CHAP, xvii METAPHYSICS OF NATURAL SELECTION 2OQ 



Is it the only cause ? In an evolving world B implies 

 C as a minimum, and suggests A as a possibility. 

 Does A anywhere actually exist ? Does natural se- 

 lection anywhere operate by itself alone ? That is 

 our narrowed problem. That is our burning ques- 

 tion. One school will say, Natural selection is so 

 strong a force that we need postulate no other besides 

 it. Another school will reply, Natural selection is 

 perfectly credible as an auxiliary or accelerating force, 

 but perfectly incredible as the only force. Soup 

 (once more) is the better for a handful of salt, but you 

 will never make salt into soup. If selection gets hold 

 of a good thing it knows how to keep hold of it, or 

 even how to push it on ; but it can originate nothing. 

 It will also be possible to hold an opinion midway 

 between these extremes. " Natural selection " by 

 itself may be a conceivable cause of distinct species, 

 yet it may be thought that other causes exist in 

 nature which do the work more rapidly (Natural 

 Selection A possible ; plurality of causes comes in, 

 and Natural Selection C is the actual process). 



Analysis of Natural Selection C. The example of 

 one concrete force assumed to be working in com- 

 bination with natural selection may make our mean- 

 ing clearer. Let us take use-inheritance. Lamarckism 

 and Darwinism can be held separately, or they may 

 be united ; but [we have argued that] since Darwin 

 has pointed to natural selection no one can reason- 

 ably ignore it or utterly deny it. If we are to be 

 Lamarckians at all, we must now be Darwinian 

 Lamarckians. We may differ from Darwin as to the 

 relative value of the two forces. Probably any direct 

 evolutionary force which exists and operates must 



