The need to inquire about the foundations of ethics arises intermittently; when it does arise, it generally represents a point of crisis for a culture. In different periods in the past of our own culture the oracles that have been resorted to in such situations have been of various kinds: Hellenistic cults, the imperium of Augustus, and the rule of St. Benedict all represent responses to such crises. But at least three times it has been the moral philosophers who have been summoned: in the twelfth century when "Ethica" took on the meaning transmitted to our word "ethics"; in the eighteenth and nineteenth centuries when a shared, secular rational form of moral justification was required to fill the place left empty by the diminution of religious authority; and now.