[Footnote 1: This is Cardinal Newman's proof of the existence of God from Conscience: see pp. 124, 125, and _Grammar of Assent_, pp. 104-111, ed. 1895. With Newman's, "Conscience has both a critical and a judicial office," compare Plato, _Politicus_, 260 B, [Greek: sumpasaes taes gnostikaes to men epitaktikon meros, to de kritikon]. The "critical" office belongs to Ethics: the "judicial," or "preceptive" office [Greek: to epitaktikon] to Deontology; and this latter points to a Person who commands and judges, that is, to God.] In this volume, pp. 1-108 make up the treatise on Ethics: pp. 109-176 that on Deontology. Aristotle writes: "He that acts by intelligence and cultivates understanding, is likely to be best disposed and dearest to God. For if, as is thought, there is any care of human things on the part of the heavenly powers, we may reasonably expect them to delight in that which is best and most akin to themselves, that is, in intelligence, and to make a return of good to such as supremely love and honour intelligence, as cultivating the thing dearest to Heaven, and so behaving rightly and well. Such, plainly, is the behaviour of the wise. The wise man therefore is the dearest to God" (Nic. Eth. X. ix. 13). But Aristotle does not work out the connexion between God and His law on the one hand and human conscience and duty on the other. In that direction the Stoics, and after them the Roman Jurists, went further than Aristotle. By reason of this deficiency, Aristotle, peerless as he is in Ethics, remains an imperfect Moral Philosopher. PREFACE TO THE FOURTH EDITION (1918) 1. I have altered the opening pages in accordance with the Preface to the edition of 1905. 2. I have added a paragraph on Syndicalism (pp. 291-2). 3. Also a new Table of _Addenda et Corrigenda_, and a new Index. The quotations from St. Thomas may be read in English, nearly all of them, in the Author's _Aquinas Ethicus_, 2 vols.; 12s. (Burns and Oates.) CONTENTS. PART I.--ETHICS. CHAPTER I.--OF THE OBJECT-MATTER AND PARTITION OF MORAL PHILOSOPHY. CHAPTER II.--OF HAPPINESS. Section I.--Of Ends. Section II.--Definition of Happiness. Section III.--Happiness open to Man. Section IV.--Of the Object of Perfect Happiness. Section V.--Of the use of the present life. CHAPTER III.--OF HUMAN ACTS. Section I.--What makes a human act less voluntary. Section II.--Of the determinants of Morality in any given action. CHAPTER IV.--OF PASSIONS. Section I.--Of Passions in general. Section II.--Of Desire. Section III.--Of Delight. Section IV.--Of Anger. CHAPTER V.--OF HABITS AND VIRTUES. Section I.--Of Habit. Section II.--Of Virtues in general. Section III.--Of the difference between Virtues, Intellectual and Moral. Section IV.--Of the Mean in Moral Virtue. Section V.--Of Cardinal Virtues. Section VI.--Of Prudence. Section VII.--Of Temperance. Section VIII.--Of Fortitude. Section IX.--Of Justice. PART II.--DEONTOLOGY.