Something that I wanted to do through the film is try to explore the roots of belief, because everything has to do with beliefs. When I studied the side of the rationalists and the skeptics, and the side of the believers and so-called psychics, I found out that both of them, no matter what they claim to do, behave in a very similar way. They only accepted what confirmed their previous positions, and tended to reject everything that put them at risk.

If you believe in God, that's a belief. If you are an atheist, it's a belief too, because you cannot prove that God does not exist.

Debunking certain things is important, first because you question things, which is always healthy, and second because there's a part that has to do with show biz, which is pretty harmless, but there's another part that has to do with people's vulnerability. That needs to be exposed.

Once I do something, I need to be obsessed - or maybe I don't need to be obsessed, but I get obsessed because that's just the way my brain works - but I need to pay a lot of attention to detail. Because everything counts to me once I do something, even if it's a movie that nobody cares about. That's why I need to choose very well what I want to do. But in real life, when I watch TV or whatever, I guess I'm not that obsessive guy, and I'm pretty boring.

There are many films I would happily spend two hours with, not so many I would spend two years with. I need to be obsessed about films, because the way I work, that means two years without sleeping at all, and losing part of your life. I need to put all of my energy and heart and soul and bones and blood and skin and muscles in the things that I do.

There are a couple of things that are, in the present, floating in front of my face, and once one of them gets enough energy to become a voice that I cannot not hear, then I will become a steamroller. When you've made your film, you stop hearing the voice.

Even when you expose something, when you have a true believer, that person rejects that proof; he thinks it's just a set-up. We believe what's more convenient for us to believe. We always behave this way. We start with the conclusion, and then we create a body of theories around it. We choose what allows us not to change.