THE EVOLUTION OF THE IDEA 



by which the formula was framed. We should 

 have to fall back upon some such expression of ig- 

 norance as the word "intuition" and leave the 

 matter there. 



But, as a matter of fact, the formula of evolution 

 was arrived at by a strictly inductive process, pre- 

 cisely comparable to that which enabled Newton 

 to educe the law of gravitation save that Spencer 

 was his own Kepler, so to say. The formula, as 

 we now have it, is the product of years of thought, 

 during which it was greatly modified and amplified. 

 Only some years after it was published as we 

 have seen did Spencer discover that there is a 

 correlative process which he called dissolution, but 

 which he would probably have done better to term 

 involution. But what, finally, was it that set 

 Spencer on the right line? The answer to this 

 question seems to me to be of such interest to 

 everybody, and especially to every one with any 

 love of words, phrases, and literary form, that we 

 may fitly dwell upon it here. 



In his first book, Social Statics, Spencer had 

 reached a generalization which contained the 

 germ of the idea of evolution. All the material 

 was in his mind, the conclusion had been reached 

 but there the process stopped. The idea bore no 

 fruit. Then Spencer came across his own conclu- 

 sion, independently reached by a German scientist, 

 but stated in a new form. Von Baer, the great 

 founder of embryology, enunciated the truth that 

 all progress in the organic world consists essentially 

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