14 MODES OF RESEARCH IN GENETICS 



defensible position and has been so universally 

 adopted as to have become almost a common- 

 place of scientific thought. 1 It, however, has 

 nothing to do with the value or meaning of de- 

 scription as a method of research. 



To return to the discussion of the biometric 

 method in genetics, the second point to be made 

 concerns the reasoning involved in the use of the 

 correlation method in the study of hereditary 

 resemblances. It has repeatedly been the boast 

 of the biometric writers on this subject that their 

 results were absolutely free from any biological 

 theories. To this some of the more wicked critics 

 have retorted that their results were also quite 

 free from any biological significance. Such a 

 criticism is not true, but it has in it an element of 

 verity. The reason why it has I pointed out some 

 years ago in another place, 2 but for the sake of 

 the argument it may be sketched here. The 

 essential point is the difficulty of interpreting any 

 correlation coefficient in the terms of the causes 

 which led to its existence. Baldly stated the 

 argument of the current biometric method of 

 studying heredity is this : Since by the method of 

 correlation the degree of resemblance between 



1 One should note that the completely restrictive element of this 

 view is by no means universally accepted. Cf. Royce's Introduction 

 to Enriques' "Problems of Science," Open Court Pub. Co., 1914. 



2 Cf. infra, chap. II. "Biometric Ideas and Methods in Biology," 

 pp. 42-72. 



