Acknowledgement is made to the following publishers for permission to use passages cited in this book: Catholic University of America Press, Augustine, The Fathers of the Church, vols. 1, 2, 8, 14, 45, 59 (New York: CIMA Publishing Co., 1948- ); Charles Scribner’s Sons, Boethius, The Second Edition of the Commentaries on the Isagoge of Porphyry, trans. R. McKeon, Selections from Medieval Philosophers I: Augustine to Albert the Great (New York: Charles Scribner’s Sons, 1957); Doubleday & Co., Inc., Aquinas, Summa Contra Gentiles, trans. A.C. Pegis (Garden City, N.Y.: Image Books, A Division of Doubleday, 1955); Macmillan Co., Erigena, Liber de praedestinatione, De divisione naturae, Annotationes in Marcianum, and Abelard, Glosses on Porphyry, trans. J. Wippel and A. Woltar, Medieval Philosophy (New York: Free Press, 1969); Harvard University Press, W. Jaeger, Early Christianity and Greek Paideia (Cambridge, Mass.: The Belknap Press, 1969); Henry Regnery Co., Aquinas, On Truth, trans. R. W. Mulligan (Chicago: Henry Regnery Co., 1952); McGraw-Hill Book Co., Aquinas, Suma of Theology, ed. T. Gilby (New York: McGraw Hill and Blackfriars, 1964); Open Court Publishing Co., Anselm, St. Anselm, trans., S. N. Deane (la Salle, Ill.: Open Court Publishing Co., 1964); Pontifical Institute of Medieval Studies, Aquinas, The Division and Method of the Sciences, trans. A. Maurer (Toronto, Canada: Pontifical Institute of Medieval Studies, 1963); Random House, Inc., E. Gilson, The Christian Philosophy of St. Augustine (New York: Random House, 1960); Seabury Press, Aquinas, On the Soul, trans. J. P. Rowan (New York: B. Herder Book Co., Seabury Press, 1949); Sheed & Ward, Inc., C. Dawson, Monument to Saint Augustine (New York: Sheed & Ward, 1945); St. Anthony Guild Press, Bonaventure, The Works of Bonaventure, trans. J. de Vinck (Paterson, N.J.: St.