PSYCHICAL EVOLUTION 14 



difficult to deal with than material phenomena, 

 and hence are always more tardily attended to in 

 the application of any theory. But taking every- 

 thing into account, including the close connection 

 between physical and psychical phenomena, it 

 may be asserted that it is not more certain that 

 the physical structure of man has been derived 

 from sub-human forms of life than it is that the 

 human mind has also been similarly derived. 



Man is the adult of long evolution. The human 

 soul has ancestors and consanguinities just as the 

 body has. It is just as reasonable to suppose 

 that the human physiology, with its definitely 

 elaborated tissues, organs, and systems, is unrelated 

 to the physiology of vertebrates in general, and 

 through vertebrate physiology to the physiology 

 of invertebrates, as to suppose that the states 

 and impulses constituting human nature and con- 

 sciousness began to exist in the anthropic type of 

 anatomy and are unrelated to the states and im- 

 pulses of vertebrate consciousness in general, and 

 through vertebrate consciousness to those remoter 

 types of sentiency lying away at the threshold 

 of organic life. Human psychology is a part of 

 universal psychology. It has been evolved. It 

 has been evolved according to the same laws of 

 heredity and adaptation as have physiological 

 structures. And it is just as impossible to under- 

 stand human nature and psychology unaided b}' 

 those wider prospects of universal psychology as 

 it is to understand the facts of human physiology 

 unaided by analogous universalisations. 



10 



