Luck is the attentive photographer's best teacher.
A photographer's best work is, alas, generally done for himself.
Photography's central sense of purpose and aesthetic: the precise and lucid description of significant fact.
The goal is not to make something factually impeccable, but seamlessly persuasive.
The basic material of photographs is not intrinsically beautiful. It's not like ivory or tapestry or bronze or oil on canvas. You're not supposed to look at the thing, you're supposed to look through it. It's a window.
Photography was not invented to serve a clearly understood function. There was in fact widespread uncertainty, even among its inventors, as to what it might be good for.