278 THE MEANING OF EVOLUTION 



modified plants of yesterday, that civilized man of 

 to-day is the savage of yesterday and the tree-dweller 

 of the day before, is no longer debatable to the great 

 mass of biologists. To older men hampered by the 

 convictions of an earlier age this dictum of modern 

 science may still be a little uncertain. 



The working biologists of the world have no doubt. 

 They differ radically as to what brought about this 

 change, they dispute vigorously as to the rate of 

 change, but as to the fact of the change there is no 

 difference of opinion. Under these conditions the 

 thinking man is out of joint wath the times when he 

 sets himself against the idea of evolution. He may 

 be so immersed in other lines as to be indifferent to 

 the problem; but w^hen he is hostile to it, he marks 

 himself as clearly against his day. Many have been 

 against their day and have been right. Very great 

 men have often been against the opinions of their 

 times and have come to be leaders of the world's 

 later thought. But ordinary men in ordinary times 

 who think differently on a special subject from the 

 specialists of the times are not very likely to be right. 

 It is safe for most of us to accept as true an opinion ' 

 on which specialists on that subject agree. It seems 

 clear to me then that the thinking man to-day has in 

 the matter of evolution a double duty. He must 

 become reasonably acquainted with the theory that 



