HISTORY OF SCIENCE 



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textbooks — are indispensable. Without them science could hardly 

 be transmitted from one generation of students to the next, but it 

 must be understood that they are always provisional and pre- 

 carious. They must be periodically revised. Now, how would that 

 be possible if the history of science did not show us our way 

 through all the unutilized experience of the past? History is, so 

 to say, the guide, the catalogue without which new syntheses and 

 selections made from fresh points of view would hardly be pos- 

 sible. All the vicissitudes and recantations of science prove con- 

 clusively that no man can ever flatter himself that he has definitely 

 and completely exhausted a scientific fact or theory. No particle 

 of human experience, however small, can be entirely neglected. 

 To assert this is to assert, at the same time, the necessity of his- 

 torical research. 



Moreover, among scientific works there are some, the genesis 

 of which cannot be explained in the ordinary analytical way. 

 They introduce abrupt discontinuities into the evolution of 

 science, because they so far anticipate their own time. These 

 works of genius are never entirely explored, and the interest they 

 offer is never entirely exhausted. It is perhaps because it is almost 

 inexhaustible, that true genius is so mysterious. Sometimes cen- 

 turies pass before the doctrines of a man of genius are appraised 

 at their true value. A great deal of benefit is still to be reaped from 

 reading in the works of Aristotle, Diophantus, Huygens or New- 

 ton. They are full of hidden treasures. It is a gross mistake to think 

 that there is nothing more in such works than the facts and ideas 

 which are positively formulated; if that were true, of course, it 

 would be useless to refer to them: the enunciation of these facts 

 and ideas would suffice. But that is not true, and I cannot but ad- 

 vise those who have any doubt about it, to try. They will find 

 that nothing excites the mind more than this return to the sources. 

 Here, also, it is the historian's business to point out to the scien- 

 tist the very sources where he will most likely invigorate his mind 

 and start a fresh impulse. 



I wish now to give a few examples to illustrate the preceding 



