ATTEMPTS TO EXPLAIN EVOLUTION. 245 



Darwin rather than Darwin himself who believed in 

 the universal power of natural selection. Darwin 

 did not even at first claim that his law would ex- 

 plain every thing, and in his later works he admits, 

 with exemplary candor, that he had formerly 

 overrated its power to produce changes. He still 

 considered it to be the most important factor in the 

 development of species, although he acknowledged 

 that the difficulties were greater than he had at first 

 thought. 



While, then, the theory of evolution as a method 

 of creation has become quite firmly established, the 

 explanation offered for the theory has almost disap- 

 peared. But it is little satisfaction to admit the 

 theory if it is no longer intelligible. If it is impos- 

 sible to tell any thing about the laws which have 

 governed the modifications of the animal kingdom, 

 science is not much better off than it was before. 

 It was natural selection, and not evolution, which 

 made Darwin a leader in modern science. Since 

 this principle can no longer be regarded as- satisfac- 

 tory, naturalists have been everywhere searching to 

 discover some laws which may supplement it, and 

 enable it to meet the difficulties raised. No one 

 would be inclined to-day to deny that natural selec- 

 tion is a law of nature, and that many changes are 

 induced by it. But while some believe it to be the 

 all-important law of organic life, others would con- 

 sider it a secondary and very subordinate principle, 

 whose effect is of little importance. Between these 

 two extremes all grades may be found. 



It is much easier to raise objections to theories 



