Monday, January 11, 2010

Using time travel - lessons from The Terminator

So you've decided to write a time-travel movie. Congratulations! Now you can look forward to all manner of story discussions about causality, paradox and other wonderful issues that will confuse the hell out of your audience if they don't make sense, and probably will confuse them even more when they do make sense.

The very first question you should ask yourself if time-travel is part of your idea is: "Am I dealing with a 'closed loop' theory of time-travel or a 'multiple timeline theory?'" Confused yet? Hold on, we'll take it piece-by-piece.

Closed loop time-travel is the easiest to explain. Essentially what it means is that your characters can't change history because there is only ONE timeline. Even if they go into the past to change things, those "changes are already accounted for in the history they left. In a closed loop, when one enters the past, they aren't changing history, they're fulfilling it.

The first Terminator movie is an excellent example of a closed loop. In an attempt to alter history, Skynet sends a Terminator back in time to kill John Conner, the future leader of the resistance against them. To do so, they actually send their machine after his mother Sarah before she becomes pregnant, the theory being if she dies, John won't be born. However, the Resistance sends back their own fighter to protect her, a man named Reese. Though he dies fighting the Terminator, he eventually preserves her life - but not before sleeping with her. At the end of the movie, Sarah is pregnant with Reese's child, the baby who will become John Conner.

See the closed loop? If the Terminator hadn't come back, than Reese wouldn't have come back and fathered John. Thus, the Terminator couldn't have ever succeeded in its mission because the mere fact that John's birth - a conception that the Terminator attack is a catalyst for - is a part of the future it left means that those events are set in stone. The Terminator could no more kill Sarah and alter its own past than Hitler could suddenly win World War II and immediately alter the history we know.

Another movie that plays well with this theory of time travel is Bill & Ted's Excellent Adventure, when the titular characters realize that their future selves can get them out of present jams so long as they remember to come back in time and make certain things possible for them.

When working with time travel it is essential that you lay down your rules at the earliest stages of plotting. I've read some scripts that start off with clear evidence of the closed loop theory, only to have the characters suddenly able to rewrite history in the third act.

One of my current scripts deals with characters who think they're dealing with a closed loop sort of time travel, only to have the events of the movie reveal the timeline is more malleable. It's been a tricky one to plot because I have to make sure all the evidence lines up the right way without any inconsistency by the end. It's a tricky thing to plot because I have to make sure that the characters' misunderstanding makes sense. The evidence all needs to track in the end, and I need to make sure that all the misinterpretations can be explained away.

On Wednesday, we'll discuss examples where the future is mutable. Bring your Advil. I feel a headache coming on.


  1. What's interesting in the Terminator example is how the movies follow clsoed loop logic, but the Sarah Connor Chronicles TV show switched to a multiple timeline theory.

    When I say 'interesting' I really mean 'confusing as all hell for a blonde like myself to understand, let alone explain to my motehr when we watched it together.'

  2. I would contend both examples you sited are "open loop time travel." The antaganonist's desire in "The Terminator" is to change history. The big fear in "Bill and Ted's Excellent Adventure" is that those nitwits will change history. The threat of an alternate history is present in both, and if it wasn't both stories would lose a lot of suspence.

    In one of my favorite time travel movies of all-time, "13 Going on 30" time travel is by "wishing dust." Maybe the hookiest means of time travel in cinema, BUT if you let that pass the story unfolds like God giving someone a glimpse into how their future will play-out so that they have the perspective of time not loose out on one of the greatest things in their life, which in this show is Jenna Rinks (Jennifer Garner) friendship with her next door neighbor, Matt Flemhaff (Mark Ruffalo).
    In the case of "13 Going on 30" time travel in the future persepective leads to the main character changing their life's path, thus altering their future. Different outcome, similiar device; open loop time travel.

    When I think of the phrase, "closed loop time travel" I think of time travel without interaction of the traveling party and the people in the place they're going. They're like pure spectators with no interaction with anyone. THUS their is no real chance to upset the past or future's equilibruim. "Closed loop" then refers to the fact their is no possiblity of change.

    What-chya think of that, dude?

    - E.C. Henry from Bonney Lake, WA

  3. Deja Vu is an excellent example of a film that can't make up its mind between closed and open loop. It switches back and forth in a headache inducing fashion.

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  5. I was having an insomniac night a few weeks ago. Bill and Ted's Bogus Journey was on. I watched it for the first time since it came out.

    And I just kept thinking that if Bogus Journey doesn't have any major plot holes, which it doesn't, than what excuse does Terminator: Salvation have?

    Which just aggravated the insomnia...

    Anyway, here's a pretty good visual breakdown of Primer that might help for this series:

  6. A Closely Guarded Secret: Agreed. Actually, each Terminator sequel seems to operated under a different theory. T2 suggests it IS possible to change the future by destroying Cyberdyne, and in fact there were scenes shot of the "new" future which totally would have shot all time travel logic to hell. (The way it was left in the final cut at least leaves open the possibility that all of this was "supposed" to happen.)

    T3 shows that though time has been altered, Judgement Day is inevitable, which again seems to fly in the face of the first film's elegent handling, and then you've got the TV series which really carries this out to an extreme to the point where you're right - it doesn't really work.

    E.C. - It doesn't really matter what the antagonist's intentions are. In a closed loop, their actions are already a part of the history - as happens in Terminator. There is no possibility of change because John Conner won't exist if the machines don't try to kil his mom - and they won't try to kill his mom UNLESS he already exists.

    13 Going on 30 IS an example where the future is mutable, though.

  7. Anyone who even thinks about writing a time travel movie should have to watch ALL of the Dr. Who episodes from the original series. Especially the episodes from back in the 70's and 80's when Robert Holmes, and Douglas Adams were writing. Dr. Who has done every time travel plot you could possibly think of, and done it better, even with the shaky sets and no budget of original series.

    This clip from the 1980 episode "Meglos" is a good example of how to get out of a time loop.

  8. Actually, Dr. Who is a good example - 'Blink' from Season Three of the new series (with David Tennant) is a great time travel story, albeit one where enthusiasm rather than consistent logic carries the story through its beats.

  9. Another example of closed-loop time travel would be Premonition with Sandra Bullock. Definitely not as confusing as some of the others.