PREFACE 



THIS volume is based on notes begun during a 

 trip to Egypt in 1906, when it occurred to me that 

 a discussion of certain human problems from the 

 biological standpoint might prove helpful to my 

 children. It had long seemed to me that the serious 

 student of biological processes might in time reach 

 views respecting the mystery of life, which should 

 throw some light on the attitude of people toward 

 nature and especially toward other human beings. 

 Having reached a time of life when I began to feel 

 confidence that the laws of biology might often prove 

 reliable guides to the understanding of puzzling 

 situations in life, I experienced a desire to state my 

 views to my children in a manner more definite than 

 is possible in conversation. I am now led to publish 

 my interpretation of biological laws in their bearing 

 on human life in the hope that they may prove of 

 some service to persons who have faith that an under- 

 standing of such laws is frequently a help to more 

 intelligent and humane conduct. 



I know there are still many cultivated persons 

 who are unfriendly or actively hostile to a rational- 

 istic standpoint in relation to ethical questions. 

 They believe that religious teachings are the best 



vii 



