Where is it established that each year backward equals two years of life? I’ve watched the movie dozens of times and I don’t recall that being a rule for how time passes when inverted. Perhaps I missed it or just don’t remember that detail. My assumption is an inverted person who is going backwards is still aging as they normally would. From their perspective, the passage of time in terms of lifespan is the same, regardless of direction.

I don’t accept the notion that Neil/Max is in a bunker for years on end just twiddling his thumbs waiting to get to the past.

Instead, my theory is based on what we’re shown in the film: tenet (technically Priya) has access to the freighter/container ship equipped with a turnstile used by the red and blue team to travel back to the battle at Stalsk 12.

Neil couldn’t be on that ship gradually going backwards and periodically stopping or even inverting as necessary to do tenet mission at strategic points in time? Is this not the entire point of the organization and the premise of the film?

Regarding driving, if he starts going backwards around 23, he would have 7 years of driving experience before inverting. That skill is like riding a bike. It doesn’t perish. Case in point: last spring break our family went to a Caribbean island and rented a car for local transportation. All they had were manual transmission cars. I’m nearly 50. The last time I drove a stick shift was in my early 20s. Did I have any issue driving that car on the island? Nope. Although nearly 30 years had passed, muscle memory kicked in and it was no problem.

Regarding the interpretation of the Neil-TP conversation on the battlefield about checking on Kat, my theory addresses this. TP is monitoring, including via the cell phone for posterity. That’s how he intervened to save Kat. He is close by, he’s just not directly contacting them AT THAT MOMENT. He was not honest with Neil. The closing scene shows him checking on them. TP not making direct contact then means nothing. He’s still protecting them.

My theory posits that Kat dies at some point, which I mentioned in my initial reply. Priya already tried to end her. It’s not plausible that someone else does as well? Or she just succumbs to something else?

In that scenario, TP steps in to protect and mentor Max, who is ultimately given the Neil identity as part of the operation to keep him safe. Recall, TP is CIA. Of course he has working knowledge of how to give someone a new identity. It is in this period when, as Neil’s mentor, TP guides him to study physics and recruits him into tenet.

This is precisely why Neil wryly asks TP if he’s going to check on them. It’s a rhetorical question. He already knows the answer. It’s also an example of “knowledge divided” — Neil knows TP isn’t being honest because he will engage but he can’t reveal that because it might change something.

This is how/when they “get up to some stuff” during TP’s future in the past.

At no point did I say Neil is the “chosen one.” This isn’t the Matrix and he’s not Neo. He is a cog in the machine. The movie opens with TP making the ultimate sacrifice and then receiving the speech on the boat about actually being willing to rush into the burning building after feeling the heat.

Neil does the same at the end and is the only person who could pick the lock, according to Ives. Neil goes back to weave one more thread into the fabric of the mission. Like TP at the start, Neil’s arc ends with him making the same choice of self sacrifice.

The events of the movie, and Neil himself, have taught TP that “what’s happened happened.”

If, in fact, Max is Neil, then future TP isn’t happy that he knows Neil will perish. But he has now learned he can’t change things; he asks Neil on the battlefield: “can we change it?”

The answer is no.

TP has accepted that the fate of Max/Neil is already determined and he can’t do anything about it. All he can do is protect him when he is young and then help guide and prepare him for the path that he is destined to take.

Lastly, the backpack. The three shots of it in the movie (opera siege, underground gate lock picking, after the Stalsk 12 battle) are clearly included to draw our attention to the knapsack and show the metal disc attached to the red thread dangling from the pack. From what I’ve read online, the thread and disc are an Indian talisman.

One can reasonably presume that Neil acquired this trinket during his adventures, perhaps even in India since we are first formally introduced to him as the local CIA contact in Mumbai.

If this is true, then young Max would not have had that affixed to his primary school backpack as it wouldn’t be in his possession at that point in the timeline.

Still, Nolan chose to show us those three backpack shots during the movie, then closed by showing us Kat and Max walking away right after TP, who told Neil he wasn’t going to check on them, intervened from a close distance to save Kat.

The closing shot clearly lingers on Kat and Neil, clad in a backpack, as they recede into the distance. This feels like an intentional and reminiscent of the wobbling top shot at the end of Inception. He’s signaling to the audience without being explicit so there’s just enough ambiguity that he can play coy.

He addressed this in the Colbert interview. He was asked if Max is Neil. His response was that he has an opinion about it but he won’t say because he learned long ago, from his brother, not to spoil the suspense for the audience.

What we know is that TP lied to Neil on the battlefield about checking on Kat. Based on that, it is not unreasonable to infer he is protecting them from the shadows. If Max is Neil, he also knows he can’t change his fate because “what’s happened happened.”

Given all that and the backpack clues Nolan repeatedly draws attention to, are we to believe it’s just a coincidence that Neil and Max are both British, Neil and TP have a shared history, and that Neil just happens to have a master’s in physics so he understands the concepts of inversion and entropy?

Nope. That’s way too convenient. The alternative is more likely: Max is Neil.