With a view to showing the truth of this opinion, I shall take up one by one the philosophical sciences. Of the history of philosophy I shall not speak in this part of the work, but shall treat of it in Chapter XXIII. 66. THE TRADITIONAL LOGIC.--Most of us begin our acquaintance with logic in the study of some such elementary manual as Jevons' "Lessons in Logic." In such books we are shown how terms represent things and classes of things or their attributes, and how we unite them into propositions or statements. It is indicated at length what statements may be made on a basis of certain other statements and what may not; and emphasis is laid upon the dangers which arise out of a misunderstanding of the language in which we are forced to express our thoughts. Finally, there are described for us the experimental methods by which the workers in the sciences have attained to the general information about the world which has become our heritage. Such books are useful. It is surely no small profit for a student to gain the habit of scrutinizing the steps by which he has come into the possession of a certain bit of information, and to have a quick eye for loose and inconsistent reasonings. But it is worthy of remark that one may study such a book as this and yet remain pretty consistently on what may be called the plane of the common understanding. One seems to make the assumptions made in all the special sciences, _e.g._ the assumption that there is a world of real things and that we can know them and reason about them. We are not introduced to such problems as: What _is_ truth? and Is _any_ knowledge valid? Nor does it seem at once apparent that the man who is studying logic in this way is busying himself with a philosophical discipline. 67. THE "MODERN LOGIC."--It is very puzzling for the student to turn from such a text-book as the one above mentioned to certain others which profess to be occupied with the same science, and which, yet, appear to treat of quite different things. Thus, in Dr. Bosanquet's little work on "The Essentials of Logic," the reader is at once plunged into such questions as the nature of knowledge, and what is meant by the real world. We seem to be dealing with metaphysics, and not with logic, as we have learned to understand the term. How is it that the logician comes to regard these things as within his province?