Part 3 The Movement of Reflection; Chapter 18 The General Nature of Understanding; Chapter 19 How Reflection Starts; Chapter 20 Specifying the Problem; Chapter 21 Observation; Chapter 22 Invention and Association; Chapter 23 The Nature of Invention; Chapter 24 The Subconscious in Invention; Chapter 25 The Tests of Truth; Chapter 26 Coherence as the Nature of Truth; Chapter 27 Coherence and Degrees of Truth; Part 4 The Goal of Thought; Chapter 28 Empiricism and Necessity; Chapter 29 Formalism and Necessity; Chapter 30 Logical Positivism and Necessity; Chapter 31 Concrete Necessity and External Relations; Chapter 32 Concrete Necessity and Internal Relations;