FALLACIES OF CONFUSION. 563 



CHAPTER VII. 



FALLACIES OF CONFUSIOJf. 



§ 1. Under this fifth and last class it is convenient to arrange all those 

 fallacies in which the source of error is not so much a false estimate of the 

 probative force of known evidence, as an indistinct, indefinite, and fluctua- 

 ting conception of what the evidence is. 



At the head of these stands that multitudinous body of fallacious rea- 

 sonings in which the source of error is the ambiguity of terms: when 

 something which is true if a word be used in a particular sense, is reasoned 

 on as if it were true in another sense. In such a case there is not a mal- 

 estimation of evidence, because there is not properly any evidence to the 

 point at all; there is evidence, but to a different point, which from a con- 

 fused apprehension of the meaning of the terms used, is supposed to be 

 the same. This error will naturally be oftcner committed in our ratiocina- 

 tions than in our direct inductions, because in the former we are decipher- 

 ing our own or other people's notes, while in the latter we have the things 

 themselves present, either to the senses or to the memory. Except, indeed, 

 when the induction is not from individual cases to a generality, but from 

 generalities to a still higher generalization ; in that case the fallacy of am- 

 biguity may affect the inductive process as well as the ratiocinative. It 

 occurs in ratiocination in two ways : when the middle term is ambiguous, 

 or when one of the terms of the syllogism is taken in one sense in the 

 premises, and in another sense in the conclusion. 



Some good exemplifications of this fallacy are given by Archbishop 

 Whately. " One case," says he, " which may be regarded as coming under 

 the head of Ambiguous Middle, is (what I believe logical writers mean by 

 ^Fallacia Figurce Dictionis^) the fallacy built on the grammatical struc- 

 ture of language, from men's usually taking for granted that paronymous 

 (or conjugate) words, i. e., those belonging to each other, as the substantive, 

 adjective, verb, etc., of the same root, have a precisely corresponding mean- 

 ing ; which is by no means universally the case. Such a fallacy could not 

 indeed be even exhibited in strict logical form, which would preclude even 

 the attempt at it, since it has two middle terms in sound as well as sense. 

 But nothing is more common in practice than to vary continually the terms 

 employed, with a view to grammatical convenience ; nor is there any thing 

 unfair in such a practice, as long as the meaning is preserved unaltered ; 

 e. g., * murder should be punished with death ; this man is a murderer, 



client all that his client might honestly do for himself. Is not the word in italics frequently 

 omitted ? Might any man honestly try to do for himself all that counsel frequently try to do 

 for him ? We are often reminded of the two men who stole the leg of mutton ; one could 

 swear he had not got it, the other that he had not taken it. The counsel is doing his duty 

 by his client, the client has left the matter to his counsel. Between the unexecuted inten- 

 tion of the client, and the unintended execution of the counsel, there may be a wrong done, 

 and, if we are to believe the usual maxims, no wrong-doer." 



The same writer justly remarks (p. 251) that there is a converse fallacy, a dicto simpliciter 

 ad dictum secundum quid, called by the scholastic logicians yhZ/acta accidentis; and another 

 which may be called a dicto secundum quid ad dictum secundum alterum quid (p. 265). For 

 apt instances of both, I must refer the reader to Mr. De Morgan's able chapter on Fallacies. 



