CHAPTER II. 



OF INDUCTIONS IMPROPERLY SO CALLED. 



1. INDUCTION, then, is that operation of the mind, by 

 which we infer that what we know to be true in a particular 

 case or.cases, will be true in all cases which resemble the former 

 in certain assignable respects. In other words, Induction is 

 the process by which we conclude that what is true of certain 

 individuals of a class is true of the whole class, or that what 

 is true at certain times will be true in similar circumstances at 

 all times. 



This definition excludes from the meaning of the term In- 

 duction, various logical operations, to which it is not unusual 

 to apply that name. 



Induction, as above defined, is a process of inference ; it 

 proceeds from the known to the unknown ; and any operation 

 involving no inference, any process in which what seems the 

 conclusion is no wider than the premises from which it is 

 drawn, does not fall within the meaning of the term. Yet in 

 the common books of Logic we find this laid down as the 

 most perfect, indeed the only quite perfect, form of induction. 

 In those books, every process which sets out from a less general 

 and terminates in a more general expression, which admits 

 of being stated in the form, " This and that A are B, there- 

 fore every A is B," is called an induction, whether any- 

 thing be really concluded or not: and the induction is as- 

 serted not to be perfect, unless every single individual of 

 the class A is included in the antecedent, or premise : that is, 

 unless what we affirm of the class has already been ascer- 

 tained to be true of every individual in it, so that the 

 nominal conclusion is not really a conclusion, but a mere 

 reassertion of the premises. If we were to say, All the 

 planets shine by the sun's light, from observation of each 



