Time Travel Without a DeLorean

I am a complete sucker for time travel/alternate reality plotlines. I'll watch damn-near anything if it's got those elements. It's how I ended up seeing pretty much every episode of a couple Star Trek shows over the years. It's just something about causality. I need to know that every event had its cause somewhere in the story. If it's not there, I'm pissed.

Which is why I end up avoiding a lot of time travel shows/movies. I find out how the time travel works and if it doesn't hold up, I bail. I save myself the mental acrobatics of trying to explain "science is magic."

When I first saw "Donnie Darko," I didn't read, watch, do, or really think of much of anything else for 18 hours. However, eventually I got a handle on it and it made sense. Even if the answer was "God said so," the logic worked.

I go back to other bits and I'm legitimately pissed, sometimes:

Terminator - perfect sense
Primer - perfect sense
Donnie Darko - insanely complex but deceptively simple and perfect
fucking Dragonball Z - almost makes sense
Star Trek - like 80% of the time, including the new movies

Back to the Future … internal logic error.

What? Back to the Future doesn't make sense? How is that even possible? They have Mr. Fusion. They have instant hydrating Pizza Hut. They have flux capacitors. Their time travel is so simple Christopher Lloyd drew it on a chalkboard with three intersecting lines. What has gone wrong here?

Here's my rant of nerd-logic:

There are only three types of functional cinematic time travel: Donnie Darko Time Travel, Terminator Time Travel and Dragonball Z Time Travel.

Everything you do to branch off from the
original timeline circles back to nullify
itself. Life continues as-is.

Donnie Darko Time Travel: Whatever it is you do that changes the timeline was always supposed to happen. Predetermination is the case, and the only times you can violate this is when "God" or something similar says you can. In fact, *SPOILERS* the way I understand the movie, the whole thing is God saying, "Man, I wish I could give this troubled boy some happiness before he dies." Then God gives him the ability to violate predetermination, creating a tangent universe in which he gets to be happy for about 3 weeks until this improper universe caves in on itself and the kid dies happy in bed, killed by the one thing to survive the tangent universe's brief existence and destruction.

Primer explained it much better: You decide to go back in time so you turn on the box (because it can only send you back as far as the box was turned on, since there wasn't working a time machine to exit from before that). You kill 3 hours doing whatever, researching how to change your world, perhaps. Then you get in the box and move backwards in time for 3 hours, exiting the box right after you turned it on. You go out in the world to change history, while your former self is sitting at home figuring out to do just that. After three hours, he goes back in time and becomes you from 3 hours ago and the box shuts off, closing a loop paradox-free.

Terminator Time Travel: You go back in time, you change something, but you don't really know until the thing you supposedly avoided doesn't happen. Terminator seems to indicate that some things have to happen, but that's likely more the "inevitable downfall of humanity do to the species' own hubris" than true predestination. You can totally alter the How and When of these things occurring. That doesn't preclude things in the future from causing events in the past via time-loop, but "No future but what we make," still can hold true at other times. There's one timeline, and you're in it, baby.

Interestingly, Terminator actually follows Donnie Darko logic, while T2-T4 and The Sarah Connor Chronicles follow Terminator logic proper. In T1 the very act of sending a robot back to kill John Connor's mom results in a future soldier being sent back to save Sarah Connor and (no *SPOILER* here unless you're maybe 14) father the future savior of humanity. In T2, they don't so much avert Judgement Day as they push it back. T3 keeps the timeline moving ahead without altering much history, however various support leaders to John's future resistance are killed as young adults, so the future is likely altered somewhat. T4 verifies this, as well as the idea that the future is drastically different from the one Kyle Reese originally came back from.

And Sarah Connor actually did a great job on the concept if they had only cycled back into the main continuity in the last 5 minutes of the last episode from season 2, but instead they borked everything by setting up a third season and getting canceled.

Star Trek follows the same rules. Something from the future can alter the past in such a way that it would never go back to alter the past, but that's okay because it's now in the "present" and untouchable by whatever temporal shitstorm rewrites history. Voyager ended with just such a 'paradox' and J.J. Abrams kicked off a whole rebooted franchise with that logic.

Dragonball Z Time Travel: Amusingly, Dragonball Z followed the same basic idea during one of the late-middle-ish story arcs, but with the twist that multiple timelines exist concurrently and there's not much you can really do about anything in yours. Here, time machines are also technically dimensional transports. Two of the characters' kid ("Trunks") comes back from a post-apocalyptic future to change history and does, however even after he theoretically fixes it, he returns to his timeline to find nothing has changed. This is actually a legitimate time travel theory: that you can do whatever you want in the past because you can only ever travel to an alternate reality past. Grandfather Paradox doesn't work if it's not technically your grandpa.

This is almost the same as Dr. Who, except the Doctor really doesn't give a shit about what he does to any particular timeline. Like Trunks's ship, the TARDIS keeps its occupants outside the timestream and thus immune to alteration.


Here's where Back to the Future pisses me off. Doc Brown clearly shows what's going on in Part II:

It's the alternate-concurrent-timeline again, except only from the perspective of someone from the original history. When they changed 1955, 1985 got tweaked and no one knew the difference because it was never any other way for them, except for Doc and Marty who only experienced the original timeline and were protected from being overwritten by being outside the rewritten era.

Except since he and Marty were not in the DeLorean when Old Biff went back to 1955 and changed history again, they shouldn't have been protected because they didn't time travel until after that. In fact, the entire universe should be written over, but it's not. Instead it's still in place because Marty and the Doc are going to reverse the changes in 1955, but they won't know to do it unless they try to go back to a time after 1955 first and see some changes.

So it's a predestination loop.

Except, in Part I Marty almost fades away because his parents don't get together, until they do and he doesn't. So clearly Marty can be erased, even if he was going to have fixed everything.

Add to that that the present is changed at the end of I and artifacts from the present and future erase in the past and present respectively when Marty changes events, and it looks like there isn't predetermined causality, even though there has to be for the rest of the story to work.

Basically, there's causality when they need special effects and plot twists, and there isn't when it would benefit the characters.

And if Marty tweaked 1985 so his family was better off and Biff was a tool, why would he befriend Doc and end up going back in time at all? Shouldn't there be an extra Marty? Did they just kill him to make sure? Unless Doc, guided by the fact that they did do all that, coerced that Marty into going back in that timeline as well, with the intent of preserving it exactly as it happened to him/in the movie. That would work, but then there would be an extra (third, really) Marty in 1955 who would arrive in the same place and time as Movie Marty, either merging with him or blowing up the universe in the exact paradox Doc always warned him about.If they merged, that'd alter the movie and screw with the timeline again in and infinitely recurring loop of subtle differences, or Original Marty takes precedence over all paradox Marties because he is "Original" and thus somehow more Universally valid than his accidental offshoots.If traveling outside your timestream makes you immune to all temporal anomalies save complete erasure, as long as you're not in your preferred chronological place, that's a pretty sweet superpower to have, especially since everybody ages while they're time traveling and then returning to the same day they left.

So yeah. "Magic."