My unconscious mind, at least that part which resides on the right side of the brain, has always been inherently attracted to a picture within a picture. In this photograph, that concept is represented by the reflection of the stark bare trees in the glass in the church doors. The mind initially expects to see through the glass, but instead is presented with another level of abstraction. Sometimes, as in the case of past work in Chicago, it can be the reflection of the world in a city sidewalk puddle from new rain, or in wilderness landscape work, the reflection of trees in a river. Conceptually, I think photographs that allow for this meta (abstraction) principle challenge viewers and hold attention longer. I am sure neuroscientists understand the principles behind this phenomenon, but I am happy to just let it be a mystery.
"The aim of every artist is to arrest motion, which is life, by artificial means and hold it fixed so that a hundred years later, when a stranger looks at it, it moves again since it is life." ~William Faulkner