DARWINISM AND EVOLUTION 183 



so, he rendered conceivable the mechanism of evolution 

 in the organic world, thus bringing another great aspect 

 of external nature within the range of the developmental 

 as opposed to the miraculous philosophy of the cosmos. 



Psychology, once more, in the hands of Herbert 

 Spencer and his followers, not wholly unaided by 

 Darwin himself, has extended the self-same evolu- 

 tionary treatment to the involved and elusive pheno- 

 mena of mind, and has shown how from the simplest 

 unorganised elements of feeling, the various mental 

 powers and faculties as we now know them, both on 

 the intellectual and on the emotional side, have been 

 slowly built up in the long and ever- vary ing inter- 

 action between the sentient organism and the natural 

 environment. It has traced the first faint inception of 

 a nervous system as a mere customary channel of com- 

 munication between part and part ; the gradual growth 

 of fibre and ganglion ; the vague beginnings of external 

 sense-organ and internal brain ; the final perfection of 

 eye and ear, of sight and hearing, of pleasure and pain, 

 of intellect and volition. It has thus done for the sub- 

 jective or mental half of our complex nature what 

 biology, as conceived by Darwin, has done for the 

 physical or purely organic half; it has traced the origin 

 and development of mind, without a single break, from 

 its first faint and half-unconscious manifestation in the 

 polyp or the jelly-fish to its final grand and varied 

 outcome in the soul of the poet or the intellect of the 

 philosopher. 



Finally, sociology has applied the evolutionary 

 method to the origin and rise of human societies, with 

 their languages, customs, arts, and institutions, their 



