5 8 CREATIVE EVOLUTION 



the special sense in which we understand it, would be 

 demonstrable in a certain aspect ^ if it could be -proved that 

 life may manufacture the like apparatus, by unlike means, 

 on divergent lines of evolution; and the strength of the proof 

 would be proportional both to the divergency between the 

 lines of evolution thus chosen and to the complexity of the 

 similar structures found in them. 



It will be said that resemblance of structure is due 

 to sameness of the general conditions in which life has 

 evolved, and that these permanent outer conditions may 

 have imposed the same direction on the forces con 

 structing this or that apparatus, in spite of the diversity 

 of transient outer influences and accidental inner changes. 

 We are not, of course, blind to the role which the 

 concept of adaptation plays in the science of to-day. 

 Biologists certainly do not all make the same use of it. 

 Some think the outer conditions capable of causing 

 change in organisms in a direct manner, in a definite 

 direction, through physico-chemical alterations induced 

 by them in the living substance ; such is the hypothesis 

 of Eimer, for example. Others, more faithful to the 

 spirit of Darwinism, believe the influence of conditions 

 works indirectly only, through favouring, in the struggle 

 for life, those representatives of a species which the 

 chance of birth has best adapted to the environment. 

 In other words, some attribute a positive influence to 

 outer conditions, and say that they actually give rise to 

 variations, while the others say these conditions have 

 only a negative influence and merely eliminate variations. 

 But, in both cases, the outer conditions are supposed 

 to bring about a precise adjustment of the organism to 

 its circumstances. Both parties, then, will attempt to 

 explain mechanically, by adaptation to similar condi 

 tions, the similarities of structure which we think are 



