306 FALLACIES. 



under some one of these classes, as to be incapable of being 

 referred to any other. Erroneous arguments do not admit of 

 such a sharply cut division as valid arguments do. An argu- 

 ment 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 of these five modes unequivocally : 

 or indeed of the first four, since the fifth, on such a supposi- 

 tion, would vanish. But it is not in the nature of bad reason- 

 ing to express itself thus unambiguously. When a sophist, 

 whether he is imposing on himself .or attempting to impose 

 on others, can be constrained to throw his sophistry into so 

 distinct a form, it needs, in a large proportion 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 reasoning 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 unconscious 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 was assuming : his confuter, unless permitted to extort it 

 from him by the Socratic mode of interrogation, must himself 

 judge what the suppressed premise ought to be in order to 

 support the conclusion. And hence, in the words of Arch- 

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

 rather, of arbitrary choice, not only to which genus each kind 

 of fallacy should be referred, but even to which kind to refer 

 any one individual fallacy ; for since, in any course of argu- 

 ment, one premise is usually suppressed, it frequently happens 

 in the case of a fallacy, that the hearers are left to the alterna- 

 tive of supplying either a premise which is not true, or else, one 

 which does not prove the conclusion : e. g. if a man expatiates 

 on the distress of the country, and thence argues that the 

 government is tyrannical, we must suppose him to assume 

 either that ' every distressed country is under a tyranny/ which 

 is a manifest falsehood, or merely that ' every country under a 



