# How do inverted objects work in Tenet?

Paradoxically I think I got the plot and timeline in Tenet to a degree, but not the basic mechanic itself.

I want to focus on the shooting range scene where the female scientist explains how inverted things work to the protagonist.

• When should the bullets have appeared on the wall from the forwards perspective?
• Were they shot when the gun was still uninverted?
• What happens if you close the drawer with the bullet casings? Does the gun just not unshoot?
• Was the protagonist pulling or releasing the trigger?
• Is there a difference between a forwards person shooting an inverted gun and an inverted person shooting an inverted gun?

And the most basic of all - how was the protagonist able to undrop objects? At least in the scene where he was fighting himself it could make sense as both versions were acting a certain way, which provides the cause and effect for the things that transpired both ways.

The inverted time physics in Tenet is coherent enough to support the plot but if you think about it long enough it falls apart in many places. There are plenty of funny things that happen that have a more or less logical explanation, an extrapolation of what time reversal would look like if it were possible. But many things end up as contradictions. When you see the movie it is OK because you don't expect to understand everything.

The movie presents the wall with bullets and other artifacts as remains of a future war. So you imagine a future war with part of the world reversed, someone shoots at a wall, some machines break and fall apart, and all this ends up burried. Since it happened in inverse time, the remains of these events move backwards in time and end up burried in the present time, where they are dug out.

But that doesn't add up. A bullet has a single timeline and is shot only once. It doesn't get shot and "unshot" by somewhere else. At least that is not how the plot works: "What happened, happened." Since we see the protagonist shooting the bullet (even though in reverse), that is when it happened. The bullets in the wall where shot by the protagonist, and never and nowhere else in the future or the past.

Another interesting question is: where did the bullets come from? Since they come from the future, to see where they come from, you have to follow their timeline back in inversed time, which is forwards in normal time. You just need to see where they go. And they go into a storeroom. If the bullets come from the future, and in the future they are in the cupboards in a storeroom, that that is how they came to the present time. Someone in the future must have reversed himself and placed the bullets and other mechanincal parts in these cupboards. Not quite the story that the movie suggests.

• When should the bullets have appeared on the wall from the forwards perspective?

From an inversed perspective the wall disintegrates slowly, the bullets rust, and end up as dust. So, from the forward perspective, patches of rust spontaneously "unrust" into bullets, the wall resolidifies around it until it gets dug out. Possibly the wall was reversed in the past. If so, it appeared simultaneously in its forwards and inverted form on both sides of a turnstile.

• Were they shot when the gun was still uninverted?

Not, they were shot by the protagonist. It is not what the movie suggests, but it is the only way it could happen in a coherent way.

• What happens if you close the drawer with the bullet casings? Does the gun just not unshoot?

The philosophy of the movie is "What happened, happened". So the casings must be where and where they were needed. We don't know what would happen if someone prevents things to happen because in the movie it is never done.

• Was the protagonist pulling or releasing the trigger?

That is one place where the details become messy. In theory, in an inversed shot it is no the finger that pulls the trigger, but the trigger that pushes the finger back. But how that works with a gun that wasn't inverted in the first place isn't quite clear.

In the movie, the instruction Barbara gives are "aim and pull the trigger".

• Is there a difference between a forwards person shooting an inverted gun and an inverted person shooting an inverted gun?

The inverted person firing an inverted gun won't notice anything unusual.

For a forward person firing an inverse gun the gun behaves in a must unusual way, as you can see when the Protagonist shoots the inverse gun.

From the point of view of the inverted gun it is like being a forward gun operated by an inverse person. An inverse person is just pressing and releasing the trigger for a short time whether it is seen forwards or backwards.

It is not clear how the shooting action is being coordinated between a forward person and an inverse gun. At some time an inverse bullet jumps out of the wall just as the Protagonist decided to press the trigger. These two events join into the firing of the gun.

• How was the protagonist able to undrop objects?

I would say the idea is that reversing entropy changes the direction of causality. While normally the past determines what the future will be, inverse-entropy objects impose to the past to be what it needs to be for the future to happen. From the inverse perspective the hand opens and the bullet falls, so from the forward perspective when you see the bullet jump up you just see the consequence of an action that didn't happen yet, but is bound to happen because you already have seen the consequences. It is unclear how it affects the protagonist's free will to prevent him to not close his hand after all. He can't act otherwise because "What happened, happened."

