In the present book these passages have been restored to their place, so that the article as it left the authors hands is now, for the first time, placed before the reader. The manuscript bears no trace of the editorial blue pencil, and the original proof no longer exists: so that a doubt may arise as to whether any particular omission may not have been made by the author himself when he corrected the proofs. But it is clear, from a comparison of manuscript and print, that his proof-corrections were few and unimportant. No real difficulty, therefore, has arisen in deciding upon the restorations. The authors style was so concise that greater brevity could not be attained without sacrifice of the matter. It should be borne in mind that the article on Logic was written and published in 1882. The supplementary articles, by which it is followed in this volume, are all contributions to the history of logic; but the first of these that on Category, also reprinted from theE ncyclopaedia Britannica, dates from six years earlier; and only the last carries the story on towards a more recent development of logical theory. Eeaders of the authors works do not need to be reminded that his own point of view underwent modification, and that there are some things here which he might have expressed differently had he revised the work himself.(Typographical errors above are due to OCR software and don't occur in the book.)About the Publisher Forgotten Books is a publisher of historical writings, such as: Philosophy, Classics, Science, Religion, History, Folklore and Mythology.Forgotten Books' Classic Reprint Series utilizes the latest technology to regenerate facsimiles of historically important writings. Careful attention has been made to accurately preserve the original format of each page whilst digitally enhancing the aged text.