THEORIES OF MENTAL EVOLUTION 269 



have already arrived at, that acquired traits are not trans- 

 missible, this hypothesis totally fails to account for the 

 formation of many important instincts. For instance, many 

 insects at the end of their lives lay their eggs in a particular 

 place and in a particular way. The action is performed only 

 once and at a time when the eggs have ceased, in any true 

 sense, to be portions of the parent organism. Under the 

 circumstances, not only can no facility in performance be 

 acquired by the individual, but even were it acquired, none 

 could be transmitted. Yet Mr. Lewes' hypothesis of the 

 genesis of instinct pre-supposes both the acquirement of 

 facility and the transmission of it. Therefore, while it is 

 conceivable that this instinct arose by the survival of the 

 fittest during a severe process of Natural Selection, it is 

 inconceivable that it should have arisen through a lapsing of 

 intelligence. All this is equally true of the mating instinct. 

 If Mr. Lewes be right, the ancestors of lowly animals that 

 reproduce bi-parentally must have possessed extraordinary 

 intelligence. Moreover, were it true that instincts had such 

 origins as he supposes, they would be most numerous and 

 best developed in higher animals, and intelligence in the 

 lower, whereas the reverse is the case ; for in the highest 

 animals e.g. man intelligence predominates and instinct 

 is at a minimum, while in lower animals e. g. fish instinct 

 predominates and intelligence is at a minimum. Very 

 plainly, therefore, in the higher animals there has, on the 

 whole, been regression, not evolution, as regards instinct. 

 Again, instinct and reason do not merge at any point, as they 

 would were one derived from the other. The fact that one is 

 " inborn " and the other " acquired " separates them sharply ; 

 and if in the case of any given action, which is the outcome 

 of both instinct and intelligence, as for instance a man's 

 choice of a wife, we are unable to say how much of it is 

 instinctive and how much intelligent, our difficulty is due to 

 our ignorance, not to there being no dividing line but a 

 border space. 



434. According to Mr. Spencer, " rational action arises out 

 of instinctive action when the latter grows too complex to 

 be perfectly automatic." x His hypothesis, like Mr. Lewes', 

 necessarily involves the supposition that there is a border 

 space where the instinctive and the intelligent merge. We 

 have seen that he describes instinct as compound reflex 

 action. In his view, therefore, intelligent action is reflex still 

 more compounded. Concerning instinct he says: "In its 

 1 The, Principles of Psychology, vol. i., p. 458. 



