INTRODUCTORY CHAPTER I THE MEANING OF THE WORD "PHILOSOPHY" IN THE PAST AND IN THE PRESENT 1. The Beginnings of Philosophy. 2. The Greek Philosophy at its Height. 3. Philosophy as a Guide to Life. 4. Philosophy in the Middle Ages. 5. The Modern Philosophy. 6. What Philosophy means in our Time. CHAPTER II COMMON THOUGHT, SCIENCE, AND REFLECTIVE THOUGHT 7. Common Thought. 8. Scientific Knowledge. 9. Mathematics. 10. The Science of Psychology. 11. Reflective Thought. PART II PROBLEMS TOUCHING THE EXTERNAL WORLD CHAPTER III IS THERE AN EXTERNAL WORLD? 12. How the Plain Man thinks he knows the World. 13. The Psychologist and the External World. 14. The "Telephone Exchange." CHAPTER IV SENSATIONS AND "THINGS" 15. Sense and Imagination. 16. May we call "Things" Groups of Sensations? 17. The Distinction between Sensations and "Things." 18. The Existence of Material Things. CHAPTER V APPEARANCES AND REALITIES 19. Things and their Appearances. 20. Real Things. 21. Ultimate Real Things. 22. The Bugbear of the "Unknowable". CHAPTER VI OF SPACE 23. What we are supposed to know about It. 24. Space as Necessary and Space as Infinite. 25. Space as Infinitely Divisible. 26. What is Real Space? CHAPTER VII OF TIME 27. Time as Necessary, Infinite, and Infinitely Divisible. 28. The Problem of Past, Present, and Future. 29. What is Real Time? PART III PROBLEMS TOUCHING THE MIND CHAPTER VIII WHAT IS THE MIND? 30. Primitive Notions of Mind. 31. The Mind as Immaterial. 32. Modern Common Sense Notions of the Mind. 33. The Psychologist and the Mind. 34. The Metaphysician and the Mind. CHAPTER IX MIND AND BODY 35. Is the Mind in the Body? 36. The Doctrine of the Interactionist. 37. The Doctrine of the Parallelist. 38. In what Sense Mental Phenomena have a Time and Place. 39. Objections to Parallelism. CHAPTER X HOW WE KNOW THERE ARE OTHER MINDS 40. Is it Certain that we know It? 41. The Argument for Other Minds. 42. What Other Minds are there? 43. The Doctrine of Mind-stuff. CHAPTER XI OTHER PROBLEMS OF WORLD AND MIND 44. Is the Material World a Mechanism? 45. The Place of Mind in Nature. 46. The Order of Nature and "Free-will." 47. The Physical World and the Moral World. PART IV SOME TYPES OF PHILOSOPHICAL THEORY CHAPTER XII THEIR HISTORICAL BACKGROUND 48. The Doctrine of Representative Perception. 49. The Step to Idealism. 50. The Revolt of "Common Sense." 51. The Critical Philosophy. CHAPTER XIII REALISM AND IDEALISM 52. Realism. 53. Idealism. CHAPTER XIV MONISM AND DUALISM 54. The Meaning of the Words. 55. Materialism. 56. Spiritualism. 57. The Doctrine of the One Substance. 58. Dualism. 59. Singularism and Pluralism. CHAPTER XV RATIONALISM, EMPIRICISM, CRITICISM, AND CRITICAL EMPIRICISM