CLASSIFICATION OF FALLACIES. 517 



foundation of our inference ; and yet, because the premises ai*e false, or 

 because we have inferred from them what they will not support, our con- 

 clusion may be erroneous. But a case, perhaps even more frequent, is that 

 in which the error arises from not conceiving our premises with due clear- 

 ness, that is (as shown in the preceding Book*), with due fixity: form- 

 ing one conception of our evidence when we collect or receive it, and an- 

 other when we make use of it ; or unadvisedly, and in general unconscious- 

 ly, substituting, as we proceed, different premises in the place of those 

 with which we set out, or a different conclusion for that which we under- 

 took to prove. This gives existence to a class of fallacies which may be 

 justly termed (in a phrase borrowed from Bentham) Fallacies of Confu- 

 sion ; comprehending, among others, all those which have their source in 

 language, whether arising from the vagueness or ambiguity of our terms, 

 or from casual associations with them. 



When the fallacy is not one of Confusion, that is, when the proposition 

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

 and unambiguously exjjressed, there remain to be made two cross divisions. 

 The Apparent Evidence may be either particular facts, or foregone general- 

 izations ; that is, the process may simulate either simple Induction or De- 

 duction ; and again, the evidence, whether consisting of supposed facts or 

 of general propositions, may be false in itself, or, being true, may fail to 

 bear out the conclusion attempted to be founded on it. This gives us first. 

 Fallacies of Induction and Fallacies of Deduction, and then a subdivision 

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

 conclusive. 



Fallacies of Induction, where the facts on which the induction proceeds 

 are erroneous, may be termed Fallacies of Observation. The term is not 

 strictly accurate, or, rather, not accurately co-extensive with the class of fal- 

 lacies which I propose to designate by it. Induction is not always ground- 

 ed on facts immediately observed, but sometimes on facts inferred ; and 

 when these last are erroneous, the error may not be, in the literal sense of 

 the term, an instance of bad observation, but of bad inference. It will bo 

 convenient, however, to make only one class of all the inductions of which 

 the error lies in not sufficiently ascertaining the facts on which the theory 

 is grounded ; whether the cause of failure be malobservation, or simple non- 

 observation, and whether the malobservation be direct, or by means of in- 

 tei'mediate marks which do not prove what they are supposed to prove. 

 And in the absence of any comprehensive term to denote the ascertainment, 

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

 /enture to retain for this class of fallacies, under the explanation now given, 

 he title of Fallacies of Observation. 



The other class of inductive fallacies, in which the facts are correct, but 

 he conclusion not warranted by them, are properly denominated Fallacies 

 )f Generalization ; and these, again, fall into various subordinate classes or 

 latural gi'oups, sqme of which will be enumerated in their proper place. 



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

 orrect argumentation in which the premises, or some of them, are general 

 »ropositions, and the argument a ratiocination ; we may of course subdi- 

 ide these also into two species similar to the two preceding, namely, those 

 /hich proceed on false premises, and those of which the premises, though 

 ' rue, do not support the conclusion. But of these species, the first must 



* Supra, p. 137. 



