MIND IN EVOLUTION 



on evolution as thus defined is therefore on its upward 

 passage. 



Thus what from our point of view is essential to the idea 

 of evolution is upward passage by progressive steps (some- 

 times very little steps, sometimes big jumps) along definite, 

 recognisable lines of advance, with continuity of progress 

 from lower to higher. And of evolution in this sense there 

 is evidence in molecules, in organisms, in minds, and in 

 social institutions. 



No doubt, when we come down to adjectival details, we 

 shall find special features that are distinctive of each group, 

 and some difficulty may still be felt in defining advance. 

 I have spoken of advance to what is higher; and to illustrate 

 v/hat may be taken as a criterion of higher, I selected com- 

 plexity. But this is not the only criterion, perhaps not the 

 most important criterion. For, in the upper reaches of evolu- 

 tion, what is higher may be higher in quality. Thus one 

 man's treatment of a subject may be higher than that of 

 another man not in complexity but in what we commonly 

 speak of as "quality." A little dinner may be higher in qual- 

 ity than an elaborate banquet. This distinction may be hard 

 to define, but most people will understand what is meant. 



If, with a little attentive thought, one has grasped this 

 idea or concept of evolution as upward and progressive 

 advance, the next thing to realise is that, throughout nature, 

 including human nature, there is by no means always pro- 

 gressive advance. In every field of inquiry we find abundant 

 evidence of that which is the very opposite of evolution and 

 is sometimes called "degeneration" or "devolution." I shall 

 speak of it as dissolution. Evolution is progress, dissolution 

 is regress. What we have now to grasp is that we find 

 throughout nature not only upward passage from lower to 

 higher but downward passage from higher to lower — some- 



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