There were many people in France writing realistic novels in the nineteenth century—Balzac comes to mind—but Flaubert was the most conscious of what he was doing, and agonized about it the most. Closely observed reality, for its own sake, had not really been a part of the tradition of literature in the eighteenth century. Flaubert will spend a whole page evoking tiny sounds and motes of dust in an empty room because he's getting at something. He's saying there's meaning to be got out of the very closely observed events of ordinary reality. In literary, scientific and photographic terms—the invention of photography happened when he was in his teens—the nineteenth century, to a much greater degree than the eighteenth, was concerned with the close observation of reality. All of science in the nineteenth century was about very close observation of small things…. The nineteenth century focussed and greatly expanded these concepts. It made them central to the novel, to the symphony, to painting.

O: There's a line of Saul Bellow's—“I write to discover the next room of my fate.” In this way, I think, many novels are self-portraits—or future self-portraits, self-explorations, even if the story is set in an alien situation. You can try on this costume, that costume.

M: Somebody once asked W. H. Auden, “Is it true that you can write only what you know?”And he said,“Yes it is. But you don't know what you know until you write it.” Writing is a process of discovery of what you really do know. You can't limit yourself in advance to what you know, because you don't know everything you know.

As I began to eliminate things, I would have the feeling that I couldn't remove a certain scene, because it so clearly expressed what we were after. But after hesitating, I'd cut it anyway … forced to because of the length of the film. Then I'd have this paradoxical feeling that by taking away something I now had even more of it. It was almost biblical in its idea of abundance. How can you take away something and wind up with more of it?

The analogy I came up with was the image of a room illuminated by a bare blue lightbulb. Let's say the intention is to have “blueness” in this room, so when you walk in you see a bulb casting a blue light. And you think, This is the source of the blue, the source of all blueness. On the other hand, the lightbulb is so intense, so unshaded, that you squint. It's a harsh light. It's blue, but it's so much what it is that you have to shield yourself from it.

There are frequently scenes that are the metaphorical equivalent of that bulb. The scene is making the point so directly that you have to mentally squint. And when you think, What would happen if we got rid of that blue lightbulb, you wonder, But then where will the blue come from? Let's take it out and see. That's always the key: Let's just take it out and find out what happens.

So you unscrew the lightbulb … there are other sources of light in the room. And once that glaring source of light is gone, your eyes open up. The wonderful thing about vision is that when something is too intense, your irises close down to protect against it—as when you look at the sun. But when there is less light, your eye opens up and makes more of the light that is there.