338 MENTAL EVOLUTION IN ANIMALS. 



is the same in kind wherever it occurs and whatever degree 

 of elaboration it presents. 



But here I must meet an assertion which is often made, 

 and which has been presented by Mr. Mivart with his 

 accustomed adherence to logical form, and therefore with 

 much apparent cogency. He says : — " Two faculties are 

 distinct in kind if we may possess the one in perfection 

 without thereby implying that we possess the other ; and 

 :still more so if the two faculties tend to increase in an 

 inverse ratio, the perfection of the one being accompanied by 

 •a degradation of the other. Yet this is just the distinction 

 hetween the instinctive and rational parts of man's nature. 

 His instinctive actions are, as all admit, not rational ones ; 

 his rational actions are not instinctive. Even more than this, 

 we may say the mo7'e instinctive a man's actions the less 

 are they rational, and vice versd ; and this amounts to a 

 demonstration that reason has not, and by no possibility 

 could have been, developed from instinct. In man we have 

 this inverse ratio between sensation and perception, and in 

 brutes it is just where the absence of reason is most generally 

 admitted (e.g., in insects) that we have the very summit and 

 perfection of instinct made known to us by the ant and the 

 bee. ... Sir William Hamilton long ago called atten- 

 tion to this inverse relation ; but when two faculties tend to 

 increase in an inverse ratio, it becomes unquestionable that 

 the difference between them is one of kind."* 



Now I meet this argument by denying the alleged fact on 

 j -which it reposes. It is simply not true that there is any con- 

 ! stant inverse ratio of the kind stated. It is no doubt true in a 

 general way (as the principles of evolution would lead us to 

 anticipate), that as animals advance in the scale of mental 

 development their powers of intelligent adjustment are apt 

 to become added in larger measure to their less elaborate 

 powers of instinctive adjustment; but that there is no inverse 

 p)roportion between the two must be evident to any one who 

 has directed his attention to the mental endowments of 

 animals. Thus, so far is it from being the case that " the 

 absence of reason is most generally admitted" among the 

 ants and bees, that all the observers with whose writings I 

 am acquainted are unanimous in their opinion that there are 

 no animals among the Invertebrata which can be said to 



* Lessons from Nature, pp. 230-1. 



