Now [the present] is shaped by the past, backed by it, as it were, the way the glass of a mirror is backed by silver; it's what lies behind the present that gives it color and sheen. And now is always giving way, always becoming. It is this progression into the future which gives things the dynamic dimension of forwardness they could not have were they composed solely of a past and a present. If past and present are the glass and its silver backing, then future is what is coming-to-be in the mirror, the image that presents itself, intrudes into the frame.

- Mark Doty, Heaven's Coast