Tenet: What Exactly Is Time Inversion?

Christopher Nolan's forthcoming film Tenet is mysterious by design. All we really knew about it at the outset was that it's an "action epic" and that there's "international espionage." Once we had a full trailer at which to gape, we also knew one other thing: There are going to be some serious time shenanigans.

We also know that there's an organization trying to prevent World War III, and we know that a nuclear holocaust is not the greatest risk that our heroes face. We know that whatever might cause another war to end all wars is "something worse" than nuclear armageddon.

It's hard not to think that the "something worse" has something to do with John David Washington's character (whose name we don't even know) and his ability to witness and experience time in reverse — those are the time shenanigans we're talking about.

We've seen Nolan tackle time before, so it's not a huge surprise he's doing it again. Memento was told in reverse and from the perspective of someone with no ability to form new short-term memories. Interstellar dropped its hero, Cooper (Matthew McConaughey) back in time and on the flip, alternate-dimension side of his daughter's bookshelf so he could help her save the day. Then, of course, there's Inception's time, dilated and out-of-joint because much of its story takes place within a dream.

There's still something about Tenet's time inversion that feels different. So, what's the deal, exactly?

In an interview with Entertainment Weekly, Tenet star Kenneth Branagh opened up about the film and its treatment of time in a way we haven't heard before. The results are simultaneously illuminating and even more mysterious. "It's an espionage piece that's dealing with a global threat to the world," Branagh confirmed.

Branagh went on, however, to confirm our earlier suspicion. "A nuclear holocaust is not the greatest disaster that could befall the human race," says Branagh. "Tenet discusses an even worse possibility, and it is wrapped up in this mind-boggling treatment of time that continues Chris Nolan's preoccupations in films way back to Memento, through Interstellar and Inception."

Now that we know that this treatment of time is related to World War III, what do we know about how time inversion works? Is it time travel? Not according to the film's creator. In that same EW interview, Nolan elaborates. "This film is not a time-travel film," affirms Nolan. "It deals with time and the different ways in which time can function. Not to get into a physics lesson, but inversion is this idea of material that has had its entropy inverted, so it's running backwards through time, relative to us."

While neither Nolan nor Branagh's explanations perfectly explain entropy inversion, their thoughts can guide us a bit while we wait for Tenet's release on July 31, 2020. There is, after all, another word for reverse entropy: Negentropy. Think about it this way: Time, moving in a forward, linear fashion is all entropy, all about life moving towards death and creation moving towards destruction. As Washington says in Tenet's second trailer, however, "this reversing the flow of time — doesn't us being here now, mean it never happened?" Or, placed on a more cataclysmic scale, doesn't inverting time run the risk of making it so time, and, by that measure, all of existence never happened at all?

We'll have to wait for Tenet's arrival to know the answer to that question, and the hundreds of others we still have about just what is going on in this film.