"How charming is divine Philosophy! But musical as is Apollo's lute, And a perpetual feast of nectared sweets, Where no rude surfeit reigns." UNIVERSITY OF REVISED AND ENLARGED OM THE SECOND. EDITION. LIBRARY NEW YORK: A. S. BARNES & CO., 51 JOHN-STREET. CINCINNATI:-H. W. DERBY. 1855. Entered according to Act of Congress, in the year 1854, by ASA MAHAN, In the Clerk's Office of the District Court of the United States, for the Southern District of the State of New York. DYTIGAVIMU YRABBL WILLIAM H. SHAIN & CO., STEREOTYPERS, HUDSON, OHIO. DEDICATORY PREFACE TO THE FIRST EDITION. THE following Treatise presents the sum of a course of Lectures, which, for six or eight years past, I have been in the habit of delivering to successive classes, on the subject of Intellectual Philosophy. One thing I may say in relation to this subject, without boasting. No class have yet passed through this course, without becoming deeply interested in the science of Mental Philosophy; and, in their judgment, receiving great benefit from the truths developed, as well as from the method of development which was adopted. Hence the desire has been very generally expressed by those who have attended the course of instruction, as well as by others who have become acquainted with the general features of the system taught, to have it presented to the public in a form adapted to popular reading. In conformity to such suggestions, as well as the permanent convictions of my own mind, the following Treatise has been prepared. In preparing it, it has been my aim to reject light from no source whatever from which it could be obtained, and at the same time to maintain the real prerogative of manly independence of thought. The individuals to whom I feel most indebted as a philosopher, are Coleridge, Cousin, and Kant-three luminaries of the first order in the sphere of philosophy. How far proper discrimi nations have been made in the study of their works, the reader will be able to judge. With these remarks, I would simply add, that TO THE BELOVED AND HONORED PUPILS, WHO HAVE HITHERTO PASSED FROM UNDER MY INSTRUCTION AS A TEACHER OF MENTAL SCIENCE, THE FOLLOWING TREATISE IS NOW AFFECTIONATELY DEDICATED, WITH THE EXPRESSION OF THE FOND HOPE, THAT IN ALL FUTURE CLASSES, WHICH IT MAY BE MY PRIVILEGE TO INSTRUCT, I MAY, IN THE LANGUAGE OF ANOTHER, FIND THE SAME LOVE OF PHILOSOPHY, AND THE SAME INDULGENCE TO THE PROFESSOR." PREFATORY NOTE TO THE REVISED EDITION. SINCE the publication of the first edition of this work, the author has had the benefit resulting from successive years in teaching the same, and of a careful reading of other works upon the same subject. In this manner, he has been enabled to perceive defects that needed correction in the work, as first presented. The work is now given to the public, as the result of his mature reflections upon this fundamental science. Some of the most important chapters have been so entirely rewritten. and remodeled, as to render the present, in some important respects, a new work on Intellectual philosophy. I may notice, among others, the chapter on Sense, the examination of the true as distinguished from false systems of Philosophy, in the chapter on Miscellaneous Topics, and the development of the evidence of the being and perfections of God, in the last chapter. The author has always been fully persuaded of the correctness of his views in respect to external perception, but has felt a growing dissatisfaction with his manner of presenting the subject, in the chapter referred to. In the present edition, this subject, so fundamental to a right system of mental science, is so presented as to meet his ideas in most, if not all respects. One of the great wants of the age is a fundamental examination of false systems of Philosophy, as developed in |