CHAPTER I, sections 1-5. If the student will take a good history of philosophy, and look over the accounts of the different systems referred to, he will see the justice of the position taken in the text, namely, that philosophy was formerly synonymous with universal knowledge. It is not necessary, of course, to read the whole history of philosophy to attain this end. One may take such a text-book as Ueberweg's "History of Philosophy," and run over the summaries contained in the large print. To see how the conception of what constitutes universal knowledge changed in successive ages, compare Thales, the Sophists, Aristotle, the Schoolmen, Bacon, and Descartes. For the ancient philosophy one may consult Windelband's "History of the Ancient Philosophy," a clear and entertaining little work (English translation, N.Y., 1899).

In Professor Paulsen's "Introduction to Philosophy" (English translation, N.Y., 1895), there is an interesting introductory chapter on "The Nature and Import of Philosophy" (pp. 1-41). The author pleads for the old notion of philosophy as universal knowledge, though he does not, of course, mean that the philosopher must be familiar with all the details of all the sciences.
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.

In the "Metaphysics," for example, it is said that sensations so connect themselves together as to form what we call the system of material things (p. 105). It is intimated in a footnote that this is a provisional statement and the reader is referred to later chapters. Now, in the present book (sections 16-17), it is taught that we may not call material things groups of sensations.

The apparent contradiction is due to the fact that, in this volume, the full meaning of the word "sensation" is exhibited at the outset, and sensations, as phenomena of the subjective order, are distinguished from the phenomena of the objective order which constitute the external world. In the earlier work the word "sensation" was for a while used loosely to cover all our experiences that do not belong to the class called imaginary, and the distinction between the subjective and objective in this realm was drawn later (Chapter XXIII).

I think the present arrangement is the better one, as it avoids from the outset the suggestion that the real world is something subjective—our sensations or ideas—and thus escapes the idealistic flavor which almost inevitably attaches to the other treatment, until the discussion is completed, at least.
CHAPTER V, sections 10-21. See Chapters VIII and IX, "System of Metaphysics," "The Distinction between Appearance and Reality" and "The Significance of the Distinction."
Section 22. See Chapter XXVI, "The World as Unperceived, and the 'Unknowable,'" where Spencer's doctrine is examined at length, and references are given. I think it is very important that the student should realize that the "Unknowable" is a perfectly useless assumption in philosophy, and can serve no purpose whatever.
CHAPTER VI, sections 23-25. See Chapters X and XI, "System of Metaphysics," "The Kantian Doctrine of Space" and "Difficulties connected with the Kantian Doctrine of Space."

It would be an excellent thing for the student, after he has read the above chapters, to take up Kant's "Critique of Pure Reason," and read and analyze the argument of Antinomies I and II, with the Observations appended. One can understand these arguments without being familiar with the "Critique" as a whole; at any rate, the account of Kant's philosophy contained in section 51 of this book will serve to explain his use of certain terms, such as "the laws of our sensibility."

Kant's reasonings are very curious and interesting in this part of his book. It seems to be proved that the world must be endless in space and without a beginning or end in time, and just as plausibly proved that it cannot be either. It seems to be proved that finite spaces and times are infinitely divisible, and at the same time that they cannot be infinitely divisible. The situation is an amusing one, and rendered not the less amusing by the seriousness with which the mutually destructive arguments are taken.

When the student meets such a tangle in the writings of any philosopher, I ask him to believe that it is not the human reason that is at fault—at least, let him not assume that it is. The fault probably lies with a human reason.
Section 26. See Chapter XII, "The Berkeleian Doctrine of Space," in my "System of Metaphysics." The argument ought not to be difficult to one who has mastered Chapter V of this volume.
CHAPTER VII, sections 27-29. Compare Chapter XIII, "System of Metaphysics," "Of Time."

With the chapters on Space and Time it would be well for the student to read Chapter XIV, "The Real World in Space and Time," where it is made clear why we have no hesitation in declaring space and time to be infinite, although we recognize that it seems to be an assumption of knowledge to declare the material world infinite.
CHAPTER VIII, sections 30-32. Read, in the "System of Metaphysics," Chapters V and XVII, "The Self or Knower" and "The Atomic Self."
Section 33. The suggestions, touching the attitude of the psychologist toward the mind, contained in the preface to Professor William James's "Psychology" are very interesting and instructive.
CHAPTER IX, sections 35-36. For a strong argument in favor of interactionism see James's "Psychology," Chapter V. I wish the student would, in reading it, bear in mind what is said in my chapter on "The Atomic Self," above referred to. The subject should be approached with an open mind, and one should suspend judgment until both sides have been heard from.
Section 37. Descartes held that the lower animals are automata and that their actions are not indicative of consciousness; he regarded their bodies as machines lacking the soul in the "little pineal gland." Professor Huxley revived the doctrine of animal automatism and extended it so as to include man. He regarded consciousness as a "collateral product" of the working of the body, related to it somewhat as is the steam-whistle of a locomotive engine to the working of the machine. He made it an effect, but not a cause, of motions. See "System of Metaphysics," Chapter XVIII, "The Automaton Theory: its Genesis."

