52 THE LIFE OF SCIENCE 



less of a psychological nature. But the distinction holds good; a 

 discovery has not the same character, the same psychological im- 

 portance, if it is the almost automatic result of a technical improve- 

 ment, as it would have if it were the fruit of a mind's reaction. 



We propose to discover the general laws of the intellectual 

 evolution of mankind, if such laws exist. These studies might also 

 help us to better understand the intellect's mechanism. But of 

 course we have given up the extravagant idea of establishing a 

 priori the conditions of scientific development. On the contrary 

 our aim is to deduce them from a thorough analysis of all the 

 accumulated experience of the past. 



The best instrument for these studies is the comparative 

 method, and this means that we must not expect to reach a degree 

 of accuracy of which this method does not admit. But no scientific 

 work would be possible in the domain of biology and sociology if 

 we did not have the wisdom and patience to be satisfied with the 

 approximation fhat is within our reach. The comparisons may be 

 confined to the realm of science; I would call these the ' 'internal" 

 comparisons. They may also be made between the evolution of 

 scientific phenomena and that of other intellectual or economic 

 phenomena; and these I would call the " external" comparisons. 

 The greatest difficulty, of course, is to find evolutionary processes 

 that can be adequately compared and that are sufficiently inde- 

 pendent one of another. 



The application of this method has already supplied some re- 

 sults which have been very improperly called "historical laws," 

 and the exactitude of which is very variable. The following are 

 some examples which I list but shall refrain from discussing. Paul 

 Tannery has shown that the development of calculation gener- 

 ally precedes that of geometry. In their choice of decorative ele- 

 ments, primitive peoples always pass from animals to plants; they 

 never do the contrary. The hypothesis that has been expressed 

 about the course of civilization from the South and the East to the 

 North and West, is well known. Remember also the law of his- 

 torical periods proposed by Lamprecht, and especially the famous 



