Over the weekend, Christopher Nolan’s mind-bending Inception extracted $60.4 million from moviegoers, leaving many in a limbolike state of confusion. Where to turn for answers? Today, Vulture had the pleasure of speaking with Dileep Rao, who plays Yusuf the chemist in the film (he was also in Avatar, which makes him, in terms of box-office bankability, the Indian Will Smith). Rao helpfully revealed everything he knows — and thinks he knows — about Inception’s mechanics. SPOILERS ahead, obviously.

Let’s get the easy stuff out of the way first. Can you go over the rules of dreaming?

When you dream normally, you can use a drug to share the dream with other people. You can enter another person’s dream. It’s just the dream-sharing drug, so if you die in that dream, you just wake up — no problem. It’s frightening for a second, but up you come. The problem arises when you want to go deeper. To go deeper, we have to use a much stronger version of the drug, one that my character customizes, that is combined with a very powerful sedative. It’s like weights to keep you under when you are scuba diving. But in this situation, if you die in the dream, you go deeper and deeper until you hit limbo.

Limbo is unconstructed dream space, unless one of the dreamers has been there — in our movie’s case, someone has. And while you’re in limbo, your brain can be destroyed. Like, you would be in a coma, or you could just leave your mind behind.

Also, you can be in limbo for years and years, subjective limbo time, but in reality only moments have passed.

Yes, a lifetime can go by, because each layer is ten times dilated by going into a dream within a dream within a dream. Um, within a dream.

Digging a little deeper into the story now, can you walk me through whose dream is whose?

Okay. So first there’s reality. We get on the plane. We go to sleep. Then we’re in my dream, Yusuf’s dream. Because my pee urge causes it to rain. That’s how I see it. The architecture is Ariadne’s (Ellen Page’s) design, but it’s my dream. Then we drop down a level and go to the bar, to the hotel. I think we’re in Arthur’s (Joseph Gorden-Levitt’s) dream at that point. Then — this is where it gets mind-bending — we drop down into Fischer’s (Cillian Murphy’s) dream, even though he thinks they’re going to Browning’s (Tom Berenger’s) dream.

There seems to be a rule of thumb, then, that whoever “sticks around” in a level, that person had to be the dreamer, right? It’s why you’re stuck driving the van and Joseph Gordon-Levitt chills out in the hotel.

I think that’s a great signifier and it makes the most sense, because how the hell would it continue on that level if the person who was dreaming took off?

But that made me think the third level, the snow fort, was Eames’s (Tom Hardy’s) dream.

Except in the hotel room, Ellen Page asks whose subconscious we’re going into, and Cobb answers, “Fischer’s.”

You’re right, it has to be Fischer’s, because that’s the level where they’re planning to do the inception. That also means that in the hotel room, when Browning is talking to Fischer, we’re actually watching —

— an internal debate going on in Fischer’s mind. He’s filling Joseph Gordon-Levitt’s dream with his subconscious. And then one level down, in the snow of his own mind, he drops down to limbo when he dies, which means your rule of thumb isn’t quite right. Because Mal shoots him, which means Cobb’s own subconscious has taken Fischer to limbo.

So how do Leo and Ellen Page get to limbo?

They open up a suitcase and they lie down on the floor, and go under. It’s a limbo party now — who can go lower? — because Ken Watanabe is on his way down there soon, too.

So if it’s a limbo party, it seems like limbo is a shared creative space, in a sense?

Right. Limbo is like unconstructed dream space. Nothing exists, except whatever has been constructed previously in the subconscious by any of the dreamers in the dream. Among our characters, Leo is the only one who’s been there.

I think a lot of people are confused by the ending/beginning where Ken Watanabe is an old man in limbo, but Leo is still super handsome.

Well, two ideas. One: Leo is aged, too, but he’s been down there less time and from a younger age. Cobb is in his forties and Saito in the eighties by the time they meet.

Is there anything to the idea that Leo knows he’s in limbo?

Well, that’s option two: He knows where he is, so he can keep track a bit better of where he is, who he is.

