THE SCIENCE OF HAPPINESS 



meet, and who therefore count as four persons in reckon- 

 ing the child's inherited possibilities. 



The offspring of cousins may therefore be theo- 

 retically expected to have (i) less than the average 

 diversity of tendencies, and (2) an abnormal instability 

 of tendencies, due to the accentuation of certain groups. 

 And here practical observation fully sustains theory. 

 It is by the application of these principles that all the 

 specialized races of domestic animals have been so 

 rapidly developed. 



This, then, I say, is the only answer which heredity 

 alone can give as to why individuals vary in their tend- 

 encies and qualities. The answer does not seem suffi- 

 cient, for to be tangible it is evident that the unions must 

 be in close consanguinity, and it is well known that 

 such unions are everywhere exceptional. Even bar- 

 barians go to outside families, and even to outside tribes 

 for wives. But aside from this objection the argument 

 contains a fallacy in that an element not accounted for 

 by heredity alone has been introduced unwittingly. 

 And in some respects the interpolation is of more 

 importance than the original document. 



Let us look more critically. We have just assumed 

 that every individual inherits all the tendencies of all 

 his ancestors. If, then, all the tendencies of the race 

 were represented in that remote common ancestry to 

 which we are referring, and all these tendencies again 

 were epitomized in each and every descendant, it is not 

 apparent why it should make much difference whether 

 a being has six great-grandparents or eight, since the 



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