Chapter IV. Of the Requisites of a Philosophical Language, and the Principles of Definition. § 1. First requisite of philosophical language, a steady and determinate meaning for every general name 215 2. Names in common use have often a loose connotation 215 3. —which the logician should fix, with as little alteration as possible 218 4. Why definition is often a question not of words but of things 220 5. How the logician should deal with the transitive applications of words 224 6. Evil consequences of casting off any portion of the customary connotation of words 229 [Pg x] Chapter V. On the Natural History of the Variations in the Meaning of Terms. § 1. How circumstances originally accidental become incorporated into the meaning of words 236 2. —and sometimes become the whole meaning 238 3. Tendency of words to become generalized 240 4. —and to become specialized 243 Chapter VI. The Principles of a Philosophical Language further considered. § 1. Second requisite of philosophical language, a name for every important meaning 248 2. —viz. first, an accurate descriptive terminology 248 3. —secondly, a name for each of the more important results of scientific abstraction 252 4. —thirdly, a nomenclature, or system of the names of Kinds 255 5. Peculiar nature of the connotation of names which belong to a nomenclature 257 6. In what cases language may, and may not, be used mechanically 259 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 [Pg xi]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