vii.] INDUCTION. 149 



soon surpass our powers of memory, and serve but to 

 confuse. Hence Perfect Induction, even as a process of 

 abbreviation, is absolutely essential to any high degree of 

 mental achievement. 



Transition from Perfect to Imperfect Induction. 



It is a question of profound difficulty on what grounds 

 we are warranted in inferring the future from, the present, 

 or the nature of undiscovered objects from those which we 

 have examined with our senses. We pass from Perfect to 

 Imperfect Induction when once we allow our conclusion to 

 apply, at all events apparently, beyond the data on which 

 it was founded. In making such a step we seem to gain a 

 net addition to our knowledge ; for we learn the nature of 

 what was unknown. We reap where we have never sown. 

 We appear to possess the divine power of creating know- 

 ledge, and reaching with our mental arms far beyond the 

 sphere of our own observation. I shall have, indeed, to 

 point out certain methods of reasoning in which we do 

 pass altogether beyond the sphere of the senses, and 

 acquire accurate knowledge which observation could 

 never have given ; but it is not imperfect induction that 

 accomplishes such a task. Of imperfect induction itself, 

 I venture to assert that it never makes any real addition 

 to our knowledge, in the meaning of the expression some- 

 times accepted. As in other cases of inference, it merely 

 unfolds the information contained in past observations ; 

 it merely renders explicit what was implicit in previous 

 experience. It transmutes, but certainly does not create 

 knowledge. 



There is no fact which I shall more constantly keep 

 before the reader's mind in the following pages than that 

 the results of imperfect induction, however well authen- 

 ticated and verified, are never more than probable. Wo 

 never can be sure that the future will be as the present. 

 We hang ever upon the will of the Creator: and it is 

 only so far as He has created two things alike, or maintains 

 the framework of the world unchanged from moment to 

 moment, that our most careful inferences can be fulfilled. 

 All predictions, all inferences which reach beyond their 

 data, are purely hypothetical, and proceed on the assump- 



