570 FALLACIES. 



versa; or when the middle terra is collective in one premise, distributive 

 in the other. As if one were to say (I quote from Archbishoj) Whately), 

 "All the angles of a triangle are equal to two right angles: ABC is 



an angle of a triangle ; therefore A B C is equal to two right angles 



There is no fallacy more common, or more likely to deceive, than the one 

 now before us. The form in which it is most usually employed is to es- 

 tablish some truth, separately, concerning each single member of a certain 

 class, and thence to infer the same of the whole collectively^ As in the 

 argument one sometimes hears, to prove that the world could do without 

 great men. If Columbus (it is said) had never lived, America would still 

 have been discovered, at most only a few years later; if Newton had never 

 lived, some other person would have discovered the law of gravitation ; 

 and so forth. Most true : these things would have been done, but in all 

 probability not till some one had again been found with the qualities of 

 Columbus or Newton. Because any one great man might have had his 

 place supplied by other great men, the argument concludes that all great 

 men could have been dispensed with. The term "great men" is distribu- 

 tive in the premises and collective in the conclusion. 



" Such also is the fallacy which probably operates on most adventurers 

 in lotteries ; e. g., ' the gaining of a high prize is no uncommon occui'rence ; 

 and what is no uncommon occurrence may reasonably be expected ; there- 

 fore the gaining of a high prize may reasonably be expected ;' the conclu- 

 sion, when applied to the individual (as in practice it is), must be under- 

 stood in the sense of ' reasonably expected by a certain individual;'' there- 

 fore for the major premise to be true, the middle term must be under- 

 stood to mean, ' no uncommon occurrence to some one particidar person ;' 

 whereas for the minor (which has been placed first) to be true, you must 

 understand it of 'no uncommon occurrence to some one or other;'' and thus 

 you will have the Fallacy of Composition. 



" This is a Fallacy with which men are extremely apt to deceive them- 

 selves; for when a multitude of particulars are presented to the mind, 

 many are too weak or too indolent to take a comprehensive view of them, 

 but confine their attention to each single point, by turns ; and then decide, 

 infer, and act accordingly; e.g., the imprudent spendthrift, finding that he 

 is able to afford this, or that, or the other expense, forgets that all of them 

 together will ruin him." The debauchee destroys his health by successive 

 acts of intemperance, because no one of those acts would be of itself suffi- 

 cient to do him any serious harm. A sick person reasons with himself, 

 "one, and another, and another, of my symptoms do not prove that I have 

 a fatal disease ;" and practically concludes that all taken together do not 

 prove it. 



§ 2. We have now sufficiently exemplified one of the principal Genera 

 in this Order of Fallacies ; where, the source of error being the ambiguity 

 of terms, the premises are verbally what is required to support the conclu- 

 sion, but not really so. In the second great Fallacy of Confusion they are 

 neither verbally nor really sufficient, though, from their multiplicity and 

 confused arrangement, and still oftener from defect of memory, they are 

 not seen to be what they are. The fallacy I mean is that of Petitio Prin- 

 cipii, or begging the question ; including the more complex and not un- 

 common variety of it, which is termed Reasoning in a Circle. 



Petitio Principii, as defined by Archbishop Whately, is the fallacy " in 

 which the premise either appears manifestly to be the same as the conclu-- 