Ellen Page warns him something along those lines just before she leaves him in limbo …

But Leo also starts out younger. In fact, he looks even younger in real life than as Cobb in the film. He looks so young!

I kept thinking about how much he looks like Bizarro Chris Nolan.

He does! It’s weird.

And if movies are the director’s dream, that means Leo as Nolan is …

Stop.

Okay, well, can you explain how totems work?

The behavior of the object is subject to rules it follows in real life, but your having made it in secret means that it will tell you if you’re in reality. Like you in your dream, have it behave in an unreal way. So the top will keep spinning forever if Cobb is in a dream. He chose the top because it was Mal’s. One, it’s a deep symbolic connection to her, and the idea he planted in her on purpose that she brought back up into reality. And two, he knows it represents getting trapped in non-reality so it’s an extra-strong totem. (That second part is my speculation.)

Oh good, because I want to get really speculative later. But first, as the chemist who invented the sedative, why is it important to synchronize the kicks, the triggers to wake you up?

Well here’s the key: You want to wake all the way up, because if you don’t, you can’t go back up to rekick and wake yourself up. The sedative leaves inner-ear function unimpaired, so you have to feel a jolt in the level you’re asleep in to wake from the level below. If the synchronized kick fails, you would only wake up where it reached you. It’s like a concussive wave. It has to reach all the way down, or else you have to get lucky for some other kick, or for someone who’s awake to wake the other person up. So, I transmit a kick down to Arthur, he transmits it below, and so on.

Hence at the top level, the van has the fail-safe kick of falling and hitting the water?

Right. And above that, in reality, the drug is fed by a machine that turns off. It has a timer on it and the sedative has to stop flowing. That’s the one that’s real.

So at the end when they’re sitting on the riverbank in Yusuf’s dream, it’s no big deal because they’re not going to have to sit around too long …

Sure, but if you miss a kick and you’re down below, you won’t wake up. You’ll disappear into that level, or go to limbo, because you can’t wake up. Or you can and your mind might not come back because subjectively you’ve been there too long. That’s the danger.

Any thoughts on how Cobb and Mal ended up in limbo way back when?

Personal experimentation, to test the limits of the art, and I think that’s kind of the interesting and haunting thing about it, is that they stretched their full limits and found a material weakness in the process, and his way of fixing it ended up snapping back up from the benthic depths with her, into reality, and had her utterly flummoxed. She lost her mind, her touch with reality, and she did the unthinkable. Because, remember, she’s been dealing with the passage of levels the whole time, so reality just felt like another, since she spent her whole life down there with Leo. They grew old together.

I used to have this dream, or rather, this idea, that I’d just wake up at some point and I would be 4 years old again. And this life was just one trajectory my life could have gone on. But that’s the thing that Mal got messed up by, because she lived so long on the lower level. Like, for me, how could waking up as a 4-year-old seem real — jibe with what I’ve experienced as real? How do you believe in it, right?

So what about the final shot, when the top seems like it could keep spinning before we cut to black. Let’s call it the n-1 theory, where the whole film is all a dream, even the “reality” level. In other words, every level is one lower than we think it is.

Yeah. I don’t think the “It’s all a dream” theory makes much sense to me, because where is “the real” Cobb? We never see n. We never see reality. We have no idea who this man is, what his circumstances are. To me, there’s really only two paths: Either it’s a wobbling top, which it does sound like at the end, and it’s real; or the whole thing, regardless of totems, moments, girls, children, people, machines, the whole thing — it’s all some dream. And that’s more philosophy. I think the film does this wonderful exploration of the entire idea to the nth degree. It feels so full. Because of that, there’s so many weird bits that seem to warp our sense of the real and unreal.

I felt a very dreamlike feeling when Cobb is being chased by the Cobol guys and Ken Watanabe shows up to save him. I mean, squeezing through the wall when they’re coming for him, I’ve had so many nightmares like that.

Archetypes. We all dream in certain ways. Teeth falling out, being chased … and that stuff is poignant. But the more you explore it, the more you realize that Chris has already thought about it. I think there is a definitive answer, but it’s hidden so you have to take time to think about it. But I do think it’s real because it’s an apostatic act on art itself to suddenly say “Well, none of this happened, and I have no explanation.”

