314 INDUCTION. 



they arrived at their conclusions as deserving of study, inde- 

 pendently of the conclusions themselves. 



2. For the purposes of the present inquiry, Induction 

 maybe defined, the operation of discovering and proving general 

 propositions. It is true that (as already shown) the process of 

 indirectly ascertaining individual facts, is as truly inductive as 

 that by which we establish general truths. But it is not a different 

 kind of induction ; it is a form of the very same process : since, 

 on the one hand, generals are but collections of particulars, de- 

 finite in kind but indefinite in number ; and on the other hand, 

 whenever the evidence which we derive from observation of 

 known cases justifies us in drawing an inference respecting 

 even one unknown case, we should on the same evidence be 

 justified in drawing a similar inference with respect to a whole 

 class of cases. The inference either does not hold at all, or 

 it holds in all cases of a certain description ; in all cases 

 which, in certain definable respects, resemble those we have 

 observed. 



If these remarks are just ; if the principles and rules of in- 

 ference are the same whether we infer general propositions or 

 individual facts ; it follows that a complete logic of the sciences 

 would be also a complete logic of practical business and com- 

 mon life. Since there is no case of legitimate inference from 

 experience, in which the conclusion may not legitimately be a 

 general proposition; an analysis of the process by which 

 general truths are arrived at, is virtually an analysis of all in^ 

 duction whatever. Whether we are inquiring into a scientific 

 principle or into an individual fact, and whether we proceed by 

 experiment or by ratiocination, every step in the train of in- 

 ferences is essentially inductive, and the legitimacy of the in- 

 duction depends in both cases on the same conditions. 



True it is that in the case of the practical inquirer, who is 

 endeavouring to ascertain facts not for the purposes of science 

 but for those of business, such for instance as the advocate or 

 the judge, the chief difficulty is one in which the principles of 

 induction will afford him no assistance. It lies not in making 

 his inductions, but in the selection of them ; in choosing from 



