At the end of the movie Saving Private Ryan, Thomas Ryan, having survived combat in WWII, and now retired decades later, with tears in his eyes, asks his wife whether he has led a worthy life - whether the life he had lived was worth the dozen or so soldiers who sacrificed themselves so that he could survive and return to civilian life. I had a recent conversation with my sister, who, at 44, is now in late stages of cancer, in which she wondered whether her life has had worth. How do we know? How do we gauge the worth of life? How do we make our lives worthwhile?