256 ESSAYS OF A BIOLOGIST 



Finally, we come to the psychological aspect of 

 the universe. We have already touched on it in 

 connection with biology, and found that in many 

 ways at least the development of mind follows the 

 same lines as that of living matter, and helps forward 

 the general trend of life. 



But finally a kink occurs, a critical point similar 

 to that seen at the origin of living from non-living 

 matter. There the attributes of living matter which 

 mark it off from inorganic matter become dominant 

 — its capacity for self-reproduction, its tendency to 

 organisation. The colloid carbon compound had 

 been the highest known independent unit ; from 

 now on this place was taken by the organism. 



In exactly the same way, in the final stages of 

 evolution (as witnessed abundantly by fossil mammals) 

 complexity of purely bodily organization had reached 

 a limit, and survival, as is evidenced by increasing 

 size of brain, came to be determined more and more 

 by mental qualities. Finally the curve of mental 

 development caught up with that of body, and inter- 

 sected it : mind became the dominant factor in the 

 new type of organism, and in the subsequent history 

 of the evolutionary process. The organism ceased 

 to be the highest unit, and gave place to the person^ 

 or self-conscious individual with organized mind. 



This new critical point was reached when man 

 arose ; many authors recognize it for what it is, 

 the beginning of a new era, by christening the sub- 



