* The early Greek ethics of Socrates, Plato, Aesara, Aristotle, Epicurus and the stoics.
* The Christian ethics of St. Augustine, St. Hildegard, Heloise, and St. Thomas Aquinas
* The descriptivist ethics of Thomas Hobbes and David Hume
* The rationalistic ethics of Immanuel Kant
* The utilitarian ethics of Jeremy Bentham and John Stuart Mill
* The aristocratic ethics of Friedrich Nietzsche