CHAPTER XI. 



PHILOSOPHY OF INDUCTIVE INFERENCE. 



WE have inquired into the nature of the process of 

 perfect induction, whereby we pass backwards from certain 

 observed combinations of qualities or events, to the logical 

 conditions governing such combinations. We have also 

 investigated the grounds of that theory of probability, 

 which must be our guide when we leave certainty behind 

 us, and dilute knowledge with ignorance. There is now 

 before us the difficult task of endeavouring to decide how, 

 by the aid of that theory, we can ascend from the facts to 

 the laws of nature ; and may then with more or less 

 success anticipate the future course of events. All our 

 knowledge of natural objects must be ultimately derived 

 from observation, and the difficult question arises How 

 can we ever know anything which we have not directly 

 observed through one of our senses, the apertures of the 

 mind ? The practical utility of reasoning is to assure 

 ourselves that, at a determinate, time or place, or under 

 specified conditions, a certain phenomenon may be ob- 

 served. When we can use our senses and perceive that 

 the phenomenon does occur, reasoning is superfluous. If 

 the senses cannot be used, because the event is in the 

 future, or out of reach, how can reasoning take their 

 place ? Apparently, at least, we must infer the unknown 

 from the known, and the mind must itself create an 

 addition to the sum of knowledge. But I hold that it is 

 quite impossible to make any real additions to the con- 



