Darwinism does not explain Variation 



should suffice to satisfy any unbiassed person ; 

 firstly, that natural selection is an important 

 factor in evolution ; secondly, that the position 

 taken up by Wallace and his followers, that 

 natural selection, acting on minute variations, 

 is the one and only factor in organic evolution, 

 is untenable. 



1. It has been urged that the Darwinian 

 theory makes no attempt to explain variation, 

 and that, until we know what it is that causes 

 variations, we are not in a position to explain 

 evolution. This of course is quite true, but the 

 objection is scarcely a fair one, since, as we have 

 seen, Darwin freely admitted that his theory 

 made no attempt to explain the origin of varia- 

 tions. It is not reasonable to object to a theory 

 because it fails to explain phenomena with which 

 it expressly states that it is not concerned. On 

 the other hand, the objection is one that must be 

 reckoned with, for, as we shall see, it makes a 

 great difference to the importance of natural 

 selection as a factor in evolution if variations 

 appear indiscriminately in all directions, as 

 Darwin tacitly assumed they do, or whether, 

 as some biologists believe, they are determinate 

 in direction, being the result of a growth-force 

 inherent in all organisms. 



2. Very similar to the above-mentioned objec- 

 tion is that which points out that it is a long 

 journey from Amoeba to man. It is difficult to 



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