62 Heredity and Instinct 



in its application to this problem of instinct, is called ; 

 in other words, to show that Darwin, Romanes, and the 

 Neo-Lamarckians are not right in considering instinct as 

 ' inherited habit.' 



2. Instinct and Lamarckism: Co-adaptation 



The argument from co-adaptation in the case of instinct 

 requires the presence of some sort of intelligence in an ani- 

 mal species, the point being that since the coordination 

 of muscular movements found in the instincts are so co- 

 adapted they could not have arisen by gradual variation. 

 Partial adaptations tending in the direction of an instinct 

 would not have been useful ; and intelligence alone would 

 suffice to bring about the coordinations which are too com- 

 plex to be accounted for as spontaneous variations. These 

 intelligent coordinations then become habits by repetition 

 in the individual and show themselves in later generations 

 as inherited habits due to 'lapsed intelligence.' Assum- 

 ing, then, with Romanes whom we may cite as a very 

 recent upholder of the view the existence of some intel- 

 ligence in a species antecedently to the appearance of the 

 instinct in question, we may be allowed that supposition 

 and resource. 



I. But now let us ask how the intelligence brings about 

 coordinations of muscular movement. The psychologist is 

 obliged to reply : Only by a process of selection (through 

 pleasure, pain, experience, association, etc.) from certain 

 alternative complex movements which are already pos- 

 sible to the individual animal. These possible combina- 

 tions are already there, born with him, or resulting from 

 his previous habits. The intelligence can never, by any 

 possibility, create a new movement ; nor effect a new com- 



