176 



HABIT AND INTELLIGENCE. 



[chap. 



Eeversion 

 to ances- 

 tral cha- 

 racters. 



Laws of 

 habit are 

 elemen- 

 tary and 

 universal 

 laws of 

 life. 



Active 

 habits 

 strengthen, 

 passive 

 impres- 

 sions 

 weaken, 

 by repe- 

 tition. 



It is a well-known instance of this, that when the use of 

 an art, or of a language, has been laid aside so long that, at 

 the first attempt to recommence it, it appears to be totally 

 lost, a little practice will often prove sufficient to regain it 

 in a mere fraction of the time that would be necessary to 

 learn it if it were really new. This is a case of the rapid 

 reappearance of a latent habit under favouring circum- 

 stances. The most remarkable instance of the spontaneous 

 reappearance of a habit is the reversion of individuals, 

 and, as I believe, of species, to ancestral characters after 

 the lapse of many generations ; which, according to general 

 belief, sometimes occurs in the human race, and beyond all 

 question does occur among domesticated breeds of animals.^ 

 The characters of the breed which have arisen under 

 domestication, and consequently are of later date than 

 those of the species, are prominent habits : those of the 

 species which reappear in these cases of reversion are 

 tenacious habits, which may, as it were, be overlaid and 

 concealed by the later acquired ones for a great number of 

 generations, and yet reappear at last. I shall have to 

 speak, farther on, of the importance of this class of facts in 

 accounting for the characters of species. 



In the chapter on the Dynamics of Life I have stated my 

 belief that the differentia of life consists in certain powers, 

 which all living beings possess, of transforming matter 

 and energy. Except the laws of those transformations, I 

 believe the elementary laws of habit are the only laws of 

 life which are at once elementary and universal. T regard 

 these as ultimate laws, like the laws of gravitation and 

 of the affinities of the chemical elements, and, like them, 

 incapable of being referred to any others. 



It is an important result of the laws of habit, that while 

 active habits are strengthened by the repetition of the act, 

 passive impressions are weakened by the repetition of the 

 impression.^ Both of these facts are perfectly familiar : 



1 Darwin's Origin of Species, pp. 15, 190. The most remarkable instances, 

 both of variation and of reversion, are those of the domestic pigeon. 



* So far as I am aware, this remark was first made in Butler's " Analogy 

 of Religion." 



