HISTORY OF SCIENCE 47 



chemist and the engineer have a vital interest in knowing the 

 processes that have fallen into disuse, but to which the very 

 progress of science may give from one day to the next a new 

 career. The history of science is to them, so to say, what aban- 

 doned mines are to the prospector. 



But in my opinion, however important its heuristic value may 

 be, there are still deeper reasons why the scientist should give 

 his attention to the history of science. I am thinking of those 

 which have been so splendidly illustrated by Ernst Mach in his 

 "Mechanics. For one thing, it is obvious that "they that know the 

 entire course of the development of science will, as a matter of 

 course, judge more freely and more correctly of the significance of 

 any present scientific movement than they who, limited in their 

 views to the age in which their own lives have been spent, con- 

 template merely the momentary trend that the course of intellec- 

 tual events takes at the present moment." In other words, in order 

 to understand and appraise at its just value what one possesses, it 

 is well to know what the people possessed who came before us; 

 this is as true in the domain of science as it is in daily life. It is 

 historical knowledge that discloses to the scientist his precise at- 

 titude toward the problems with which he has to grapple, and that 

 enables him to dominate them. 



Moreover, while research workers exert themselves to extend 

 the boundaries of science, other scientists are more anxious to 

 ascertain whether the scaffolding is really solid, and whether their 

 more and more daring and complex edifices do not risk giving 

 way. Now the task of the latter, which is neither less important 

 nor less lofty than that of discovery, necessarily implies a return 

 to the past. This critical work is essentially of an historical nature. 

 While it helps to make the whole fabric of science more coherent 

 and more rigorous, at the same time it brings to light all the acci- 

 dental and conventional parts of it, and so it opens new horizons 

 to the discoverer's mind. If that work were not done, science 

 would soon degenerate into a system of prejudices; its principles 



