1 6 Darwin, and after Darwin. 



natural causation. This conception of the uniformity 

 of nature is one that has only been arrived at step by 

 step through a long and arduous course of human 

 experience in the explanation of natural phenomena. 

 The explanations of such phenomena which are first 

 given are always of the supernatural kind ; it is not 

 until investigation has revealed the natural causes 

 which are concerned that the hypotheses of super- 

 stition give way to those of science. Thus it follows 

 that the hypotheses of superstition which are the latest 

 in yielding to the explanations of science, are those 

 which refer to the more recondite cases of natural 

 causation ; for here it is that methodical investigation 

 is longest in discovering the natural causes. Thus it 

 is only by degrees that fetishism is superseded by 

 what now appears a common-sense interpretation of 

 physical phenomena; that exorcism gives place to 

 medicine ; alchemy to chemistry ; astrology to astro- 

 nomy ; and so forth. Everywhere the miraculous is 

 progressively banished from the field of explanation 

 by the advance of scientific discovery ; and the places 

 where it is left longest in occupation are those where 

 the natural causes are most intricate or obscure, and 

 thus present the greatest difficulty to the advancing 

 explanations of science. Now, in our own day there 

 are but very few of these strongholds of the mira- 

 culous left. Nearly the whole field of explanation is 

 occupied by naturalism, so that no one ever thinks of 

 resorting to supernaturalism except in the compara- 

 tively few cases where science has not yet been able to 

 explore the most obscure regions of causation. One 

 of these cases is the origin of life ; and, until quite 

 recently, another of these cases was the origin of 



