Other Applications 333 



These illustrations, drawn from biology, may serve the 

 purpose of showing the sort of application the axioms 

 stated above may have. They might be illustrated with 

 great force by questions which involve the relation of 

 biology to psychology, of psychology to ethics, etc. But 

 these topics are too far remote from the main discussions 

 of this work. It may be allowable, however, to point out 

 that the principles stated above as third and fourth are 

 especially apropos of certain recent topics of much dis- 

 cussion. 



The fourth axiom lays stress upon the actual tracing 

 of each genetic series as it occurs, for itself ; but it recog- 

 nizes the possible sameness of mode in different series 

 which are parallel or, in the sense of an earlier definition, 



* concurrent.' The case in biology and also in psychology 

 in which this possibility is realized is that of psychophysi- 

 cal parallelism as worked out and defended in our earlier 



E. Warren (on ' Variation in the Parthenogenic Generations of Aphis ' ) in 

 Vol. I., Part 2, of Biometrica (the journal recently established for the publica- 

 tion of biological measurements), in which he recognizes the requirement, here 

 laid down, that the same conditions of environment should hold for all the 

 cases treated (see especially p. 146 of his article ; see also Weldon's criticism 

 of the 'Mutation theory' in the same journal, I., 3, p. 367). Possibly the 

 other point — that requiring the same stage of development — is also recog- 

 nized. It would still seem, however, to be almost impossible to fulfil these 

 requirements. At any rate, although we recognize fully the value of the 

 quantitative studies of the new science of * Biometrics,' and concede that in 

 problems for which the statistical data are adequate it introduces a new era into 

 biology; yet we hold that it illustrates just the point made here — that quantita- 

 tive science deals with cross-sections, with accomplished organizations, not with 

 transitions and growths as such. The business of the old-school naturalist, 

 who has not the training to do work in * Biometrics,' is not entirely ruined. 

 And we may express the hope that among the brilliant formulations of ' bio- 

 metricians ' we may not find too many that may be termed bio-meretricious ! 

 Some such have been produced in fact in the attempt to construct a 



* Psychometrics.' 



