230 THE LESSON OF EVOLUTION 



affinity, and we can imagine the Universe without 

 them. 



Our knowledge of Mind. In the next place, what 

 do we know about mind? We define it as the 

 intellectual power or thought ; that is, the power of 

 recognising the relations between different pheno- 

 mena or between cause and effect. The facts re- 

 lating to it are the following. 



1. Mind has increased in quantity on the earth. 

 It does not come to us, with radiant energy, from 

 outside ; and it is spread only by assimilation. And, 

 although we are constantly losing it by death, yet 

 it has largely increased in quantity since the day 

 when the whole of the life on the earth was con- 

 tained in a single cell. Mind also increases in 

 quantity in each individual as it develops, and then 

 suddenly disappears. 



2. Mind on the earth has improved in intensity. 

 Take first the history of the mutual development of 

 mind and tissue. 



(a) The first stage is protoplasmic irritability, 

 or sensitiveness to physico-chemical agents ; and 

 its capability of performing adaptive movements 

 to meet them. 



(b) The second stage is nervous sensation or 

 feelings ; where a nervous centre has been estab- 

 lished, connected by nerves with peripheral re- 

 ceiving organs; and, later, with special nerves 

 for the special senses. 



(c) The third stage is self -consciousness, or 

 the capacity of thinking of ourselves, of knowing 

 what we are doing. It is the general opinion of 