I will try to answer the questions one bye one, because the understading of the way of working of inverted objects seems to vary from the living being's one:

• When should the bullets have appeared on the wall from the forwards perspective?

In the future, someone will shoot the wall with a gun. After that, the piece of wall will be introduced in the turning device and, in some moment, delivered to the organization the girl in the lab is working for.

• Were they shot when the gun was still uninverted?

Yes. Original shooter and the all the equipment (ammo, gun and wall) will be in "the forward state" during the shootage.

In the lab scene the shooter is the only thing that keeps his state, the other things are "inverted".

• What happens if you close the drawer with the bullet casings? Does the gun just not unshoot?

The film is casuistic and determinist in both ways, forward and inverse time. If all conditions don't allign, things shouldn't happen. Something could happen in the lab room that allow the bullet casing to return inside the gun with the bullet projectile.

Maybe, if you try to shoot with the drawer closed:

a) the girl in the lab will remember she put her pencil in the drawer and she will open it just before you shoot, or b) the table leg will break, making the table falling, opening the drawer and releasing the casings, or c) drawer is loose so it will open a little bit alone, allowing the casings out...

You know: determinism.

We can find another example in Neil (getting into the helicopter and coming back to the opening door moment instead of avoiding being there). Neil could escape or maybe have a flight accident that doesn't allow him to accomplish his goal, but this won't happen: he is loyal to the "contract" he made and nothing could block his path to the door moment, following the rule the leader of the soldiers told them just before the first time the main character gets into the inverter wheel: "Check if you are exiting the wheel". Determinism is there.

• Was the protagonist pulling or releasing the trigger?

Thinking about it, you can find that pulling the trigger is always accompanied by the automatic release of it. Could we say that it is palindrome movement?

• Is there a difference between a forwards person shooting an inverted gun and an inverted person shooting an inverted gun?

Assuming the trigger movement creates the same effect in both ways, I would like to focus this question according to the place where the bullet is. In this case, what I think is:

Forwards person shooting an inverted gun with bullets in the chamber: nothing happens. Forwards person shooting an inverted gun with bullets outside the chamber (e.g. in a wall): Bullets return to the gun, dealing damage to anyone in the trajectory.

Inverted person shooting an inverted gun with bullets in the chamber: shoot. Inverted person shooting an inverted gun with bullets outside the chamber (e.g. in a wall): nothing happens.

I based this on the body behaviour of an inverted person being burnt, getting cold instead of hot. For the gunpowder in the bullet and its detonation, it could work in the same way.

I hope I've solved your questions, although I expect that new doubts could appear about this topic. I have found quite interesting content and information in the reddit of the film: https://www.reddit.com/r/tenet/ . I hope it will be useful for you too.

Anyway, don't try to find a explanation for everything in the story. Don't forget that Nolan itself stated that:

"... though weâ€™re not going to make any case for this being scientifically accurate. But it is based roughly on actual science."

• If the piece of the wall with the bullets was also inverted and sent back that makes sense. But what about the Opera scene for example? When did the bullet appear in the wall there from the forward perspective? Also could you explain the undropping of stuff? – ndnenkov Aug 31 at 10:50
• That's one of the examples in the movie that remains unexplained. The broken driving mirror at the beginning of the cars persecution scene is other. – Gerifalte Aug 31 at 16:00
• Unexplained as in the movie doesn't explicitly say one way or the other or as in no one has come up with a consistent explanation yet? – ndnenkov Aug 31 at 16:02
• The film doesn't show this to the viewer. There are a couple of posibilities: a) Neil, as a "secret agent", prepared the scenario of his missions. He visited the Opera before/after (forward/inverted time flow) and left the bullet there. He did the same with the broken mirror, leaving it that way, knowing that the clash would repair it. b) Determinism. The same way the inverted main character left the bullets holes in the glass next to the inversion wheel in the Oslo port, and later they are "recovered" during the fight, another inverted left the bullet in the Opera, who knows why and how. – Gerifalte Aug 31 at 16:14
• While I don't quite buy into every single thing you say (I still think the specific inverted bullet idea isn't fully thought through in the film, even if that doesn't really hurt the logical consistency and overall themes of the story), you certainly make a good attempt at trying to explain it. +1 – Napoleon Wilson Sep 1 at 11:29