What does it all mean?

[u/BaconJets]

So I've seen this film three times now, and after my third watch it's a subjective 10/10 for me. I've never gotten so much value out of a single film before, showing it to my friends to watch them get mindfucked (And selfishly, for me to rewatch and gather more details) has been my favourite thing to do as of late.

Unlike Nolan's other films however, I can't find a clear meaning behind it all, not that there has to be per se. Inception was at it's core about a man trying to get home to his kids. Interstellar was about love for your kids transcending time and space. Tenet though? The only thing I've got is that it's about the complexities of global intelligence agencies and the insane situations that can come out of that mess. Does anybody else have theories?

[u/tgillet1]

To me it’s about free will. TP learns that what happened happened and can’t be changed (at least everything he is taught and then experiences enforces that), and we operate in a world that constrains us, but within that framework we still make choices. The more we incorporate an understanding of how the world works, the more we can exploit that understanding to control our future, even given the constraints placed on us, even with the knowledge we have of what already happened/will happen.

While the movie adds science fiction and an amazingly mind bending narrative, the message is still relevant to our lives. The usual view is that if we live in a deterministic world then we don’t have free will. As it turns out it doesn’t matter if the universe is deterministic or stochastic in terms of free will (I can expand on that if you’d like), but the point is that even if the universe is deterministic, we are pieces of that world with knowledge, feelings, and an understanding of the world. We are pieces of the deterministic universe making decisions. These views are compatible.

[u/BaconJets → u/tgillet1]

This is an excellent way of looking at it. It's hard to see the determinism of Tenet as anything but nihilistic at times, I find it quite existentially challenging to imagine watching yourself reverse exit a turnstile, basically the universe telling you that your fate is to enter that turnstile. The fact that they win the battle against the future has been the only silver lining until I read this interpretation.

[u/tgillet1 → u/BaconJets]

I like to think along these lines further. The universe might be entirely deterministic in the usual sense, but there also might be many possible futures. This interpretation probably could never be proven, but it would provide a mechanism for how the universe so cleanly prevents paradoxes. The notion here is that there are in fact multiple timelines, but only those that have no paradoxes persist, which entails scenarios where either some physical constraints exist to prevent a paradox in a situation in which a character would otherwise choose to cause one, or a character’s motivations line up to avoid a paradox. We see both things happen numerous times in Tenet.

If this is true it makes no difference in terms of free will… unless you are considering that possible explanation as a character who gets to make decisions. You would be further motivated to avoid a paradox because for all you know it would result in your timeline ceasing to exist. And yet, even if there are other versions of you who made different choices (or more likely ended up in different situations), you still don’t have any control of the mechanisms of the universe that make you up. The same is true for a stochastic universe without many worlds, though in the world of Tenet that explanation for the universe seems immensely unlikely given how perfectly paradoxes are avoided.