Nov 1, 2019 7:00 AM

Let's Unravel the Time Travel Paradox of Terminator: Dark Fate

If you apply the Novikov self-consistency principle to the franchise, it holds up—until it doesn't.

A woman fires a large weapon and smoke comes out of both ends

Terminator has been retconned within an inch of its own life. The long-lived franchise, which began in 1984 with The Terminator, has been sequelized (twice) and rebooted (three times) and adapted for TV (once). And because all of them involve some element of time travel—generally a sentient AI system sending back a Terminator to kill the human that would eventually overthrow the machines—the canonical timeline looks something like an ouroboros Möbius strip.

Terminator: Dark Fate is the latest loop. This time around, a new hero, Grace (an enhanced human hybrid played with raw energy by Mackenzie Davis), goes back in time to protect Dani (Natalia Reyes) from a Terminator that’s even more advanced than the ones fans are used to. That’s because, thanks to some time-travel tap-dancing, it’s been sent by a different entity—not Skynet!—to ward off a war that happened after the other wars were won by the humans. Or something. Sarah Connor (played by Linda Hamilton, reprising her role) is still around because she never came from the future. But her son, John Connor, who happened to be the guy who stopped the machines before, is dead, killed by a Terminator who, she says, was sent from “a future that never happened.”

Confused yet? Yeah, everyone is. That’s OK. The Terminator franchise never really set out to, like, make sense. The whole point is robots, and guns, and explosions, and computers, and more explosions. There’s no need to complicate things with actual physics. They’re not meant to hold up to actual time-travel paradigms. But if you know the Novikov self-consistency principle, they’re a hell of a lot more fun to watch.

A primer: The Novikov self-consistency principle holds that, well, time paradoxes are not entirely possible. What physicist Igor Dmitriyevich Novikov stipulated in the 1980s was: If you went back in time, the probability that you could change the past in any significant way is zero. Novikov and his contemporaries held that while the theory of general relativity maintained that “closed timelike curves” were possible, and thus so were trips back in time, people could only perform actions that wouldn’t change the past; they had to be consistent with what had already happened (hence the name). Unlike the grandfather paradox, which frets over what happens if you go back and kill your father or mother’s dad and eliminate your own existence, Novikov’s principle states that you simply would not, could not do that. What’s already happened has already happened.

The Terminator movies can adhere to Novikov principle, mostly, if you generally accept the timeline that John Connor sent back Kyle Reese to protect his mother, Sarah Connor, knowing that Reese would then become his father. It falls apart, though, in Dark Fate, where the events of Judgement Day mean Skynet was never created and thus a new AI, called Legion, pops up in its place. These events, theoretically, couldn’t have happened because the time travel would’ve changed the larger outcome. There is also an implication, which we won’t entirely spoil here, where the leader of the new resistance, Dani, implies that she won’t allow something that the audience just saw happen to occur again. This is a huge no-no.

(Also, if you ever try to apply this principle to Donnie Darko—you know, for fun—think of it this way: The movie can hold up if you believe that the plane engine that falls through Donnie’s ceiling was always meant to kill him. When he got out of bed and survived the crash, he created a tangent universe that he then corrects through his actions in the movie. None if this explains Frank, the dude in the freaky bunny costume. If you try to apply it to Avengers: Endgame ... actually, don't.)

What’s more interesting, though, is applying the Novikov principle to the actions of Skynet and/or Legion. For as long as there have been Terminator films there has been this idea that an all-powerful artificial intelligence decided the best way to stop their own demise is to send a Terminator back in time to kill the person who is trying to overthrow them. (It’s never made sense that they could figure out time travel but not better security against human infiltration, but I digress.) If you want proof that AIs aren’t really that smart, look no further than the fact that they learned everything about time travel, but never read Kip Thorne or his contemporaries. If they had, they’d know all these shape-shifting, time-traveling machines are futile.

But again, the actions taken by Skynet, Legion, and the humans seeking to stop them aren’t futile. They’ve generated hours upon hours of entertainment and millions of dollars in box office totals. The point isn’t to be consistent, it’s to be entertaining, big ol' Timey-Wimey Ball and all. Terminator: Dark Fate erased quite a bit of what came before it, keeping the good parts (Hamilton, Schwarzenegger) and shedding the rest. As retcons go, it’s a mighty good one. Now if only someone could go back in time and undo Terminator: Genisys.