5-8-39 J.A gt-wenley Lif 15-2-39 PREFACE. My object in preparing this volume has been to provide a "First Logic Book" which may be used in teaching beginners, and at the same time furnish a connected, though brief, sketch of the science. I am aware that a large number of elementary Text-books and Manuals of Logic have appeared in recent years; and my only excuse for adding to the number is the hope I entertain that what I have to say may be of use, and may help to remove certain difficulties which are familiar to all teachers of Logic, and which have been very forcibly pressed upon my attention during an experience of several years, in teaching elementary Logic. In the present volume I have attempted to set forth, as simply and systematically as possible, views indicated in a small book-substantially a collection of Notes on difficult points in Logic-which I wrote three years ago. In that book I discussed fully the cases in which I diverge from traditional doctrines, and my reasons for the divergence; and this obviates, I hope, any necessity for introducing controversial matter in the present work-in which, of course, it would be peculiarly inappropriate. In the former book I acknowledged my obligations to various thinkers and writers, as far as I was definitely conscious of them; but in such matters it is perhaps never possible to trace more than a very small part of the debt which one owes to others. My whole scheme, as here presented, follows naturally from the view taken of the twofold character of Terms—which, as Names of Things, have both application and signification. On this datum, together with the recognition that things have a plurality of Characteristics and a consequent plurality of Names, depends (I think) the possibility of Significant Assertion, and the whole doctrine of Inference, Mediate and Immediate. The Principle of Excluded Middle suggests and supports a recognition of the relatedness of things to one another; and a consideration of Bacon's doctrine of Form suggests a modification of Mill's view of Induction. The relation of Induction to Deduc tion appears to me to be so close that it is more convenient to regard all Logic as one, than to make a radical and fundamental division between Deductive (or Formal') and Inductive (or Material') Logic. Upon the twofold character of Terms, again, depends the explicit recognition of the Law of Identity as a Law of Identity in Diversity. And I believe that what I have to say about Relative Propositions in Section IV. and elsewhere, about Quantification in Section VII., the view of Disjunctives in Section VI., and of the force and interdependence of the Principles of Logic in Section XIX., is to some extent new; likewise the systematisation of Fallacies in Section XVIII., and-in part-the elaboration of Immediate Inferences in Section X. My view that Logic is concerned with Assertions expressed in language, and that it is distinctly not a department of Psychology, is not peculiar to me. I have omitted from the text any matters of which the interest is largely historical, or which are not of direct importance for the theoretical outline which is all that I have attempted to give. But for convenience of reference, a brief account of such of these as are generally included in elementary text-books is |