148 ORGANIC EVOLUTION— MENTAL 



there is no border-space, where the one merges into the 

 other, but a sharply dividing line. The truth, therefore, 

 appears to be, that reflex action, instinct, and reason are 

 not derived the one from any other, but that each one 

 is distinct from and has arisen independently of the 

 others — is not a more or less complex form of the 

 others. Concerning the latter two faculties, I think we 

 have no choice but to believe that, when, by the action 

 of Natural Selection during the phylogeny, a nervous 

 system was evolved, then, in consequence of the high 

 compounding of reflex action, another and totally 

 distinct faculty, instinct, was evolved, and was super- 

 imposed on reflex action, the evolution of it being 

 rendered possible by the developed state of the nervous 

 system. But this faculty was an entirely new thing, as 

 was also reason, which was subsequently evolved, its 

 evolution being rendered possible by a still greater 

 development of the nervous system. To illustrate the 

 subject, however faultily, we may compare the evolu- 

 tion of the nervous system with these three faculties 

 to the evolution of the fore limbs of mammals with 

 three faculties which may be possessed by them. 

 Reflex action may be compared to locomotion, to which 

 the limbs were primarily devoted ; instinctive action to 

 the power of delivering blows with the fore limbs as in 

 bears, a thing totally distinct from locomotion, yet only 

 possible to the fore limbs in consequence of the evolu- 

 tion of the organs of locomotion ; rational action to the 

 power of carrying objects, as in man — a thing distinct 

 both from locomotion and the delivering of blows, yet only 

 possible because of still further evolution in the organs 

 which subserve locomotion and the delivering of blows. 



