140 Determinate Evolution 



correlated with them. These being of such importance, 

 the species would accumulate variations in this charac- 

 ter, and the individuals would be relieved of the neces- 

 sity of making the private accommodations over again in 

 each generation. Again (2) there would be no tendency 

 to the exclusive production of reflexes, as would be the 

 case under use-inheritance ; since in cases in which the 

 continued accomplishment of a function by individual ac- 

 commodation was of greater utility than its accomplishment 

 by reflexes or instinct — in these cases the former way 

 would be perpetuated by natural selection. In the case of 

 intelligent adaptations, for example, the increase of the 

 intelligence with the nervous plasticity which it requires is 

 of the greatest importance ; we find that creatures having 

 intelligence continue to acquire their adaptations intelli- 

 gently with the minimum of instinctive equipment.^ There 

 is thus a constant interplay between instinct and accom- 

 modation, as the emergencies of the environment require the 

 survival of one type of function or the other. This is illus- 

 trated by the fact that in creatures of intelhgence we find 

 sometimes both the instinctive and also the intelligent per- 

 formance of the same function ; each serving a separate 

 utility.2 



(3) The remaining objection — and it holds equally of 

 both the current views — is that arising from the cases of 

 structures which begin in a very small way with no appar- 

 ent utility — such as the bony protuberances in places where 



1 Groos, Play of Animals, Eng. trans., pp. 71 «• (see also his Play of Man, 

 Eng. trans., pp. 283 f., where he admits the contention that the reverse may 

 also be the case), has pointed out the function of imitation as aiding the 

 growth of intelligence with the breaking up of instincts under the operation 

 of natural selection. (See the passages in Chap. II. § 4 and Chap. XIV. § 3, 

 where this function is cited to illustrate correlated variations.) 



2 See \he statement above, Chap. VI. § i, on ♦ Duplicated Functions.' 



