There’s been some big news recently, so I have to ask: If two years ago you found out there was water on Mars, what would you changed in the movie?

It’s funny, I need to educate myself a little more. This has all happened while I’ve been traveling [to promote The Martian]. What we would do is, Andy and I would sit down and talk about what are the realistic implications of this. The truth is, in the movie he has his own survival water. The thing that may have to change is how he generates lots of water to farm. But we may not [have changed] it, truthfully, because I’d have to study where that water is on Mars, how quickly he can collect it, and how he could use that to water crops. It may be that synthesizing water with hydrazine still is the smartest thing he can do.

Unless there’s something immediately nearby.

A river. But we know there’s not a river, so it may still be hard. And even that’s a minor plot point, so on the big scheme of things he has water in the movie. Food is a much bigger problem for him. If they suddenly discovered potato mines on Mars, that would change our story substantially.

"If they suddenly discovered potato mines on Mars, that would change our story substantially."

There have been rumors. It could be coming.

I don’t know that there’s not potato mines down there. I don’t know that.

I’m really interested in the process of adapting this story. It was just an ebook when you started, right?

Andy was giving it away for free. The way Amazon [Kindle] works, is you have to charge at least a dollar. But before that he was just giving it away on his website, chapter by chapter, over three years I think. So my friend Aditya Sood, who’s a producer over at Fox called me, and he said "You know, I found this book. It’s special. Check it out." And I’m like, "Wait, it’s an ebook?" He said "I know, but I think you’re going to like it." And he sent it over and I did, I knew from the first sentence.

The first sentence is, "I’m pretty much fucked." Which is a great first sentence, because it’s not "I’m fucked." It’s "I’m pretty much fucked," so weirdly, the whole movie to me is in those four words: I’m in trouble, but there’s some hope, you know? And it’s funny! The optimism and the humor is in those four words "I’m pretty much fucked." And I just responded to that right away. And then I kept reading, and the book kept getting better and better, and I saw these themes that interested me coming up over and over as I read it. And you know you’re just looking for something that haunts you. You’re looking for something to connect on a deeper level. And I was just being haunted by the book.

It seems like something that could be a hard sell for a studio. Because of the math, because of the science…

And it was an ebook! It’s a best seller now; it was not a best seller then. It didn’t even have a publishing deal. So it’s essentially like going to a studio and saying: Here’s a very complicated movie about science that takes place on Mars, which traditionally is box-office poison. It’s not based on anything; there’s no IP, as it were, that studios seem to get all excited about. But I loved it.

And that’s what we did. I went in and said, "I’m going to tell you all the reasons you’re going to say no, and if at the end of that you still are interested, I’m going to tell you all the reasons why you should say yes." And [president of production] Emma Watts over at Fox just got it. We started talking about it and she voiced her concerns which were all very fair — the main one being in order to sell something like this, we’re going to need a movie star. And I said that’s fine, I think we’ll get one. [Mark Watney] is a great part. When I read the book, that was one of the big selling points to me, was we’re going to get a great actor because it’s such a phenomenal part.

Because the story celebrates math and science, it feels like a film that could inspire people to pursue those fields. Was that something you were intentionally hoping for?

"Think of it as a religious movie. It's just that the religion is science."

Sort of. You hope that the movie connects, and you hope that what you love about it, other people will love. But you can’t worry too much about the bigger place in things or you’ll just do a bad job. It’ll just be a cynical sort of approach. But I did feel like I was responding so strongly to the book because there wasn’t a lot out there like it. It was striking a chord that I felt was important, this idea of science.

One of the things that I said in that very first meeting at Fox when I was talking about what my approach would be to making it, I told them: Think of it as a religious movie, because it very much is. It’s just that the religion in this movie is science. But the approach is the same: a man has a set of beliefs, he gets stranded, and he has to trust his own faith to get him through this. When I was talking about the movie, i was talking about things like The Ten Commandments and stuff like that. There are parallels there, just replace the Christian story with hexadecimals. [Laughs] But structurally, I saw an interesting overlap in a way to approach it.

Even though it’s based on a book, The Martian is essentially original IP in contrast to the larger franchises out there. As a writer and director, you’ve been able to work in both of those worlds. Do you find one more satisfying than the other?

I don’t know, I like both. The truth is I try to just do what I love, and work on what I love. And I love lots of different things, so you just sort of go with it. I love Daredevil, I have always loved that character, so I said okay, that sounds like a fun thing to think about. And then I loved Andy’s book, so I said okay, that sounds like a fun thing to think about. The times that I’ve made mistakes in my career are when I’ve thought, "Oh that was a good piece of business, I should do that." That gets me in trouble, because I don’t love it, and you get tired of it pretty quickly. But when you love something, you just go with it.

The thing that I realized when we were doing the first Martian test screening, the thing that I hadn’t really thought about, is that I do think we’re living in a time where cinema has gotten a little polarized. Where there’s blockbuster movies, and then there’s niche movies for adults. You’re either 13, or you want a gritty, adult movie — and I keep thinking, "No, there’s a middle ground here." There are movies that can be fun and optimistic but aren’t just lowest common denominator storytelling.