from three different points of view: First, what is the general nature of argument? - Second, what are the various classes of argument? And third, what are the tests to be applied to each of the various classes? Since argument is one of the two essential elements of proof, a thorough knowledge of this subject from these different points of view is indispensable to all students of debate who are ambitious to acquire a complete mastery of the art. CHAPTER III FALLACY1 Importance of the Study of Fallacy. No consideration in debate is more important than that proof should be entirely free from fallacy; for whenever the element of fallacy enters into proof, no reliance may be placed on its conclusions. Every debater, therefore, should be thoroughly familiar with the subject of fallacy, in order that he may be able to avoid fallacy in his own proof and expose it in the proof of his opponents. Definition of Fallacy. - Fallacy consists of any defect in proof that destroys its validity. Detection of Fallacy. To detect a fallacy in proof, a debater may employ either one of two methods. He may, for instance, apply to the evidence and argument involved in proof the tests previously enumerated for determining their validity; 2 or he may examine the proof to see whether it contains any defect that conforms with the definition of a particular fallacy. Three General Divisions of Fallacy in Logic. The subject of fallacy, as treated in logic, usually involves three general divisions: namely, 1. Fallacies of Interpretation; 2. Formal Fallacies; and 3. Material Fallacies. 1 For lesson assignments on Fallacy see Appendix A. 2 See pages 61-62, 101-103. Fallacies of interpretation are those that arise from errors of understanding in respect to the meaning or implication of propositions. Formal fallacies are those that arise from errors in the application of rules for the syllogism.1 And material fallacies are those that arise from errors in regard to the nature and relationship of matters involved in proof. Among these three general divisions of fallacy, those that may be used most effectively in debate are material fallacies. Only fallacies of this type, therefore, will be considered in detail; and, if the debater is interested in the study of other fallacies, he may find a thorough treatment of them in almost any text on logic.2 Three Main Classes of Material Fallacies. - For the general division of material fallacies, many different methods of classification have been used; but the method that is likely to prove most serviceable in debate is one that distinguishes fallacies according to whether they represent defects of the premise, defects of the inference, or defects of the conclusion. According to such a method of classification, all material fallacies may be represented under three main classes: namely, 1. The Fallacy of Begging the Question ; 2. The Fallacy of Non-Sequitur; and 3. The Fallacy of Argument Beside the Point. The fallacy of begging the question represents a defect in a premise; the fallacy of non-sequitur represents a defect 1 See pages 79, 82, 83. 2 See Creighton's Introductory Logic (Macmillan, 1907), pp. 152–171. in an inference; and the fallacy of argument beside the point represents a defect in a conclusion.1 Table of Material Fallacies. A complete table of all the more important material fallacies to be avoided in debate is given below: I. Fallacies of Begging the Question A. Simple Iteration B. Iteration by Generalization C. Argument in a Circle D. Non-Evident Premise II. Fallacies of Non-Sequitur A. Post Hoc B. Composition or Division C. Accident D. Equivocation III. Fallacies of Argument Beside the Point A. Argumentum ad Hominem I. BEGGING THE QUESTION Fallacies of Begging the Question. — The first main class of material fallacies consists in begging the question. Fallacies of this type are those that arise from assuming in a premise the truth of a conclusion to be proved. The Fallacy of Simple Iteration. One of the most common forms of begging the question is found in the fallacy of simple iteration. This type of fallacy is one in which a con 1 See page 50. clusion to be proved is used to prove itself by being repeated immediately, either verbatim, or with different phraseology. A formula that may be used to represent this kind of fallacy appears in the following argument: I. This thing is so; because The fallacy of simple iteration rarely appears in such an obvious form, however, as that represented in the formula given above; but more commonly appears in the form of a rhetorical question, or with a difference in phraseology between the conclusion and the premise. The following argument illustrates the fallacy of simple iteration by means of the rhetorical question: I. The State should establish an old-age pension system; for A. Is it not the duty of the State to establish such a system? The following argument illustrates the fallacy of simple iteration by means of a difference in phraseology : I. The State should establish an old-age pension system; for A. An old-age pension system should most certainly be established by the State. The Fallacy of Iteration by Generalization. - Another common form of begging the question is found in the fallacy of iteration by generalization. This type of fallacy is one in which a conclusion to be proved is used to prove itself by being repeated in the form of a more inclusive general state ment. The following argument, for example, contains the fallacy of iteration by generalization: |