A wistfulness overcomes me when, crossing a set of railroad tracks, I pause to look, to see as far as the rails are straight -- to the next bend or the crest of the grade --and the disappearing tracks leave a question: What's beyond?
The same thing happens when I walk down to the river. Where we live, the river runs from the northeast upstream to the southwest downstream. In one sense, I know what's beyond: The mountains upstream, the ocean downstream.
But there is a pull nonetheless. I want to follow the water downstream, always and immediately, and when I cannot, I"m not fully at peace.