Chap. VII. INSTINCT LIKE HABIT. 209 



If we suppose any habitual action to become inhe- 

 rited — and I think it can be shown that this does 

 sometimes happen — then the resemblance between what 

 originally was a habit and an instinct becomes so close 

 as not to be distinguished. If Mozart, instead of playing 

 the pianoforte at three years old with wonderfully little 

 practice, had played a tune with no practice at all, he 

 might truly be said to have done so instinctively. But 

 it would be the most serious error to suppose that the 

 greater number of instincts have been acquired by habit 

 in one generation, and then transmitted by inheritance 

 to succeeding generations. It can be clearly shown that 

 the most wonderful instincts with which we are ac- 

 quainted, namely, those of the hive-bee and of many 

 ants, could not possibly have been thus acquired. 



It will be universally admitted that instincts are 

 as important as corporeal structure for the welfare 

 of each species, under its present conditions of life- 

 Under changed conditions of life, it is at least possible 

 that slight modifications of instinct might be profitable 

 to a species ; and if it can be shown that instincts do 

 vary ever so little, then I can see no difficulty in natural 

 selection preserving and continually accumulating vari- 

 ations of instinct to any extent that may be profitable. 

 It is thus, as I believe, that all the most complex and 

 wonderful instincts have originated. As modifications 

 of corporeal structure arise from, and are increased by, 

 use or habit, and are diminished or lost by disuse, so I do 

 not doubt it has been with instincts. But I believe that 

 the effects of habit are of quite subordinate importance 

 to the effects of the natural selection of what may be 

 called accidental variations of instincts ; — that is of vari- 

 ations produced by the same unknown causes which pro- 

 duce slight deviations of bodily structure. 



No complex instinct can possibly be produced through 



