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CHAPTER IV. 



OF TRAINS OF REASONING, AND DEDUCTIVE 

 SCIENCES. 



I. IN our analysis of the syllogism it appeared 

 that the minor premiss always affirms a resemblance 

 between a new case, and some cases previously known ; 

 while the major premiss asserts something which, 

 having been found true of those known cases, we con- 

 sider ourselves warranted in holding true of any other 

 case resembling the former in certain given parti- 

 culars. 



If all ratiocinations resembled, as to the minor 

 premiss, the examples which we exclusively employed 

 in the preceding chapter ; if the resemblance, which 

 that premiss asserts, were obvious to the senses, as 

 in the proposition " Socrates is a man," or were at 

 once ascertainable by direct observation ; there would 

 be no necessity for trains of reasoning, and Deductive 

 or Ratiocinative Sciences would not exist. Trains of 

 reasoning exist only for the sake of extending an 

 induction, founded as all inductions must be upon 

 observed cases, to other cases in which we not only 

 cannot directly observe what is to be proved, but 

 cannot directly observe even the mark which is to 

 prove it. 



2. Suppose the syllogism to be, All cows rumi- 

 nate, the animal which is before me is a cow, there- 

 fore it ruminates. The minor, if true at all, is 

 obviously so : the only premiss the establishment of 

 which requires any anterior process of inquiry, is the 



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