262 MENTAL EVOLUTION IN ANIMALS. 



between the reflex and the instinctive, this possible third 

 mode in which rudimentary instincts may arise need not claim 

 consideration with reference to the origin of instincts in 

 general, although the subject is, as we have seen, of much 

 importance in relation to the origin of consciousness. 



It only remains to point out that if instincts ever do 

 arise by way of this third mode, the implication would appear 

 to be, as Mr. Spencer admits, that " survival of the fittest 

 must always be a co-operating cause." I should, however, 

 even here be inclined to go further, and to say that survival 

 of the fittest must in this co-operation be of more than the 

 subordinate importance which Mr. Spencer attributes to it. 

 For instance, taking again the case of the Medusae seeking 

 the light, and supposing the action to have become dimly 

 conscious and so incipiently instinctive ; when the tendency 

 to seek the light first began to manifest itself, and the indi- 

 viduals which sought the light were thereby enabled to pro- 

 cure more food than those which did not, natural selection 

 would at once begin to develop the reflex association between 

 luminous stimulation and movement towards light. Here, in 

 fact, the intervention of any other cause of a directly equili- 

 brating kind seems out of the question, inasmuch as, apart 

 from high intelligence, which ex Jiypothesi is absent, there 

 could be no bond of union between the stimulus supplied by 

 light and the obtaining of food in the light. Only by natural 

 selection could such a bond have here been established ; and 

 the same considerations apply to many or most of the quasi- 

 instinctive actions exhibited by low animals. 



So much then for the view which would regard all in- 

 stincts as outgrowths of reflex action. But scarcely less 

 objectionable is the other extreme view which would regard 

 all instincts as outgrowths of intelligence. This, as I have 

 said, is the view expressed by Lewes, and also, I may add, by 

 the Duke of Argyll, who seems never to have read Mr. 

 Darwin's doctrine of the development of instincts by natural 

 selection.* But be individual oi)inion what it may, surely it 

 is sufficiently evident, as pointed out at the commencement 

 of our discussion, that to assign all instincts to an intelligent j 



* See Contemporary Review, Noyember, 1880, where the Duke argues 

 that the origin of many instincts is hopelessly obscure, because they cannot be 

 explained by the unaided principle of lapsing intelligence — without once 

 alluding to the immense field of possibilities which is opened up by the intro- 

 duction of the principle of natural selection. 



