vin DARWINISM AND DESIGN 145 



the total effect was due to the factor which he called 

 Natural Selection. To solve this problem he adopted, 

 no doubt instinctively, the method by which all scientific 

 investigation proceeds in dealing with a complicated 

 problem. This method is that of abstraction, of abstrac 

 tion as a means of simplification. We isolate the factor 

 of which we seek to determine the value by taking cases 

 in which the other factors may be supposed to neutralize 

 each other, and so to be irrelevant to the result. Our result 

 is abstract, but, if the analysis has been carefully done, 

 it is applicable to the concrete facts. 



This is precisely what Darwin did. The phenomena 

 of life are immensely complicated, and there was ample 

 reason to suppose that they were affected by all sorts 

 of influences. To lay bare the effect of Natural Selection, 

 it was necessary to simplify them by constructing an 

 ideal case from which other influences might be excluded. 

 This is the logical significance of the fundamental 

 assumptions of Darwinism. Darwin knew that organisms 

 varied. He did not know how much, or in what direction. 

 But if there was a definite direction about the variation 

 of organisms, this clearly might in various ways retard 

 or accelerate the action of Natural Selection, and would 

 in any event cloak it. It is obvious, for example, that 

 if a race of elephants tend to vary in the direction of 

 whiteness, then, though that variety may be weaker and 

 less well equipped for the struggles of life, there will 

 always be a certain supply of not-yet-eliminated white 

 elephants. 1 Again the fate of the variety will be widely 

 different, according as men consider them unlucky and 

 kill them, or sacred and watch over them with especial 

 care. 



In order, therefore, to avoid the initial complications 

 introduced by a possible tendency of variation in a 

 definite direction, it was logically necessary for Darwin 

 to assume that as a whole Variation had no definite 

 direction. Variations occurred of all sorts, advantageous, 



1 It is supposed that albinos tend to be produced by in-breeding, and hence 

 the supply is always kept up in spite of Natural Selection. 



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