We owe the doctrine of parallelism, in its original form, to Spinoza. It was elaborated by W. K. Clifford, and to him the modern interest in the subject is largely due. The whole subject is discussed at length in my "System of Metaphysics," Chapters XIX-XXI. The titles are: "The Automaton Theory: Parallelism," "What is Parallelism?" and "The Man and the Candlestick." Clifford's doctrine is presented in a new form in Professor Strong's recent brilliant work, "Why the Mind has a Body" N.Y., 1903.
Section 38. See "System of Metaphysics," Chapter XXIV, "The Time and Place of Sensations and Ideas."
CHAPTER X, sections 40-42. See "System of Metaphysics," Chapters XXVII and XXVIII, "The Existence of Other Minds," and "The Distribution of Minds."

Writers seem to be divided into three camps on this question of other minds.

(1) I have treated our knowledge of other minds as due to an inference. This is the position usually taken.

(2) We have seen that Huxley and Clifford cast doubts upon the validity of the inference, but, nevertheless, made it. Professor Strong, in the work mentioned in the notes to the previous chapter, maintains that it is not an inference, and that we do not directly perceive other minds, but that we are assured of their existence just the same. He makes our knowledge an "intuition" in the old-fashioned sense of the word, a something to be accepted but not to be accounted for.

(3) Writers who have been influenced more or less by the Neo-Kantian or Neo-Hegelian doctrine are apt to speak as though we had the same direct evidence of the existence of other minds that we have of the existence of our own. I have never seen a systematic and detailed exposition of this doctrine. It appears rather in the form of hints dropped in passing. A number of such are to be found in Taylor's "Elements of Metaphysics."
Section 43. The "Mind-stuff" doctrine is examined at length and its origin discussed in Chapter XXXI of the "System of Metaphysics," "Mental Phenomena and the Causal Nexus." It is well worth while for the student to read the whole of Clifford's essay "On the Nature of Things-in-themselves," even if he is pressed for time.
CHAPTER XI, section 44. See "System of Metaphysics," Chapter XV, "The World as Mechanism."
Section 45. See Chapter XXXI, "The Place of Mind in Nature."
Section 46. For a definition of Fatalism, and a description of its difference from the scientific doctrine of Determinism, see Chapter XXXIII, "Fatalism, 'Freewill' and Determinism." For a vigorous defense of "Freewill" (which is not, in my opinion, free will at all, in the common acceptation of the word) see Professor James's Essay on "The Dilemma of the Determinist," in his volume, "The Will to Believe."

Fatalism and Determinism are constantly confused, and much of the opposition to Determinism is attributable to this confusion.
Section 47. See Chapter XXXII, "Mechanism and Teleology."
CHAPTER XII, section 48. The notes to Chapter III (see above) are in point here. It is well worth the student's while to read the whole of Chapter XI, Book IV, of Locke's "Essay." It is entitled "Of our Knowledge of the Existence of Other Things." Notice the headings of some of his sections:—
Section 1. "It is to be had only by sensation."
Section 2. "Instance whiteness of this paper."
Section 3. "This, though not so certain as demonstration, yet may be called 'Knowledge,' and proves the existence of things without us."

Locke's argument proceeds, as we have seen, on the assumption that we perceive external things directly,—an assumption into which he slips unawares,—and yet he cannot allow that we really do perceive directly what is external. This makes him uncomfortably conscious that he has not absolute proof, after all. The section that closes the discussion is entitled: "Folly to expect demonstration in everything."
Section 49. I wish that I could believe that every one of my readers would sometime give himself the pleasure of reading through Berkeley's "Principles of Human Knowledge" and his "Three Dialogues between Hylas and Philonous." Clearness of thought, beauty of style, and elevation of sentiment characterize them throughout.

The "Principles" is a systematic treatise. If one has not time to read it all, one can get a good idea of the doctrine by running through the first forty-one sections. For brief readings in class, to illustrate Berkeley's reasoning, one may take sections 1-3, 14, 18-20, and 38.

The "Dialogues" is a more popular work. As the etymology of the names in the title suggests, we have in it a dispute between a man who pins his faith to matter and an idealist. The aim of the book is to confute skeptics and atheists from the standpoint of idealism.

For Hume's treatment of the external world, see his "Treatise of Human
Nature," Part IV, section 2. For his treatment of the mind, see Part
IV, section 6.
Section 50. Reid repeats himself a great deal, for he gives us asseveration rather than proof. One can get the gist of his argument by reading carefully a few of his sections. It would be a good exercise to read in class, if time permitted, the two sections of his "Inquiry" entitled "Of Extension" (Chapter V, section 5), and "Of Perception in General" (Chapter VI, section 20).
Section 51. For an account of the critical Philosophy, see Falckenberg's "History of Modern Philosophy" (English translation, N.Y., 1893). Compare with this the accounts in the histories of philosophy by Ueberweg and H?ffding (English translation of the latter, London, 1900). Full bibliographies are to be found especially in Ueberweg.

It is well to look at the philosophy of Kant through more than one pair
of eyes. Thus, if one reads Morris's "Kant's Critique of Pure Reason"
(Chicago, 1882), one should read also Sidgwick's "Lectures on the
Philosophy of Kant" (N.Y., 1905).
CHAPTER XIII, sectio............