which Nature teaches us to analyze the objects, which she presents to our observation. In "An Essay on the Elements, Principles, and different Modes of Reasoning," by Richard Kirwan, LL. D., all the subjects, which properly fall within the precincts of Logick, are amply discussed. But this work is too minute and prolix to be used as a text book in seminaries of education. Every person who is much conversant with this department of knowledge, must have perceived the want of a treatise of Logick, more elementary, and better accommodated to the present improved state of the philosophy of the mind, than any of those, which are now in use. The professed object of Logick is to furnish rules for the direction of the understanding in its various inquiries after knowledge. It should, therefore, teach the principles of every species of reasoning, which we have. occasion to make use of, both in the pursuits of science, and in the ordinary transactions of life. Demonstrative reasoning can be employed only about general truths, and such relations as are in their nature immutable. It is of little use in regulating our judgments and conclusions concerning events, which are irregular in their occurrence, and which depend on contingent circumstances. To reason on subjects of this kind, it is necessary to understand the nature of moral evidence, and the grounds of probability. It is by moral evidence alone, that we reason on historical facts, and the casual occurrences of life. It is also this evidence, which influences our conclusions on the important and interesting subjects of government, morals, and religion. Under these impressions, the writer of this compend has pursued the following plan. After passing through the customary distinctions of terms and propositions, he has given a brief account of moral evidence, and pointed out the circumstances, which distinguish it from demonstrative. A concise view is then given of the different forms of reasoning, with the principles, on which they respectively proceed. The books, which have been principally consulted in forming this summary, and in which the greatest part of the following principles may be found, are Watts's Logick, Locke's Essay on the Understanding, Reid's Essays on the Intellectual Powers, Stewart's Elements of the Philosophy of the Mind, Beattie's Essay on Truth, Tatham's Chart and Scale of Truth, Collard's Essentials of Logick, Kirwan's Logick, Campbell's Philosophy of Rhetorick, Gambier's Introduction to Moral Evidence, Belsham's Compendium of Logick, and Scott's Elements of Intellectual Philosophy. Where passages have been borrowed entire, credit is given in the usual way. At the close of the several chapters may be found the names of those authors, from whom particular assistance has been derived. PREFACE TO THE THIRD EDITION. The THE present edition of the elements of Logick is printed in a smaller type than either of the preceding, in order that the copies may be afforded at a reduced price. author has carefully revised the work, and has enlarged it by the addition of a few pages, containing some general principles and rules respecting controversy, and also a system of rules for the interpretation of written documents. These have been collected with care from authors of high reputation, and, it is hoped, will not be thought an unsuitable appendage to a system of logick. In a few places, slight alterations have been made in the language and in the arrangement; and some notes have been inserted at the end of the book, which were not in the preceding editions. Harvard College, Nov. 1821. |