26o ESSAYS OF A BIOLOGIST 



we can. An interesting point arises from this way 

 of thinking. Apart from the guarantee of our own 

 convictions, the observable direction of living nature 

 is our guarantee of right : or one had better say that 

 it is at once the guarantee and the touchstone of our 

 convictions. But two things may be moving in the 

 same direction, and, if one be moving much slower 

 than the other, the slower may impede the faster ; 

 a pedestrian procession making eastward along Fleet 

 Street will hold up the life of the city for a time, 

 and cows walking along railways are treated as 

 obstacles by trains proceeding in the same direction. 

 So it comes about that much that was once pro- 

 gressive in organic evolution has become an obstacle 

 or a drag to psychozoic evolution ; it is relatively 

 retrogressive, and, from our present standpoint, bad. 

 To take the simplest and most fundamental example : 

 evolution by blind natural selection was the method 

 of progress for organisms below man. Unceasing 

 struggle and courage was the chief fector in producing 

 the grandeur and strength of the lion, the swiftness 

 and grace of deer, the brilliance and lightness of the 

 birds. But if the same end can be obtained both 

 more quickly and more bloodlessly by new methods, 

 then the old stands condemned. Here lies the key 

 to the problem propounded bv Huxley in his Romanes 

 Lecture — the problem of man's relation to the rest 

 of the cosmic process, at once sprung from it by 

 gradual generation and separated from it by an 



