An Introduction to a Biology 



was not the best shape for a tilling implement, so 

 he would alter the spear-head and adapt it to a 

 new purpose, or make a rude mattock and see how 

 it worked. A different type of implement would 

 be required for a hatchet, a different one for grind- 

 ing corn, and so on. How interesting these early 

 experimentings must have been ! How man's whole 

 mind must have been taken up with this new joy 

 of making something ! What new sources of interest 

 were discovered to him when he first made a flint 

 knife ! 



Not only was this new occupation for his mind 

 operating through his hand absorbingly interesting, 

 it was immensely advantageous too. It not only 

 satisfied his mind, it also brought clothing for his 

 back and food for his larder, and kept the wolf 

 from the door. And, all the time, the fashioning of 

 implements and the growth of his intelligence were 

 playing into each other's hand in a variety of ways. 



One thing the invention of the detachable limb 

 did was to set free an immense amount of energy. 

 It is probable (but I do not press this point now) 

 that the making of an implement by the modifi- 

 cation of one's own body requires much more highly 

 concentrated, that is to say, much more energy 

 than conducting, outside of oneself, the manufacture 

 of a detachable implement. (If this point seems 

 nonsensical to the reader it is because he is assum- 

 ing what we are about to discuss, the truth of a 

 mechanistic theory of the organism, and a mechan- 

 istic theory of evolution — namely, natural selection.) 

 But whether this is so or not, it is certain that a 

 great amount of energy was saved by getting rid 



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