i 7 8 CREATIVE EVOLUTION 



may be reduced to two types, which are often inter 

 mingled. One type, following the principles of neo- 

 Darwinism, regards instinct as a sum of accidental 

 differences preserved by selection : such and such a 

 useful behaviour, naturally adopted by the individual 

 in virtue of an accidental predisposition of the germ, 

 has been transmitted from germ to germ, waiting for 

 chance to add fresh improvements to it by the same 

 method. The other type regards instinct as lapsed 

 intelligence : the action, found useful by the species or 

 by certain of its representatives, is supposed to have 

 engendered a habit, which, by hereditary transmission, 

 has become an instinct. Of these two types of theory, 

 the first has the advantage of being able to bring in 

 hereditary transmission without raising grave objection ; 

 for the accidental modification which it places at the 

 origin of the instinct is not supposed to have been 

 acquired by the individual, but to have been inherent 

 in the germ. But, on the other hand, it is absolutely 

 incapable of explaining instincts as sagacious as those 

 of most insects. These instincts surely could not have 

 attained, all at once, their present degree of complexity ; 

 they have probably evolved ; but, in a hypothesis like 

 that of the neo-Darwinians, the evolution of instinct 

 could have come to pass only by the progressive 

 addition of new pieces which, in some way, by happy 

 accidents, came to fit into the old. Now it is evident 

 that, in most cases, instinct could not have perfected 

 itself by simple accretion : each new piece really re 

 quires, if all is not to be spoiled, a complete recasting 

 of the whole. How could mere chance work a recast 

 ing of the kind ? I agree that an accidental modifica 

 tion of the germ may be passed on hereditarily, and 

 may somehow wait for fresh accidental modifications 



