Life exists for itself, as a reaffirmation of that that merely exists itself. Existence begets existence. Life forms pass through the ages, one onto the other. The decay or entropy around one is merely unaccounted natural order that cannot be helped. As the sun and stars and planets will not last, why should you last? As they will go, you must die. One’s goal is to exist and exist as best one can. What eternity there can be in life must be made in progress and through the time of eternity. One would ask “why so short?” but then the question would be “why death at all?” Life has only meaning or action in its striving not to die, and you are the only thing that lives. The rest simply is. The universe itself is the only thing eternal, unless some advanced life were to try to be eternal. Then the question would be “when is it eternal?”