EVOLUTION THE MASTER-KEY 



query: "Shall my words be the only things in all 

 the universe that do not evolve?" 



The reality which is the quest of all philosophy, 

 and the truth which expresses it these alone are 

 immutable: which is my reason for pronouncing 

 uncritical the aphorism with which this chapter 

 begins. But all else changes even our purest 

 and oldest forms of truth. Wordsworth has ex- 

 pressed this thought in noble lines: 



"Truth fails not; but her outward forms that bear 

 The longest date do melt like frosty rime, 

 That in the morning whitened hill and plain 

 And is no more; drop like the tower sublime 

 Of yesterday, which royally did wear 

 His crown of weeds, but could not even sustain 

 Some casual shout that broke the silent air, 

 Or the unimaginable touch of Time." 



We are to learn, then, that all things change, 

 that species of animals are not immutable, nor 

 species of atoms, nor aught else. This is a belief 

 as old as human thinking, and some epochs in its 

 history must be traced. Thereafter we shall be 

 concerned with its latest and most complete ex- 

 pression in the evolutionary philosophy. 



Evolution, the word which Spencer introduced 1 

 to express this truth, is more than a synonym for 

 ordered change. It expresses the truth taught by 

 Wordsworth, in the earlier part of the sonnet from 



1 Until his time, evolution and epigenesis were the names of 

 two rival theories in embryology, both of which have now 

 been rendered meaningless, largely by his work. 

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