CHAPTER VII. _Of Classification, as subsidiary to Induction._ § 1. Classification as here treated of, wherein different from the classification implied in naming 266 2. Theory of natural groups 267 3. Are natural groups given by type, or by definition? 271 4. Kinds are natural groups 274 5. How the names of Kinds should be constructed 280 CHAPTER VIII. _Of Classification by Series._ § 1. Natural groups should be arranged in a natural series 284 2. The arrangement should follow the degrees of the main phenomenon 285 3. --which implies the assumption of a type-species 287 4. How the divisions of the series should be determined 288 5. Zoology affords the completest type of scientific classification 289 BOOK V. ON FALLACIES. CHAPTER I. _Of Fallacies in General._ § 1. Theory of fallacies a necessary part of logic 295 2. Casual mistakes are not fallacies 297 3. The moral sources of erroneous opinion, how related to the intellectual 297 CHAPTER II. _Classification of Fallacies._ § 1. On what criteria a classification of fallacies should be grounded 301 2. The five classes of fallacies 302 3. The reference of a fallacy to one or another class is sometimes arbitrary 305 CHAPTER III. _Fallacies of Simple Inspection, or à priori Fallacies._ § 1. Character of this class of Fallacies 309 2. Natural prejudice of mistaking subjective laws for objective, exemplified in popular superstitions 310 3. Natural prejudices, that things which we think of together must exist together, and that what is inconceivable must be false 314 4. Natural prejudice, of ascribing objective existence to abstractions 321 5. Fallacy of the Sufficient Reason 322 6. Natural prejudice, that the differences in nature correspond to the distinctions in language 325 7. Prejudice, that a phenomenon cannot have more than one cause 329 8. Prejudice, that the conditions of a phenomenon must resemble the phenomenon 332 CHAPTER IV. _Fallacies of Observation._ § 1. Non-observation, and Mal-observation 341