In the most general terms, the Enlightenment goes back to Plato's belief that truth and beauty and goodness are connected; that truth and beauty, disseminated widely, will sooner or later lead to goodness. (While we're making at effort at truth and goodness, beauty reminds us what we're hold out for.)

Moral Clarity: A Guide for Grown-up Idealists (ed. Random House, 2009) - ISBN: 9781409077596