FALLACIES OF CONFUSION. 



537 



premise to be true, the middle term 

 must be understood to mean, ' no un- 

 common occurrence to some one pai'- 

 ticular person ; ' whereas for the 

 minor (which has been placed first) 

 to be true, you must understand it of 

 * no xmcommon occurrence to some one 

 or othei' ; ' and thus you will have the 

 Fallacy of Composition. 



" This is a Fallacy with which 

 men are extremely apt to deceive 

 themselves; 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 de- 

 cide, 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 suc- 

 cessive acts of intemperance, because 

 no one of those acts would be of itself 

 BuflBcient 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 practi- 

 cally concludes that all taken together 

 do not prove it. 



§ 2. We have now sufficiently ex- 

 emplified 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 con- 

 clusion, but not really so. In the 

 second great Fallacy of Confusion 

 they are neither verbally nor really 

 sufficient, though, from their multi- 

 plicity and confused arrangement, 

 and still oftener from defect of me- 

 mory, they are not seen to be what 

 they are. The fallacy I mean is that 

 of Petitio Principii, or begging tlie 

 question, including the more com- 

 plex and not uncommon 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 con- 

 clusion, or is actually proved from the 

 conclusion, or is such as would natur- 

 ally and properly so be proved." By 

 the last clause I presume is meant, that 

 it is not susceptible of any other proof ; 

 for otherwise there would be no fal- 

 lacy. To deduce from a proposition 

 propositions from which it would 

 itself more naturally be deduced, is 

 often an allowable deviation from the 

 usual didactic order ; or at most what, 

 by an adaptation of a phrase familiar 

 to mathematicians, may be called a 

 logical inelegance* 



The employment of a proposition to 

 prove that on which it is itself depen- 

 dent for proof, by no means implies 

 the degree of mental imbecility which 

 might at first be supposed. The diffi- 

 culty of comprehending how this fal- 

 lacy could possibly be committed dis- 

 appears when we reflect that all per- 

 sons, even the instructed, hold a great 

 number of opinions without exactly 

 recollecting how they came by them. 

 Believing that they have at some for- 

 mer time verified them by sufficient 

 evidence, but having forgotten what 

 the evidence was, they may easily be 

 betrayed into deducing from them the 

 very propositions which are alone cap- 

 able of serving as premises for their 

 establishment. "As if," says Arch- 

 bishop Whately, " one should attempt 

 to prove the being of a God from 

 the authority of Holy Writ ; " which 

 might easily happen to one with 

 whom both doctrines, as fundamental 

 tenets of his religious creed, stand on 

 the same ground of familiar and tra- 

 ditional belief. 



* In his later editions. Archbishop 

 Wliate y confines tho n;ime of Petitio 

 Privcipii "to those cjiaes in whicii one of 

 the premises either is manifestly the sai?ie 

 in siiise with the conclusion, or is actunlly 

 proved from it, or is such as the ])er8on8 

 vou are •• ddiessing are not likely to know, 

 or to admit, except a-^ an inference from 

 the conclusion: as, eg. if anyone should 

 infer ti e authenricity of a certain history 

 from its recf)rding such and such facts, the 

 reality of which rosts on th« •videuco of 

 that history." 



