If a Martian (who, we’ll imagine, never dies except by accident) came to Earth and saw this peculiar race of creatures—these humans who live about seventy or eighty years, knowing that death is going to come—it would look to him like a terrible problem of psychology to live under those circumstances, knowing that life is only temporary. Well, we humans somehow figure out how to live despite this problem: we laugh, we joke, we live.
The only difference for me and Arlene was, instead of fifty years, it was five years. It was only a quantitative difference—the psychological problem was just the same. The only way it would have become any different is if we had said to ourselves, “But those other people have it better, because they might live fifty years.” But that’s crazy. Why make yourself miserable saying things like, “Why do we have such bad luck. What has God done to us? What have we done to deserve this?”—all of which, if you understand reality and take it completely into your heart, are irrelevant and unsolvable. They are just things that nobody can know. Your situation is just an accident of life.
Richard Feynman, What Do You Care What Other People Think?: Further Adventures of a Curious Character, New York, 1988, pp. 33-34