The symmetry of non-being

In book III of On the Nature of Things, Lucretius offers a simple argument against the fear of being dead: set the eternity that will follow your death beside the infinite eternity that preceded your birth. That earlier non-being never troubled you; why dread the later one, which resembles it in every way? Where death is, you are no longer, and a subject who is no more can suffer no harm. The exercise does not console grief or erase the worth of living: it targets one precise fear, the fear of being dead, and returns it to ataraxia, peace of mind.