220 REASONING. 



reflected that this expectation could not be justifiable unless 

 from the same evidence he was warranted in concluding 

 some general proposition, as, for instance, that all Roman 

 emperors are just rulers; he would immediately have thought 

 of Nero, Domitian, and other instances, which, showing the 

 falsity of the general conclusion, and therefore the insufficiency 

 of the premises, would have warned him that those premises 

 could not prove in the instance of Commodus, what they were 

 inadequate to prove in any collection of cases in which his was 

 included. 



The advantage, in judging whether any controverted in- 

 ference is legitimate, of referring to a parallel case, is univer- 

 sally acknowledged. But by ascending to the general propo- 

 sition, we bring under our view not one parallel case only, but 

 all possible parallel cases at once ; all cases to which the same 

 set of evidentiary considerations are applicable. 



When, therefore, we argue from a number of known cases 

 to another case supposed to be analogous, it is always possible, 

 and generally advantageous, to divert our argument into the 

 circuitous channel of an induction from those known cases to 

 a general proposition, and a subsequent application of that 

 general proposition to the unknown case. This second part of 

 the operation, which, as before observed, is essentially a pro- 

 cess of interpretation, will be resolvable into a syllogism or a 

 series of syllogisms, the majors of which will be general pro- 

 positions embracing whole classes of cases ; every one of which 

 propositions must be true in all its extent, if the argument is 

 maintainable. If, therefore, any fact fairly coming within the 

 range of one of these general propositions, and consequently 

 asserted by it, is known or suspected to be other than the 

 proposition asserts it to be, this mode of stating the argument 

 causes us to know or to suspect that the original observations, 

 which are the real grounds of our conclusion, are not sufficient 

 to support it. And in proportion to the greater chance of our 

 detecting the inconclusiveness of our evidence, will be the 

 increased reliance we are entitled to place in it if no such 

 i vidence of defect shall appear. 



The value, therefore, of the syllogistic form, and of the 



