The Marty McFly Paradox

My friend Eric has written an awesome post about the massive holes in the Back to the Future trilogy’s time-travel logic. It’s too long to summarize, but here’s one choice riff:

But here’s the weird thing– when he returns to 1985, he goes back to the parking lot to find the scene from the beginning of the movie play out exactly as it did the first time (except of course that (MASSIVE SPOILER ALERT) the Doc is now wearing a bullet proof vest). Except the Marty who he watches go back in time had a COMPLETELY DIFFERENT SET OF LIFE EXPERIENCES. I’ll accept that to protect the space time continuum, Doc Brown made sure that he still became friends with Marty and he still sent him back to the past at the exact same moment as before (he had seen the video footage of same). But here’s what I’m wondering– and this would have been an interesting additional sequel. What exactly did the alternate, better-1985 version of Marty do when he went back in time.

While I haven’t read what are probably numerous hardcore, follow-the-premise-to-its-logical-conclusion sci-fi stories, my sense is there are two possible conclusions to a logically sound time travel story: infinite recursion on the one hand; the instant un-existing of the time traveling character (and anything else introduced in that character’s original moment in time) on the other.

I think Back to the Future is playing with the infinite recursion scenario when Marty returns to 1985 and sees himself drive off into the past. That is, Marty isn’t watching “the alternate, better-1985 version of Marty” (or “Marty 2,” as Eric calls him). It’s meant to be Marty literally watching himself re-enact the movie we just saw. Of course this makes no sense, since the revamped McFly clan was all changed thanks to Marty’s actions on his first trip back to 1955; Marty should be changed too, transformed into Eric’s Marty 2. But here the movie breaks from its already strained logic in order to toss out the cool, mind-bending idea of a single Marty McFly doomed to infinitely re-enact his time-traveling life.

This bad logic shows up again in Part II, when

Marty goes back to the past from the future (in order to get the sports almanac back from Biff). And he sees the exact version of himself that I was just talking about and, as he sees, that Marty does the EXACT SAME THING HE DOES IN THE FIRST MOVIE!! That’s weird!

Eric’s right that this should be Marty 1 watching Marty 2, but the movie instead walks away from its premise; it’s simply Marty 1 again watching himself. Which, again, makes no sense.

Anyway, if the first two BTTF movies blew your mind back in the 80s, go read Eric’s post and prepare to experience your own mental-infinite recursion. (Like contemplating infinity, ever-expanding space, and death, thinking about Back to the Future for too long makes my head hurt.)

10 responses to “The Marty McFly Paradox

  1. Make no mistake– lest you, the reader of Josh Korr’s blog, think I was writing that out of criticism of the movie, know that it was all out of love. (That’s probably obvious given my ability to quote scenes so vividly). I love those movies– especially the plot holes. Time travel movies rule and I think you’ll always run into some kind of head spinning paradox if you try to tell a time travel story. So I love that the Back to the Future movies kept in the head spinning stuff, but also treated us to the meta-stuff like having Marty revisit the first movie. Yes, it doesn’t make sense, but having the main character of a movie relive scenes of that movie as an audience member is really compelling in its own way. The two key scenes are, of course, where he watches his dad punch out Biff (and goes and takes the magazine, prompting the immortal “I think he took his wallet!” line) and when he climbs across the scaffolding while “he” plays Johnny B. Goode. But there’s actually a really interesting part– he had the magazine and had knocked out Biff’s henchmen and was about to make a clean break, but then he pauses to watch him talking to his parents post-concert and he stands there kind of mesmerized for a second at watching his own moment of semi-triumph from the first movie. One of the cool things about time travel is that in theory you could relive great moments in your life as an audience member. He’s kind of lost in a moment of reverie, and that’s how Biff catches up to him again, leading to the car chase in the tunnel at the end of the movie.

  2. Now I want someone to make a meta-BTTF movie — something with the flavor of “Being John Malkovich” or “Adaptation” but the film grain and wardrobe of “Back to the Future.” It can explain all of this. I think at some point someone has to be a robot.

  3. Ha! That would be awesome. Jonze/Kaufman/Gondry/Peter Jackson and the best minds in Hollywood should get together with Zemeckis to do that as a tribute to Michael J. Fox.

    Meanwhile, I can only assume that the best minds in silicon valley have already launched an Apollo-style project to make Mr. Fusions and Hoverboards viable.

  4. nomananisland

    I like the writer Robert A. Heinlein’s way out of the “trap” of time travel paradoxes: every time you “change” history, you in fact enter an alternate dimension. The “old” history still exists in the previous dimension, so you in fact changed nothing, but instead created an alternate timeline running in parallel.

