Another short update today!
On this page Marty asks Doc what his plans are, and Doc says he's gonna wait till the cops are gone from the parking lot, go back to his van, pick up the plutonium pellets there and take a look at the future. How far?
Doc shrugged. "I figure I'll take it slow at first," he replied. "Maybe I'll go about thirty years, just to get my feet wet. Then maybe I'll take a look-see at the 22nd or 23rd centuries..."
"Well, good luck," Marty said.
The 22nd and 23rd centuries part stands out as being weird, but whatever, maybe it's cool that the temporal expanse of Back To The Future can get enlarged a bit! The time machine is good at travelling through all through time, we don't need to limit ourselves to within a claustrophobic plus or minus 100 years of 1985!
Doc says "It's funny, isn't it? I had to wait thirty years to catch up with you. Now you've gotta wait thirty years to catch up with me. Ain't life weird..." and then he winks and closes the door and drives off.
Then Marty presumably walks home and goes to bed and the next morning wakes up and thinks it's was all a crazy dream! But then he pinches himself and it's not! So he pulls out his record company submission form from the trash and puts it in a mailing envelope ("Why not? My music has been wowing them for three decades. I'm a cinch to win.") and then goes downstairs his house and family is all different!1 Weird!
1. So! Let's talk about Marty. Specifically, let's talk about this sequence of events:
The Marty we've been reading about (Marty Prime) goes back in time at the Twin Pines Mall.
Marty Prime has some adventures that change things (the name of the mall, the circumstances of his parents meeting, his family's history)
Marty Prime goes back to the present, goes to the Lone Pine Mall, and watches himself go back in time again.
See the problem? Whether or not you buy my meta-time explanation of Back To The Future's time-travel mechanics (though you TOTALLY SHOULD because it TOTALLY WORKS), Marty has returned to a future where at least SOME things have changed: we know for sure the name of the mall has, and we know for sure that Doc's spent the past 30 years trying to act natural while knowing he's totally going to invent a time machine and meet Marty and wear a bullet-proof vest someday! And if you don't buy my theory of changes to the timeline themselves take time, then you're arguing that EVERYTHING in 1985 has already been altered, and we're already fully in this Improved 1985 that Marty created for himself.
Either way, the world we're in isn't identical to the one that Marty left at the beginning of the story. And that's a problem. It's actually a huge problem, because it means the Marty going back in time NOW isn't the same Marty that left at the beginning of the story, and time travel is basically the poster child for sensitivity to initial conditions.
This new Marty has had different experiences, from things as small as the name of the mall to as large as what his family does for a living and whether or not they hire their old high-school bully and sexual assaulter to wax their car (yes this happens, no I dunno why). Due to different life experience, this Marty is a different person than the one we met at the beginning of this story. Let's call him Marty 2.
Marty 2, being that different person, is absolutely going to have different adventures in 1955 than Marty Prime did. There's a few ways these adventures could turn out, especially considering how narrowly Marty Prime avoided disaster when he was running through them:
Marty 2 doesn't get his parents back together, and so he ceases to exist. RESULT: Marty 2 and Marty Prime were never born, which causes major damage to the space-time continuum.
Marty 2 does get his parents back together, but slightly differently, as Marty 2 would interact with Doc differently, blabs about the future differently, steps on different bugs, etc). This results in a new, again altered 1985 where Marty 2 watches Marty 3 go back in time. RESULT: a loop, potentially infinite. The timeline may never stabilize into a solid reality ever again, and Marty 2212626 could watch Marty 2212627 go back in time. This is probably a bad thing.
Marty 2 doesn't mess with his parents meeting at all, and so has a different adventure in 1955! At the end of this, either he returns or he doesn't.
If he DOESN'T return, then no Marty returned to 1985, INCLUDING THE MARTY PRIME WHICH CREATED HIM. RESULT: Paradox, Marty 2 ceases to exist (and maybe the entire universe does too? I dunno)
If he DOES return, then he still altered 1955 as he must interact with Doc to get the machine to work, and we're left with the again-altered 1985 where Marty 2 watches Marty 3 go back and all the potential for infinite loops that presents.
So either Marty is never born, Marty's successful trip back to 1985 gets erased (undoing all the work Doc and Marty have put into it and maybe destroying the universe in a paradox), or the timeline starts looping, never reaching a stable new reality. Those are really the only options we've got, and none of them are great! They all kinda suck, actually!
"But Ryan!" you're saying, "The movie doesn't show any of these catastrophes happening! So there's got to be a different way."
