2. Non-observation of instances, and non-observation of circumstances 341 3. Examples of the former 342 4. --and of the latter 347 5. Mal-observation characterized and exemplified 352 CHAPTER V. _Fallacies of Generalization._ § 1. Character of the class 356 2. Certain kinds of generalization must always be groundless 356 3. Attempts to resolve phenomena radically different into the same 357 4. Fallacy of mistaking empirical for causal laws 359 5. _Post hoc, ergo propter hoc_; and the deductive fallacy corresponding to it 364 6. Fallacy of False Analogies 366 7. Function of metaphors in reasoning 373 8. How fallacies of generalization grow out of bad classification 375 CHAPTER VI. _Fallacies of Ratiocination._ § 1. Introductory Remarks 377 2. Fallacies in the conversion and æquipollency of propositions 377 3. Fallacies in the syllogistic process 379 4. Fallacy of changing the premises 379 CHAPTER VII. _Fallacies of Confusion._ § 1. Fallacy of Ambiguous Terms 384 2. Fallacy of Petitio Principii 396 3. Fallacy of Ignoratio Elenchi 405 BOOK VI. ON THE LOGIC OF THE MORAL SCIENCES. CHAPTER I. _Introductory Remarks._ § 1. The backward state of the Moral Sciences can only be remedied by applying to them the methods of Physical Science, duly extended and generalized 413 2. How far this can be attempted in the present work 415 CHAPTER II. _Of Liberty and Necessity._ § 1. Are human actions subject to the law of causality? 417 2. The doctrine commonly called Philosophical Necessity, in what sense true 418 3. Inappropriateness and pernicious effect of the term Necessity 420 4. A motive not always the anticipation of a pleasure or a pain 424 CHAPTER III. _That there is, or may be, a Science of Human Nature._ § 1. There may be sciences which are not exact sciences 426 2. To what scientific type the Science of Human Nature corresponds 429