being in too long alone.  It could also be an effect of exposure to time travel along with prolonged use of the device.

The shotgun from the party is a possible theory and it does make sense until you enter one last piece of evidence for the earpiece theory that in my opinion kind of cinches it..

During the end of the movie, when there is just too much to take in to notice some of the smaller details, two things occur.  We see Abe now also wearing an earpiece in his right ear, surrounded by scenes of him bleeding out of his right ear.  There is not a lot of attention called to this and it is easy to miss.  This occurs about 1 hour and 6 minutes in.