“Time is said to be irreversible. And this is true enough in the sense that ‘you can’t bring back the past,’ as they say. But what exactly is this ‘past’? Is it what has passed? And what does ‘passed’ mean for a person when for each of us the past is the bearer of all that is constant in the reality of the present, of each current moment? In a certain sense the past is far more real, or at any rate more stable, more resilient than the present. The present slips and vanishes like sand between the fingers, acquiring material weight only in its recollection… Time cannot vanish without trace for it is a subjective, spiritual category; and the time we have lived settles in our soul as an experience placed within time.” —Andrei Tarkovsky, Sculpting in Time