INTRODUCTORY 7 



matter, and of their interactions upon each other. It is this 

 correlation of animate nature with natural forces and natural laws 

 which gives to the doctrine of evolution its most general importance. 

 For it thus supplies the keystone in the arch of our interpretation of 

 nature and gives it unity ; for the first time it makes it possible to 

 form a conception of a world-mechanism, in which each stage is the 

 result of the one before it, and the cause of the succeeding one. 



How deeply all our earlier opinions are affected by this doctrine 

 will become clear if we fix our attention on a single point, the 

 derivation of the human understanding from that of animal ancestors. 

 What of the reason of Man, of his morals, of his freedom of will ? may 

 be asked, as it has been, and still is often asked. What has been 

 regarded as absolutely distinct from the nature of animals is said to 

 differ from their mental activities only in degree, and to have evolved 

 from them. The mind of a Kant, of a Laplace, of a Darwin — or to 

 ascend into the plane of the highest and finest emotional life, the 

 genius of a Raphael or a Mozart — to have any real connexion, how- 

 ever far back, with the lowly psychical life of an animal ! That is 

 contrary to all our traditionary, we might say our inborn, ideas, and it 

 is not to be wondered at that the laity, and especially the more cultured 

 among them, should have opposed such a doctrine whose dominating 

 power was unintelligible to them, because they were ignorant of 

 the facts on which it rests. That a man should feel his dignity 

 lowered by the idea of descent from animals is almost comical to the 

 naturalist, for he knows that every one of us, in his first beginning, 

 occupied a much lowlier position than that of our mammalian 

 ancestors — was, in fact, as regards visible structure, on a level with 

 the Amoeba, that microscopically minute unicellular animal, which 

 can hardly be said to possess organs, and whose psychical activities 

 are limited to recognizing and engulfing its food. Very gradually at 

 first, and step by step, there develop from this single cell, the ovum, 

 more and more numerous cells ; this mass of cells segregates into 

 different groups, which differentiate further and further, until at last 

 they form the perfect man. This occurs in the development of every 

 human being, and we are merely unaccustomed to the thought that it 

 means nothing else than an incredibly rapid ascent of the organism 

 from a very low level of life to the highest. 



Still less is it to be wondered at that the Evolution doctrine 

 met with violent opposition on the part of the representatives of 

 religion, for it stood in open contradiction to that remarkable and 

 venerable cosmogony, the Mosaic story of Creation, which people had 

 been accustomed to regard, not as what it is — a conception of nature 



