Heredity and Conduct 97 



which tends to the welfare and progress of 

 the group of which we are members, and by 

 immoral conduct the reverse. The gratifi- 

 cation of instinct, in this case the instinct to 

 ' social ' conduct, is the * reason ' for social 

 conduct. There is a correlation between 

 happiness and the fulfilment of instinct, and 

 the source of the instinct is the continual 

 selection for survival of those groups with 

 more social instinct in the struggle of group 

 against group. 



Now if we admit this view, two divisions 

 of our topic for to-day at once confront us : 



1. What is our present knowledge with 

 regard to heredity in man ? 



2. How does this bear upon conduct on 

 the action of individuals in relation to the 

 welfare of society as a whole ? 



With regard to the first division, we find 

 from observation a perfectly definite inheri- 

 tance of physical characters. 



[The lecturer here illustrated by tables and diagrams 

 the inheritance of characters from father to son ; the 

 average son inherits '4 to '5 of the deviation from 

 mediocrity of the father.] 



The same inheritance can be traced in all 

 human characters upon which investigations 

 have hitherto been made. So universal, 

 indeed, is this principle of inheritance, that 

 if the main characteristics of a number of 

 parents are given we can safely predict the 



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