8 WHAT IS SCIENCE? 



between what are now regarded as different kinds of 

 knowledge. Our ancestors would have strenuously 

 denied that a great mathematician could be ignorant of 

 philosophy or a great philosopher ignorant of science. 

 One of the widest differences between modern and 

 ancient thought is the recognition that there are inde- 

 pendent systems of thought and independent bodies of 

 knowledge, and that errors in one branch are not 

 necessarily accompanied by errors in another. 



SCIENCE AND OTHER STUDIES 



Of course the branches into which pure learning has 

 separated have been changed greatly since, and in virtue 

 of, their separation. None has been more affected in 

 this manner than science ; the great development of 

 science of the last century is intimately connected with 

 its divorce from philosophy. And the changes are 

 so great that it is perhaps hardly right to regard the 

 science of to-day as the same thing as the science which 

 was not distinguished from other studies in Greek and 

 mediaeval thought. Nevertheless this discussion has not 

 been irrelevant ; for it reminds us that science, like all 

 other attempts to satisfy the curiosity of man, has its 

 ultimate roots in the simplest and most instinctive 

 speculations. It shows us also that, however distinct 

 from all other kinds of pure learning the science of to-day 

 may appear, the exact line of division and the exact 

 criterion are likely to be difficult to lay down ; a dis- 

 tinction that was overlooked for 2,000 years is not likely 

 to be discoverable by a casual inspection. Again it 

 suggests that, since the separation of science has taken 

 place in times so recent, one way to discover the dis- 

 tinction may be to inquire into its history of the word. 



This history is quite simple. When it was recognized 

 that the studies which now form part of science required 



