CHAPTER XIV. 



FALLACIES, 



1. IN works on Logic a chapter is generally devoted 

 to the discussion of Fallacies, that is, to the description 

 and classification of the different ways in which the rules 

 of Logic may be transgressed. The analogy of Probability 

 to Logic is sufficiently close to make it advisable to adopt 

 the same plan here. In describing his own opinions an 

 author is, of course, perpetually obliged to describe and 

 criticise those of others which he considers erroneous. But 

 some of the most widely spread errors find no supporters 

 worth mentioning, and exist only in vague popular misap 

 prehension. It will be found the best arrangement, there 

 fore, at the risk of occasional repetition, to collect a few of 

 the errors that occur most frequently, and as far as possible 

 to trace them to their sources; but it will hardly be worth 

 the trouble to attempt any regular system of arrangement 

 and classification. We shall mainly confine ourselves, in 

 accordance with the special province of this work, to problems 

 which involve questions of logical interest, or to those 

 which refer to the application of Probability to moral and 

 social science. We shall avoid the discussion of isolated 

 problems in games of chance and skill except when some 

 error of principle seems to be involved in them. 



