Many pagan, Jewish, Christian and Muslim philosophers from Antiquity to the Enlightenment made no meaningful distinction between philosophy and religion. Instead they advocated a philosophical religion, arguing that God is Reason and that the historical forms of a religious tradition serve as philosophy s handmaid to promote the life of reason among non-philosophers. Carlos Fraenkel provides the first account of this concept and traces its history back to Plato. He shows how Jews and Christians appropriated it in Antiquity, follows it through the Middle Ages in both Islamic and Jewish forms...