Premature death may come as a result of sickness, but—like birth—death as such is not a sickness at all. It is the natural and necessary end of human life—as natural as leaves falling in the autumn. (Perpetual leaves are, as we know, made of plastic, and there may come a time when surgeons will be able to replace all our organs with plastic substitutes, so that you will achieve immortality by becoming a plastic model of yourself.)