70 Life and Matter [chap. iv. 



knowledge of what one does not know just as 

 important as knowing what one does know .... 

 " The development of exact natural knowledge 

 in all its vast range, from physics to history and 

 criticism, is the consequence of the working out, 

 in this province, of the resolution to c take nothing 

 for truth without clear knowledge that it is such ' ; 

 to consider all beliefs open to criticism ; to 

 regard the value of authority as neither greater 

 nor less, than as much as it can prove itself to 

 be worth. The modern spirit is not the spirit 

 1 which always denies/ delighting only in destruc- 

 tion ; still less is it that which builds castles in 

 the air rather than not construct ; it is that spirit 

 which works and will work 'without haste and 

 without rest,' gathering harvest after harvest of 

 truth into its barns, and devouring error with 

 unquenchable fire" (p. viii.). 



The harvesting of truth is a safe enough 

 enterprise, but the devouring of error is a 

 more dangerous pastime, since flames are 

 liable to spread beyond our control ; and 

 though, in a world overgrown with weeds 

 and refuse, the cleansing influence of fire is 

 a necessity, it would be cruel to apply the 

 same agency again at a later stage, when a 

 fresh young crop is springing up in the 

 cleared ground. 



