Section 6. In justification of the meaning given to the word "philosophy" in this section, I ask the reader to look over the list of courses in philosophy advertised in the catalogues of our leading universities at home and abroad. There is a certain consensus of opinion as to what properly comes under the title, even among those who differ widely as to what is the proper definition of philosophy. CHAPTER II, sections 7-10. Read the chapter on "The Mind and the World in Common Thought and in Science" (Chapter I) in my "System of Metaphysics," N.Y., 1904. One can be brought to a vivid realization of the fact that the sciences proceed upon a basis of assumptions which they do not attempt to analyze and justify, if one will take some elementary work on arithmetic or geometry or psychology and examine the first few chapters, bearing in mind what philosophical problems may be drawn from the materials there treated. Section 11. The task of reflective thought and its difficulties are treated in the chapter entitled "How Things are Given in Consciousness" (Chapter III), in my "System of Metaphysics." CHAPTER III, sections 12-13. Read "The Inadequacy of the Psychological Standpoint," "System of Metaphysics," Chapter II. I call especial attention to the illustration of "the man in the cell" (pp. 18 ff.). It would be a good thing to read these pages with the class, and to impress upon the students the fact that those who have doubted or denied the existence of the external material world have, if they have fallen into error, fallen into a very natural error, and are not without some excuse. Section 14. See "The Metaphysics of the Telephone Exchange," "System of Metaphysics," Chapter XXII, where Professor Pearson's doctrine is examined at length, with quotations and references. It is interesting to notice that a doubt of the external world has always rested upon some sort of a "telephone exchange" argument; naturally, it could not pass by that name before the invention of the telephone, but the reasoning is the same. It puts the world at one remove, shutting the mind up to the circle of its ideas; and then it doubts or denies the world, or, at least, holds that its existence must be proved in some roundabout way. Compare Descartes, "Of the Existence of Material Things," "Meditations," VI. CHAPTER IV, sections 15-18. See Chapters VI and VII, "What we mean by the External World," and "Sensations and 'Things,'" in my "System of Metaphysics." In that work the discussion of the distinction between the objective order of experience and the subjective order is completed in Chapter XXIII, "The Distinction between the World and the Mind." This was done that the subjective order might be treated in the part of the book which discusses the mind and its relation to matter. As it is possible that the reader may be puzzled by differences of expression which obtain in the two books, a word of explanation is not out of place.