From the PREFACE.
THIS work has been written to supply a double want, namely, the combination of a purely elementary logic with the art of argumentative discourse. Nor has this last feature of the subject been added out of deference to a revival of an intellectual interest in collegiate debate, but it has been suggested both by the practical value of logic as mental discipline and its close connection with the proper and orderly discussion of all subjects in which educated men are expected to engage. Logic as a practical art may be made quite free from discussion of the theory of knowledge; and thus free from philosophic problems, may be made most serviceable in the field of clear and systematic thinking wherever a man is called upon to form and express his opinions. The author has long felt that formal and applied logic of the elementary kind can be taught as well in the earlier as in the later part of a collegiate course, so that the student can receive the benefit of it throughout his whole academic career. It is especially a subject which ought to follow closely upon mathematics. The value of this latter science lies in the habit of reasoning which it fosters, but it labors under one grave fault, if it is not supplemented by a knowledge of practical logic on other data, and this is the encouragement which it may unconsciously offer to over-confidence in the legitimacy of our reasoning in subjects where our propositions do not resemble those in mathematics. Mathematics is the most important science in which to begin our discipline in reasoning, because we are not complicated with all those modifications of meaning which the subjects of distribution and equivocation introduce into the process in other sciences. But it ought to be followed closely by logic in a long and careful application to practical examples that may contribute to general knowledge while they also effect mental discipline.
For a somewhat similar reason I have connected it with one department of rhetoric, but only that which is concerned with the treatment of arguments. But I have not more than merely outlined this aspect of the subject, leaving to the instructor the development both of detailed rules and of practical work in themes. The outline and discussion of any thesis often depends upon a variety of circumstances for which only the most general rules can be given, and hence I have endeavored only to assist the teacher in saving time by giving the student the general principles in order to limit the amount of lecturing and dictation. The practical exercises will afford all the opportunity necessary for the special elucidation of principles.
The work has also been written so that the part devoted to rhetoric can easily be omitted and the remainder used for purely elementary logic. The treatment of induction has been made very brief, as not being adapted to as easy mastery as deductive logic. But I have carefully outlined the subject of fallacies and methods of argumentation. It is hoped that the work may encourage an earlier study of logic than prevails in many institutions.