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THE TRADITIONAL DOCTRINE OF FALLACIES
ARISTOTLE'S CLASSIFICATION OF FALLACIES
§ 197. The received classification of fallacies, -adopted by the schoolmen from Aristotle,– though remarkable for its profound insight, has but few pretensions to scientific accuracy; and it is to be suspected that much of the obscurity and confusion that surround the subject results from the undue authority given to it by logi. cians. It has, however, so profoundly affected logical doctrine and nomenclature that, apart from its intrinsic value, it must always remain one of the principal subjects for the student's attention.
$ 198. TABLE OF FALLACIES.-According to this scheme, fallacies are divided into two classes, called by the schoolmen and by later logicians, Fallacies in Dictione, or in Voce (i. e., in diction or speech), and Fallacies extra Dictionem, or in Re (i. e., not in diction, but in matter). Of the former class six forms or examples are given, and of the latter, seven, which are as follows:
Aristotle's Division of Fallacies
(1) Homonymia (Ambiguity of Terms).
(1) F. Accidentis (F. of Accident).
pliciter (Illicit Substitution of Unquali
fied for Qualified Terms). (3) Ignoratio Elenchi (Irrelevant Conclusion). (4) F. Consequentis (Non-Sequitur). (5) Petitio Principii (F. of Illicit Premise). (6) Non-Causa pro Causa (Mistaking Cause). (7) F. Plurium Interrogationum (F. of Several
Issues in One). $ 199. OBSERVATIONS UPON THIS CLASSIFICATION.-As will be seen presently, all the fallacies In Dictione are simply cases of Equivocation, and of the fallacies Extra Dictionem all except the 4th (F. Consequentis) are Fallacies of Judgment; under which head most of them have already been considered at large. The excepted fallacy (the F. Consequentis) includes all the Fallacies of Inference, except Equivocation. It is obvious, therefore, that the current expressions (In Dictione and Extra Dictionem) —whether from being a mistranslation of Aristotle's language or otherwise-do not truly express the nature of the distinction between the two kinds of fallacies, and are, therefore, calculated to mislead us — as they have Whately and others--with regard to it.
$ 200. The true scheme of division is as fol. lows:
Table of Fallacies I. FALLACIES IN DictioNE (EQUIVOCATION).
(Including the six forms specified in the
first table.) II. FALLACIES EXTRA DICTIONEM. (1) Fallacies of Fudgment.
(Including all fallacies Extra Dictionem
given in the table, except F. Conse
(Including all Fallacies of Inference ex
cept Equivocation.) (a) Formal Fallacies (i. e., of Inference).
(Including Undistributed Middle, Il
(Including Illicit Substitutions of New
The terms “Formal" and "Material Fallacies " correspond to the “ Logical ” and “Material Fallacies " of Whately, whose
Semi-logical Fallacies” correspond precisely to the fallacies In Dictione of Aristotle, or, in other words, to the Fallacy of Equivocation. This division of Whately's has, since his time, been very generally adopted; but, as is remarked by Mansel, it“ is not the ancient principle of distinction which is stated with more or less clearness by several logicians," as, l.g. in the following definitions of Sanderson: “Every fallacy In Dictione arises from some ambiguity (multiplicitate) of expression.' “ Fallacies Extra Dictionem are those in which the deception happens, not so much from some ambiguity latent in the words themselves, as from ignoring things ” (i. e., the notions expressed). “ The former arise,” says Mansel, "from defects in the arbitrary signs of thought, and hence are generally confined to a single language, and disappear on being translated into another. The latter are in the thought itself, whether materially, in the false application of notions to things, or formally, in the violation of the laws by which the operations of the reason should be governed; and thus adhere to the thought in whatever language it may be expressed. Under this head are thus included both false judgments and illogical reasonings'
(i. e., both Fallacies of Judgment and Fallacies of Inference) (Mansel's Aldrich, p. 132).
FALLACIES IN DICTIONE (EQUIVOCATION) § 201 (1) (2). HOMONYMY AND AMPHI. BOLY.-These are both cases of the Fallacy of Equivocation, the former consisting in the illicit use of ambiguous terms, the latter in the illicit use of ambiguous sentences. They are essentially of the same nature; and we, there. fore, as is most in accord with the usage of our language, class them together under the common name of Equivocations.
This fallacy has already been fully considered.
$ 202 (3) (4). COMPOSITION AND DIVISION.These fallacies are essentially of the same nature. They consist in using a term successively in a distributive and in a collective sense, or, in other words, in substituting for a term used distributively the same term used collectively, or vice versa. The former constitutes the Fallacy of Composition, the latter the Fallacy of Division.
The following are examples of the Fallacy of Composition:
3 and 2 (distributively) are two numbers; 5 is 3 and 2 (collectively); .: 5 is two numbers. He who necessarily goes or stays (i, e., either