i897. THE GENEALOGY OF THE SCIENCES. 397 



investigator, demands an acquaintance with the most modern 

 tendencies of oceanography ; and this can only be expected of an 

 oceanographer. What is true of oceanography is equally true of 

 other sciences. All scientific men recognise this, and this is why the 

 Royal Society Committee preferred to wait and reflect, before setting 

 to work. The London Congress did well in refusing to adopt any 

 system. 



The decimal notation then does not solve the question. Even 

 if one admits this notation for the classification of scientific papers, 

 a base of operations is necessary, i.e. a classification of the sciences. 

 And one cannot take any classification ; a purely conventional one 

 will not suffice, it must be a natural one, i.e. simple and corresponding 

 to reality : a philosophical classification. 



It is not possible to trace in a few words the history of the classi- 

 fication of the sciences. I will not even describe the classifications 

 of Ampere, A. Comte, Herbert Spencer, Raoul de la Grasserie, and 

 many others, — because that would have nothing in common with the 

 end in view. On the other hand I have no intention of formulating a 

 new classification in all its details. I desire simply to explain the 

 principles of a classification based on the history of the natural 

 development of science, a classification which must be drawn up by 

 competent specialists, and which would supply, without doubt, the 

 needs not only of a bibliography of science, but many other needs as 

 well. The subject is too vast and dilhcult for me to discuss 

 adequately; I content myself with setting forth various considerations 

 merely to fix our ideas. 



The universal division of science is into pure and applied ; then, 

 setting aside applied sciences, we are wont to divide the pure sciences 

 into abstract and concrete. For the rest, classifiers merely 

 enumerate the chief " abstract " sciences without defining them. 

 Thus it is left to each of us, with his own peculiar prejudices, to 

 decide what is meant by mathematics, astronomy, physics, and so 

 forth. Helmholtz, in dividing science into " Naturwissenschaften " 

 and " Geisterwissenschaften," was equally conventional. Equally 

 with those who speak of concrete and abstract sciences, he regarded 

 sciences as definite and stable units, believing it potssible to define a 

 science. But what do we understand by the Natural Sciences ? For 

 Delboeuf, Geometry is a natural science. And I, who had the good 

 fortune to follow his lectures on the philosophy of the sciences, was 

 convinced by his arguments, and so am perfectly prepared to admit 

 that geometry comes within the realm of Natural Science. Never- 

 theless only few naturalists, I think, will accept such a heresy. We 

 should, then, have to discuss what was meant by natural sciences, — 

 and it would be just the same with any conventional term. 



To take an example. Since sciences are divided into concrete 

 and abstract, let us ask if any science, say chemistry, is an abstract 

 science ? If yes — what do we understand by chemistry ? All the 



