Arendt’s description of the ideas of Plato as “invisible spiritual yardsticks”

Discuss Arendt’s description of the ideas of Plato as “invisible spiritual yardsticks” that support ethics and public authority. What role does Arendt assign to Plato’s “tales of the hereafter” (his account of an afterlife, or “Hades”)? Arendt argues that moral and political authority founded on religion, especially where this relies on a model of rewards and punishments in the hereafter, is no longer an adequate basis for motivating people to be ethical. Why does relinquishing a focus on the afterlife return us to “the elementary problems of human living-together”? (You may also refer to Plato, Phaedo—2 page PDF handout, for this question.)