Logic Books

CHAPTER I INTRODUCTORY § 1. Logic is the science that explains what conditions must be fulfilled in order that a proposition may be proved, if it admits of proof. Not, indeed, every such proposition; for as to those that declare the equality or inequality of numbers or other magnitudes, to explain the conditions of their proof belongs to Mathematics: they are said to be quantitative. But as to all... more...

One critic, who was kind enough to look at this book in manuscript, recommended me to abandon the design of Publishing it, on the ground that my logic was too like all other logics; another suggested to me to cut out a considerable amount of new matter. The latter advice I have followed; the former has encouraged me to hope that I shall not be considered guilty of wanton innovation. The few novelties... more...

CHAPTER I. INTRODUCTORY. The Universe contains ‘Things.’ [For example, “I,” “London,” “roses,” “redness,” “old English books,” “the letter which I received yesterday.”] Things have ‘Attributes.’ [For example, “large,” “red,” “old,” “which I received yesterday.”] One Thing may have many Attributes; and one Attribute may belong to many Things. [Thus, the... more...