HEREDITY 



argument will give a better orientation for the remarks 

 on the applicability of genetic philosophy to sociology, to 

 which the concluding pages of the chapter are devoted. 



The convictions of the radical behaviorists are wholly 

 emotional in character. For some unknown reason, they 

 wish to believe in the innate intellectual parity of all 

 members of the human race. Their minds are firmly condi- 

 tioned in this respect, to use one of their own terms; hence, 

 a knowledge of the genetic facts, if one grants such enlight- 

 enment, has little influence. Their sole argument, stripped 

 of all verbiage, is an example of a paradox in logic that 

 would have given William de Morgan great pleasure. They 

 grant that the human race exhibits heritable differences in 

 all sorts of external features, and in various parts of the 

 skeletal, muscular, circulatory, digestive, and secretory 

 systems. They admit that the central nervous system is the 

 physical basis of mental capacity and that heritable defects 

 in it may cause feeble-mindedness. And despite these admis- 

 sions, they stolidly maintain that the normal central nerv- 

 ous system does not vary. At least their arguments are all 

 reducible to this simple and obvious fallacy. 



The least illogical attempt to justify the position of the 

 absolute environmentalist is the comment that since the tre- 

 mendous range in intellectual attainments shown by 

 different individuals is not paralleled by detectable physical 

 variations, the environment must have more to do with 

 mental than with physical development. But this argument 

 also is fallacious. One may also say that training brings 

 out innate differences in mentality and thus offers a method 

 of detecting the physical differences. 



It is regrettable that so many social workers, physicians, 

 and psychologists should tend to minimize the role which 

 heredity plays in human affairs merely because they jump 

 to the erroneous conclusion that if this role is trivial, their 

 own vocations are of more importance. On the contrary, 



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