A friend posted a quotation from Diane Arbus on Facebook:
The more specific you are, the more general it’ll be.
I really liked the idea because it connected with what I've been preaching to my students in a class on poetry and songwriting: be specific! But I also wanted the source, and especially the context, so I did some digging and found a passage from the introduction to a 1972 collection of Arbus's photographs published as "an Aperture monograph" and edited by Doon Arbus and Marvin Israel:
I remember a long time ago when I first began to photograph I thought, there are an awful lot of people in the world and it’s going to be terribly hard to photograph all of them, so if I photograph some kind of generalized human being, everybody’ll recognize it. It’ll be like what they used to call the common man or something. It was my teacher, Lisette Model, who finally made it clear to me that the more specific you are, the more general it’ll be.
I was right to want the context, because now the grand generalization about specificity is so much more specific. The context acts out two things that are lost in the quotable quote at the end: first of all, how the generalization is built on a specific experience; secondly, how that experience is a matter of learning something.