SOCIETAL EVOLUTION 133 



not exempt. The process merely changes its mode. It is no 

 longer evolution of the organic type, resulting in structural 

 adjustment; it is evolution of another grade, resulting in 

 another sort of adjustment. There must be adjustment just 

 the same, as a condition of existence. Evolution goes on as 

 long as adjustment to immutable life-conditions goes on that 

 is, as long as life lasts. It is this typically human phase of 

 evolution which we want to identify and examine. 



When human beings get into a situation (a cold climate, for 

 instance) which, for animals, evokes physical adaptation (such 

 as a thicker coat), we find, perhaps, some small adjustment 

 by way of bodily change; but typically and generally what we 

 see is the employment of materials external to the body skins, 

 wood, metal which are interposed to form the instruments 

 of adjustment. It takes a certain brain-action to arrive at 

 such utilization of the things available in nature. When bees 

 build combs, it is by an instinct that represents a single adjust- 

 ment, once and for all, whereas man has, in the brain, a sort 

 of specialized adjuster capable of being turned upon this and 

 then upon that situation. His brain is somewhat like one of 

 these tool-handles which include in one instrument the possi- 

 bility of a variety of operations, except that the brain is in- 

 finitely more protean in its transformations. 



The brain clothes its adjustments in material form. They 

 are thus realized or made real materialized, or rendered in 

 terms of matter externalized, or worked out in things ex- 

 ternal to the body. Every such realized thought is a piece of 

 culture or of the apparatus of civilization. Such are the 

 climbing-irons of the linesman, which are the cultural counter- 

 part of the natural climbing-foot; such is the aeroplane, as 

 compared with the wings of the bird. Tools, weapons, houses, 

 parachutes all these are objects of material culture which are 

 counterparts of what nature has developed over countless ages 

 of organic evolution for the beaver, whose tools are teeth; 



