168 THE PRINCIPLES OF SCIENCE. 



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 

 pass, at all events apparently, beyond the clata on which it 

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

 nett 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 

 knowledge, and reaching with our mental arms far beyond 

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

 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 ac- 

 complishes 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 sometimes 

 accepted. As in other cases of inference it merely unfolds 

 the information contained in past observations or events ; 

 it merely renders explicit what was implicit in previous 

 experience. It transmutes knowledge, 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 authenti- 

 cated and verified, are never more than probable. We 

 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 



