CLASStflCATlOX OP FALLACIES. 453 



from them what they will not support, our conclusion may be cito- 

 noous. But a case, j^orhaps c,\c.ii more iroquent, is that in which 

 the error arises from not conceivinjr our pri'misses with due clearness, 

 that is, (as shown in the preceding book,*) witli due fixity : forminfr 

 one conception of our evidence whon we collect or receive it, ami 

 another wlien we make use of it ; or unadvisedly and in general un- 

 consciously substituting,, as we proceed, difltjrent premisses in the 

 })lace of Uiose with which we set out, or a different conclusion for that 

 which we undertook to prove. This gives existence to a class of fal- 

 lacies which may be justly termed Fallacies of Confusion ; compre- 

 hending, among others, all those which have their source in language; 

 whether arising frohi £he vagueness or ambiguity of oui* terras, or from 

 casual associations with them. 



When the -fallacy is not one of Confusion, that is, when the propo- 

 sition believed, and the evidence on which it is believed, are steadily 

 apprehended and unambiguously expressed, there remain to be made 

 two cross divisions, giving rise to four classes. The Apparent Evidence 

 may be either particular facts, or foregone generalizations ; that is, 

 the process may simulate either simple Induction, 6t Deduction : and 

 again, the evidence, whether consisting of facts or general propositions, 

 may be false in itself, or, being true, may fail to beai* out the conclu- 

 sion attempted to be founded upon it. This gives us, first. Fallacies 

 of Induction and' Fallacies of Deduction, and thou a subdivision of 

 each of these, according as the supposed evidence is false, or true but 

 inconclusive. 



Fallacies of Induction, where the facts upon which the induction 

 proceeds are erroneous, may be termed Fallacies of Observation. The 

 tenn is not strictly accurate, or rather, not accurately coextensive with 

 the class of fallacies which I propose to designate by it. Induction is 

 not always grounded upon facts immediately observed, but sometimes 

 upon facts inferred : and when these last are erroneous, the error is not, 

 in the literal sense of the term, an instance of bad observation, but of 

 bad inference. It will be convenient, however, to make only one class 

 of all the inductions of which the error lies in not sufliciently ascer- 

 taiiung tlie facts on which the theory is grounded ; whether the cause 

 of failure be raal-observation, or simple non-observation, and whether 

 the mal-obsen'ation be direct, or by means of intermediate marks 

 which do not prove what they are suj)posed to prove. And in the 

 absence of any comprehensive term to denote the asceitainment, by 

 whatever means, of the facts on which an induction is grounded, 1 will 

 venture to retain for this class of fallacies, under the explanation already 

 given, the title, Fallacies of Observation. 



The other class of inductive fallacii^s, in which the facts are correct, 

 but the conclusion not wan-anted by them, are properly denominated 

 Fallacies of Generalization : and these, again, fall into various subor- 

 dinate classes, or natural groups, some of which will be enumerated 

 in their pro{)cr place. 



When we now turn to Fallacies of Deduction, namely, those modes 

 of incorrect argumentation in wliicli the jiremisses, or some of them, are 

 general j)ropositions, and the argument a ratiocination ; we may of 

 coUree subdivide these also into two species, similar lo the twopreced- 



• Supra, p. 300. 



