56 CREATIVE EVOLUTION [chap. 



The Darwinian idea of adaptation by automatic elimina- 

 tion of the unadapted is a simple and clear idea. But, 

 just because it attributes to the outer cause which con- 

 trols evolution a merely negative influence, it has great 

 difficulty in accounting for the progressive and, so to say, 

 rectilinear development of complex apparatus such as we 

 are about to examine. How much greater will this diffi- 

 culty be in the case of the similar structure of two extremely 

 complex organs on two entirely different lines of evolution ! 

 An accidental variation, however minute, implies the 

 working of a great number of small physical and chemical 

 causes. An accumulation of accidental variations, such 

 as would be necessary to produce a complex structure, 

 requires therefore the concurrence of an almost infinite 

 number of infinitesimal causes. Why should these causes, 

 entirely accidental, recur the same, and in the same order, 

 at different points of space and time? No one will hold 

 that this is the case, and the Darwinian himself will probably 

 merely maintain that identical effects may arise from 

 different causes, that more than one road leads to the same 

 spot. But let us not be fooled by a metaphor. The place 

 reached does not give the form of the road that leads there; 

 while an organic structure is just the accumulation of 

 those small differences which evolution has had to go 

 through in order to achieve it. The struggle for life and 

 natural selection can be of no use to us in solving this 

 part of the problem, for we are not concerned here with 

 what has perished, we have to do only with what has 

 survived. Now, we see that identical structures have 

 been formed on independent lines of evolution by a gradual 

 accumulation of effects. How can accidental causes, 

 occurring in an accidental order, be supposed to have 

 repeatedly come to the same result, the causes being in- 

 finitely numerous and the effect infinitely complicated? 



