Logical Position of Evolution Theory 55 



bringing about evolutionary change, but no one has 

 any hesitation in regard to the fact. The reason for 

 this - is that the evolution formula — which defines a 

 certain mode of becoming — fits all the observed data. 

 It is a key that opens all the locks — only, however, to 

 disclose other locks; namely, the precise course of 

 events involved in an evolutionary change, such as the 

 emergence of birds from extinct reptiles, or of mam- 

 mals from extinct reptiles. And behind these are 

 other locks ; namely, the causal factors that brought 

 about each step. 



When one says, "The elephant of to-day acquired 

 its long trunk (the nose and part of the upper lip) as 

 the entailed result of the use that antecedent ele- 

 phants made of their shorter trunk," one is stating 

 a Lamar ckian theory of the factors operative in a 

 particular case. Many zoologists would refuse to 

 accept this theory, but no one of them has any doubt 

 that the modern elephants evolved from smaller and 

 simpler ancestral Proboscideans of which, happily, 

 much is known. Similarly, when one says that the 

 whiteness of some snow-animals is the result of Na- 

 ture's sifting (the Natural Selection) of the fitter 

 among the many inborn heritable variations — good, 

 bad, and indifferent — that are always cropping up, 

 one is stating the Darwinian view of the factors 

 operative in a particular case^ Many zoologists have 

 their doubts as to the satisfactoriness of this causal 

 theory, but it is intellectually dishonest or intellectu- 

 ally dull-witted to use any such confession of scientific 



