454 



FALLACIES. 



ino-, namely, those which proceed on false premisses, and those of 

 ■which the premisses, though true, do not support the conclusion. But 

 of these species, the first must necessarily fall within some one of the 

 heads already enumerated. For the error must be either in those 

 premisses which are general propositions, or in those which assert 

 individual facts. In the former case it is an Inductive Fallacy, of one 

 or the other class ; in the latter it is a Fallacy of Observation : unless, 

 in either case, the erroneous premiss has been assumed on simple 

 inspection, in which case the fallacy is a priori. Or, finally, the prem- 

 isses, of whichever kind they are, may never have been conceived in 

 so distinct a manner as to produce any clear consciousness by what 

 means they were aiTived at ; as in the case of what is called reasoning 

 in a circle : and then the fallacy is of Confusion. 



There remains, therefore, as the only class of fallacies having prop- 

 erly their seat in deduction, those m which the premisses of the ratio- 

 cination do not bear out its conclusion ; the various cases, in short, 

 of vicious argumentation, provided against by the rules of the syllogism. 

 We shall call these. Fallacies of Ratiocination. 



We have thus five distinguishable classes of fallacy, which may be 

 expressed in the following synoptic table : — 

 ■ of Simple Inspection 



Fallacies i 



'from evidence 

 distinctly con- 

 ceived 



from evidence 

 indistinctly 

 conceived 



Inductive 

 Fallacies 



Deductive i 

 Fallacies 



1. Fallacies a priori. 



2. Fallacies of Observation. 



Fallacies of Generalization. 



4. Fallacies of Ratiocination. 



5. Fallacies of Confusion. 



§ 3. We must not, however, expect to find that men's actual errors 

 always, or even commonly, fall so unmistakably under some one of 

 these classes, as to be incapable of being referred to any other. Erro- 

 neous arguments do not admit of such a sharply cut division as valid 

 arguments do. An argument fully stated, with all its steps distinctly 

 set out, in language not susceptible of misunderstanding, must, if it be 

 erroneous, be so in some one, and one only, of these five modes; or 

 indeed of the first four, since the fifth, on such a supposition, would 

 vanish. But it is not in the nature of bad reasoning to express itself 

 thus unambiguously. When a sophist, whefher he is imposing upon 

 himself or attempting to impose upon others, can be constrained to 

 throw his sophistry into so distinct a form, it needs, in a large propor- 

 tion of cases, no further exposure. 



In all arguments, everywhere but in the schools, some of the links 

 are suppressed ; a fortiori when the arguer either intends to deceive, 

 or is a lame and inexpert thinker, little accustomed to bring his rea- 

 soning processes to any test : and it is in those steps of the reasoning 

 which are made in this tacit and half-conscious, or even wholly uncon- 

 scious manner, that the error oftenest lurks. In order to detect the 

 fallacy, the proposition thus silently assumed must be supplied ; but the 

 reasoner, most likely, has never really asked himself what he wa.« as- 

 suming : his confuter, if unable to extort it from him by the Socratic 

 mode of interrogation, must himself judge what the suppressed ])jemiss 

 ought to be in order to support the conclusion. And hence, in the 

 words of Archbishop Whately, " it must be often a matter of doubt, or 



