104 Instinct and its Lessons 



acquired, there is no difficulty in its perpetuation. And 

 just as sharper claws or a longer beak may have been 

 produced by the survival of individuals whose organs 

 chanced to vary in such direction, so the migratory 

 instinct of the Swallow, the architectural skill of the 

 Chaffinch, or the surgical accuracy of the Sphex, may be 

 accounted for. 



It is obvious that whatever truth be conceded to this 

 statement of the matter, it does not take us very far on 

 the road to an absolute explanation. Just as the 

 Natural Selection theory requires life to begin with, and 

 capability of variation to work upon, so this hypothesis 

 by which instincts are to be explained demands instinct 

 1 to start with, and instinct, moreover, capable of develop- 

 ment. It is of no avail putting an egg into an incubator, 

 unless that egg contains a germ which the fitting con- 

 ditions of ventilation, moisture, and warmth, will develop 

 into a chick ; nor can an instinct be hatched by any 

 combination of circumstances except from an instinctive 

 principle. Yet on the origin of such principle Mr. 

 Darwin emphatically assures us, he can throw no light. 

 "I must premise, that I have nothing to do with the 

 origin of the primary mental powers, any more than I 

 have with that of life itself." 1 At this point therefore 

 we are, on any theory, stopped short by a great gulf, 

 which our reasonings cannot pass, and in our explanation 

 of what seems mysterious we must perforce leave un- 

 touched the greatest mystery of all. This only is 

 allowed us, striking the track on the verge of this infinite 

 void to follow it through the fields of nature, and to 

 search out the conclusion to which it leads. " We are 

 concerned," Mr. Darwin tells us, " only with the diver- 

 sities of instinct and of the other mental qualities of 

 animals within the same class. 



Without at present stopping to examine this most 



important limitation of the field, let us see what there is 



left for us to explore. Prescinding from the question of 



their origin, does Natural Selection sufficiently explain 



1 Origin of Species > p. 207. 



