PREFACE THIS book is intended as a text-book and not at all as a contribution to logical theory. It aims to present an outline of scientific method as briefly and as concretely as possible. It is not designed to serve as an introduction to general philosophy. Its chief claim to novelty is in the arrangement of the subject matter. The traditional arrangement in which the deductive processes are presented first usually leaves with the student the impression that method is chiefly deduction, and that there is no very close connection between this and the rest of subject. The arrangement, which is here adopted, was selected on pedagogical grounds and not in the interests of any epistemological theory. The justification for dogmatic statements on disputed points is also pedagogical. Argument on such points in a text-book usually fails to interest the student and often tends to make him think that the whole subject is in an uncertain state and mostly a matter of opinion. Some subjects are treated much more briefly than they deserve, but I wished to keep them in due proportion with the rest. Fallacies are first discussed along with the processes with which they are connected, but they are all brought together in a later chapter.' Many of the exercises are new, but I have also drawn freely from other textbooks. The longer exercises at the end of the book give the student an opportunity to bring to bear al most the whole of scientific method, and for this reason they seem to me to be very important. My indebtedness to Jevons, Hyslop, Mill, and Bowley will be obvious. I owe much to Aikins' Principles of Logic; his broader treatment of many topics and his chapters on Testimony, Averages, Statistics, etc., were very suggestive. Sidgwick's The Use of Words in Reasoning, Creighton's treatment of the Figures of the Syllogism in his Introduction to Logic, Hibben's use of the idea of system in his Logic and Cramer's The Method of Darwin, were also suggestive. I have tried to give credit in each case in which I am conscious of having borrowed. I am much indebted to three of my former colleagues in Princeton University: to Professor W. T. Marvin for going over the whole of the copy and giving me much useful advice, and to Professors W. H. Sheldon and E. M. Rankin for assistance with the proof; and to my colleagues, Professors Woodbridge and Montague, for many valuable discussions of logical problems. NEW YORK, April, 1909. A. L. J. CONTENTS Science and Common Sense-Induction and Deduction in- cluded in Scientific Method-The Beginning of knowl- edge-Natural Sciences and others-The Sources of Knowledge, Direct and Indirect-Organizing knowledge -Classification as a preliminary step-Language as a Facts and the ways in which they are known-Perception PAGE Kinds of Propositions-Propositions and Terms-The Rela- tion of Subject and Predicate-The Distribution of Generalization and what it includes-Causal Connection- Verification and Deduction-Systematic Knowledge-How propositions are related to each other-Relations of Opposition among propositions which have not identical terms-Conversion-Obversion-Contraposition The Principles of Syllogistic Reasoning-The First Figure The Enthymeme-Prosyllogism and Episyllogism-The So- |