38 THE ADVANCE OF SCIENCE 



ural Philosophy in its original sense. In 

 this region, the invention of verifiable 

 hypotheses is not only permissible, but is 

 one of the conditions of progress, 

 and mu- Historically, no branch of science has 



tual as- 

 sistance followed this order of growth ; but, from 



vation, the dawn of exact knowledge to the pres- 

 ment 1 " en * ^Jt observation, experiment, and 

 and speculation have gone hand in hand ; and, 

 whenever science has halted or strayed 

 from the right path, it has been, either 

 specula- because its votaries have been content 

 with mere unverified or unverifiable spec- 

 ulation (and this is the commonest case, 

 because observation and experiment are 

 hard work, while speculation is amusing) ; 

 or it has been, because the accumulation 

 of details of observation has for a time 

 excluded speculation. 

 Recogni- The progress of physical science, since 

 these the revival of learning, is largely due to 

 recent m *he fact that men have gradually learned 

 times, fo i a y as i(j e the consideration of unverifia- 



