RATIONAL LIFE 277 



the top of the scale, just as at the bottom of it; but, 

 when the life of man is considered, unity of action is 

 no longer traceable by external observation. The 

 source of nerve activity is within ; that activity does 

 not originate from environment. This difference is 

 one of vast significance. Biology has no account to 

 make, no explanation to offer, of the most potent 

 agency in Nature. The conscious experience and 

 activity of man, while it cannot be explained apart 

 from environment, cannot be explained by it ; while 

 it cannot be accounted for without continual reference 

 to the activity of the organism, it cannot be interpreted 

 as lying within the laws of organic action. The next 

 stage of the argument follows logically. If we have 

 not continuity of action in accordance with which 

 activity of organism can pass over into activity of mind, 

 evolution of organism cannot carry an explanation 

 of the appearance and development of mind. Even as 

 a member of the physical world, the distinction of 

 man is not in his organism, but in his power to use 

 it as he does. This is the testimony for a rational 

 life, disclosing the vastness of the change in the 

 world s history, which is consequent on the appear 

 ance of rational agency. 



Consider how biology is placed in view of the de 

 mand for a scientific account of rational life. It has 

 claimed that man belongs to Nature, and the claim 

 is valid ; but it fails to include man s intelligent 

 activity. Biology is not a completed science of 

 Nature. It cannot make good its claim to be so re 

 garded. The science of mind outstretches the science 

 of biology. Man s life is superior to all animal life, 

 possessing powers which are not shared by the 



