72 Heredity and Instinct 



i. Duplicated Functions 



I. The argument from 'selective value' has a further 

 and very interesting application by Romanes. He uses 

 the very fact upon which the argument in the earlier 

 pages is based to get further support for the inheritance 

 of habits. The fact is this, that intelligence may perform 

 the same acts that instinct does. So granting, he argues, 

 that the intelligent performance of these acts comes first 

 in the species' history, this intelligent performance of the 

 actions serves all the purposes of utility which are claimed 

 for the instinctive doing of the same actions. If this be 

 true, then variations which would secure the instinctive 

 performance of these actions do not have selective value, 

 and so the species would not acquire them by the opera- 

 tion of natural selection. By the Lamarckian theory, how- 

 ever, he concludes, the habits of intelligent action give 

 rise to instincts for the performance of the same actions 

 which are already intelligently performed, the duplicate 

 functions often existing side by side in the same creature. 1 



This is an ingenious turn, and raises new questions of 

 fact. Several things come to mind in the way of comment. 



First. It rests evidently on the state of things required 

 by my earlier argument against the Lamarckian claim 

 that co-adaptation could not have been gradually acquired 

 by variation ; the state of things which shows the intelli- 

 gence preventing the ' incidence of natural selection ' by 

 supplementing partial co-adaptation. Romanes now as- 

 sumes that intelligence prevents the operation of natural 

 selection on further variations, and so rules out the origin 



1 op. cit., pp. 74-81. 



