Introduction; Part I The Data of Natural Science and Principles of Systematization; Chapter 1 Phenomenalism and Kindred Doctrines; Chapter 2 An Alternative to Phenomenalism; Chapter 3 The Categories of Substance and Causation and Their Use in Modern Natural Science; Chapter 4 Demands, Postulates, and Subjective Factors in Knowledge; Part II Problems of Biological Knowledge; Chapter 5 The Antithesis between Vitalism and Mechanism; Chapter 6 The Theory of Biological Explanation; Chapter 7 The Antithesis between Structure and Function; Chapter 8 The Antithesis between Organism and Environment; Chapter 9 The Antithesis Between Preformation and Epigenesis; Chapter 10 The Antithesis between Teleology and Causation; Chapter 11 The Antithesis between Mind and Body; Chapter 12 The Future of Biology;