4 THE LESSON OF EVOLUTION 



Evidently this scientific process is a very laborious 

 one, but it is to be more trusted than speculation. 

 For we can never be certain that any single proposi- 

 tion is quite true, or that it contains the whole truth ; 

 and, as it is impossible to allow for modifying circum- 

 stances, reasoning alone may lead us far astray ; while, 

 with the scientific method attention is directed to 

 errors of observation, which can be corrected ; and 

 new facts are constantly confronting us which tend 

 to prove, or to disprove, or to modify our theories. 

 These theories, in time, get established as what we 

 call " laws of nature " ; that is, accurate records of 

 observed cause and effect ; and they thus form a touch- 

 stone of exact knowledge, by which the speculative 

 philosophies must be tried. 



No doubt these two processes of observation and 

 speculation went on in a desultory, impulsive manner 

 for several thousands of years, during which man not 

 only learnt a great deal about the material world, but 

 was led to spec'ulate about the immaterial, or spiritual 

 world, which he believed to encompass him on all 

 sides. We can never know with certainty how the 

 conception of an invisible, spiritual world arose in the 

 human mind ; but we know, as a matter of fact, that 

 it did do so at an early stage of the human intellect. 



Judging from the beliefs now held by the lowest 

 races of mankind, it seems probable that when man 

 first began, in an incoherent manner, to speculate on 

 himself and his surroundings, the remarkable facts 

 connected with sleep and dreams made him conclude 

 that his intelligence was due to an unsubstantial body, 

 or spirit, living inside him, which could leave him, 

 travel about, and return. Dreaming of dead friends 



