RATIONALISM AND SCIENCE 67 



the great need of mankind is to discern between 

 those who lead to what is good, and those who 

 seduce to what is evil. The really practical 

 questions have to do with the tests by which ideas 

 are to be tried. 



In such testing it seems to me that, ever since 

 Darwin and his school came upon the stage, the 

 appeal to fact, to experience, to results has been 

 steadily gaining in efficacy, at the expense of 

 what may be called the rationalist appeal to a 

 priori principles and beliefs. The reason is not 

 far to seek. The constantly growing restlessness 

 of mankind, the changes in our surroundings both 

 social and economic, the drain of those who lived 

 in the country towards the great cities with their 

 life of fevered activity, have made it hard for any 

 accepted principles to hold their place. The 

 tendency is to call in question all the beliefs 

 whereby in times past men have directed their 

 actions. And on the other hand, science, which 

 is of course only organized and formulated obser- 

 vation and experience, has been maturing with a 

 rapidity compared with which its previous pro- 

 gress was but slow even in the most active and 

 intellectual ages of the world's history, the ages 

 of Aristotle and of Leibnitz. Into every branch 

 of knowledge we are introducing method ; the pro- 

 gress of discovery is advancing into fields never 

 yet occupied; the test of results is the one test 

 which is always accepted. 



I am not concerned to justify this progressive 



