21 



utility but which exists mainly on account of the static conceptions of 

 organic relations. 



The dynamic or process concept is a difficult one to attain, and to 

 apply in all cases, as any one will soon learn if he strives to do this 

 consistently ; and yet as a scientific ideal there can he no doubt that it 

 has the same superiority oyer the older static methods and point of 

 view that an explanation has over an empirical description. 



3. DYNAMIC AND GENETIC CEASSlElCATlON OE ENVIRONMENTS 



In the natural history sciences we have two main sorts of classifi- 

 cations of phenomena, those which we call "natural" and those which 

 we call "artificial." Natural classifications are those in which 

 the basal criteria are of origin, the method of processes or gen- 

 esis. A classification of lakes upon the basis of the processes ivhicJi 

 operated in their origin — crustal movements of the earth, the mean- 

 ders of streams, the work of an ice-sheet, volcanic activity, etc. — 

 would at the same time furnish an explanation of them in terms of 

 their origin. Artificial classifications are those in which the criteria 

 are arbitrarily chosen. Any character may be made the basis for an 

 artificial classification. Thus lakes may be classified upon the basis of 

 their size, depth, color of the water, distance from cities, number ot 

 boats upon them, etc., but such classification would not furnish the 

 basis for ^scientific explanation of lakes. The artificial is often useful 

 or convenient for a special purpose; the genetic is illuminating from 

 the standpoint of scientific interpretation. This method may be ap- 

 plied to any kind of environment, physical, physical and biological 

 combined, or solely biological. To the degree that the environment is 

 dominated by the physical conditions the laws of physical change and 

 physical genesis wall preponderate in the origin of such environments, 

 and corresponding relations apply to biological environment^;. 



The dependence of the genetic method upon causes and conditions 

 makes it impossible to divorce it from the local conditions. This is 

 at once the strength and weakness of this method, for it is particular, 

 and g^eneralized averages mean little because origins are different un- 

 der different conditions ; this is the key to individuality. Thus streams 

 viewed as stages in the progressive transformation of a li(|ui(l medium 

 for life, may be formed in many diverse ways, and for this reason the 

 general principles of the method of genesis may be expressed most 

 simply in an ideal case. Genetic series are unending, they extend into 

 the past and will continue in the future. The point of departure for 

 study must therefore be arbitrarily chosen, and the more nearly a nat 

 ural basis can be approximated the simpler its application becomes 