  5. Nice. I like Stephen King’s story The Langoliers, where time and space are actually eaten up by fuzzball monsters after they occur. Though I’m not sure he thought through the logic of that one any more than Zemeckis did for BTTF.

  6. The alternate dimension approach (which is basically the approach that Marvel and DC comics took, though that was more a matter of expedience when dealing with several dozen titles by several dozen writers where all of the characters ostensibly existed in the same universe– you had to have ways to deal with potential inconsistencies) is interesting, and is really the one that the Back to the Future movies are working with. As Doc and Marty travel through time and mess with stuff, they create new dimensions and thanks to the Delorean and the Flux Capacitor, they can travel between them. But that doesn’t explain my original confusion about why Marties from other dimensions are doing the exact same things as Marty did in his original dimension.

  7. It’s possible the two marty’s swapped timelines. marty 1 returns to lone pine universe from 1955 and marty 2 ends up in 1955, but has extra plutonium and returns to twin pines univerese. in that universe doc is dead as a result of the libyans and his parents are numb skulls. but if marty 2 ended up in twin pines, wouldn’t he risk the space time continuum and go back some other time and warn doc of his fate.
    this probably explains some thing in bttf part 2. if you go 30 years into the future, you’re skipping time. you won’t be there for 30 years. so the marty we see in 2015, the older marty, is the one we see escaping the terrorists at the end of part 1. it explains why theirs no doc in this future, coz he was shot in 1985 in the tp universe. this could be 2 universes joined together, as marty wouldn’t have had his accident with a rolls royce, unless he raced needles on his skateboard and made himself look a right idiot. so it seems marty we see through the trilogy swapped dimensions with the one we see at the end of part 1. possible part 4, 5, 6 story?

  8. if bttf part 4 was made, there wouldn’t be a hover conversion. so the reality 2015, we see in part 2 is tp universe. as you may recall before marty went 1955, doc said he forgot extra plutonium. after marty goes to 1955 and this other marty from LP reality arrives, he’s more interested in the dead doc. what if the terrorists got their hands on the left over plutonium and blew up the institution and hill valley was failing. but mayor goldie wilson started working with other countries to stop nuclear wars and decided to use easy waste disposal, get rid rid of oil and built hover conversions, run by garbage. but if this is true, how could marty, doc and jennifer end up back in that alternate reality. what happened betwen 1985 and 2015 (at the end of part I and beginning of parts II?)??

  9. The posts here are intriguing and thougt provoking–Stephen Hawking would be proud. However, there is on miniscule detail from the BTTF movies that has bugged me since I first watched them. It might seem trite and irrelevant, but for me, anyway, is a small detail that is of some concern–like a small splinter in your ass–that needs to be explained.

    What about Einstein (the dog in the first BBTF) whom Doc Brown alledged became the world’s first time traveler? There have been volumes of arguments and thesis’ of there being to Martys, but wasn’t Einstein, the dog, the causal ripple in this whole affair?

    Ok, let’s look at something a bit simpler. In an episode of The Simpsons, Homer travels back to prehistoric Springfield and finds there are dinosaurs living there. There is an annoying bug that is pestering Homer and he smashes it. Upon his arrival back in present day Springfield, Homer finds that Ned Flanders is running everything. The bug was what caused that whole syndrome. Just an aside, this episode was based on Ray Bradbury’s “The Sound of Thunder”.

    But, back to BBTF, to me anyway, Einstein the dog, was the one cause that set of the chain of events and caused the disruption in the space time continuum. The possibility of two Einsteins, or at least one Einstein that caused the whole mess, shouldn’t be discounted. Maybe it’s just me. The way I see it, Einstein the dog traveling in time (even two minutes into the future) was the jumping off point for the whole shebang. Would be interested in feedback on this. Don’t worry I’m a big boy and telling me to STFU, Stupid Boo won’t hurt my feelings. LOL

  10. Well Lucifer, that is an intriguing theory!

    The ostensible premise of the movies is that Marty changes the future with his actions in the past (Part I)/causes an alternate 1985 with his actions in the future (Part II).

    But going by the Homer-esque “I wish I wish I hadn’t squashed that fish” time travel logic (i.e. the smallest changes in the past can cause major ripples in the future) you’re probably right. Einstein’s going to the future first — the simple fact of his breathing, bacteria or microbes living and dying and jumping back and forth from past to future — should have caused the ripples as much as anything Marty did. (Of course, that would have been just a tad of a different movie.)

    Also I can’t remember if this is covered in the movie: How is Einstein supposed to have driven the car himself? Did Doc presumably gun the engine and leap out in the present, and then future Doc did the same to send Einstein home?