What if Leo is the one being “incepted” with an idea? We keep hearing the phrase “Do you want to become an old man, filled with regret?” and it’s like someone — maybe Ellen Page’s character because she’s the catalyst of his emotional catharsis — has set this all up so he can let go of his regret over Mal’s death. That’s why at the end with Saito he offers to come back and be young again (not old, full of regret). Even the Edith Piaf song they use to signal ten seconds before kick translates to “No, I regret nothing.” And there’s so many scenes where Ellen Page is talking to Leo, getting him to reveal his issues, in the same way that Eames tricks Fischer into revealing his issues. Also, Leo’s kids are the same age at the end, right?

I’m not trying to be authoritative, so this is just my understanding of how I approached it from my work on it. But you’re saying it’s like some sort of crazy-ass psychotherapy session where the whole thing is a constructed narrative of massive complexity only to distract Cobb so that he will achieve his change? I mean sure, you could totally say that that’s what it is. In a way, that’s what we’re doing to Fischer, so it’s not unfounded.

The problem for me is that you’re using negative evidence to support a story that isn’t there. I don’t know what to say about a character who only exists before and after the movie. You’re talking about a character who isn’t onscreen. And I mean on one hand, it’s awesome that this movie can sustain that kind of discussion. It shows you just how well-thought-through and comprehensive it is, but I mean I don’t know where that kind of speculation ends. It’s like people who are convinced 9/11 is an inside job. It’s a mental heuristic failure to think that one or two minor details explain absolutely everything. I mean, kids wear the same clothes all the time.

To me, it’s a far more elegant story if it’s a vast job that Leo has to pull off. The threat is real, the growth is real, the adversary is real. The weakness of “It’s all a dream” — why we hate that, why we feel cheated when narratively anything is revealed to be all a dream — is that you’ve just asked me to spend so much time and emotional capital investing in the stakes of this, and you’ve now swept it away with the most anti-narrative structuralism that doesn’t have anything to substitute in its place. It’s laughing at you for even taking it seriously. You don’t want to feel like a victim of the narrative, and I don’t think Christopher Nolan would do that.

For me, though, this film could say “It’s all a dream” and I would feel even more satisfied. Because the premise is “through a very complex dream, we can enact real change in a character.” All of the sudden it’s not a fake-out bullshit journey, if that’s the case. In other words, if I’m satisfied by the success of Fischer’s transformation, then Leo’s growth is just as satisfying.

But he doesn’t have to be dreaming for that growth. If, by way of example, in the last scene where Cobb ran off to hug his kids, there were a reflection of Mal in the window? That would make it far more vague and I’d say, sure. But that’s not there.

Close your eyes and listen to the sound at the end. I really do think the top wobbles and that it’s real. Cobb does go on a journey, because that’s what movies are, and I think that’s what leads audiences to this kind of speculation. Because of the story he chose to tell, Nolan is also commenting on the nature of stories themselves, all stories, which is why Leo’s change can’t be evidence that it’s all a dream.

To me, the real story all boils down to Saito’s line in the helicopter. Leo wants to go home and see his kids. Saito says, “I can help you, but it’ll have to be an act of faith.” Leo has to trust Saito, and he does this while putting total faith in himself and the team, and everything goes apeshit wrong, but he has to believe that if he does the job, Saito will do what he promised. And they’ve grown, they’ve become friends, which is why Leo says “Come back and let’s be young men together.” Leo’s follow-through on that act of faith is his transformation. He becomes a person who can take a chance.

There’s also kind of a beautiful negative symmetry between that leap of faith, and Mal begging him to make a similar leap of faith. After he did that with her, and the guilt plagues him, he can’t function anymore. He’s exploring his memories in a dangerous, unhealthy way, and he’s going to let that go by the time the movie’s over.

Everyone’s so concerned about whether the top falls or not, but no one seems to care that Leo walked away without caring. The moment he sees their face, he can walk away. That’s testimony to the fact that he’s gained that faith.

Related: The Hidden ‘Inception’ Within Inception

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