The Axioms of Genetic Science 323 



nomena to lower terms, is the genetic aspect. It is the 

 mistake of treating all phenomena by the method of ' cross- 

 sections,' without supplementing such treatment with that 

 involving the * longitudinal section.' This is one self- 

 repeating source of confusion. It fails to recognize the 

 existence of genetic modes. 



In a general and incomplete survey such as this, we 

 may put in the following form the principles which we are 

 justified in adopting, as axioms of the theory of genetic 

 modes. 



Firsty the phenomena of science at each higher level 

 show a form of synthesis which is not accounted for by 

 the formulations which are adequate for the phenomena 

 of the next lower level. By ' lower ' and * higher ' I mean 

 genetically before and after, in the essential sense already 

 explained. 



Second, the formulations of any lower science are not 

 invalidated in the next higher, even in cases in which new 

 formulations are necessary for the formal synthesis which 

 characterizes the genetic mode of the higher. 



Third, the generahzations and classifications of each 

 science, representing a particular genetic mode, are 

 peculiar to that mode and cannot be constructed in anal- 

 ogy to, or a fortiori on the basis of, the corresponding 

 generalizations or classifications of the lower mode. 



Fourth, no formula for progress from mode to mode, 

 that is, no strictly genetic formula in evolution or in devel- 

 opment, is possible except by direct observation of the 

 facts of the series which the formulation aims to cover, or 

 by the interpretation of other series which represent the 

 same or parallel modes. 



We may now take some given illustrations drawn from 



