Almost everyone has heard the statement, “Time flies when you are having fun.” As is so oft observed, life is fleeting. We are young one day and seemingly old the next. “Remember how short my time is: wherefore hast thou made all men in vain?” (Psalms 89:47). Why do we perceive our lifespan this way? Haven’t we all wondered why time seems like sand running through our fingers? One explanation for this could be called the memory retention theory.