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PREFACE 



Are you an evolutionist? Are you an anti-evolutionist? 

 It really does not matter. What matters is the quality of 

 thinking you do to justify your position. 



We take our beliefs and our labels very seriously; and we 

 should, for after all they are ours, they represent our very 

 selves. And yet, not too seriously; for we may be worrying 

 unnecessarily about beliefs and labels that are not truly 

 our own. We may have picked them up inadvertently. 

 They may have been stuck into our pockets during a fit of 

 abstraction. They may have been sold to us when we were 

 off guard. All sorts of very nice people have this belief, or 

 that one. It's quite all right for you to have your belief, 

 whatever it is. But how did you come by it? 



It is not the purpose of this book to prove or disprove 

 " evolution." For one thing, the word evolution stands for 

 too many different kinds of ideas that have nothing to do with 

 one another, or, for that matter, with the main idea of this 

 book. For another thing, some ideas cannot be " proved " in 

 any strict sense. We can prove the presence or absence of 

 silver alloy in a golden crown, but we cannot prove that Ar- 

 chimedes ran naked through the streets of Syracuse shouting 

 Eureka, or that he ever took a bath. We know that a young 

 man in love will go to great lengths, but we cannot prove that 

 Leander swam the Hellespont. We can find evidence that 

 the plants and animals now inhabiting the earth are different 

 from the inhabitants of a former age; but we can not prove 

 that the later " evolved " from the earlier. 



Because the word evolution stands for so many different 

 ideas it has been necessary to explain the sense in which the 

 word is used in various connections. We are concerned 

 chiefly with organic evolution, the process whereby the stream 



