The feeling that emerges from these glimpses of city life is roughly equivalent to what one feels when looking at a photograph. Cartier-Bresson's 'decisive moment' is perhaps the crucial idea to remember in this context. The important thing is readiness: you cannot walk out into the street with the expectation of writing a poem of taking a picture, and yet you must be prepared to do so whenever the opportunity presents itself. Because the 'work' can came into being only when it has been given to you by the world, you must be constantly looking at the world, constantly doing the work that will lead to a poem even if no poem comes of it. Reznikoff walks through the city — not, as most poets do, with 'his head in the clouds,' but with his eyes open, his mind open, his energies concentrated on entering the life around him. Entering it precisely because he is apart from it. And therefore this paradox, lodged in the heart of the poem: to posit the reality of this world, and then to cross into it, even as you find yourself barred at all its gates. The poet as solitary wanderer, as man in the crowd, as faceless scribe. Poetry as an art of loneliness.
[...]Paul Auster, "The Decisive Moment" in The Art of Hunger and Other Essays. Menard Press of London. 1982