FITNESS AND ADAPTATION 65 



serving the othei with materials and forces that could 

 not otherwise be provided ; and that on and around this 

 broader mutual fitness and mutual service are built 

 many minor fitnesses and services. That both plants and 

 animals, at all times, are fitted to live in a very narrow 

 stratum of terrestrial conditions between earth and air, 

 and these narrowly prescribed conditions are eminently 

 fitted to sustain life. 



III. Fitness by Design and Fitness by Mutual 

 Influences 



In this usage of the terms fitness and adaptation, the 

 idea may be conveyed, or implied, that there is a pre- 

 meditated design and a designer involved; that man, 

 for example, was expressly made in such a way that he 

 can and does utilize machinery to his own profit, and 

 that man himself designs and makes machines expressly 

 to that end. 



Whether man was designed to use machines, we do 

 not know. But we do know that, in that sense, no ma- 

 chine ever purposely designed and made another ma- 

 chine for its own uses, although machines, as contingent 

 parts of human life, grow like living organisms, by the 

 summations and adaptations of countless mutually ser- 

 viceable constructions and inventions. All that man 

 does, in any case, is to select certain fitting materials and 

 forces already in existence, the qualities of which are 

 already established and which he can in no wise change, 

 shape them, and put them rightly together. If they 

 are rightly moulded and rightly put together, the vari- 

 ous parts will cooperate just the same, whether put to- 

 gether by accident or by design. Each part will per- 



