It's a little bit like talking about the life of writing. The life of writing may be about many things, but it always begins with the writer. With the kernel of an idea, or a character, or an idea or a theme, or even an outcome. But for documentary photographers, photographs begin at that intersection of the real world and the imaginative inner world.

"You know you are seeing such a photograph if you say to yourself, "I could have taken that picture. I've seen such a scene before, but never like that." It is the kind of photography that relies for its strengths not on special equipment or effects but on the intensity of the photographer's seeing. It is the kind of photography in which the raw materials-light, space, and shape-are arranged in a meaningful and even universal way that gives grace to ordinary objects."

Photography, alone of the arts, seems perfected to serve the desire humans have for a moment - this very moment - to stay.

The class that I teach is called "The Life of a Photograph." It takes up the question, of the billion photographs that were taken today, how many will have a life, and why? So the new reality has made the question more pertinent, not less pertinent.

Richard Prince's most famous photograph was made by me.

I did a story for the Geographic on Meriwether Lewis and William Clark, and Stephen Ambrose was the writer. He said, "I've got the easiest job in the world. I just have to re-tell the story of the greatest fishing, camping, hunting, canoeing trip of all time. You, Sam, have the hardest job, which is, pretend like nothing has happened in the last 200 years.

[ My time and our common culture] it's what I'm photographing, and I'm very involved with that.