The more vast the amount of time we've left behind us, the more irresistible is the voice calling us to return to it. This pronouncement seems to state the obvious and yet it is false. Men grow old, the end grows near, each moment becomes more and more valuable and there is no time to waste on recollection. It's important to understand the mathematical paradox in nostalgia, that it is most powerful in early youth , when the volume of life that has passed is quite small.