From the PREFACE. THE matters collected in this Syllabus will be found in those of my writings of which the titles follow:-- I. On the Structure of the Syllogism.... (Cambridge Transactions, vol. viii, part 3, 1847 II. Formal Logic, or the Calculus of Inference, necessary and probable (London, Taylor and Walton, 1847, 8vo.). III. On the Symbols of Logic, the Theory of the Syllogism, and in particular of the Copala, .... (Cambridge Transactions, vol. ix, part 1, 1850). "IV. On the Syllogism, No. iii, and on Logic in general (Cambridge Transactions, vol. x, part 1, 1858). Of these works the formulae and notation of the first are entirely superseded; the notation only of the second (the Formal Logic) may be advantageously replaced (see � 24) by that of the third and fourth and of the present tract. There is very little in the first three writings on which my opinion has varied; but of all three it is to be said that they are entirely based on what I now call the arithmetical view of the proposition and syllogism 8, 173, 174), extending this term not merely to the numerically definite syllogism, but to the ordinary form, to my own extension of it, and to Sir W. Hamilton's departure from it. The relations of my work on Formal Logic to the present syllabus are as follows. Chapter I, First Notions, may afford previous knowledge to the student who has hitherto paid no attention to the subject. Chapter III, On the abstract form of the Proposition may be consulted at 93 of this syllabus. Chapters IV, On Propositions, and V and VI, On the Syllogism, are rendered more easy by the notation of this syllabus, and are partially superseded. Chapter XIV, On the verbal Description of the Syllogism, is entirely superseded. All the rest of the work may be read as the titles of the chapters suggest. A syllabus deals neither in development nor in diversified example : and does not make the space occupied by any detail a measure of its importance as a part of the whole. I have omitted many subjects which are to be found in all the books, or dwelt lightly upon them: partly because more detail is contained in my Formal Logic, partly because any one who masters this tract will be able to judge for himself what I should have written on the omitted subjects. I have also endeavoured to remember that as a work of this kind proceeds, less detail of explanation is necessary....