I had some big ups and downs when I was in my 20s and the one thing I learned was, no matter how low it gets, something good will come along - something always comes out of that dark period.

Now there is so much expertise and brainpower it's hard to be at the cutting edge of what's cool and not do something that's totally geeky.

CGI means, just to be clear, creating any type of image with a computer. Basically, starting off with nothing, or with images and manipulating them. The way we did it, everything was actual photographed images. A lot of that stuff was shot through a microscope of chemical reactions, yeast growing, lots of weird things, by Peter Parks. We put it into a computer and collaged it, manipulated it. Meaning we digitally shaped it to fit with other images. But there was no computer-generated imagery at all.

Classical scores go up and down; they're kind of hysterical in a way. And movie scores are much more - they just drive and move forward, and they build and can't go up and down at that same speed. It's a big job to turn that into something that pushes the movie along.

I don't make films that are easy to market, unfortunately. I think that 'Pi' was the easiest one, because we had that symbol to stick up everywhere, so that was a good gimmick, and created a good mystery, and we didn't have to do huge scale.

I wasn't a big fan of social anthropology. And, luckily, that created room for me to work in visual arts because I sort of ignored my requirements. I think I was attracted to social anthropology because I liked to travel and was always interested in far-off places.

People have been screaming about the end of times forever, it's always the end of times. But there's just so much evidence that the world is changing so radically right now. How much can the world take?