"I think that ideas exist outside of ourselves. I think somewhere, we're all connected off in some very abstract land. But somewhere between there and here ideas exist. And I think the mind isn't conscious enough to go all the way to where we're connected, but it's conscious of a certain amount of that territory. And when these ideas fly into the conscious part, then you can capture them. But if they're outside of the conscious part, you don't even know about them. So you just hope that you can make the conscious part of your mind bigger or that these ideas will fly into your airspace, so you can shoot them down and grab them and take them home. So that's all you try to do. Sometimes an idea will strike you when you're sitting in a quiet chair. But sometimes an idea will strike you when you're standing. Sometimes music will also help you. If I thought I could just sit still in a quiet place and get ideas, I would do that all the time, but sometimes nothing happens. There's no rhyme or reason to it. But you've got to write them down right away. I forget so many things. Then if I forget it and try to remember it, my whole day is ruined because I can't remember and I feel horrible. And I imagine that it was one of the all time great ideas. And it probably isn't."
(from IMDB mini biography, more profound stuff there as well)
Amazing validation of film in general.