EVOLUTION THE MASTER-KEY 



in a change from the homogeneous to the heterogeneous. 

 The simplest organisms have many parts all alike 

 and practically independent. Progress consists in 

 the development of forms which consist of many 

 parts that are unlike, and interdependent. Of this 

 the human body is, of course, the supreme illus- 

 tration; and the Latin fable about the revolt of 

 the other organs against the pampered stomach is 

 the ancient expression of the same idea. Though 

 Spencer had shown that the same holds true of so- 

 cieties the lowest consisting of individuals very 

 independent and very similar, the highest of in- 

 dividuals with' very various functions and there- 

 fore entirely dependent on one another, the soldier 

 on the agriculturist, and the agriculturist on the 

 soldier yet he had gone no further. It was only 

 when he met his own idea, crystallized in a terse and 

 lucid form, that, given this "convenient instru- 

 ment for thinking," he was enabled to take the 

 first step towards the formula under which all the 

 knowable phenomena of the unknowable can now 

 be included. We shall yet see many instances in 

 which this same gift for phrase-making enabled 

 Spencer to serve human thought; but it was this 

 gift, in the hands of another, that first guided him 

 towards the greatest generalization in all philoso- 

 phy. Thus we may perceive a serious and valu- 

 able truth in Stevenson's delightful piece of irony: 

 " Man lives not by bread alone, but chiefly by catch- 

 words." 



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