44 THE LIFE OF SCIENCE 



dentally proves that the study of the history of science has also 

 some moral advantages. 



However, the history of superstitions and errors must not make 

 us forget that it is the history of truth — the most complete and 

 the highest truths — that interests us primarily. Besides, one may 

 aim at retracing the history of truth in its entirety, because it is 

 naturally limited; but the history of errors is infinite! Therefore 

 it is necessary to fix some artificial limits to the latter and to 

 choose judiciously between the errors and the superstitions. A 

 great simplification is obtained by classifying the errors in groups. 

 Indeed, the same mistakes and superstitions appear over and over 

 again in different shapes, and it is useful to know the various 

 types of errors in order to understand the mechanism of intellect. 



It is much to be regretted that many scientists decline to admit 

 the utility of historical research, or consider it simply as a kind 

 of pastime of small importance. They base their contempt on the 

 following argument: "All the best of ancient science has been 

 assimilated and incorporated in our own science. The rest only 

 deserves oblivion, and it is awkward to over-burden our memory 

 with it. The science that we are learning and teaching is the result 

 of a continuous selection which has eliminated all the parasitic 

 parts in order to retain only that which is of real value/' 



It is easy to see that this argument is not sound. For one thing, 

 who will guarantee that the successive selections have been well 

 made? This is so much the more a matter of doubt in that this se- 

 lective and synthetic work is generally done not by men of genius, 

 but by professors, by authors of textbooks, vulgarizers of all 

 kinds, whose judgment is not necessarily irreproachable and 

 whose intuitions are not always successful. Besides, as science is 

 constantly evolving, and as new points of view are introduced every 

 day, any idea that has been neglected may be considered later on 

 as very important and fertile. It often happens also that some 

 facts, scarcely known, all at once become very interesting, because 

 they can be inserted into a new theory that they help to illustrate. 

 Of course scientific syntheses — such as those represented by our 



