PREFACE 7 



from the established facts and principles of science, 

 as premises, the conclusions and deductions have 

 been drawn by rational, coherent processes of 

 reasoning. They explain phenomena otherwise not 

 rationally explicable. The demonstrations conform 

 throughout to the rule of parsimony. 



The argument is coherent from first to last. Each 

 chapter is devoted to a co-ordinate part of it. 

 Twenty-two foot-notes are scattered through the 

 book. They contain matters supplementary to the 

 argument, which do not strictly form parts of it. 

 Considerations of relevancy, reliability, and the fit- 

 ting of expression to thought have not been so 

 strictly adhered to in these as in the main text. 



In Chapters I to and including VIII, discussion 

 is limited to conditions existing before man had 

 begun to use clubs and missiles. In Chapters IX 

 and X this limitation has been disregarded. 



On account of their remoter relations to the 

 main line of argument, certain phases of "Articu- 

 late Speech, Memory, Altruism," have been treated 

 in Appendix Notes. 



Appendix Xote IV, — A Search for the Origin of 

 Life, Sex, Species, etc., is little more than a prelim- 

 inary, crude sketch of a line of thought hereby 

 submitted for criticism and review. Besides having 

 important bearings on some of the problems pre- 

 sented in these essays, this note suggests new and 

 promising fields for original research work. 



If the opinion with reference to barrenness ex- 



