This collection of readings with extensive editorial commentary brings together key texts of the most influential philosophers of the medieval era to provide a comprehensive introduction for students of philosophy. . This collection of readings with extensive editorial commentary brings together key texts of the most influential philosophers of the medieval era to provide a comprehensive introduction for students of philosophy. . Text Sources and Credits viii Acknowledgments xiii General Introduction 1(26) PART I LOGIC AND EPISTEMOLOGY 27(124) Introduction 27(4) Philosophy, Theology, Logic, and the Sciences 31(1) Augustine on Ancient Philosophy 31(12) Dialetica Monacensis (anonymous, twelfth century) on the Division of Science 43(2) Thomas Aquinas on the Nature and Scope of Sacred Doctrine 45(14) The Problem of Universals 59(1) Boethius Against Real Universals 59(4) John of Salisbury on the Controversy over Universals 63(3) The Summa Lamberti on the Properties of Terms 66(5) William Ockham on Universals 71(8) John Buridan on the Predicables 79(4) Illumination vs. Abstraction, and Scientific Knowledge 83(1) Augustine on Divine Ideas and Illumination 83(4) Thomas Aquinas on Illumination vs. Abstraction 87(11) Thomas Aquinas on our Knowledge of the First Principles of Demonstration 98(5) Henry of Ghent on Divine Illumination 103(7) Duns Scotus on Divine Illumination 110(7) Knowledge and Skepticism 117(1) Augustine on the Certainty of Self-Knowledge 117(3) Thomas Aquinas on whether the Intellect Can Be False 120(3) Henry of Ghent on whether a Human Being Can Know Anything 123(11) Nicholas of Autrecourt on Skepticism about Substance and Causality 134(9) John Buridan on Scientific Knowledge 143(8) PART II PHILOSOPHY OF NATURE, PHILOSOPHY OF THE SOUL, METAPHYSICS 151(152) Introduction 151(6) Hylomorphism, Causality, Natural Philosophy 157(1) Thomas Aquinas on the Principles of Nature 157(11) Thomas Aquinas on the Mixture of Elements 168(3) Giles of Rome on the Errors of the Philosophers 171(9) Selections from the Condemnation of 1277 180(10) John Buridan and the Impetus Theory of Projectile Motion 190(5) Human Nature and the Philosophy of the Soul 195(1) Augustine on the Soul 195(3) Averroes on the Immateriality of the Intellect 198(5) Siger of Brabant on the Intellective Soul 203(4) Thomas Aquinas on the Nature and Powers of the Human Soul 207(12) John Buridan on the Immateriality of the Soul 219(6) Metaphysics, Existence, and Essence 225(1) Avicenna on Common Nature 225(2) Thomas Aquinas on Being and Essence 227(23) John Buridan on Essence and Existence 250(5) God's Existence and Essence 255(1) Augustine on Divine Immutability 255(4) Anselm of Canterbury on God's Existence 259(7) Thomas Aquinas on God's Existence and Simplicity 266(37) PART III PRACTICAL PHILOSOPHY 303(79) Introduction 303(6) Goodness and Being 309(1) Augustine on Evil as the Privation of Goodness 309(2) Augustine on the Origin of Moral Evil 311(7) Boethius on Being and Goodness 318(4) Thomas Aquinas on the Convertibility of Being and Goodness 322(3) Freedom of the Will 325(1) Augustine on the ``Divided Will'' 325(6) Boethius on Divine Providence and the Freedom of the Will 331(6) Anselm of Canterbury on Free Will 337(12) Henry of Ghent on the Primacy of the Will 349(4) Virtues and Happiness 353(1) Boethius of Dacia on the Supreme Good 353(5) Thomas Aquinas on Happiness 358(3) Divine Law, Natural Law, Positive Law 361(1) Thomas Aquinas on Natural Law and Positive Law 361(14) John Duns Scotus on Natural Law and Divine Law 375(7) Suggestions for Further Reading 382(6) Index 388