WHY WE MUST BE EVOLUTIONISTS 

 By J. Arthur Thomson 



Regius Professor of Natural History in Aberdeen University 



Evidences of Evolution 



We use the familiar phrase "evidences of evolution" with 

 some misgiving, because it does not suggest the right way 

 of looking at the question. Evolution means a way of 

 Becoming. Just as it is certain that all the many races of 

 domesticated pigeon are descended from the wild rock dove, 

 so, it is argued, have all the different kinds of wild animals 

 and wild plants descended from ancestors that were on the 

 whole somewhat simpler, and these from simpler ancestors 

 still, and so back and back until we come to the first living 

 creatures, whose origin is all in the mist. Evolution just 

 means that the present is the child of the past and the 

 parent of the future. 



But it is not possible to prove this conclusion in an abso- 

 lutely rigorous way. We can, indeed, see evolution going 

 on now, but we cannot, so ta speak, reverse the world-film 

 and see precisely what took place long ago. The records 

 in the rocks do clearly reveal what happened in the past, 

 even millions of years ago, but not in so clear and so detailed 

 a way as the developing Q:gg of a hen reveals the gradual 

 rise and progress of the chick. 



Although we do not know of any competent biologist 



[13] 



