Contents: I. Appearance and Reality II. The Existence of Matter III. The Nature of Matter IV. Idealism V. Knowledge by Acquaintance and Knowledge by Description VI. On Induction VII. On our Knowledge of General Principles VIII. How A Priori Knowledge is Possible IX. The World of Universals X. On Our Knowledge of Universals XI. On Intuitive Knowledge XII. Truth and Falsehood XIII. Knowledge, Error, and Probable Opinion XIV. The Limits of Philosophical Knowledge XV. The Value of Philosophy Bibliographical Not Index