450 FALLACIES. 



§ 3. There is another branch of what may be called the Philosophy 

 of Error, which must be mentioned here, though only to be excluded 

 from our subject. The sources of erroneous opinions are two-fold, 

 moral and intellectual. Of these, the moral do not fall within the com- 

 pass of this work. They may be classed under two general heads ; 

 Indifference to the attainment of truth, and Bias : of which last the 

 most common case is that in which we are biased by our wishes ; but 

 the liability is almost as gi'eat to the undue adoption of a conclusion 

 which is disagi-eeable to us as of one which is agreeable, if it be of a 

 nature to bring into action any of the stronger passions. Persons of 

 timid character are the more predisposed to believe any statement, the 

 more it is calculated to alarm them. Indeed, it is a psychological law, 

 deducible from the most general laws of the mental constitution ot 

 man, that any strong passion renders us credulous as to the existence 

 of objects suitable to excite it. 



But the moral causes of our opinions, though real and most powerful, 

 are but remote causes : they do not act immediately, but by means ot 

 the intellectual causes ; to which they bear the same relation that the 

 circumstances called, in the theory of medicine, predisposing causes, 

 bear to exciting causes. Indifference to tiaith cannot, in and by itself, 

 produce erroneous belief; it operates by preventing the mind fi-om 

 collecting the proper evidences, or from applying to them the test of a 

 legitimate and rigid induction ; by which omission it is exposed unpro- 

 tected to the influence of any species of apparent evidence which 

 occurs spontaneously, or which is elicited by that smaller quantity of 

 trouble which the mind may be not unwilling to take. As little is 

 Bias a direct source of wrong conclusions. We cannot believe a 

 proposition only by wishing, or only by dreading, to believe it. The 

 most violent inclination to find a set of propositions true will not enable 

 the weakest of mankind to believe them without a vestige of intel- 

 lectual grounds, without any, even apparent, evidence. It can only 

 act indirectly, by placing the intellectual grounds of belief in an in- 

 complete or distorted shape before his eyes. It makes him shrink 

 from the irksome labor of a rigorous induction, when he has a mis- 

 giving that its result may be disagi'ceable ; and in such examination as 

 he does institute, it makes him exert that which is in a certain measure 

 voluntary, his attention, unfairly, giving a larger share of it to the 

 evidence which seems favorable to the desired conclusion, a smaller 

 to that which seems unfavorable. And the lilve when the bias arises 

 not from desire but fear. Although a person afraid of ghosts believes 

 that he has seen one on evidence wonderfully inadequate, he does not 

 believe it altogether without evidence ; he has perceived some unusual 

 appearance, while passing through a chiirch-yard : he saw something 

 start up near a gi-ave, which looked white in the moonshine. Thus 

 eveiy erroneous inference, though originating in moral causes, involves 

 the intellectual operation of admitting insufficient evidence as sufficient; 

 and whoever was on his guard against all kinds of inconclusive evidence 

 which can be mistaken for.- conclusive, would be in no danger of being 

 led into eiTor even by the strongest bias. There have been minds so 

 strongly fortified on the intellectual side, that they could not blind 

 themselves to the light of truth, however really desirous of doing so ; 

 they could not, with all the inclination in the world, pass off" upon 

 themselves bad arguments for good ones. If the sophistry of the in- 



