This work has had the great advantage of having been revised, while still in manuscript, by Mr. Alfred Robinson, Fellow of New College, to whom I cannot sufficiently express my obligation. I have availed myself to the full of the series of criticisms which he was kind enough to send me. As some additions have been made since then, he cannot be held in anyway responsible for the faults which less kindly critics may detect. For the examples at the end I am mainly indebted to others, and to a large extent to my ingenious friend, the Rev. W. J. Priest of Merton College. My thanks are due also to my friend and former pupil, Mr. Gilbert Grindle, Scholar of Corpus, who has been at the pains to compose an index, and to revise the proofs as they passed through the press. And last, but not least, I must set on record my gratitude to Commander R. A. Stock, R.N., one of Her Majesty's Knights of Windsor, without whose brotherly aid this work might never have been written, and would certainly not have assumed exactly its present shape. OXFORD, _October_ 22, 1888. CONTENTS. PREFACE. INTRODUCTION, §§ 1-56. PART I. Of Terms, §§ 57-171. CHAP. I. Of the Term as distinguished from other words, §§ 57-76. II. Of the Division of Things, §§ 77-85. III. Of the Divisions of Terms, §§ 86-165. IV. Of the Law of Inverse Variation of Extension and Intension, §§ 166-171. PART II. Of Propositions, §§ 172-185. CHAP. I. Of the Proposition as distinguished from other Sentences, §§ 172-185. II. Of the Copula, §§ 186-201. III. Of the Divisions of Propositions, §§ 202-273. IV. Of the Distribution of Terms, §§ 274-294. V. Of the Quantification of the Predicate, §§ 295-312. VI. Of the Heads of Predicables, §§ 313-346. VII. Of Definition, §§ 347-384. VIII. Of Division, §§ 385-425. PART III. Of Inferences, §§ 426-884. CHAP. I. Of Inferences in general, §§ 426-441. II. Of Deductive Inferences, §§ 442-448. III. Of Opposition, §§ 449-478. IV. Of Conversion, §§ 479-495. V. Of Permutation, §§ 496-502. VI. Of Compound Forms of Immediate Inference, §§ 503-532. VII. Of Other Forms of Immediate Inference, §§ 533-539. VIII. Of Mediate Inferences or Syllogisms, §§ 540-557. IX. Of Mood and Figure, §§ 558-568. X. Of the Canon of Reasoning, §§ 569-581. XI. Of the General Rules of Syllogism, §§ 582-598. XII. Of the Determination of the Legitimate Moods of Syllogism, §§ 599-605. XIII. Of the Special Rules of the Four Figures, §§ 606-620. XIV. Of the Determination of the Moods that are valid in the Four Figures, §§ 621-632. XV. Of the Special Canons of the Four Figures, §§ 633-647. XVI. Of the Special Uses of the Four Figures, §§ 648-655. XVII. Of the Syllogism with Three Figures, §§ 656-666. XVIII. Of Reduction, §§ 667-700. XIX. Of Immediate Inference as applied to Complex Propositions, §§ 701-730. XX. Of Complex Syllogisms, §§ 731-743.