I love films that don't end when they end, that go on in your head a couple of days later.

I think being self-taught is the only way of really learning things, because you have to question everybody. You don't simply absorb axioms or so-called truths like they are rules. You have to test them, and you need to reflect on them, to consider the effect they create. So, you have very significant opinions about things, because they come out from your own reflections.

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.

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.

I love films that don't end when they end, that go on in your head a couple of days later.

And as a director, you constantly try to solve problems, so you have to focus on that. You take away all the other parts. Of course, when the shot finishes, you remember that you have Robert De Niro in front of you. But when you're shooting, you just see a character in front of you, and an actor, and you try to search for very truthful moments. That's what obsesses you.

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.