vi SCIENCE AND THE HUMAN MIND 



its own kingdom, has had on sociology, on philosophy 

 and on religion. 



Perhaps a word of personal explanation may be 

 forgiven. For the past ten years we have been 

 collecting material for the subjects of the present 

 volume. Science, like life, to be seen singly must be 

 seen whole. To estimate the value of any piece of 

 work, it must be fitted into the larger scheme of our 

 knowledge of nature, and that again must find its 

 proper place in the general record of human activity. 

 Therefore, merely as an apologia pro vita nostra, it 

 seemed inevitable, sooner or later, to write this book. 



In the course of the work it has been necessary to 

 gain a knowledge of branches of science and depart- 

 ments of thought beyond the confines of the some- 

 what restricted region of physics in which our own 

 previous researches were carried on. At various 

 stages, problems appeared where personal experience 

 seemed essential. Hence, for instance, we have found 

 ourselves at one time carrying out unsuccessful 

 investigations on radio-activity, and, at another, 

 putting together pedigrees showing the descent of 

 mental or physical qualities, or breeding Mendelian 

 hens wherewith to supply the needs of our breakfast 

 table. 



Among our former works, The Recent Development 

 of Physical Science (1904), The Family and the Nation 

 (1909), and Heredity and Society (1912) are milestones 

 along the road of preparation ; while the Life of 