And this is true. When we reach a conclusion from a set of facts that doesn't match up with reality, our only option is to look at our reasoning and find the flaw in it. And I totally slipped in an unfounded assumption earlier on you guys when I was talking about the sequence of events. It's this part:
3. Marty Prime goes back to the present, goes to the Lone Pine Mall, and watches himself go back in time again.
Here's the thing: we only saw Marty 2 travel through time. We never were told his destination. And I submit to you this hypothesis, this wham-bang anagnorisis that changes everything now and forever:
Marty 2 didn't go back in time.
At least, not like Marty Prime did.
Doc's a smart guy, and he's had thirty years to work out the consequences of what happened during that week in 1955. He would've gone through this reasoning and made all the same conclusions we did here. So what's the third way? How do we solve this? There's two solutions:
Step 1: Kill Marty McFly.
Step 1: use these thirty years to design a different time machine, one which rather than travelling within one timeline, allows you to also travel sideways to a different timeLINE.
Step 2: (Optional) Kill Marty McFly.
Option 1 is the cleanest, but it's pretty clear why Doc didn't chose it. If he had, all he had to do was send Marty 5 billion years into the future, when the sun's a red giant. Poof: Marty McFly killed instantly in a causality-free way, he never goes back in time, and we avoid the undesirable outcomes of "Marty never born/universe destroyed" or "Timeline constantly in flux". Instead, Marty dies, Doc never got warned about the terrorists so Doc dies too, and the timeline stabilizes at the cost of both Doc and Marty's life.
Option 2 is trickier, but it's the only thing that gets us to what we were shown happening in the movie and book, so it must've been what happened. Here's how it goes down.
Doc uses the thirty years head start he has to design a new DeLorean, one that looks the same but operates slightly differently. Rather than go back in time along one timeline, it takes a step sideways and sends you back in time in a parallel timeline. That means that Marty 2 goes to Hill Valley X, and Doc doesn't have to worry about Marty anymore. Our Doc's timeline has finally stabilized, with Marty 2 disappearing and replaced by Marty Prime, who watched this whole thing happen.
But Marty 2's not dead! He's in 1955 in Hill Valley X, where he can mess up all he wants and it'll only affect the future of Marty X, who is causally unrelated to him. This is the critical part. Marty 2 no longer can mess up his own birth, only Marty X's birth. Let's say he ends up keeping Marty X alive and then makes it back to 1985. When Marty 2 arrives in 1985 in Hill Valley X2, he'll watch Marty X2 (as both the town and Marty X himself were altered by Marty 2's actions) travel through time.
The problem is this: if Doc X lets Marty X2 go into ANOTHER new parallel timeline, this whole mess repeats, only instead of a constantly-shifting timeline we now have a messy and potentially-infinite explosion of parallel timelines. That's probably not wise. So instead Doc X (perhaps informed by a note Bulletproof Vest Doc hid in the machine) punches in a different demonstration date of 5 billion years in the future, and Marty X2 quickly burns to death in the heart of our dying sun.
And that's it! Both timelines are now stable AND we've eliminated the chance of them being altered by killing off an alternate Marty as he makes his first trip in time. Things are stable, the timeline avoided both catastrophic destruction AND an infinite series of Marties, and all it cost us was the life of one Marty X2 McFly.
I'd say that's worth it, and it seems like both Doc and Doc X agreed with me.
(It's worth noting that the book and the movie both gloss over this point and skip right to the scene of Marty 2 arriving in 1985 Hill Valley X2, which I can only assume was for time concerns.1)
1. "But Ryan," you're saying, "if that's true, why does Marty 2 react to Marty X's family with such surprise?" and the solution is obvious: as we skipped over Marty 2's household (recall we only get to see Marty X2's family), we can conclude that his family life was different from the X2 universe too, hence his surprise.
END OF FOOTNOTE FOOTNOTES
OH SNAP I JUST REALIZED YOU COULD TOTALLY ARGUE THAT THIS IS WHAT THAT STUPID "DOC FLIPS A MYSTERIOUS SWITCH" SCENE ON THE LAST PAGE WAS ABOUT!! Doc's putting the time machine back to "travel within one timeline" mode in preparation for his trip to the future, because he wants to be able to return to the very same timeline he departed from. It all fits! HOT DAMN, GIPE! YOU WERE ONE STEP AHEAD OF US ALL THIS ENTIRE TIME!!
MY BALLS ARE BEING SO TRIPPED!!
