 Aquinas, Thomas: moral, political, and legal philosophy |  Aristotle, General Topics: ethics |  Duns Scotus, John |  ethics: natural law tradition |  Holbach, Paul-Henri Thiry (Baron) d’ |  Kant, Immanuel: and Hume on morality |  Moore, George Edward: moral philosophy |  morality, definition of |  Nietzsche, Friedrich: moral and political philosophy |  Plato: ethics |  voluntarism, theological 